研究者データベース

笠原 正典(カサハラ マサノリ)
総長、理事・副学長
理事・副学長

基本情報

所属

  • 総長、理事・副学長

職名

  • 理事・副学長

学位

  • 医学博士(北海道大学)

ホームページURL

J-Global ID

研究キーワード

  • ゲノム科学   がん   疾患感受性   免疫系の起源と進化   胸腺   主要組織適合遺伝子複合体   プロテアソーム   抗原提示   NKレセプター   

研究分野

  • ライフサイエンス / 医化学
  • その他 / その他 / 病態検査学
  • ライフサイエンス / 胎児医学、小児成育学
  • ライフサイエンス / 免疫学
  • ライフサイエンス / 実験病理学

職歴

  • 2017年 - 現在 北海道大学大学院医学研究院 分子病理学教室 教授
  • 2017年 - 現在 北海道大学 理事・副学長
  • 2013年 - 2017年 北海道大学大学院医学研究科 研究科長・医学部長
  • 2004年 - 2017年 北海道大学大学院医学研究科 分子病理学分野 教授
  • 2011年 - 2013年 北海道大学大学院医学研究科 副研究科長
  • 2005年 - 2007年 北海道大学病院病理部 部長
  • 1998年 - 2004年 総合研究大学院大学先導科学研究科 教授
  • 1992年 - 1998年 北海道大学医学部 助教授

学歴

  • 1980年 - 1984年   北海道大学   大学院医学研究科   博士課程病理系修了
  • 1974年 - 1980年   北海道大学   医学部   医学科卒業

所属学協会

  • 日本比較免疫学会   日本組織適合性学会   日本胸腺研究会   日本癌学会   日本免疫学会   日本病理学会   

研究活動情報

論文

  • Ohta Y, Kasahara M, O'Connor TD, Flajnik MF
    Journal of immunology (Baltimore, Md. : 1950) 203 7 1882 - 1896 2019年10月 [査読有り][通常論文]
  • Utano Tomaru, Saori Konno, Syota Miyajima, Rikuto Kimoto, Mari Onodera, Shizuka Kiuchi, Shigeo Murata, Akihiro Ishizu, Masanori Kasahara
    Cell reports 26 3 639 - 651 2019年01月15日 [査読有り][通常論文]
     
    The thymoproteasome subunit β5t is specifically expressed in cortical thymic epithelial cells (TECs) and generates unique peptides to support positive selection. In this study, using a mouse model ubiquitously expressing β5t, we showed that aberrant expression of self-peptides generated by β5t affects CD8+ T cell homeostasis, including thymic selection and maintenance of the peripheral naive pool of CD8+ T cells. In mice in which β5t was expressed both in cortical and medullary TECs, the abundance of CD8+ lineage thymocytes was reduced, and extra-thymic expression of β5t caused accumulation of CD8+ T cells with the memory or exhausted phenotype and induced autoreactive T cell responses. We found that thymoproteasomes are essential for positive selection but that the subsequent change in peptide repertoire in the medulla is also crucial for thymic selection and that β5t-derived peptide must be confined to the thymus to avoid autoimmunity in peripheral tissues.
  • Yoshida S, Shime H, Matsumoto M, Kasahara M, Seya T
    Frontiers in immunology 10 671  2019年 [査読有り][通常論文]
  • Kasahara M, Flajnik MF
    Immunogenetics 71 3 251 - 261 2019年01月 [査読有り][通常論文]
  • Kasahara M, Flajnik MF, Takahama Y
    Immunogenetics 71 3 137 - 139 2019年01月 [査読有り][通常論文]
  • Mizuho Kajikawa, Toyoyuki Ose, Yuko Fukunaga, Yuki Okabe, Naoki Matsumoto, Kento Yonezawa, Nobutaka Shimizu, Simon Kollnberger, Masanori Kasahara, Katsumi Maenaka
    Nature communications 9 1 4330 - 4330 2018年10月18日 [査読有り][通常論文]
     
    The MILL family, composed of MILL1 and MILL2, is a group of nonclassical MHC class I molecules that occur in some orders of mammals. It has been reported that mouse MILL2 is involved in wound healing; however, the molecular mechanisms remain unknown. Here, we determine the crystal structure of MILL2 at 2.15 Å resolution, revealing an organization similar to classical MHC class I. However, the α1-α2 domains are not tightly fixed on the α3-β2m domains, indicating unusual interdomain flexibility. The groove between the two helices in the α1-α2 domains is too narrow to permit ligand binding. Notably, an unusual basic patch on the α3 domain is involved in the binding to heparan sulfate which is essential for MILL2 interactions with fibroblasts. These findings suggest that MILL2 has a unique structural architecture and physiological role, with binding to heparan sulfate proteoglycans on fibroblasts possibly regulating cellular recruitment in biological events.
  • Miyatake Y, Kuribayashi-Shigetomi K, Ohta Y, Ikeshita S, Subagyo A, Sueoka K, Kakugo A, Amano M, Takahashi T, Okajima T, Kasahara M
    Scientific reports 8 1 14054  2018年09月 [査読有り][通常論文]
  • Murata S, Takahama Y, Kasahara M, Tanaka K
    Nature immunology 19 9 923 - 931 2018年08月 [査読有り][通常論文]
  • Miyatake Y, Ohta Y, Ikeshita S, Kasahara M
    Oncotarget 9 52 29845 - 29856 2018年07月 [査読有り][通常論文]
  • Park JK, Otsuka N, Tomaru U, Suzuki H, Azuma M, Okamoto K, Yamashiro K, Kasahara M
    Human pathology 80 104 - 112 2018年06月 [査読有り][通常論文]
  • Yoshida S, Shime H, Takeda Y, Nam JM, Takashima K, Matsumoto M, Shirato H, Kasahara M, Seya T
    Cancer science 109 4 956 - 965 2018年04月 [査読有り][通常論文]
  • Sutoh Y, Mohamed RH, Kasahara M
    Frontiers in immunology 9 1059  2018年 [査読有り][通常論文]
  • Junya Ono, Hiroaki Shime, Hiromi Takaki, Ken Takashima, Kenji Funami, Sumito Yoshida, Yohei Takeda, Misako Matsumoto, Masanori Kasahara, Tsukasa Seya
    JOURNAL OF BIOMEDICAL SCIENCE 24 1 79  2017年10月 [査読有り][通常論文]
     
    Background: Intestinal tumorigenesis is promoted by myeloid differentiation primary response gene 88 (MyD88) activation in response to the components of microbiota in Apc(Min/+) mice. Microbiota also contains double-stranded RNA (dsRNA), a ligand for TLR3, which activates the toll-like receptor adaptor molecule 1 (TICAM-1, also known as TRIF) pathway. Methods: We established Apc(Min/+) Ticam1(-/-) mice and their survival was compared to survival of Apc(Min/+) Myd88(-/-) and wild-type (WT) mice. The properties of polyps were investigated using immunofluorescence staining and RT-PCR analysis. Results: We demonstrate that TICAM-1 is essential for suppression of polyp formation in Apc(Min/+) mice. TICAM-1 knockout resulted in shorter survival of mice compared to WT mice or mice with knockout of MyD88 in the Apc(Min/+) background. Polyps were more frequently formed in the distal intestine of Apc(Min/+) Ticam1(-/-) mice than in Apc(Min/+) mice. Infiltration of immune cells such as CD11b(+) and CD8 alpha(+) cells into the polyps was detected histologically. CD11b and CD8 alpha mRNAs were increased in polyps of Apc(Min/+) Ticam1(-/-) mice compared to Apc(Min/+) mice. Gene expression of inducible nitric oxide synthase (iNOS), interferon (IFN)-gamma, CXCL9 and IL-12p40 was increased in polyps of Apc(Min/+) Ticam1(-/-) mice. mRNA and protein expression of c-Myc, a critical transcription factor for inflammation-associated polyposis, were increased in polyps of Apc(Min/+)Ticam1(-/-) mice. A Lactobacillus strain producing dsRNA was detected in feces of Apc(Min/+) mice. Conclusion: These results imply that the TLR3/TICAM-1 pathway inhibits polyposis through suppression of c-Myc expression and supports long survival in Apc(Min/+) mice.
  • Ohigashi I, Ohte Y, Setoh K, Nakase H, Maekawa A, Kiyonari H, Hamazaki Y, Sekai M, Sudo T, Tabara Y, Sawai H, Omae Y, Yuliwulandari R, Tanaka Y, Mizokami M, Inoue H, Kasahara M, Minato N, Tokunaga K, Tanaka K, Matsuda F, Murata S, Takahama Y
    JCI insight 2 10 2017年05月 [査読有り][通常論文]
  • Shizuka Kiuchi, Utano Tomaru, Akihiro Ishizu, Makoto Imagawa, Takayuki Kiuchi, Sari Iwasaki, Akira Suzuki, Noriyuki Otsuka, Takahiro Deguchi, Tomohiro Shimizu, Katsuji Marukawa, Yoshihiro Matsuno, Masanori Kasahara
    HUMAN PATHOLOGY 60 66 - 74 2017年02月 [査読有り][通常論文]
     
    Cathepsins are a group of proteolytic enzymes of the endosomal/lysosomal pathway involved in the thymic development of T cells restricted by major histocompatibility complex class II molecules. In the normal thymus, cathepsin V (CTV) and cathepsin S (CTS) are expressed in cortical and medullary epithelial cells, respectively. To investigate whether cathepsins could serve as a diagnostic marker, we performed immunohistochemical analysis for CTV and CTS in 77 cases of thymic epithelial tumors. Almost all cases (59/ 60) of thymoma expressed CTV, whereas 28 of 60 cases of thymoma expressed CTS. Notably, CTS was expressed in most cases of type A and type AB thymomas, but not in type B thymoma. The expression of cathepsins in type AB thymoma showed a clear correlation with histologic features; CTV was found predominantly in the type B component, and CTS was frequently expressed in the type A component. In thymic carcinoma, CTV was expressed in less than half cases (7/17), and the ratio of CTS-positive cases was equivalent to that of thymoma (8/17). Cases of CTV-negative thymic carcinoma tended to have a higher incidence of recurrence than did CTV-positive cases. Although further studies with a larger number of cases are required to confirm the utility of cathepsin immunostaining, CTV and CTS appear to serve as auxiliary diagnostic and/or prognostic markers in thymic epithelial tumors. (C) 2016 Elsevier Inc. All rights reserved.
  • Sumito Yoshida, Hiroaki Shime, Kenji Funami, Hiromi Takaki, Misako Matsumoto, Masanori Kasahara, Tsukasa Seya
    PLOS ONE 12 1 e0169360  2017年01月 [査読有り][通常論文]
     
    L-Ergothioneine (EGT) is a naturally-occurring amino acid which is characterized by its antioxidant property; yet, the physiological role of EGT has yet to be established. We investigated the immune-enhancing properties of EGT, and found that it acts as a potentiator of toll-like receptor (TLR) signaling. When mouse bone marrow-derived macrophages (BMDMs) were pretreated with EGT, TLR signal-mediated cytokine production was augmented in BMDMs. The results were reproducible with TLR2, 3, 4 and 7 agonists. In particular, IL-6 and IL-12p40 were elevated further by pretreatment with EGT in BMDMs, suggesting the induction of M1 polarization. In co-culture assay with OT-II CD4(+) T cells and splenic F4/80(+) macrophages, EGT significantly induced Th17 skewing in CD4(+) T cells. Thus, EGT is an immune modifier as well as a redox controller under TLR stimulation that induces M1 macrophages and a Th17 shift in inflammation.
  • Jun Kasamatsu, Mengyao Deng, Masahiro Azuma, Kenji Funami, Hiroaki Shime, Hiroyuki Oshiumi, Misako Matsumoto, Masanori Kasahara, Tsukasa Seya
    BMC IMMUNOLOGY 17 1 9  2016年05月 [査読有り][通常論文]
     
    Background: Triggering receptors expressed on myeloid cells (Trem) proteins are a family of cell surface receptors used to control innate immune responses such as proinflammatory cytokine production in mice. Trem genes belong to a rapidly expanding family of receptors that include activating and inhibitory paired-isoforms. Results: By comparative genomic analysis, we found that Trem4, Trem5 and Trem-like transcript-6 (Treml6) genes typically paired receptors. These paired Trem genes were murine-specific and originated from an immunoreceptor tyrosine-based inhibition motif (ITIM)-containing gene. Treml6 encoded ITIM, whereas Trem4 and Trem5 lacked the ITIM but possessed positively-charged residues to associate with DNAX activating protein of 12 kDa (DAP12). DAP12 was directly associated with Trem4 and Trem5, and DAP12 coupling was mandatory for their expression on the cell surface. In bone marrow-derived dendritic cells (BMDCs) and macrophages (BMDMs), and splenic DC subsets, polyinosinic-polycytidylic acid (polyI: C) followed by type I interferon (IFN) production induced Trem4 and Treml6 whereas polyI: C or other TLR agonists failed to induce the expression of Trem5. PolyI: C induced Treml6 and Trem4 more efficiently in BMDMs than BMDCs. Treml6 was more potentially up-regulated in conventional DC (cDCs) and plasmacytoid DC (pDCs) than Trem4 in mice upon in vivo stimulation with polyI: C. Discussion: Treml6-dependent inhibitory signal would be dominant in viral infection compared to resting state. Though no direct ligands of these Trem receptors have been determined, the results infer that a set of Trem receptors are up-regulated in response to viral RNA to regulate myeloid cell activation through modulation of DAP12-associated Trem4 and ITIM-containing Treml6.
  • The next top models. Ancient immunity
    Kasahara M
    Cell 163 1 19 - 19 2015年09月 [査読有り][招待有り]
  • Masanori Kasahara, Yoichi Sutoh
    IMMUNOLOGICAL REVIEWS 267 1 72 - 87 2015年09月 [査読有り][通常論文]
     
    NKG2D ligands (NKG2DLs) are a group of stress-inducible major histocompatibility complex (MHC) class I-like molecules that act as a danger signal alerting the immune system to the presence of abnormal cells. In mammals, two families of NKG2DL genes have been identified: the MIC gene family encoded in the MHC region and the ULBP gene family encoded outside the MHC region in most species. Some mammals have a third family of NKG2DL-like class I genes which we named MILL (MHC class I-like located near the leukocyte receptor complex). Despite the fact that MILL genes are more closely related to MIC genes than ULBP genes are to MIC genes, MILL molecules do not function as NKG2DLs, and their function remains unknown. With the progress of mammalian genome projects, information on the MIC, ULBP, and MILL gene families became available in many mammalian species. Here, we summarize such information and discuss the origin and evolution of the NKG2DL gene family from the viewpoint of host-pathogen coevolution.
  • Tomaru U, Tsuji T, Kiuchi S, Ishizu A, Suzuki A, Otsuka N, Ito T, Ikeda H, Fukasawa Y, Kasahara M
    Histopathology 67 2 235 - 244 2015年08月 [査読有り][通常論文]
     
    AimsThe majority of patients with Down syndrome (DS), trisomy 21, have morphologically abnormal thymuses and present with intrinsic immunological abnormalities affecting mainly the cellular immune response. The aim of this study was to examine whether the expression of functionally important molecules is altered in thymic stromal cells in patients with DS. Methods and resultsWe analysed thymic tissues from patients with trisomy 13 (n=4), trisomy 18 (n=14) and trisomy 21 (n=13) for histological alterations, and for the expression of functionally important molecules such as 5t, a thymoproteasome subunit, and cathepsins L and S. In patients with trisomy 13 and trisomy 18, the thymus was morphologically normal or showed only mild depletion of cortical thymocytes. In contrast, the thymus showed variable histological changes in patients with trisomy 21; six of 13 cases showed severe depletion of thymocytes accompanied by the disappearance of thymic lobular architecture. In such thymuses, spindle-shaped keratin-positive cells were densely distributed, and expression of 5t, but not of cathepsin L, was markedly decreased. ConclusionsThe present study suggests that abnormal thymic architecture and decreased expression of functionally important molecules in thymic stromal cells may be involved in immunological abnormalities in DS patients.
  • Yosuke Yamada, Utano Tomaru, Akihiro Ishizu, Tomoki Ito, Takayuki Kiuchi, Ayako Ono, Syota Miyajima, Katsura Nagai, Tsunehito Higashi, Yoshihiro Matsuno, Hirotoshi Dosaka-Akita, Masaharu Nishimura, Soichi Miwa, Masanori Kasahara
    LABORATORY INVESTIGATION 95 6 625 - 634 2015年06月 [査読有り][通常論文]
     
    Chronic obstructive pulmonary disease (COPD) is a disease common in elderly people, characterized by progressive destruction of lung parenchyma and chronic inflammation of the airways. The pathogenesis of COPD remains unclear, but recent studies suggest that oxidative stress-induced apoptosis in alveolar cells contributes to emphysematous lung destruction. The proteasome is a multicatalytic enzyme complex that plays a critical role in proteostasis by rapidly destroying misfolded and modified proteins generated by oxidative and other stresses. Proteasome activity decreases with aging in many organs including lungs, and an age-related decline in proteasomal function has been implicated in various age-related pathologies. However, the role of the proteasome system in the pathogenesis of COPD has not been investigated. Recently, we have established a transgenic (Tg) mouse model with decreased proteasomal chymotrypsin-like activity, showing age-related phenotypes. Using this model, we demonstrate here that decreased proteasomal function accelerates cigarette smoke (CS)-induced pulmonary emphysema. CS-exposed Tg mice showed remarkable airspace enlargement and increased foci of inflammation compared with wild-type controls. Importantly, apoptotic cells were found in the alveolar walls of the affected lungs. Impaired proteasomal activity also enhanced apoptosis in cigarette smoke extract (CSE)-exposed fibroblastic cells derived from mice and humans in vitro. Notably, aggresome formation and prominent nuclear translocation of apoptosis-inducing factor were observed in CSE-exposed fibroblastic cells isolated from Tg mice. Collective evidence suggests that CS exposure and impaired proteasomal activity coordinately enhance apoptotic cell death in the alveolar walls that may be involved in the development and progression of emphysema in susceptible individuals such as the elderly.
  • Rania Hassan Mohamed, Yoichi Sutoh, Yasushi Itoh, Noriyuki Otsuka, Yukiko Miyatake, Kazumasa Ogasawara, Masanori Kasahara
    PLOS ONE 10 4 e0123258  2015年04月 [査読有り][通常論文]
     
    Dendritic epidermal T cells, which express an invariant V.5V delta 1 T-cell receptor and account for 95% of all resident T cells in the mouse epidermis, play a critical role in skin immune surveillance. These gamma delta T cells are generated by positive selection in the fetal thymus, after which they migrate to the skin. The development of dendritic epidermal T cells is critically dependent on the Skint1 gene expressed specifically in keratinocytes and thymic epithelial cells, suggesting an indispensable role for Skint1 in the selection machinery for specific intraepithelial lymphocytes. Phylogenetically, rodents have functional SKINT1 molecules, but humans and chimpanzees have a SKINT1-like (SKINT1L) gene with multiple inactivating mutations. In the present study, we analyzed SKINT1L sequences in representative primate species and found that all hominoid species have a common inactivating mutation, but that Old World monkeys such as olive baboons, green monkeys, cynomolgus macaques and rhesus macaques have apparently functional SKINT1L sequences, indicating that SKINT1L was inactivated in a common ancestor of hominoids. Interestingly, the epidermis of cynomolgus macaques contained a population of dendritic-shaped gamma delta T cells expressing a semi-invariant V.10/V delta 1 T-cell receptor. However, this population of macaque T cells differed from rodent dendritic epidermal T cells in that their V.10/V delta 1 T-cell receptors displayed junctional diversity and expression of V.10 was not epidermis-specific. Therefore, macaques do not appear to have rodent-type dendritic epidermal T cells despite having apparently functional SKINT1L. Comprehensive bioinformatics analysis indicates that SKINT1L emerged in an ancestor of placental mammals but was inactivated or lost multiple times in mammalian evolution and that Skint1 arose by gene duplication in a rodent lineage, suggesting that authentic dendritic epidermal T cells are presumably unique to rodents.
  • Hiromi Fujita, Yutaka Hatanaka, Yoichi Sutoh, Yuta Suzuki, Koji Oba, Kanako C Hatanaka, Tomoko Mitsuhashi, Noriyuki Otsuka, Kazunori Fugo, Masanori Kasahara, Yoshihiro Matsuno
    The journal of histochemistry and cytochemistry : official journal of the Histochemistry Society 63 3 217 - 27 2015年03月 [査読有り][通常論文]
     
    The MHC class I-chain-related proteins (MICs) and the UL16-binding proteins (ULBPs) are inducible stress response molecules that work as activators of a specific receptor, NKG2D, which is expressed on effector cells, such as NK cells and subsets of T cells. In this study, we sought to explore the biological significance of NKG2D ligands in human neoplasms by comprehensively examining the immunohistochemical expression profile of NKG2D ligands in a variety of human epithelial neoplasms. Following careful validation of the immunohistochemical specificity and availability of anti-human ULBP antibodies for formalin-fixed paraffin-embedded (FFPE) materials, the expression of NKG2D ligands was analyzed in FFPE tissue microarrays comprising 22 types of epithelial neoplastic tissue with their non-neoplastic counterpart from various organs. Hierarchical cluster analysis demonstrated a positive relationship among ULBP2/6, ULBP3, ULBP1, and ULBP5, whose expression patterns were similar across all of the neoplastic tissues examined. In contrast, MICA/B, as well as ULBP4, did not appear to be related to any other ligand. These expression profiles of NKG2D ligands in human neoplasms based on well-validated specific antibodies, followed by hierarchical cluster analysis, should help to clarify some functional aspects of these molecules in cancer biology, and also provide a path to the development of novel tumor-type-specific treatment strategies.
  • Chihiro Iinuma, Masashi Waki, Ai Kawakami, Madoka Yamaguchi, Utano Tomaru, Naomi Sasaki, Sakiko Masuda, Yuki Matsui, Sari Iwasaki, Tomohisa Baba, Masanori Kasahara, Takashi Yoshiki, Daniel Paletta, Thomas Herrmann, Akihiro Ishizu
    INTERNATIONAL IMMUNOLOGY 27 2 105 - 114 2015年02月 [査読有り][通常論文]
     
    We previously generated a rat model that spontaneously developed small vessel vasculitis (SVV). In this study, a T cell clone reactive with rat vascular endothelial cells (REC) was established and named VASC-1. Intravenous injection of VASC-1 induced SVV in normal recipients. VASC-1 was a TCR alpha beta/CD3-positive CD4/CD8 double-negative T cell clone with expression of NKG2D. The cytokine mRNA profile under unstimulated condition was positive for IL-4 and IFN-gamma but negative for IL-2 and IL-10. After interaction with REC, the mRNA expression of IL-2, IL-5 and IL-6 was induced in VASC-1, which was inhibited by blocking of CD1d on the REC surface. Although the protein levels of these cytokines seemed to be lower than the detection limit in the culture medium, IFN-gamma was detectable. The production of IFN-gamma from the VASC-1 stimulated with LPS-pre-treated REC was inhibited by the CD1d blockade on the REC. These findings indicated VASC-1 as an NKT cell clone. The NKT cell pool includes two major subsets, namely types I and II. Type I NKT cells are characterized by expression of semi-invariant TCRs and the potential to bind to marine sponge-derived alpha-galactosylceramide (alpha-GalCer) loaded on CD1d; whereas, type II NKT cells do not manifest these characteristics. VASC-1 exhibited a usage of TCR other than the type I invariant TCR alpha chain and did not bind to alpha-GalCer-loaded CD1d; therefore, it was determined as a type II NKT cell clone. The collective evidence suggested that REC-reactive type II NKT cells could be involved in the pathogenesis of SVV in rats.
  • Miyatake Y, Sheehy N, Ikeshita S, Hall WW, Kasahara M
    Cancer letters 357 1 355 - 363 2015年02月 [査読有り][通常論文]
     
    Adult T-cell leukemia/lymphoma (ATL) is an intractable T-cell malignancy accompanied by massive invasion of lymphoma cells into various tissues. We demonstrate here that ATL cells cultured on a layer of epithelial-like feeder cells form anchorage-dependent multicellular aggregates (Ad-MCAs) and that a fraction of MCA-forming ATL cells acquire CD44 high cancer stem cell-like phenotypes. ATL cells forming Ad-MCAs displayed extracellular microvesicles with enhanced expression of CD44v9 at cell synapses, augmented expression of multidrug resistance protein 1, and increased NF-kappa B activity. Blockade of the NF kappa B pathway dramatically reduced Ad-MCA formation by ATL cells and the emergence of CD44 high ATL cells, but left a considerable number of ATL cells adhering to the feeder layer. Disruption of vimentin cytoskeleton by treatment with withaferin A, a natural steroidal lactone, suppressed not only the adhesion of ATL cells to the feeder layer but also subsequent Ad-MCA formation by ATL cells, suggesting the involvement of vimentin in anchoring ATL cells to the feeder layer. Ad-MCA formation by ATL cells on a layer of epithelial-like feeder cells may mimic critical events that occur in metastatic colonization. (c) 2014 Elsevier Ireland Ltd. All rights reserved.
  • Shizuka Kiuchi, Shunji Ikeshita, Yukiko Miyatake, Masanori Kasahara
    EXPERIMENTAL AND MOLECULAR PATHOLOGY 98 1 41 - 46 2015年02月 [査読有り][通常論文]
     
    Pancreatic cancer is one of the most lethal cancers with high metastatic potential and strong chemoresistance. Its intractable natures are attributed to high robustness in tumor cells for their survival. We demonstrate here that pancreatic cancer cells (PCCs) with an epithelial phenotype upregulate cell surface expression of CD44 variant 9 (CD44v9), an important cancer stem cell marker, during the mitotic phases of the cell cycle. Of five human CD44(+) PCC lines examined, three cell lines, PCI-24, PCI-43 and PCI-55, expressed E-cadherin and CD44 variants, suggesting that they have an epithelial phenotype. By contrast PANC-1 and MIA PaCa-2 cells expressed vimentin and ZEB1, suggesting that they have a mesenchymal phenotype. PCCs with an epithelial phenotype upregulated cell surface expression of CD44v9 in prophase, metaphase, anaphase and telophase and downregulated CD44v9 expression in late-telophase, cytokinesis and interphase. Sorted CD44v9-negative PCI-55 cells resumed CD44v9 expression when they re-entered the mitotic stage. Interestingly, CD44v9(bright) mitotic cells expressed multidrug resistance protein 1 (MDR1) intracellularly. Upregulated expression of CD44v9 and MDR1 might contribute to the intractable nature of PCCs with high proliferative activity. (C) 2014 Elsevier Inc. All rights reserved.
  • Kasahara M
    Results and problems in cell differentiation 57 175 - 192 2015年 [査読有り][通常論文]
  • Shunji Ikeshita, Yukiko Miyatake, Noriyuki Otsuka, Masanori Kasahara
    EXPERIMENTAL AND MOLECULAR PATHOLOGY 97 1 171 - 175 2014年08月 [査読有り][通常論文]
     
    Infiltrating macrophages accumulate in fatty streak lesions and transform into foam cells, leading to the formation of atherosclerotic plaques. Inflammatory mechanisms underlying the plaque formation mediated by NKG2D-positive lymphocytes such as CD8(+) T cells, natural killer cells and natural killer T cells have been extensively investigated. Yet, the involvement of the NKG2D system itself remains poorly understood. Recent work in mouse models has shown that blockade of an NKG2D receptor ligand interaction reduces plaque formation and suppresses inflammation in aortae. In this study, we conducted immunohistochemical analysis of NKG2D ligand expression in autopsy-derived aortic specimens. Foam cells expressing NKG2D ligands MICA/B were found in advanced atherosclerotic lesions accompanied by a large necrotic core or hemorrhage. Human monocyte-derived macrophages treated in vitro with acetylated low-density lipoproteins enhanced expression of MICA/B and scavenger receptor A, thus accounting for NKG2D ligand expression in foam cells infiltrating atherosclerotic plaques. Our results suggest that, as in mice, the NKG2D system might be involved in the development of atherosclerosis in humans. (C) 2014 Elsevier Inc. All rights reserved.
  • Ando R, Noda K, Tomaru U, Kamoshita M, Ozawa Y, Notomi S, Hisatomi T, Noda M, Kanda A, Ishibashi T, Kasahara M, Ishida S
    Investigative ophthalmology & visual science 2014年07月 [査読有り][通常論文]
  • Venkatesh B, Lee AP, Swann JB, Ohta Y, Flajnik MF, Kasahara M, Boehm T, Warren WC
    Nature 511 E9 - 10 7508 2014年07月 [査読有り][通常論文]
  • Yoichi Sutoh, Masanori Kasahara
    IMMUNOGENETICS 66 6 403 - 409 2014年06月 [査読有り][通常論文]
     
    Unlike jawed vertebrates that use T cell and B cell receptors for antigen recognition, jawless vertebrates represented by lampreys and hagfish use variable lymphocyte receptors (VLR) as antigen receptors. VLRs generate high levels of diversity by assembling variable leucine-rich repeat (LRR) modules. Of the three VLRs thus far identified, VLRB is expressed on B cell-like lymphocytes and functions as antibodies, whereas VLRA and VLRC are expressed on T cell-like lymphocytes and function as membrane-bound receptors. In the present study, we show that the copy number of LRRV modules in lamprey and hagfish VLRB transcripts follows a binominal distribution with the success rates of 15.5 and 22.4 %, respectively. By contrast, the copy number distribution of LRRV modules in VLRA and VLRC transcripts deviates from the binominal distribution mainly because transcripts with two or less LRRV modules occur infrequently. Notably, the second LRRV module shows distinctive sequence signatures in VLRA and VLRC, but not in VLRB transcripts. These observations suggest that distinct functional constraints operate on VLRs expressed by agnathan T cell-like and B cell-like lymphocytes.
  • Philipp Stroebel, Elena Hartmann, Andreas Rosenwald, Joerg Kalla, German Ott, Godehard Friedel, Berthold Schalke, Masanori Kasahara, Utano Tomaru, Alexander Marx
    HISTOPATHOLOGY 64 4 557 - 566 2014年03月 [査読有り][通常論文]
     
    AimsMorphological complexity hampers the histological classification of thymomas. Our aim was to determine whether the use of novel differentiation and maturation markers of cortical and medullary thymic epithelial cells (cTECs and mTECs) might provide an approach to understanding the underlying biology of these tumours. Methods and resultsFifty-seven thymomas were studied by immunohistochemistry. The cortical markers used were B5T, PRSS16, and cathepsin V. The medullary markers used were CD40, claudin-4, AIRE, and desmin. Involucrin and cytokeratin 10 were used to study terminal mTEC maturation. Irrespective of histological subtype, most thymomas contained distinct areas with cortical and medullary differentiation. Type B1, type B2 and type AB thymomas showed marked bi-lineage differentiation, with lack of terminal mTEC maturation in type AB. Type AB thymomas were unique in showing areas where cells with either cortical or medullary differentiation were intimately mixed' at the single-cell level. Type B3 and type A thymomas showed only abortive lineage differentiation and maturation. ConclusionsThymomas show highly characteristic patterns of bi-lineage TEC differentiation that reflect the histological subtypes recognized by the WHO classification. We hypothesize that thymomas arise from thymic precursor cells with different cortical and/or medullary maturation defects.
  • Yamada Y, Tomaru U, Ishizu A, Kiuchi T, Kasahara M, Matsuno Y
    Journal of clinical pathology 67 3 276 - 278 3 2014年03月 [査読有り][通常論文]
     
    Type AB thymoma is a thymic epithelial tumour composed of lymphocyte-poor type A and lymphocyterich type B components. Although it is categorised as a single entity in the classification of WHO, it shows a broad range of morphology. To investigate whether the functional characteristic of neoplastic cells in type AB thymoma relates to morphological diversity, we performed immunohistochemical analysis using anti-beta 5t antibody in 20 cases of type AB thymoma. beta 5t is a recently discovered proteasomal beta subunit expressed exclusively in cortical thymic epithelial cells and tumour epithelial cells of thymomas with cortical differentiation. Consistent with our previous observation, beta 5t was predominantly expressed in the type B component. When the type B component was divided into three groups morphologically, beta 5t was expressed more frequently in cases with round to polygonal than spindle to oval tumour cells. Furthermore, the ratio of terminal deoxynucleotidyl transferase (TdT)-positive lymphocytes was increased in components with higher expression of beta 5t. These results indicate that the histological diversity of type AB thymoma correlates with expression of a functional marker beta 5t and abundance of TdT-positive lymphocytes.
  • Ibusuki A, Kawai K, Yoshida S, Uchida Y, Nitahara-Takeuchi A, Kuroki K, Kajikawa M, Ose T, Maenaka K, Kasahara M, Kanekura T
    The Journal of investigative dermatology 134 2 396 - 404 2014年02月 [査読有り][通常論文]
     
    Murine epidermal gamma delta T cells, known as dendritic epidermal T cells (DETCs), survey tissue stress through the invariant T-cell receptor (TCR) and non-clonotypic receptors such as NKG2D. NKG2D signaling via the DAP10-phosphatidylinositol 3-kinase (PI3K) pathway directly stimulates cytotoxicity in natural killer (NK) cells and costimulates CD8(+) T cells to augment TCR signals. In activated murine NK cells, NKG2D signals also via the DAP12-Syk/ZAP70 pathway that triggers both cytotoxicity and cytokine production. It remains controversial whether NKG2D on DETCs is a primary activating receptor or functions only as a costimulatory receptor, and signaling pathways initiated by NKG2D ligation in DETCs have not been analyzed. We show that stimulation of short-term DETC lines with recombinant NKG2D ligands triggers degranulation (exocytosis of cytotoxic granules) via the PI3K-dependent signaling pathway, but does not induce cytokine production or Syk/ZAP70 activation. Coengagement of TCR or Syk/ZAP70 signaling was not crucial for DETC-mediated killing of NKG2D ligand-expressing target cells. Thus, NKG2D can function as a coactivating stress receptor that directly triggers cytotoxicity in DETCs, at least after priming, via the PI3K-dependent, Syk/ZAP70-independent signaling pathway.
  • Byrappa Venkatesh, Alison P. Lee, Vydianathan Ravi, Ashish K. Maurya, Michelle M. Lian, Jeremy B. Swann, Yuko Ohta, Martin F. Flajnik, Yoichi Sutoh, Masanori Kasahara, Shawn Hoon, Vamshidhar Gangu, Scott W. Roy, Manuel Irimia, Vladimir Korzh, Igor Kondrychyn, Zhi Wei Lim, Boon-Hui Tay, Sumanty Tohari, Kiat Whye Kong, Shufen Ho, Belen Lorente-Galdos, Javier Quilez, Tomas Marques-Bonet, Brian J. Raney, Philip W. Ingham, Alice Tay, LaDeana W. Hillier, Patrick Minx, Thomas Boehm, Richard K. Wilson, Sydney Brenner, Wesley C. Warren
    NATURE 505 7482 174 - 179 2014年01月 [査読有り][通常論文]
     
    The emergence of jawed vertebrates (gnathostomes) fromjawless vertebrates was accompanied by major morphological and physiological innovations, such as hinged jaws, paired fins and immunoglobulin-based adaptive immunity. Gnathostomes subsequently diverged into two groups, the cartilaginous fishes and the bony vertebrates. Here we report the whole-genome analysis of a cartilaginous fish, the elephant shark (Callorhinchus milii). We find that the C. milii genome is the slowest evolving of all known vertebrates, including the ` living fossil' coelacanth, and features extensive synteny conservation with tetrapod genomes, making it a goodmodel for comparative analyses of gnathostome genomes. Our functional studies suggest that the lack of genes encoding secreted calcium-binding phosphoproteins in cartilaginous fishes explains the absence of bone in their endoskeleton. Furthermore, the adaptive immune system of cartilaginous fishes is unusual: it lacks the canonical CD4 co-receptor and most transcription factors, cytokines and cytokine receptors related to the CD4 lineage, despite the presence of polymorphic major histocompatibility complex class II molecules. It thus presents a new model for understanding the origin of adaptive immunity.
  • Ryo Kanda, Yoichi Sutoh, Jun Kasamatsu, Katsumi Maenaka, Masanori Kasahara, Toyoyuki Ose
    PLOS ONE 9 1 e85875  2014年01月 [査読有り][通常論文]
     
    Jawless vertebrates represented by lampreys and hagfish use variable lymphocyte receptors (VLRs) as antigen receptors to mount adaptive immune responses. VLRs generate diversity that is comparable to immunoglobulins and T-cell receptors by a gene conversion-like mechanism, which is mediated by cytosine deaminases. Currently, three types of VLRs, VLRA, VLRB, and VLRC, have been identified in lampreys. Crystal structures of VLRA and VLRB in complex with antigens have been reported recently, but no structural information is available for VLRC. Here, we present the first crystal structure of VLRC from the Japanese lamprey (Lethenteron japonicum). Similar to VLRA and VLRB, VLRC forms a typical horseshoe-like solenoid structure with a variable concave surface. Strikingly, its N-terminal cap has a long loop with limited sequence variability that protrudes toward the concave surface, which is the putative antigen-binding surface. Furthermore, as predicted previously, its C-terminal cap lacks a highly variable protruding loop that plays an important role in antigen recognition by lamprey VLRA and VLRB. Recent work suggests that VLRC+ lymphocytes in jawless vertebrates might be akin to gamma delta T cells in jawed vertebrates. Structural features of lamprey VLRC described here suggest that it may recognize antigens in a unique manner.
  • Masanori Kasahara, Yoichi Sutoh
    ADVANCES IN IMMUNOLOGY, VOL 122 122 59 - 90 2014年 [査読有り][通常論文]
     
    Unlike jawed vertebrates that use T-cell and B-cell receptors for antigen recognition, jawless vertebrates represented by lampreys and hagfish use variable lymphocyte receptors (VLRs) as antigen receptors. VLRs generate diversity comparable to that of gnathostome antigen receptors by assembling variable leucine-rich repeat modules. The discovery of VLR has revolutionized our understanding of how adaptive immunity emerged and highlighted the differences between the adaptive immune systems (AISs) of jawed and jawless vertebrates. However, emerging evidence also indicates that their AISs have much in common. Particularly striking is the conservation of lymphocyte lineages. The basic architecture of the AIS including the dichotomy of lymphocytes appears to have been established in a common ancestor of jawed and jawless vertebrates. We review here the current knowledge on the AIS of jawless vertebrates, emphasizing both the similarities to and differences from the AIS of jawed vertebrates.
  • Tomaru U, Kasahara M
    Archivum immunologiae et therapiae experimentalis 61 357 - 365 5 2013年10月 [査読有り][通常論文]
  • Kasahara M
    Immunology and cell biology 2013年10月 [査読有り][通常論文]
  • Yukiko Miyatake, Andre L. A. Oliveira, Mohamed Ali Jarboui, Shuichi Ota, Utano Tomaru, Takanori Teshima, William W. Hall, Masanori Kasahara
    AMERICAN JOURNAL OF PATHOLOGY 182 5 1832 - 1842 2013年05月 [査読有り][通常論文]
     
    Adult T-cell leukemia/lymphoma (ATL) is a highly invasive and intractable T-cell malignancy caused by human T-cell leukemia virus-1 infection. We demonstrate herein that normal tissue-derived epithelial cells (NECs) exert protective effects on the survival of leukemic cells, which may partially account for high resistance to antileukemic therapies in patients with ATL. Viral gene-silenced, ATL-derived cell Lines (ATL cells) dramatically escaped from histone deacetylase inhibitor-induced apoptosis by direct co-culture with NECs. Adhesions to NECs suppressed p21(Cip1) expression and increased a proportion of resting G0/G1 phase cells in trichostatin A (TSA)-treated ATL cells. ATL cells adhering to NECs down-regulated CD25 expression and enhanced vimentin expression, suggesting that most ATL cells acquired a quiescent state by cell-cell interactions with NECs. ATL cells adhering to NECs displayed highly elevated expression of the cancer stem cell marker CD44. Blockade of CD44 signaling diminished the NEC-conferred resistance of ATL cells to TSA-induced apoptosis. Co-culture with NECs also suppressed the expression of NKG2D Ligands on TSA-treated ATL cells, resulting in decreased natural killer cell-mediated cytotoxicity. Combined evidence suggests that interactions with normal epithelial cells augment the resistance of ATL cells to TSA-induced apoptosis and facilitate immune evasion by ATL cells.
  • Masanori Kasahara
    SEMINARS IN CELL & DEVELOPMENTAL BIOLOGY 24 2 81 - 82 2013年02月 [査読有り][通常論文]
  • Fukaya S, Matsui Y, Tomaru U, Kawakami A, Sogo S, Bohgaki T, Atsumi T, Koike T, Kasahara M, Ishizu A
    Laboratory investigation; a journal of technical methods and pathology 93 1 72 - 80 1 2013年01月 [査読有り][通常論文]
     
    TNF-alpha-converting enzyme (TACE) can cleave transmembrane proteins, such as TNF-alpha, TNF receptors, and epidermal growth factor receptor (EGFR) ligands, to release the extracellular domains from the cell surface. Recent studies have suggested that overexpression of TACE may be associated with the pathogenesis of inflammation and fibrosis. To determine the roles of TACE in inflammation and fibrosis, TACE transgenic (TACE-Tg) mice, which overexpressed TACE systemically, were generated. As the transgene-derived TACE was expressed as an inactive form, no spontaneous phenotype developed in TACE-Tg mice. However, the transgene-derived TACE could be converted to an active form by furin in vitro and by phorbol myristate acetate (PMA) in vivo. Subcutaneous injection of PMA into mice induced inflammatory cell infiltration 1 day later and subsequent dermal fibrosis 7 days later. Interestingly, the degree of dermal fibrosis at day 7 was significantly higher in TACE-Tg mice than in wild-type mice. Correspondingly, PMA increased the expression of type I collagen in the primary culture of dermal fibroblasts derived from TACE-Tg mice. Furthermore, phosphorylated EGFR was increased in the fibroblasts by the PMA treatment. The collective findings suggest that TACE overexpression and activation in fibroblasts could shed off putative EGFR ligands. Subsequently, the soluble EGFR ligands could bind and activate EGFR on fibroblasts, and then increase the type I collagen expression resulting in induction of dermal fibrosis. These results also suggest that TACE and EGFR on fibroblasts may be novel therapeutic targets of dermal fibrosis, which is induced after diverse inflammatory disorders of the skin. Laboratory Investigation (2013) 93, 72-80; doi:10.1038/labinvest.2012.153; published online 12 November 2012
  • Masanori Kasahara, Shigeru Yoshida
    IMMUNOGENETICS 64 12 855 - 867 2012年12月 [査読有り][通常論文]
     
    NKG2D ligands (NKG2DLs) are a group of major histocompatibility complex (MHC) class I-like molecules, the expression of which is induced by cellular stresses such as infection, tumorigenesis, heat shock, tissue damage, and DNA damage. They act as a molecular danger signal alerting the immune system for infected or neoplastic cells. Mammals have two families of NKG2DL genes: the MHC-encoded MIC gene family and the ULBP gene family encoded outside the MHC region in most mammals. Rodents such as mice and rats lack the MIC family of ligands. Interestingly, some mammals have NKG2DL-like molecules named MILL that are phylogenetically related to MIC, but do not function as NKG2DLs. In this paper, we review our current knowledge of the MIC, ULBP, and MILL gene families in representative mammalian species and discuss the origin and evolution of the NKG2DL gene family.
  • Masuda S, Iwasaki S, Tomaru U, Sato J, Kawakami A, Ichijo K, Sogo S, Baba T, Katsumata K, Kasahara M, Ishizu A
    PloS one 7 12 e52918  12 2012年12月 [査読有り][通常論文]
     
    The whole blood erythrocyte lysis method is the most common protocol of sample preparation for flow cytometry (FCM). Although this method has many virtues, our recent study has demonstrated false-positive results when surface markers of monocytes were examined by this method due to the phenomenon called Fc gamma receptor (Fc gamma R)-mediated trogocytosis. In the present study, similar Fc gamma R-mediated trogocytosis-based false-positive results have been demonstrated when granulocytes were focused on instead of monocytes. These findings indicated that not only monocytes but also granulocytes, the largest population with Fc gamma R expression in peripheral blood, could perform Fc gamma R-mediated trogocytosis. Since the capacity of Fc gamma R-mediated trogocytosis was different among blood samples, identification of factors that could regulate the occurrence of Fc gamma R-mediated trogocytosis should be important for the quality control of FCM. Our studies have suggested that such factors are present in the serum. In order to identify the serum factors, we employed the in vitro model of Fc gamma R-mediated trogocytosis using granulocytes. Investigation with this model determined the serum factors as heat-labile molecules with molecular weight of more than 100 kDa. Complements in the classical pathway were initially assumed as candidates; however, the C1 inhibitor did not yield an obvious influence on Fc gamma R-mediated trogocytosis. On the other hand, although immunoglobulin ought to be resistant to heat inactivation, the inhibitor of human anti-mouse antibodies (HAMA) effectively blocked Fc gamma R-mediated trogocytosis. Moreover, the inhibition rates were significantly higher in HAMA(high) serum than HAMA(low) serum. The collective findings suggested the involvement of heterophilic antibodies such as HAMA in the mechanism of false-positive results in FCM due to Fc gamma R-mediated trogocytosis.
  • Daigo Nakazawa, Utano Tomaru, Akira Suzuki, Sakiko Masuda, Risa Hasegawa, Toshiaki Kobayashi, Saori Nishio, Masanori Kasahara, Akihiro Ishizu
    ARTHRITIS AND RHEUMATISM 64 11 3779 - 3787 2012年11月 [査読有り][通常論文]
     
    Objective Neutrophil extracellular traps (NETs) are composed of DNA and antimicrobial proteins, including myeloperoxidase (MPO). Recent studies have demonstrated that impaired regulation of NETs could trigger an autoimmune response. Propylthiouracil (PTU), an antithyroid drug, is associated with a risk of MPO antineutrophil cytoplasmic antibody (ANCA) production and MPO ANCA-associated vasculitis (MPO AAV). This study was undertaken to clarify the mechanism of MPO ANCA production, using the PTU-induced model of MPO AAV. Methods NETs were induced by treating human neutrophils with phorbol myristate acetate (PMA) in vitro. We examined whether the addition of PTU influenced the NET formation induced by PMA and the degradation of NETs by DNase I, which is regarded as a regulator of NETs. Furthermore, we examined whether NETs generated by the combination of PMA and PTU induced MPO ANCA and MPO AAV in vivo in rats. Results When NETs were induced by PMA with PTU using human neutrophils in vitro, abnormal conformation of NETs was observed. Interestingly, the abnormal NETs were hardly digested by DNase I. Moreover, rats immunized with the abnormal NETs, which had been induced by PMA with PTU using rat neutrophils, produced MPO ANCA and developed pulmonary capillaritis. When rats were given oral PTU with intraperitoneal injection of PMA, pauci-immune glomerulonephritis and pulmonary capillaritis occurred with MPO ANCA production in the serum. Conclusion Our findings indicate that abnormal conformation and impaired degradation of NETs induced by PTU are involved in the pathogenesis of PTU-induced MPO ANCA production and MPO AAV. These findings suggest that disordered NETs can be critically implicated in the pathogenesis of MPO AAV.
  • Tomaru U, Yamada Y, Ishizu A, Kuroda T, Matsuno Y, Kasahara M
    Journal of clinical pathology 65 9 858 - 859 9 2012年09月 [査読有り][通常論文]
  • Stephanie Y. L. Ng, Billy K. C. Chow, Jun Kasamatsu, Masanori Kasahara, Leo T. O. Lee
    PLOS ONE 7 9 e44691  2012年09月 [査読有り][通常論文]
     
    VIP and PACAP are pleiotropic peptides belonging to the secretin superfamily of brain-gut peptides and interact specifically with three receptors (VPAC(1), PAC(1) and VPAC(2)) from the class II B G protein-coupled receptor family. There is immense interest regarding their molecular evolution which is often described closely alongside gene and/or genome duplications. Despite the wide array of information available in various vertebrates and one invertebrate the tunicate, their evolutionary origins remain unresolved. Through searches of genome databases and molecular cloning techniques, the first lamprey VIP/PACAP ligands and VPAC receptors are identified from the Japanese lamprey. In addition, two VPAC receptors (VPACa/b) are identified from inshore hagfish and ligands predicted for sea lamprey. Phylogenetic analyses group these molecules into their respective PHI/VIP, PRP/PACAP and VPAC receptor families and show they resemble ancestral forms. Japanese lamprey VIP/PACAP peptides synthesized were tested with the hagfish VPAC receptors. hfVPACa transduces signal via both adenylyl cylase and phospholipase C pathways, whilst hfVPACb was only able to transduce through the calcium pathway. In contrast to the widespread distribution of VIP/PACAP ligands and receptors in many species, the agnathan PACAP and VPAC receptors were found almost exclusively in the brain. In situ hybridisation further showed their abundance throughout the brain. The range of VIP/PACAP ligands and receptors found are highly useful, providing a glimpse into the evolutionary events both at the structural and functional levels. Though representative of ancestral forms, the VIP/PACAP ligands in particular have retained high sequence conservation indicating the importance of their functions even early in vertebrate evolution. During these nascent stages, only two VPAC receptors are likely responsible for eliciting functions before evolving later into specific subtypes post-Agnatha. We also propose VIP and PACAP's first functions to predominate in the brain, evolving alongside the central nervous system, subsequently establishing peripheral functions.
  • Takehiko Katsurada, Waka Kobayashi, Utano Tomaru, Tomohisa Baba, Shigeru Furukawa, Akihiro Ishizu, Kazuyoshi Takeda, Naoya Sakamoto, Masahiro Asaka, Hiroshi Takeda, Masanori Kasahara
    PLOS ONE 7 9 e44113  2012年09月 [査読有り][通常論文]
     
    To investigate the role of inhibitory natural killer receptors (iNKRs) in inflammatory bowel disease (IBD), we analyzed the expression of NKG2A, one of the iNKRs, on T cells in a mouse colitis model and human IBD. During the active phase of dextran sulfate sodium (DSS)-induced mouse colitis, the frequency of NKG2A+ T cells was significantly decreased in the peripheral blood, and increased in the intestine, suggesting the mobilization of this T cell subset to the sites of inflammation. Administration of anti-NKG2A antibody increased the number of inflammatory foci in DSS-induced colitis, suggesting the involvement of NKG2A+ T cells in this colitis model. In ulcerative colitis (UC) patients, the frequency of peripheral blood NKG2A+ T cells was significantly decreased, compared with Crohn's disease (CD) patients and healthy controls, regardless of clinical conditions such as treatment modalities and disease activity. Notably, in sharp contrast to the DSS-induced mouse colitis model, the frequency of NKG2A+ cells among intestinal T cells was also decreased in UC patients. These results suggest that inadequate local infiltration of NKG2A+ T cells may be involved in the pathogenesis of UC.
  • Shigeru Yoshida, Rania Hassan Mohamed, Mizuho Kajikawa, Jun Koizumi, Minami Tanaka, Kazunori Fugo, Noriyuki Otsuka, Katsumi Maenaka, Hideo Yagita, Hitoshi Chiba, Masanori Kasahara
    JOURNAL OF IMMUNOLOGY 188 8 3972 - 3979 2012年04月 [査読有り][通常論文]
     
    Dendritic epidermal T cells (DETCs) found in mouse skin are NKG2D-positive gamma delta T cells involved in immune surveillance and wound repair. It is assumed that the interaction of an NKG2D receptor on DETCs and an MHC class I-like NKG2D ligand on keratinocytes activates DETCs, which then secrete cytokines promoting wound repair. However, direct evidence that DETC activation through NKG2D signaling promotes wound repair is not available. In the present study, we generated mAbs for an NKG2D ligand H60c previously suggested to be expressed specifically on skin keratinocytes. Local administration of H60c-specific mAb inhibited activation of DETCs and significantly delayed wound repair. Likewise, administration of NKG2D-specific mAb impaired wound repair to a similar extent. The delay in wound closure resulting from the blockade of the NKG2D pathway was comparable to that observed in gamma delta T cell-deficient mice. These results indicate that H60c/NKG2D interactions play a critical role in wound repair. Reassessment of binding affinities showed that H60c monomers bind to NKG2D with affinity (K-d = 26 +/- 3.2 nM) comparable to those of other high-affinity NKG2D ligands. H60c is transcribed not only in skin but also in tissues such as tongue and female reproductive tract known to contain epithelium-resident gamma delta T cells expressing invariant TCRs, suggesting a more general role for H60c in the maintenance of epithelial integrity. The Journal of Immunology, 2012, 188: 3972-3979.
  • 山田 洋介, 外丸 詩野, 石津 明洋, 木内 隆之, 丸川 活司, 松野 吉宏, 笠原 正典
    北海道醫學雜誌 = Acta medica Hokkaidonensia 87 2 2012年04月01日 [査読無し][通常論文]
  • Yoshida S, Mohamed RH, Kajikawa M, Koizumi J, Tanaka M, Fugo K, Otsuka N, Maenaka K, Yagita H, Chiba H, Kasahara M
    Journal of Immunology 188 8 3972 - 3979 2012年04月 [査読有り][通常論文]
  • Utano Tomaru, Satomi Takahashi, Akihiro Ishizu, Yukiko Miyatake, Aya Gohda, Sayuri Suzuki, Ayako Ono, Jiro Ohara, Tomohisa Baba, Shigeo Murata, Keiji Tanaka, Masanori Kasahara
    AMERICAN JOURNAL OF PATHOLOGY 180 3 963 - 972 2012年03月 [査読有り][通常論文]
     
    The proteasome is a multicatalytic enzyme complex responsible for the degradation of both normal and damaged proteins. An age-related decline in proteasomal activity has been implicated in various age-related pathologies. The relevance of decreased proteasomal activity to aging and age-related diseases remains unclear, however, because suitable animal models are not available. In the present study, we established a transgenic (Tg) mouse model with decreased proteasomal chymotrypsin-like activity. Tg mice exhibited a shortened life span and developed age-related phenotypes. In Tg mice, polyubiquitinated and oxidized proteins accumulated, and the expression levels of cellular proteins such as Bcl-xL and RNase L were altered. When Tg mice were fed a high-fat diet, they developed more pronounced obesity and hepatic steatosis than did wild-type mice. Consistent with its role in lipid droplet formation, the expression of adipose differentiation-related protein (ADRP) was elevated in the livers of Tg mice. Of note, obesity and hepatic steatosis induced by a high-fat diet were more pronounced in aged than in young wild-type mice, and aged wild-type mice had elevated levels of ADRP, suggesting that the metabolic abnormalities present in Tg mice mimic those in aged mice. Our results proteasomal chymotrypsin-like activity affects longevity and aggravates age-related metabolic disorders, such as obesity and hepatic steatosis. (Am J Pathol(2012, 180:963-972; DOI. 10.1016/j.ajpath.2011.11.012)
  • Sutoh Y, Kondo M, Ohta Y, Ota T, Tomaru U, Flajnik MF, Kasahara M
    Immunogenetics 64 1 49 - 58 1 2012年01月 [査読有り][通常論文]
     
    The thymoproteasome is a recently discovered, specialized form of 20S proteasomes expressed exclusively in the thymic cortex. Although the precise molecular mechanism by which the thymoproteasome exerts its function remains to be elucidated, accumulating evidence indicates that it plays a crucial role in positive selection of T cells. In the present study, we analyzed the evolution of the beta 5t subunit, a beta-type catalytic subunit uniquely present in thymoproteasomes. The gene coding for the beta 5t subunit, designated PSMB11, was identified in the cartilaginous fish, the most divergent group of jawed vertebrates compared to the other jawed vertebrates, but not in jawless vertebrates or invertebrates. Interestingly, teleost fish have two copies of apparently functional PSMB11 genes, designated PSMB11a and PSMB11b, that encode beta 5t subunits with distinct amino acids in the S1 pocket. BLAST searches of genome databases suggest that birds such as chickens, turkey, and zebra finch lost the PSMB11 gene, and have neither thymoproteasomes nor immunoproteasomes. In mammals, reptiles, amphibians, and teleost fishes, the PSMB11 gene (the PSMB11a gene in teleost fish) is located next to the PSMB5 gene coding for the beta 5 subunit of the standard 20S proteasome, indicating that the PSMB11 gene arose by tandem duplication from the evolutionarily more ancient PSMB5 gene. The general absence of introns in PSMB11 and an unusual exon-intron structure of jawed vertebrate PSMB5 suggest that PSMB5 lost introns and duplicated in tandem in a common ancestor of jawed vertebrates, with PSMB5 subsequently gaining two introns and PSMB11 remaining intronless.
  • Thomas Boehm, Nathanael McCurley, Yoichi Sutoh, Michael Schorpp, Masanori Kasahara, Max D. Cooper
    ANNUAL REVIEW OF IMMUNOLOGY, VOL 30 30 203 - 220 2012年 [査読有り][通常論文]
     
    Lampreys and hagfish are primitive jawless vertebrates capable of mounting specific immune responses. Lampreys possess different types of lymphocytes, akin to T and B cells of jawed vertebrates, that clonally express somatically diversified antigen receptors termed variable lymphocyte receptors (VLRs), which are composed of tandem arrays of leucine-rich repeats. The VLRs appear to be diversified by a gene conversion mechanism involving lineage-specific cytosine deaminases. VLRA is expressed on the surface of T-like lymphocytes; B-like lymphocytes express and secrete VLRB as a multivalent protein. VLRC is expressed by a distinct lymphocyte lineage. VLRA-expressing cells appear to develop in a thymus-like tissue at the tip of gill filaments, and VLRB-expressing cells develop in hematopoietic tissues. Reciprocal expression patterns of evolutionarily conserved interleukins and chemokines possibly underlie cell-cell interactions during an immune response. The discovery of VLRs in agnathans illuminates the origins of adaptive immunity in early vertebrates.
  • Yamada Y, Tomaru U, Ishizu A, Kiuchi T, Marukawa K, Matsuno Y, Kasahara M
    The American journal of surgical pathology 35 9 1296 - 1304 9 2011年09月 [査読有り][通常論文]
     
    Recently, a proteasome beta subunit expressed exclusively in thymic cortical epithelial cells was discovered in mice and humans. This subunit, designated beta 5t, is a component of the thymoproteasome, a specialized type of proteasome implicated in thymic positive selection. To investigate whether beta 5t could serve as a marker for the differential diagnosis of thymic epithelial tumors, we performed immunohistochemical analysis using anti-beta 5t antibody in 54 cases of thymic epithelial tumors comprising 41 cases of thymomas and 13 cases of thymic carcinomas. beta 5t was detected in the neoplastic epithelial cells of thymomas. Among the subtypes of thymoma, expression of beta 5t was observed in most cases of type B thymoma (20 of 21) but not in type A thymomas (0 of 3). In type AB thymomas, beta 5t expression was variable (6 of 17). Type B3 thymomas (4 cases) were positive for beta 5t but negative for CD5, c-kit, and glucose transporter 1 (GLUT-1), which are known as diagnostic markers for thymic carcinomas. In contrast, thymic carcinomas were negative for beta 5t (0 of 13) but expressed at least one and usually all of CD5, c-kit, and GLUT-1. Thus, beta 5t and CD5/c-kit/GLUT-1 were differentially expressed in type B3 thymoma and thymic carcinoma. We tested beta 5t expression in 39 cases of tumors arising from other organs, which showed the specific expression of beta 5t in thymic epithelial tumors. This study demonstrates that beta 5t is expressed in most type B and in some type AB thymomas and is a marker useful in differentiating type B3 thymomas from thymic carcinomas when used in combination with other diagnostic markers.
  • Nakano F, Yabe I, Tsuji-Akimoto S, Ishizu A, Tanaka S, Kasahara M, Sasaki H
    Rinsho shinkeigaku = Clinical neurology 51 197 - 202 3 2011年03月 [査読有り][通常論文]
  • Iwasaki S, Masuda S, Baba T, Tomaru U, Katsumata K, Kasahara M, Ishizu A
    Cytometry. Part A : the journal of the International Society for Analytical Cytology 79A 1 46 - 56 1 2011年01月 [査読有り][通常論文]
     
    CD8 alpha beta heterodimers are mainly expressed on cytotoxic T lymphocytes. This study demonstrated the detection of CD8 alpha beta heterodimers on human monocytes by whole blood erythrocyte lysis method in flow cytometry. Results revealed that CD8 alpha beta heterodimers were not produced by monocytes themselves, but were transferred from T cells to monocytes when these cells were coincubated in plasma and with anti-CD8 monoclonal antibody (mAb). For completion of CD8 translocation from T cells to monocytes, cell-to-cell contact between T cells and monocytes, as well as binding of the Fc portion of the anti-CD8 mAb and Fc gamma receptor II (Fc gamma RII) on monocytes were required. Furthermore, the dynamism of cell membrane and cytoskeleton were involved in the mechanism of CD8 translocation. Interestingly, CD3 and alpha beta T cell receptor (TCR) were also transferred from T cells to monocytes accompanied by CD8. These phenomena are consistent with Ab-dependent and Fc gamma R-mediated trogocytosis, which is recently recognized as one of the intercellular communication processes of the immune system. Trogocytosis means exchange of plasma membrane including cell surface molecules in conjugates formed between immune cells. Results of this study could provide another model of trogocytosis and clearly indicated that putative plasma factors were critically implicated in the mechanism of Ab-dependent and Fc gamma R-mediated trogocytosis. (C) 2010 International Society for Advancement of Cytometry
  • Jun Kasamatsu, Yoichi Sutoh, Kazunori Fugo, Noriyuki Otsuka, Kazuya Iwabuchi, Masanori Kasahara
    PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 107 32 14304 - 14308 2010年08月 [査読有り][通常論文]
     
    Jawless vertebrates such as lamprey and hagfish lack T-cell and B-cell receptors; instead, they have unique antigen receptors known as variable lymphocyte receptors (VLRs). VLRs generate diversity by recombining highly diverse leucine-rich repeat modules and are expressed clonally on lymphocyte-like cells (LLCs). Thus far, two types of receptors, VLRA and VLRB, have been identified in lampreys and hagfish. Recent evidence indicates that VLRA and VLRB are expressed on distinct populations of LLCs that resemble T cells and B cells of jawed vertebrates, respectively. Here we identified a third VLR, designated VLRC, in the lamprey. None of the approximate to 100 VLRC cDNA clones subjected to sequencing had an identical sequence, indicating that VLRC can generate sufficient diversity to function as antigen receptors. Notably, the C-terminal cap of VLRC exhibits only limited diversity and has important structural differences relative to VLRA and VLRB. Single-cell PCR analysis identified LLCs that rearranged VLRC but not VLRA or VLRB, suggesting the presence of a unique population of LLCs that express only VLRC.
  • Jun Kasamatsu, Hiroyuki Oshiumi, Misako Matsumoto, Masanori Kasahara, Tsukasa Seya
    DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 34 8 855 - 865 2010年08月 [査読有り][通常論文]
     
    Toll-like receptors (TLRs) have been identified as pivotal sensors recognizing microbial pattern molecules in vertebrates. Whole genome analysis of the teleost Takifugu rubripes supports the existence of a fundamental family of TLR genes in fish. However, the role of the innate immune system in the context of raising acquired immunity in jawless fish remains unclear. In this study, we annotated 16 lamprey TLR genes predicted from the latest genome assembly of lamprey on the basis of homology, and identified their cDNAs from Japanese lamprey, Lethenteron japonicum. Phylogenetic analyses indicated that the repertoire of lamprey TLRs consisted of both fish (F)- and mammalian (M)-type TLRs, and it was also demonstrated that lamprey TLRs are constitutively expressed in various organs. Our results suggest that lampreys protect against microorganisms using the innate system consisting of a similar set of M- and F-type TLRs, despite possessing a unique acquired immune system. In addition, type I interferon (IFN), interferon regulatory factor (IRF)-3, and IRF7 were not identified in the lamprey genome although TLR adaptor and signal transduction genes were highly conserved upstream of (IRF)-3/7 and type I IFN in most vertebrates. This is the first report to describe the TLR repertoire and IFN system in one of the most primitive vertebrates, the lamprey. (C) 2010 Elsevier Ltd. All rights reserved.
  • Mizuho Kondo, Takako Maruoka, Noriyuki Otsuka, Jun Kasamatsu, Kazunori Fugo, Naoto Hanzawa, Masanori Kasahara
    IMMUNOGENETICS 62 7 441 - 450 2010年07月 [査読有り][通常論文]
     
    NKG2D is a major activating receptor of natural killer cells. Its ligands are major histocompatibility complex (MHC) class I-like molecules whose expression is induced by cellular stresses such as infections and tumorigenesis. Humans have two families of NKG2D ligands (NKG2DL): MHC class I-related chains (MIC) encoded in the MHC and UL16-binding proteins (ULBP) encoded outside the MHC. By contrast, mice have only the latter family of ligands; instead, they have non-MHC-encoded MILL molecules that are closely related to MIC, but do not function as NKG2DL. To gain insights into the origin and evolution of MIC, ULBP, and MILL gene families, we conducted comparative genomic analysis of NKG2DL family genes in five mammalian species. In the opossum MHC, we identified a ULBP-like gene adjacent to a previously described MIC-like gene, suggesting that ULBP genes were originally encoded in the MHC. The opossum genome also contained a transcribed MILL-like gene in a region syntenic to the rodent regions encoding MILL molecules. These observations indicate that MIC-, ULBP-, and MILL-like genes emerged before the divergence of placental and marsupial mammals. Comparison of the human, cattle, rat, mouse, and opossum genomes indicates that after emigration from the MHC, ULBP genes underwent extensive duplications in each species. In mice, some of the ULBP genes appear to have been translocated telomerically on the same chromosome, forming a major cluster of existent NKG2DL genes.
  • Kanako Tatsumi, Yu-shin Sou, Norihiro Tada, Eri Nakamura, Shun-ichiro Iemura, Tohru Natsume, Sung Hwan Kang, Chin Ha Chung, Masanori Kasahara, Eiki Kominami, Masayuki Yamamoto, Keiji Tanaka, Masaaki Komatsu
    JOURNAL OF BIOLOGICAL CHEMISTRY 285 8 5417 - 5427 2010年02月 [査読有り][通常論文]
     
    The ubiquitin fold modifier 1 (Ufm1) is the most recently discovered ubiquitin-like modifier whose conjugation (ufmylation) system is conserved in multicellular organisms. Ufm1 is known to covalently attach with cellular protein(s) via a specific E1-activating enzyme (Uba5) and an E2-conjugating enzyme (Ufc1), but its E3-ligating enzyme(s) as well as the target protein(s) remain unknown. Herein, we report both a novel E3 ligase for Ufm1, designated Ufl1, and an Ufm1-specific substrate ligated by Ufl1, C20orf116. Ufm1 was covalently conjugated with C20orf116. Although Ufl1 has no obvious sequence homology to any other known E3s for ubiquitin and ubiquitin-like modifiers, the C20orf116.Ufm1 formation was greatly accelerated by Ufl1. The C20orf116.Ufm1 conjugate was cleaved by Ufm1-specific proteases, implying the reversibility of ufmylation. The conjugation was abundant in the liver and lungs of Ufm1-transgenic mice, fractionated into membrane fraction, and impaired in Uba5 knock-out cells. Intriguingly, immunological analysis revealed localizations of Ufl1 and C20orf116 mainly to the endoplasmic reticulum. Our results provide novel insights into the Ufm1 system involved in cellular regulation of multicellular organisms.
  • Masanori Kasahara
    DEVELOPMENT OF T CELL IMMUNITY 92 7 - 36 2010年 [査読有り][通常論文]
     
    The adaptive immune system (AIS) mediated by T cells and B cells arose, similar to 450 million years ago in a common ancestor of jawed vertebrates. This system was so successful that, once established, it has been maintained in all classes of jawed vertebrates with only minor modifications. One event thought to have contributed to the emergence of this form of MS is two rounds of whole-genome duplication. This event enabled jawed vertebrate ancestors to acquire many paralogous genes, known as ohnologs, with essential roles in T cell and B cell immunity Ohnologs encode the key components of the antigen presentation machinery and signal transduction pathway for lymphocyte activation as well as numerous transcription factors important for lymphocyte development. Recently, it has been discovered that jawless vertebrates have developed an MS employing antigen receptors unrelated to T/B cell receptors, but with marked overall similarities to the MS of jawed vertebrates. Emerging evidence suggests that a common ancestor of all vertebrates was equipped with T-lymphoid and B-lymphoid lineages.
  • Martin F. Flajnik, Masanori Kasahara
    NATURE REVIEWS GENETICS 11 1 47 - 59 2010年01月 [査読有り][通常論文]
     
    The adaptive immune system (AIS) in mammals, which is centred on lymphocytes bearing antigen receptors that are generated by somatic recombination, arose approximately 500 million years ago in jawed fish. This intricate defence system consists of many molecules, mechanisms and tissues that are not present in jawless vertebrates. Two macroevolutionary events are believed to have contributed to the genesis of the AIS: the emergence of the recombination-activating gene (RAG) transposon, and two rounds of whole-genome duplication. It has recently been discovered that a non-RAG-based AIS with similarities to the jawed vertebrate AIS-including two lymphoid cell lineages-arose in jawless fish by convergent evolution. We offer insights into the latest advances in this field and speculate on the selective pressures that led to the emergence and maintenance of the AIS.
  • Kasahara M
    Progress in molecular biology and translational science 92 61; discussion 62 - 4 2010年 [査読有り][通常論文]
  • Naomi Sasaki, Yayoi Ogawa, Chihiro Iinuma, Utano Tomaru, Kazuaki Katsumata, Noriyuki Otsuka, Masanori Kasahara, Takashi Yoshiki, Akihiro Ishizu
    AIDS RESEARCH AND HUMAN RETROVIRUSES 25 9 889 - 896 2009年09月 [査読有り][通常論文]
     
    It has long been discussed whether endogenous retroviruses (ERVs) are involved in the pathogenesis of autoimmune diseases. Among various human endogenous retroviruses (HERVs), we have focused on HERV-R. To investigate the biological roles of HERV-R, we earlier established transgenic rats carrying the full sequence of the viral genome. In these HERV-R rats, however, no disease occurred. Another trigger that induces autoimmunity may be essential for the recognition of HERV-R products by the immune system. Thus, in this study, we mated HERV-R rats with env-pX rats (transgenic rats carrying the env-pX gene of human T cell leukemia virus type I) that develop autoimmune diseases, and generated double transgenic (DTG)rats. In DTG rats, autoimmune diseases occurred similarly in env-pX rats. Interestingly, deposition of rat IgM but not IgG was observed on the glomerular endothelial cells. Such IgM deposition was never seen in the parental HERV-R or env-pX rats. We considered that in situ formation of immune complexes consisted of the HERV-R env glycoprotein and anti-HERV-R env IgM antibodies (Abs) in DTG rats, according to the following evidence: (1) No dense deposit, representing deposition of circulating immune complexes, was seen on glomerular endothelial cells. (2) IgM Abs reactive with HERV-R env glycoprotein were generated in the serum. (3) HERV-R env glycoprotein was expressed in the kidney, specifically on glomerular endothelial cells. (4) IgM deposition was partly colocalized with the HERV-R env glycoprotein on the glomeruli. These findings strongly suggest that the HERV-R env glycoprotein is recognized as an autoantigen in the host with autoimmune diseases.
  • Utano Tomaru, Akihiro Ishizu, Shigeo Murata, Yukiko Miyatake, Sayuri Suzuki, Satomi Takahashi, Taku Kazamaki, Jiro Ohara, Tomohisa Baba, Sari Iwasaki, Kazunori Fugo, Noriyuki Otsuka, Keiji Tanaka, Masanori Kasahara
    BLOOD 113 21 5186 - 5191 2009年05月 [査読有り][通常論文]
     
    The ubiquitin-proteasome pathway, which degrades intracellular proteins, is involved in numerous cellular processes, including the supply of immunocompetent peptides to the antigen presenting machinery. Proteolysis by proteasomes is conducted by three beta subunits, beta 1, beta 2, and beta 5, of the 20S proteasome. Recently, a novel beta subunit expressed exclusively in cortical thymic epithelial cells was discovered in mice. This subunit, designated beta 5t, is a component of the thymoproteasome, a specialized type of proteasomes implicated in thymic positive selection. In this study, we show that, like its mouse counterpart, human beta 5t is expressed exclusively in the thymic cortex. Human beta 5t was expressed in approximately 80% of cortical thymic epithelial cells and some cortical dendritic cells. Human beta 5t was incorporated into proteasomes with two other catalytically active beta subunits beta 1i and beta 2i, forming 20S proteasomes with subunit compositions characteristic of thymoproteasomes. The present study demonstrates, for the first time, the existence of thymoproteasomes in the human thymic cortex, indicating that thymoproteasome function is likely conserved between humans and mice. (Blood. 2009; 113: 5186-5191)
  • [Structure and function of non-classical MHC class I molecules].
    Kajikawa M, Kasahara M
    Seikagaku. The Journal of Japanese Biochemical Society 81 189 - 199 3 2009年03月 [査読有り][通常論文]
  • Masanori Kasahara, Jun Kasamatsu, Yoichi Sutoh
    ZOOLOGICAL SCIENCE 25 10 969 - 975 2008年10月 [査読有り][通常論文]
     
    Extant jawless vertebrates, represented by lampreys and hagfishes, have innate immune receptors with variable domains structurally resembling those of T/B-cell receptors. However, they appear to lack cardinal elements of adaptive immunity shared by all jawed vertebrates: major histocompatibility complex molecules and T/B-cell receptors. Thus, it was widely believed that adaptive immunity is unique to jawed vertebrates. Recently, this belief was overturned by the discovery of agnathan antigen receptors named variable lymphocyte receptors. These receptors generate diversity in their antigen-binding sites through assembling highly diverse leucine-rich repeat modules. The crystal structures of hagfish variable lymphocyte receptor monomers indicate that they adopt a horseshoe-shaped structure and likely bind antigens through the hypervariable concave surface. Secreted variable lymphocyte receptors form pentamers or tetramers of dimers and bind antigens with high specificity and avidity. The fact that variable lymphocyte receptors are structurally unrelated to T/B-cell receptors indicates that jawed and jawless vertebrates have developed antigen receptors independently.
  • Linda Z Holland, Ricard Albalat, Kaoru Azumi, Elia Benito-Gutiérrez, Matthew J Blow, Marianne Bronner-Fraser, Frederic Brunet, Thomas Butts, Simona Candiani, Larry J Dishaw, David E K Ferrier, Jordi Garcia-Fernàndez, Jeremy J Gibson-Brown, Carmela Gissi, Adam Godzik, Finn Hallböök, Dan Hirose, Kazuyoshi Hosomichi, Tetsuro Ikuta, Hidetoshi Inoko, Masanori Kasahara, Jun Kasamatsu, Takeshi Kawashima, Ayuko Kimura, Masaaki Kobayashi, Zbynek Kozmik, Kaoru Kubokawa, Vincent Laudet, Gary W Litman, Alice C McHardy, Daniel Meulemans, Masaru Nonaka, Robert P Olinski, Zeev Pancer, Len A Pennacchio, Mario Pestarino, Jonathan P Rast, Isidore Rigoutsos, Marc Robinson-Rechavi, Graeme Roch, Hidetoshi Saiga, Yasunori Sasakura, Masanobu Satake, Yutaka Satou, Michael Schubert, Nancy Sherwood, Takashi Shiina, Naohito Takatori, Javier Tello, Pavel Vopalensky, Shuichi Wada, Anlong Xu, Yuzhen Ye, Keita Yoshida, Fumiko Yoshizaki, Jr-Kai Yu, Qing Zhang, Christian M Zmasek, Pieter J de Jong, Kazutoyo Osoegawa, Nicholas H Putnam, Daniel S Rokhsar, Noriyuki Satoh, Peter W H Holland
    Genome research 18 7 1100 - 11 2008年07月 [査読有り][通常論文]
     
    Cephalochordates, urochordates, and vertebrates evolved from a common ancestor over 520 million years ago. To improve our understanding of chordate evolution and the origin of vertebrates, we intensively searched for particular genes, gene families, and conserved noncoding elements in the sequenced genome of the cephalochordate Branchiostoma floridae, commonly called amphioxus or lancelets. Special attention was given to homeobox genes, opsin genes, genes involved in neural crest development, nuclear receptor genes, genes encoding components of the endocrine and immune systems, and conserved cis-regulatory enhancers. The amphioxus genome contains a basic set of chordate genes involved in development and cell signaling, including a fifteenth Hox gene. This set includes many genes that were co-opted in vertebrates for new roles in neural crest development and adaptive immunity. However, where amphioxus has a single gene, vertebrates often have two, three, or four paralogs derived from two whole-genome duplication events. In addition, several transcriptional enhancers are conserved between amphioxus and vertebrates--a very wide phylogenetic distance. In contrast, urochordate genomes have lost many genes, including a diversity of homeobox families and genes involved in steroid hormone function. The amphioxus genome also exhibits derived features, including duplications of opsins and genes proposed to function in innate immunity and endocrine systems. Our results indicate that the amphioxus genome is elemental to an understanding of the biology and evolution of nonchordate deuterostomes, invertebrate chordates, and vertebrates.
  • Rat CD4(+)CD8(+) macrophages kill tumor cells through an NKG2D-and granzyme/perforin-dependent mechanism
    Tomohisa Baba, Sari Iwasaki, Takako Maruoka, Akira Suzuki, Utano Tomaru, Hitoshi Ikeda, Takashi Yoshiki, Masanori Kasahara, Akihiro Ishizu
    JOURNAL OF IMMUNOLOGY 180 5 2999 - 3006 2008年03月 [査読有り][通常論文]
     
    We previously identified a subpopulation of monocyte/macrophage lineage cells expressing both CD4 and CD8. This subpopulation was expanded in rat peripheral blood and spleen after immunization with adjuvants containing killed tuberculosis germs. CD4(+)CD8(+) monocytes/macrophages obtained from preimmunized rats exhibited a Th1-type cytokine/chemokine profile, expressed high levels of Fas ligand, perforin, granzyme B, and NKR-P2 (rat ortholog of human NKG2D), and killed certain tumor cells. In the present study, we confirmed that CD4(+)CD8(+) monocytes/macrophages are distinct from splenic dendritic cells (DCs) or IFN-producing killer DCs. In vitro cytotoxic assays revealed that CD4(+)CD8(+) macrophages killed tumor cells in a cell-cell contact-dependent manner and that expression of the retinoic acid early transcript 1 (a ligand for NKG2D) made tumor cells susceptible to killing by CD4(+)CD8(+) macrophages. Furthermore, inhibitors of granzyme and perforin significantly decreased cytotoxic activities of CD4(+)CD8(+) macrophages. Consistent with these in vitro findings, preimmunization with adjuvants containing killed tuberculosis germs elevated the expression of granzyme B in tumor-infiltrating CD4(+)CD8(+) macrophages and significantly inhibited the growth of inoculated tumor cells. Our current work demonstrates that CD4(+)CD8(+) macrophages are a unique subpopulation of monocyte/macrophage lineage cells that kill tumor cells in an NKG2D- and granzyme/perforin-dependent mechanism.
  • Hideki Yashiroda, Tsunehiro Mizushima, Kenta Okamoto, Tomie Kameyama, Hidemi Hayashi, Toshihiko Kishimoto, Shin-ichiro Niwa, Masanori Kasahara, Eiji Kurimoto, Eri Sakata, Kenji Takagi, Atsuo Suzuki, Yuko Hirano, Shigeo Murata, Koichi Kato, Takashi Yamane, Keiji Tanaka
    NATURE STRUCTURAL & MOLECULAR BIOLOGY 15 3 228 - 236 2008年03月 [査読有り][通常論文]
     
    Eukaryotic 20S proteasomes are composed of two alpha-rings and two beta-rings, which form an alpha beta beta alpha stacked structure. Here we describe a proteasome-specific chaperone complex, designated Dmp1-Dmp2, in budding yeast. Dmp1-Dmp2 directly bound to the alpha 5 subunit to facilitate alpha-ring formation. In Delta dmp1 cells, alpha-rings lacking alpha 4 and decreased formation of 20S proteasomes were observed. Dmp1-Dmp2 interacted with proteasome precursors early during proteasome assembly and dissociated from the precursors before the formation of half-proteasomes. Notably, the crystallographic structures of Dmp1 and Dmp2 closely resemble that of PAC3-a mammalian proteasome-assembling chaperone; nonetheless, neither Dmp1 nor Dmp2 showed obvious sequence similarity to PAC3. The structure of the Dmp1-Dmp2-alpha 5 complex reveals how this chaperone functions in proteasome assembly and why it dissociates from proteasome precursors before the b-rings are assembled.
  • Two novel NKG2D ligands of the mouse H60 family with differential expression patterns and binding affinities to NKG2D
    Akio Takada, Shigeru Yoshida, Mizuho Kajikawa, Yukiko Miyatake, Utano Tomaru, Masaharu Sakai, Hitoshi Chiba, Katsumi Maenaka, Daisuke Kohda, Kazunori Fugo, Masanori Kasahara
    JOURNAL OF IMMUNOLOGY 180 3 1678 - 1685 2008年02月 [査読有り][通常論文]
     
    H60, originally described as a dominant minor histocompatibility Ag, is an MHC class I-like molecule that serves as a ligand for the NKG2D receptor. In the present study, we identified two novel mouse chromosome 10-encoded NKG2D ligands structurally resembling H60. These ligands, which we named H60b and H60c, encode MHC class I-like molecules with two extracellular domains. Whereas H60b has a transmembrane region, H60c is a GPI-anchored protein. Recombinant soluble H60b and H60c proteins bound to NKG2D with affinities typical of cell-cell recognition receptors (K(d) = 310 nM for H60b and K(d) = 8.7 mu M for H60c). Furthermore, expression of H60b or H60c rendered Ba/F3 cells susceptible to lysis by NK cells, thereby establishing H60b and H60c as functional ligands for NKG2D. H60b and H60c transcripts were detected only at low levels in tissues of healthy adult mice. Whereas H60b transcripts were detectable in various tissues, H60c transcripts were detected mainly in the skin. Infection of mouse embryonic fibroblasts with murine cytomegalovirus induced expression of H60b, but not H60c or the previously known H60 gene, indicating that transcriptional activation of the three types of H60 genes is differentially regulated. The present study adds two new members to the current list of NKG2D ligands.
  • Rebecca F. Furlong, Ruth Younger, Masanori Kasahara, Richard Reinhardt, Michael Thorndyke, Peter W. H. Holland
    MOLECULAR BIOLOGY AND EVOLUTION 24 12 2681 - 2686 2007年12月 [査読有り][通常論文]
     
    The ParaHox genes consist of 3 homeobox gene families, Gsx, Xlox, and Cdx, all of which have fundamental roles in development. Xlox (known as IPF1 or PDX1 in vertebrates), for example, is crucial for development of the vertebrate pancreas and is also involved in regulation of insulin expression. The invertebrate amphioxus has a gene cluster containing one gene from each of the gene families, whereas in all vertebrates examined to date there are additional copies resultant from ParaHox gene cluster duplications at the base of the vertebrate lineage. Extant vertebrates basal to bony and cartilaginous fish are central to the question of when and how these multiple genes arose in the vertebrate genome. Here, we report the mapping of a ParaHox gene cluster in 2 species of hagfishes. Unexpectedly, these basal vertebrates have lost a functional Xlox gene from this cluster, unlike every other vertebrate examined to date. Furthermore, our phylogenetic analyses suggest that hagfishes may have diverged from the vertebrate lineage before the duplications, which created the multiple ParaHox clusters in jawed vertebrates.
  • Masanori Kasahara
    CURRENT OPINION IN IMMUNOLOGY 19 5 547 - 552 2007年10月 [査読有り][通常論文]
     
    Nearly forty years ago, Susumu Ohno proposed that one or two rounds of whole genome duplication took place close to the origin of vertebrates. The refined version of this proposal, known as the two round (2R) hypothesis, assumes that the genome of jawed vertebrates has been shaped by two rounds of whole genome duplication that took place after the emergence of urochordates and before the radiation of jawed vertebrates. Although this hypothesis has been a focus of heated debate in recent years, it is increasingly supported by genome-wide analysis of key chordate species. The 2R hypothesis has important implications for understanding the evolution of the immune system, including the origin of the major histocompatibility complex and natural killer receptors.
  • Jing Chen, Xudong Zhao, Yurong Lai, Akira Suzuki, Utano Tomaru, Akihiro Ishizu, Akio Takada, Hitoshi Ikeda, Masanori Kasahara, Takashi Yoshiki
    EXPERIMENTAL AND MOLECULAR PATHOLOGY 83 1 125 - 130 2007年08月 [査読有り][通常論文]
     
    Although many human molecules have been suggested to affect replication of human immunodeficiency virus type 1 (HIV-1), the distribution of such cofactors in human cell types is not well understood. Rat W31/D4R4 fibroblasts expressing human CD4 and CXCR4 receptors were infected with HIV-1. The provirus was integrated in the host genome, but only a limited amount of p24 Gag protein was produced in the cells and culture supernatants. Here we found that p24 production was significantly increased by fusing HIV-1-infected W31/D4R4 cells with uninfected human cell lines of T-cell, B-cell, or macrophage lineages. These findings suggest that human cellular factors supporting HIV-1 replication are distributed widely in cells of lymphocyte and macrophage lineages. We also examined whether the amount of p24 produced by rat-human hybrid cells was correlated with expression levels of specific human genes. The results suggested that HP68 and MHC class II transactivator (CIITA) might up- and down-regulate p24 production, respectively. It was also suggested that HIV-1 replication is affected by molecules other than those examined in this study, namely, cyclin T1, cyclin-dependent kinase 9, CRM1, HP68, and CIITA. (c) 2006 Elsevier Inc. All rights reserved.
  • Jun Kasamatsu, Takashi Suzuki, Junko Ishijima, Yoichi Matsuda, Masanori Kasahara
    IMMUNOGENETICS 59 4 329 - 331 2007年04月 [査読有り][通常論文]
     
    Variable lymphocyte receptors (VLR) generate enormous diversity through assembling highly diverse leucine-rich repeat (LRR) modules and presumably function as antigen receptors in jawless vertebrates. The hagfish, which constitute major extant members of jawless vertebrates along with lampreys, have two VLR genes designated VLRA and VLRB, whereas only a single VLR gene has been identified in the lamprey. In the present study, we show by fluorescence in situ hybridization (FISH) that hagfish VLRA and VLRB are located on the same chromosome, but are far apart from each other. Analysis of available inshore hagfish complementary DNA sequences indicates that VLRA and VLRB do not share a LRR module with an identical nucleotide sequence. Physical separation of VLRA and VLRB is consistent with this observation and indicates that the two VLR genes function as separate units. The FISH protocol developed in this study should be useful for the analysis of the agnathan genome.
  • Dolores Busso, Nadia M. Goldweic, Masaru Hayashi, Masanori Kasahara, Patricia S. Cuasnicu
    BIOLOGY OF REPRODUCTION 76 4 701 - 708 2007年04月 [査読有り][通常論文]
     
    CRISP2, originally known as Tpx-1, is a cysteine-rich secretory protein specifically expressed in male haploid germ cells. Although likely to be involved in gamete interaction, evidence for a functional role of CRISP2 in fertilization still remains poor. In the present study, we used a mouse model to examine the subcellular localization of CRISP2 in sperm and its involvement in the different stages of fertilization. Results from indirect immunofluorescence and protein extraction experiments indicated that mouse CRISP2 is an intraacrosomal component that remains associated with sperm after capacitation and the acrosome reaction (AR). In vitro fertilization assays using zona pellucida-intact mouse eggs showed that an antibody against the protein significantly decreased the percentage of penetrated eggs, with a coincident accumulation of perivitelline sperm. The failure to inhibit zona pellucida penetration excludes a detrimental effect of the antibody on sperm motility or the AR, supporting a specific participation of CRISP2 at the sperm-egg fusion step. In agreement with this evidence, recombinant mouse CRISP2 (recCRISP2) specifically bound to the fusogenic area of mouse eggs, as previously reported for rat CRISP1, an epididymal protein involved in gamete fusion. In vitro competition investigations showed that incubation of mouse zona-free eggs with a fixed concentration of recCRISP2 and increasing amounts of rat CRISP1 reduced the binding of recCRISP2 to the egg, suggesting that the proteins interact with common complementary sites on the egg surface. Our findings indicate that testicular CRISP2, as observed for epididymal CRISP1, is involved in sperm-egg fusion through its binding to complementary sites on the egg surface, supporting the idea of functional cooperation between homologous molecules to ensure the success of fertilization.
  • Ho Min Kim, Se Cheol Oh, Ki Jung Lim, Jun Kasamatsu, Jin Young Heo, Beom Seok Park, Hayyoung Lee, Ook Joon Yoo, Masanori Kasahara, Jie-Oh Lee
    JOURNAL OF BIOLOGICAL CHEMISTRY 282 9 6726 - 6732 2007年03月 [査読有り][通常論文]
     
    Variable lymphocyte receptors (VLRs) are recently discovered leucine-rich repeat (LRR) family proteins that mediate adaptive immune responses in jawless fish. Phylogenetically it is the oldest adaptive immune receptor and the first one with a non-immunoglobulin fold. We present the crystal structures of one VLR-A and two VLR-B clones from the inshore hagfish. The hagfish VLRs have the characteristic horseshoe-shaped structure of LRR family proteins. The backbone structures of their LRR modules are highly homologous, and the sequence variation is concentrated on the concave surface of the protein. The conservation of key residues suggests that our structures are likely to represent the LRR structures of the entire repertoire of jawless fish VLRs. The analysis of sequence variability, prediction of protein interaction surfaces, amino acid composition analysis, and structural comparison with other LRR proteins suggest that the hypervariable concave surface is the most probable antigen binding site of the VLR.
  • Yuko Hirano, Hidemi Hayashi, Shun-ichiro Lemura, Klavs B. Hendil, Shin-ichiro Niwa, Toshilhiko Kishimoto, Masanori Kasahara, Tohru Natsume, Keiji Tanaka, Shigeo Murata
    MOLECULAR CELL 24 6 977 - 984 2006年12月 [査読有り][通常論文]
     
    The 20S proteasome is a catalytic core of the 26S proteasome, a central enzyme in the degradation of ubiquitin-conjugated proteins. It is composed of 14 distinct gene products that form four stacked rings of seven subunits each, alpha(1-7)beta(1-7)beta(1-7)alpha(1-7). It is reported that the biogenesis of mammalian 20S proteasomes is assisted by proteasome-specific chaperones, named PAC1, PAC2, and hUmp1, but the details are still unknown. Here, we report the identification of a chaperone, designated PAC3, as a component of alpha rings. Although it can intrinsically bind directly to both alpha and beta subunits, PAC3 dissociates before the formation of half-proteasomes, a process coupled with the recruitment of beta subunits and hUmp1. Knockdown of PAC3 impaired alpha ring formation. Further, PAC1/2/3 triple knockdown resulted in the accumulation of disorganized half-proteasomes that are incompetent for dimerization. Our results describe a cooperative system of multiple chaperones involved in the correct assembly of mammalian 20S proteasomes.
  • MHC class I-like MILL molecules are beta(2)-microglobulin-associated, GPI-anchored glycoproteins that do not require TAP for cell surface expression
    Mizuho Kajikawa, Tomohisa Baba, Utano Tomaru, Yutaka Watanabe, Satoru Koganei, Sachiyo Tsuji-Kawahara, Naoki Matsumoto, Kazuo Yamamoto, Masaaki Miyazawa, Katsumi Maenaka, Akihiro Shizu, Masanori Kasahara
    JOURNAL OF IMMUNOLOGY 177 5 3108 - 3115 2006年09月 [査読有り][通常論文]
     
    MILL (MHC class I-like located near the leukocyte receptor complex) is a family of MHC class I-like molecules encoded outside the MHC, which displays the highest sequence similarity to human MICA/B molecules among known class I molecules. In the present study, we show that the two members of the mouse MILL family, MILL1 and MILL2, are GPI-anchored glycoproteins associated with beta(2)-microglobulin (beta(2)m) and that cell surface expression of MILL1 or MILL2 does not require functional TAP molecules. MILL1 and MILL2 molecules expressed in bacteria could be refolded in the presence of beta(2)m, without adding any peptides. Hence, neither MILL1 nor MILL2 is likely to be involved in the presentation of peptides. Immunohistochemical analysis revealed that MILL1 is expressed in a subpopulation of thymic medullary epithelial cells and a restricted region of inner root sheaths in hair follicles. The present study provides additional evidence that MILL is a class I family distinct from MICA/B.
  • Y Miyatake, H Ikeda, A Ishizu, T Baba, T Ichihashi, A Suzuki, U Tomaru, M Kasahara, T Yoshiki
    AMERICAN JOURNAL OF PATHOLOGY 169 1 189 - 199 2006年07月 [査読有り][通常論文]
     
    Human T-cell leukemia virus type I (HTLV-1) is the causative agent of not only adult T-cell leukemia but also HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Among die rat strains infected with HTLV-1, chronic progressive myelopathy, named HAM rat disease, occurs exclusively in WKAH rats. In the present study, we found that HTLV-1 infection induces interferon (IFN)-gamma production in the spinal cords of HAM-resistant strains but not in those of WKAH rats. Neurons were the major cells that produced IFN-gamma in HTLV-1-infected, HAM-resistant strains. Administration of IFN-gamma suppressed expression of pX, the gene critically involved in the onset of HAM rat disease, in an HTLV-1-immortalized rat T-cell line, indicating that IFN-gamma protects against the development of HAM rat disease. The inability of WKAH spinal cord neurons to produce IFN-gamma after infection appeared to stem from defects in signaling through the interleukin (IL)-12 receptor. Specifically, WKAH-derived spinal cord cells were unable to up-regulate the IL-12 receptor beta 2 gene in response to IL-12 stimulation. We suggest that the failure of spinal cord neurons to produce IFN-gamma through the IL-12 pathway is involved in the development of HAM rat disease.
  • C Haruta, T Suzuki, M Kasahara
    IMMUNOGENETICS 58 2-3 216 - 225 2006年04月 [査読有り][通常論文]
     
    The jawless vertebrates, represented by hagfish and lampreys, are the most advanced animals that apparently lack T cell and B cell receptors. As such, they offer unique opportunities for understanding the evolution of antigen receptors and variable (V)-type immunoglobulin (Ig)-like domains. In the present study, we describe four hagfish Ig superfamily (IgSF) members carrying V-type domains. None of them appeared to have direct counterparts in jawed vertebrates, indicating that many IgSF molecules have either evolved independently in jawed and jawless vertebrates or diverged to the extent that clear homology is no longer recognizable. One of the members encoded a molecule closely related to the previously described membrane protein designated novel ITAM (immunoreceptor tyrosine-based activation motif)-containing IgSF receptors (NICIR). We show here that NICIR is a polymorphic multigene family with at least three members and is expressed predominantly in peripheral blood leukocytes. Phylogenetic analysis indicates that among known proteins, NICIR is most closely related to the lamprey molecule recently proposed to be a potential ancestor of T cell receptors.
  • T Baba, A Ishizu, S Iwasaki, A Suzuki, U Tomaru, H Ikeda, T Yoshiki, M Kasahara
    BLOOD 107 5 2004 - 2012 2006年03月 [査読有り][通常論文]
     
    We found a population of nonlymphoid cells expressing both CD4 and CD8 in peripheral blood mononuclear cells (PBMCs) of human T-cell leukemia virus type-I pX transgenic rats with autoimmune diseases. These cells, which showed a monocytic phenotype, were also found in wild-type rats, and their number increased by adjuvant-assisted immunization. GM-CSF increased the number of these double-positive (DIP) monocytes in PBMCs. Consistent with the idea that DIP monocytes differentiate into DIP macrophages at sites of inflammation, we found infiltration of DIP macrophages at the site of myosin-induced myocarditis in wild-type rats; these cells exhibited a T-helper 1 (Th1)-type cytokine/chemokine profile and expressed high levels of Fas ligand, perforin, granzyme B, and NKR-P2 (rat orthologue of human NKG2D). Adoptive transfer of GFP-positive spleen cells confirmed hematogenous origin of DIP macrophages. DIP monocytes had a cytotoxic phenotype similar to DID macrophages, indicating that this phenotypic specialization occurred before entry into a tissue. In line with this, DIP monocytes killed tumor cells in vitro. Combined evidence indicates that certain inflammatory stimuli that induce GM-CSF trigger the expansion of a population of DIP monocytes with a cytotoxic phenotype and that these cells differentiate into macrophages at inflammatory sites. Interestingly, human PBMCs also contain DIP monocytes.
  • T Maruoka, H Tanabe, M Chiba, M Kasahara
    IMMUNOGENETICS 57 8 590 - 600 2005年09月 [査読有り][通常論文]
     
    Mammals have several major histocompatibility complex (MHC) class-I-like genes. Although some of them are assumed to have originated before the emergence of mammals, the origin of class-I-like genes is poorly understood. We analyzed here the recently released chicken draft genome sequence and identified two families of class-I-like genes: CD1 and PROCR (the gene for the endothelial protein C receptor). Chickens have two CD1 genes, designated CD1.1 and CD1.2, located in tandem similar to 840 bp apart from each other. Chicken CD1.1 and CD1.2 are neither group 1- nor group 2-like, indicating that the two groups of CD1 emerged in a mammalian lineage. Although the database provides no information as to their chromosomal localization, we found that chicken CD1 genes are located adjacent to the previously characterized MHC B system contig on chromosome 16. We confirmed the linkage of CD1 to the B system by dual-color fluorescence in situ hybridization. Chickens have a single copy of PROCR. Among known class-I-like genes, PROCR is most closely related to CD1, indicating that CD1 and PROCR constitute a distinct subfamily of class-I-like genes that predates the emergence of mammals.
  • Z Pancer, NR Saha, J Kasamatsu, T Suzuki, CT Amemiya, M Kasahara, MD Cooper
    PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 102 26 9224 - 9229 2005年06月 [査読有り][通常論文]
     
    A previously uncharacterized type of variable lymphocyte receptors (VLR) was identified recently in the Sea lamprey. This jawless vertebrate generates an extensive VLR repertoire through differential insertion of neighboring diverse leucine-rich repeat (LRR) cassettes into an incomplete germ-line VLR gene. We report here VLR homologs from two additional lamprey species and the presence of two types of VLR genes in hagfish, the only other order of contemporary jawless vertebrates. As in the Sea lamprey, the incomplete hagfish germ-line VLR-A and -B genes are modified in lymphocyte-like cells to generate highly diverse repertoires of VLR-A and -B proteins via a presently undetermined mechanism. This jawless-fish mode of VLR diversification starkly contrasts with the rearrangement of Ig V(D)J gene segments used by all jawed vertebrates to produce diverse repertoires of T and B lymphocyte antigen receptors. The development of two very different strategies for receptor diversification at the dawn of vertebrate evolution approximate to 500 million years ago attests to the fitness value of a lymphocyte-based system of anticipatory immunity.
  • Hagfish leukocytes express a paired receptor family with a variable domain resembling those of antigen receptors
    T Suzuki, T Shin, A Fujiyama, Y Kohara, M Kasahara
    JOURNAL OF IMMUNOLOGY 174 5 2885 - 2891 2005年03月 [査読有り][通常論文]
     
    Jawed vertebrates are equipped with TCR and BCR with the capacity to rearrange their V domains. By contrast, jawless vertebrates, represented by hagfish and lampreys, apparently lack such receptors. We describe in this study a family of hagfish genes carrying a single V-type domain resembling those of TCR/BCR. This multigene family, which we call agnathan paired receptors resembling Ag receptors (APAR), is expressed in leukocytes and predicted to encode a group of membrane glycoproteins with organizations characteristic of paired Ig-like receptors, consisting of activating and inhibitory forms. APAR has a J region in its V-type domain, and its V and J regions are encoded in a single exon. Thus, APAR is a member of the emerging families of diversified, innate immune-type receptors with TCR/BCR-like V-type domains and has many of the features expected for a primordial TCR/BCR-like receptor. The extracellular domain of APAR may be descended from a V-type domain postulated to have acquired recombination signal sequences in a jawed vertebrate lineage.
  • T Suzuki, T Shin-I, Y Kohara, M Kasahara
    DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 28 10 993 - 1003 2004年08月 [査読有り][通常論文]
     
    Jawless fishes occupy a critical phylogenetic position in understanding the origin of the adaptive immune system. Here, we performed large-scale expressed sequence tag analysis of leukocytes isolated I from the inshore hagfish Eptatretus burgeri. Although we found many immunity-related genes such as those involved in lymphocyte or hematopoietic cell signaling and development as well as cytokine and cytokine receptor genes, MHC molecules or antigen receptors were not identified. We characterized two hagfish cDNAs that closely resembled mammalian proteins with essential roles in adaptive immunity, one encoding a GATA3-like molecule and another encoding a Bruton's tyrosine kinase (Btk)-like molecule. The GATA3-like gene of hagfish was equidistant from GATA3 and GATA2 in jawed vertebrates. Similarly, the hagfish Btk-like molecule was not Btk itself, but qualified as a pre-duplicated form of Btk and Bmx in jawed vertebrates. In total, our work provides circumstantial evidence that adaptive immunity is unique to jawed vertebrates. (C) 2004 Elsevier Ltd. All rights reserved.
  • Y Watanabe, T Maruoka, L Walter, M Kasahara
    EUROPEAN JOURNAL OF IMMUNOLOGY 34 6 1597 - 1607 2004年06月 [査読有り][通常論文]
     
    Mill (MHC class I-like located near the leukocyte receptor complex) is a novel family of class I genes identified in mice that is most closely related to the human MICA/B family. In the present study, we isolated Mill cDNA from rats and carried out a comparative genomic analysis. Rats have two Mill genes orthologous to mouse Mill1 and Mill2 near the leukocyte receptor complex, with expression patterns similar to those of their mouse counterparts. Interspecies sequence comparison indicates that Mill is one of the most rapidly evolving class I gene families and that non-synonymous substitutions occur more frequently than synonymous substitutions in its alpha1 domain, implicating the involvement of Mill in immune defenses. Interestingly, the alpha2 domain of rat Mill2 contains a premature stop codon in many inbred strains, indicating that Mill2 is not essential for survival. A computer search of the database identified a horse Mill-like expressed sequence tag, indicating that Mill emerged before the radiation of mammals. Hence, the failure to find Mill in human indicates strongly that it was lost from the human lineage. Our present work provides convincing evidence that Mill is akin to the MICA/B family, yet constitutes a distinct gene family.
  • M Kasahara, T Suzuki, L Du Pasquier
    TRENDS IN IMMUNOLOGY 25 2 105 - 111 2004年02月 [査読有り][通常論文]
     
    When and how adaptive immunity emerged is one of the fundamental questions in immunology. Accumulated evidence suggests that the key components of adaptive immunity, rearranging receptor genes and the MHC, are unique to jawed vertebrates. Recent studies in protochordates, in particular, the draft genome sequence of the ascidian Ciona intestinalis, are providing important clues for understanding the origin of antigen receptors and the MHC. We discuss a group of newly identified protochordate genes along with some cold-blooded vertebrate genes, the ancestors of which might have provided key elements of antigen receptors. The organization of the proto-MHCs in protochordates provides convincing evidence that the MHC regions of jawed vertebrates emerged as a result of two rounds of chromosomal duplication.
  • M Kasahara, Y Watanabe, M Sumasu, T Nagata
    PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 99 21 13687 - 13692 2002年10月 [査読有り][通常論文]
     
    Some members of the major histocompatibility complex (MHC) class I gene family are encoded outside the MHC. Here we describe a family of mouse class I-like genes mapping to the vicinity of the leukocyte receptor complex (LRC) on chromosome 7. This family, which we call Mill (MHC class I-like located near the LRC), has two members designated Mill1 and Mill2. Both genes are predicted to encode membrane glycoproteins with domain organization essentially similar to that of MHC class I heavy chains. The following features of Mill are noteworthy. (i) The deduced MILL proteins lack most of the residues known to be involved in the docking of peptides in classical MHC class I molecules. (it) Among the known members of the class I gene family, MILL1 and MILL2 are related most closely to MICA/MICB encoded in the human MHC. (fit) Unlike all other known members of the class I gene family, Mill1 and Mill2 have an exon between those coding for the signal peptide and the oil domain. (iv) Mill1 has a more restricted expression profile than Mill2. (v) The gene orthologous to Mill1 or Mill2 apparently is absent in the human. (vi) Mill1 and Mill2 show a limited degree of polymorphism in laboratory mice. The observation that the Mill family is related most closely to the MIC family, together with its apparent absence in the human, suggests its involvement in innate immunity.
  • S Murata, H Udono, N Tanahashi, N Hamada, K Watanabe, K Adachi, T Yamano, K Yui, N Kobayashi, M Kasahara, K Tanaka, T Chiba
    EMBO JOURNAL 20 21 5898 - 5907 2001年11月 [査読有り][通常論文]
     
    Two members of the proteasome activator, PA28 alpha and PA28 beta, form a heteropolymer that binds to both ends of the 20S proteasome. Evidence in vitro indicates that this interferon-gamma (IFN-gamma)-inducible heteropolymer is involved in the processing of intracellular antigens, but its functions in vivo remain elusive. To investigate the role of PA28 alpha/beta in vivo, we generated mice deficient in both PA28 alpha and PA28 beta genes. The ATP-dependent proteolytic activities were decreased in PA28 alpha (-/-)/beta (-/-) cells, suggesting that 'hybrid proteasomes' are involved in protein degradation. Treatment of PA28 alpha (-/-)/beta (-/-) cells with IFN-gamma resulted in sufficient induction of the 'immunoproteasome'. Moreover, splenocytes from PA28 alpha (-/-)/beta (-/-) mice displayed no apparent defects in processing of ovalbumin. These results are in marked contrast to the previous finding that immunoproteasome assembly and immune responses were impaired in PA28 beta (-/-) mice. PA28 alpha (-/-)/beta (-/-) mice also showed apparently normal immune responses against infection with influenza A virus. However, they almost completely lost the ability to process a melanoma antigen TRP2-derived peptide. Hence, PA28 alpha/beta is not a prerequisite for antigen presentation in general, but plays an essential role for the processing of certain antigens.
  • Evidence that human epididymal protein ARP plays a role in gamete fusion through complementary sites on the surface of the human egg
    DJ Cohen, DA Ellerman, D Busso, MM Morgenfeld, AD Piazza, M Hayashi, ET Young, M Kasahara, PS Cuasnicu
    BIOLOGY OF REPRODUCTION 65 4 1000 - 1005 2001年10月 [査読有り][通常論文]
     
    Human epididymal sperm protein ARP, a member of the cysteine-rich secretory proteins (CRISP) family, exhibits significant homology with rat epididymal protein DE, a candidate molecule for mediating sperm-egg fusion in rodents. The aim of this study was to investigate the involvement of ARP in human gamete fusion. Sequential extraction of proteins from ejaculated human sperm revealed the existence of a population of ARP that is tightly associated with the sperm surface and thus, potentially capable of participating in gamete interaction. Exposure of capacitated human sperm to a polyclonal antibody against recombinant ARP (anti-ARP) produced a significant and concentration-dependent inhibition in the ability of human sperm to penetrate zona-free hamster eggs. This inhibition was not due to a deleterious effect on the gametes because anti-ARP affected neither sperm viability or motility, nor egg penetrability. The antibody did not inhibit the occurrence of spontaneous or Ca2+ ionophore-induced acrosome reaction, nor did it inhibit the ability of sperm to bind to the oolema, supporting a specific inhibition of the antibody at the sperm-egg fusion level. As a relevant evidence for a role of ARP in gamete fusion, the existence of complementary sites for this protein on the surface of human eggs was investigated. Experiments in which zona-free human oocytes discarded from in vitro fertilization programs were exposed to ARP, fixed, and subjected to indirect immunofluorescence revealed the presence of specific ARP-binding sites on the entire surface of the human egg, in agreement with the fusogenic properties of the human oolema. Together, these results strongly support the participation of ARP in the sperm-egg fusion process, suggesting that this protein would be the functional homologue of DE in humans.
  • MF Flajnik, M Kasahara
    IMMUNITY 15 3 351 - 362 2001年09月 [査読有り][通常論文]
     
    MHC gene organization (size, complexity, gene order) differs markedly among different species, and yet all nonmammalian vertebrates examined to date have a true "class I region" with tight linkage of genes encoding the class I presenting and processing molecules. Three paralogous regions of the human genome contain sets of linked genes homologous to various loci in the MHC class I, class II, and/or class III regions, providing insight into the organization of the "proto MHC" before the emergence of the adaptive immune system in the jawed vertebrates.
  • Yawata M, Murata S, Tanaka K, Ishigatsubo Y, Kasahara M
    Immunogenetics 53 2 119 - 129 2 2001年03月 [査読有り][通常論文]
  • A half-type ABC transporter TAPL is highly conserved between rodent and man, and the human gene is not responsive to interferon-gamma in contrast to TAP1 and TAP2
    A Kobayashi, M Kasano, T Maeda, S Hori, K Motojima, M Suzuki, T Fujiwara, E Takahashi, T Yabe, K Tanaka, M Kasahara, Y Yamaguchi, M Maeda
    JOURNAL OF BIOCHEMISTRY 128 4 711 - 718 2000年10月 [査読有り][通常論文]
     
    TAPL is a half-type ABC transporter with sequence similarity to TAP1 and TAP2 that is transcribed in various rat tissues [Yamaguchi, Y,, Kasano, M., Terada, T., Sate, R., and Maeda, M. (1999) FEES Lett. 457, 231-236]. Primary structures of the human and mouse orthologous counterparts were deduced from cDNAs cloned by means of polymerase chain reaction, and they were compared with that of the rat. The mammalian TAPLs (rat, mouse, and human) are highly conserved, since about 95% of the amino acid residues are identical between rodents and man. Phylogenetic analysis demonstrated that the evolutional rate of TAPL is much slower than those of TAP1 and TAPE, although TAPL could have diverged from an ancestor of TAP1 or that of TAP1 and TAP2. The TAPL-GFP fusion protein transiently expressed in Cos-1 cells was co-localized with PDI, suggesting that TAPL is inserted into endoplasmic reticulum membrane. The conservation of the peptide-binding motifs of TAP proteins in TAPL raises the possibility that the TAPL might be a peptide transporter. The gene for human TAPL is assigned to chromosome 12q24.31-q24.32, while those for TAP1 and TAP2 are located at the MHC locus of chromosome 6p21.3. Furthermore, the transcription of TAPL gene is not responsive to interferon-gamma, in contrast to TAP1 and TAPE. These results indicate that the gene regulation of TAPL is different from those of TAP1 and TAP2.
  • A new perspective on the organization and origin of the major histocompatibility complex
    Curr. Top. Microbiol. Immunol. 248 53 - 66 2000年 [査読無し][通常論文]
  • Genome paralogy: a new perspective on the organization and origin of the major histocompatibility complex.
    Kasahara M
    Current topics in microbiology and immunology 248 53 - 66 2000年 [査読有り][通常論文]
  • Growth retardation in mice lacking the proteasome activator PA28 gamma
    S Murata, H Kawahara, S Tohma, K Yamamoto, M Kasahara, Y Nabeshima, K Tanaka, T Chiba
    JOURNAL OF BIOLOGICAL CHEMISTRY 274 53 38211 - 38215 1999年12月 [査読有り][通常論文]
     
    The proteasome activator PA28 binds to both ends of the central catalytic machine, known as the 20 S proteasome, in opposite orientations to form the enzymatically active proteasome. The PA28 family is composed of three members designated alpha, beta, and gamma; PA28 alpha and PA28 beta form the heteropolymer mainly located in the cytoplasm, whereas PA28 gamma forms a homopolymer that predominantly occurs in the nucleus. Available evidence indicates that the heteropolymer of PA28 alpha and PA28 beta is involved in the processing of intracellular antigens, but the function of PA28 gamma remains elusive. To investigate the role of PA28 gamma in vivo, we generated mice deficient in the PA28 gamma gene. The PA28 gamma-deficient mice were born without appreciable abnormalities in all tissues examined, but their growth after birth was retarded compared with that of PA28 gamma(+/-) or PA28 gamma(+/+) mice. We also investigated the effects of the PA28 gamma deficiency using cultured embryonic fibroblasts; cells lacking PA28 gamma were larger and displayed a lower saturation density than their wild-type counterparts. Neither the expression of PA28 alpha/beta nor the subcellular localization of PA28 alpha was affected in PA28 gamma(-/-) cells. These results indicate that PA28 gamma functions as a regulator of cell proliferation and body growth in mice and suggest that neither PA28 alpha: nor PA28 beta compensates for the PA28 gamma deficiency.
  • S Nishi, N Hoshi, M Kasahara, T Ishibashi, S Fujimoto
    MOLECULAR HUMAN REPRODUCTION 5 6 495 - 497 1999年06月 [査読無し][通常論文]
     
    The human deleted in azoospermia-like autosomal (DAZLA) gene is thought to be a candidate gene for azoospermia. cDNA encoding the C-terminal 94 amino acid residues of human DAZLA was used to express a bacterial fusion protein which was then used to raise polyclonal antibodies in rabbits. Immunohistochemical analyses with the human DAZLA antiserum showed that the DAZLA protein is expressed at a cytoplasmic location in female germ cells. Available evidence suggests that the DAZLA gene is a participant in human oogenesis.
  • The chromosomal duplication model of the major histocompatibility complex
    M Kasahara
    IMMUNOLOGICAL REVIEWS 167 17 - 32 1999年02月 [査読無し][通常論文]
     
    The major histocompatibility complex (MHC) is a genetic region that has been extensively studied by immunologists, molecular biologists, and evolutionary biologists. Nevertheless, our knowledge of how the MHC acquired its present-day organization is quite Limited. The recent discovery that the mammalian genome contains regions paralogous to the MHC has led us to the proposal that the MHC region of jawed vertebrates arose as a result of ancient chromosomal duplications. Here, I review the current status of this proposal.
  • The MHC class I ligand-generating system: roles of immunoproteasomes and the interferon-gamma-inducible proteasome activator PA28
    K Tanaka, M Kasahara
    IMMUNOLOGICAL REVIEWS 163 161 - 176 1998年06月 [査読有り][通常論文]
     
    Production of antigenic peptides that serve as MHC class I ligands is essential for initiation of cell-mediated immunity Accumulating evidence indicates that the proteasome, a large multisubunit protein degradative machine in eukaryotes, functions as a processing enzyme responsible for the generation of MHC class I ligands. This processing system is elaborately regulated by various immunomodulatory cytokines. In particular, interferon-gamma induces the formation of immunoproteasomes and a recently identified proteasomal regulatory factor, PA28, which in concert contribute to efficient production of MHC class I ligands. Many of the MHC-encoded genes including LMP appear to have emerged by an ancient chromosomal duplication, suggesting that modifications and renewal of pre-existing non-immune genes were instrumental in the emergence of adaptive immunity.
  • E Seboun, S Barbaux, T Bourgeron, S Nishi, A Algonik, M Egashira, N Nikkawa, C Bishop, M Fellous, K McElreavey, M Kasahara
    GENOMICS 41 2 227 - 235 1997年04月 [査読無し][通常論文]
     
    We have isolated the human homologue of the mouse germ cell-specific transcript Tpx2, which we had previously mapped to mouse chromosome 17. Sequence analysis shows that the human gene is part of the DAZ (Deleted in Azoospermia) family, represents the human homologue of the mouse Dazla and Drosophila boule genes, and is termed DAZLA. Like Dazla and boule, DAZLA is single copy and maps to 3p25. This defines a new region of synteny between mouse chromosome 17 and human chromosome 3. Unlike DAZ, which has multiple DAZ repeats, DAZLA encodes a putative RNA-binding protein with a single RNA-binding motif and a single DAZ repeat. DAZLA is more closely related to Dazla in the mouse than to the Y-linked homologue DAZ (88% identity overall with mouse Dazla compared to 76% identity with the human DAZ protein sequence). Southern blot analysis showed that DAZLA is autosomal in all mammals tested and that DAZ has been recently translocated to the Y chromosome, sometime after the divergence of Old World and New World primates. To investigate the evolutionary relatedness of DAZLA and DAZ further, their partial genomic structures were obtained and compared. This revealed that the genomic organization of both genes in the 5' region is highly conserved. DAZLA is a new member of the DAZ family of genes, which is associated with spermatogenesis and male sterility. Familial cases of male infertility in humans show an autosomal recessive mode of inheritance. It is possible that some of these families may carry mutations in the DAZLA gene. (C) 1997 Academic Press.
  • M Kasahara, J Nakaya, Y Satta, N Takahata
    TRENDS IN GENETICS 13 3 90 - 92 1997年03月 [査読無し][通常論文]
  • M Kasahara, E Kandil, L SalterCid, MF Flajnik
    RESEARCH IN IMMUNOLOGY 147 5 278 - 284 1996年06月 [査読無し][通常論文]
  • H Inoko, N MIzuki, T Shiina, A Ando, M Kimura, YY Kikuchi, H Kawata, K Sugaya, T Fukagawa, K Matsumoto, T Nagata, M Taketo, K Okumura, M Kasahara, T Ikemura
    DNA SEQUENCE 7 1 31 - 32 1996年 [査読有り][通常論文]
  • ISOLATION OF THE XENOPUS COMPLEMENT FACTOR-B COMPLEMENTARY-DNA AND LINKAGE OF THE GENE TO THE FROG MHC
    Y KATO, L SALTERCID, MF FLAJNIK, M KASAHARA, C NAMIKAWA, M SASAKI, M NONAKA
    JOURNAL OF IMMUNOLOGY 153 10 4546 - 4554 1994年11月 [査読無し][通常論文]
     
    C factor B (Bf) is the key component of the C3 convertase of the alternative C pathway, and its gene resides in the class III region of the mammalian MHC. To elucidate the evolution of both the C system and the MHC, we isolated Bf cDNA clones from Xenopus laevis, an ectothermic vertebrate in which the MHC has been well defined at both the biochemical and functional levels. A part of the serine protease domain of the Xenopus Bf mRNA was amplified by reverse transcriptase-PCR, using degenerate primers corresponding to regions encoding the perfectly conserved amino acid sequences found in both the mouse Bf and C2 proteins. A full length Xenopus Bf cDNA clone was isolated from a Xenopus liver cDNA library. The deduced amino acid sequence of 747 residues showed the same domain structure as mammalian Bf and C2: three short consensus repeat domains, a von Willebrand domain and a serine protease domain. Xenopus Bf has 40% and 30% overall amino acid identity to mouse Bf and mouse C2, respectively. Because the amino acid identity between mouse Bf and mouse C2 is 38%, the gene duplication of Bf/C2 probably occurred before the divergence of amphibians and mammals. Southern blotting analysis of the Xenopus Bf gene showed a close linkage to the MHC, indicating that the Bf gene was linked to the class I and class II genes at the time Xenopus shared a common ancestor with mouse and man, 350 X 10(6) yr ago.
  • A novel type of class I gene organization in vertebrates : A large family of non-MHC-linked class I genes is expressed at the RNA level in the amphibian Xenopus.
    EMBOJ. 12,4385-4396 1993年 [査読無し][通常論文]
  • POLYMORPHISM OF UNIQUE NONCODING DNA-SEQUENCES IN WILD AND LABORATORY MICE
    F FIGUEROA, M KASAHARA, H TICHY, E NEUFELD, U RITTE, J KLEIN
    GENETICS 117 1 101 - 108 1987年09月 [査読無し][通常論文]
  • Polymorphism of unique noncoding DNA sequences in wild and laboratoty mice.
    Genetics 117 1987年 [査読無し][通常論文]
  • Proc. Natl. Acad. Sci. U. S. A 84 1987年 [査読無し][通常論文]

書籍

作品等

  • MHC-peptide interaction
    1996年 -2001年

その他活動・業績

  • 梶川瑞穂, 笠原正典 医学のあゆみ 265 (4) 253‐258 2018年04月28日 [査読無し][通常論文]
  • ヒトHER2陰性luminalタイプ乳癌におけるNKG2Dリガンドの発現解析
    畑中 豊, 鈴木 雄太, 藤田 裕美, 畑中 佳奈子, 大庭 幸治, 三橋 智子, 山下 啓子, 笠原 正典, 松野 吉宏 日本病理学会会誌 102 (1) 333 -333 2013年04月 [査読無し][通常論文]
  • 吉田 繁, MOHAMED Rania Hassan, 梶川 瑞穂, 小泉 潤, 田中 みなみ, 冨居 一範, 大塚 紀幸, 前仲 勝美, 八木田 秀雄, 千葉 仁志, 笠原 正典 北海道醫學雜誌 = Acta medica Hokkaidonensia 87 (6) 2012年11月01日 [査読無し][通常論文]
  • 神田諒, 須藤洋一, 笠松純, 笠原正典, 前仲勝実, 尾瀬農之 日本蛋白質科学会年会プログラム・要旨集 12th 117 2012年05月31日 [査読無し][通常論文]
  • 藤田裕美, 畑中豊, 鈴木雄太, 久保田佳奈子, 大庭幸治, 三橋智子, 笠原正典, 松野吉宏 日本病理学会会誌 101 (1) 409 -409 2012年03月26日 [査読無し][通常論文]
  • Predictors of new-onset of chronic kidney disease in Japanese population
    Yasuno S, Ueshima K, Oba K, Nakao YM, Tanaka S, Kasahara M, Fujimoto A, Miyawaki T, Masuda I, Nakao K Kyoto surveillance: EuroPRevent 2012, Dublin, Ireland, 2012 2012年 [査読有り][通常論文]
  • NKG2Dリガンドの創傷治癒における役割の解析
    笠原 正典, Mohamed Rania, 小泉 潤, 富居 一範, 大塚 紀幸, 吉田 繁 MHC: Major Histocompatibility Complex 18 (2) 153 -153 2011年08月 [査読無し][通常論文]
  • 体表組織におけるナチュラルキラー細胞活性化リガンドH60cの役割
    吉田 繁, 小泉 潤, 富居 一範, 近藤 瑞穂, 大塚 紀幸, 笠原 正典 日本病理学会会誌 100 (1) 366 -366 2011年03月 [査読無し][通常論文]
  • 神田諒, 須藤洋一, 笠松純, 笠原正典, 前仲勝実, 尾瀬農之 日本結晶学会年会講演要旨集 2011 90 2011年 [査読無し][通常論文]
  • 粘膜免疫におけるナチュラルキラー細胞活性化リガンドH60cの役割
    吉田 繁, 富居 一範, 近藤 瑞穂, 大塚 紀幸, 笠原 正典 日本病理学会会誌 99 (1) 272 -272 2010年03月 [査読無し][通常論文]
  • 吉田繁, 富居一範, 梶川瑞穂, 近藤瑞穂, 大塚紀幸, 前仲勝実, 笠原正典 MHC 16 (2) 178 -178 2009年08月25日 [査読無し][通常論文]
  • 梶川瑞穂, 笠原正典 生化学 81 (3) 189 -199 2009年03月25日 [査読無し][通常論文]
  • 吉田繁, 富居一範, 梶川瑞穂, 笠松純, 皿田雄二, 大塚紀幸, 笠原正典 日本病理学会会誌 98 (1) 366 2009年03月20日 [査読無し][通常論文]
  • 笠松純, 須藤洋一, 笠原正典 日本免疫学会総会・学術集会記録 38 67 2008年11月05日 [査読無し][通常論文]
  • 梶川瑞穂, 尾瀬農之, 笠原正典, 前仲勝実 生化学 81回・31回 2T20-1 -1 2008年11月 [査読無し][通常論文]
  • 新規NKG2DリガンドH60b、H60cの機能解析(Functional analysis of novel members of NKG2D ligand, H60b and H60c)
    富居 一範, 吉田 繁, 大塚 紀幸, 外丸 詩野, 笠原 正典 日本癌学会総会記事 67回 443 -444 2008年09月 [査読無し][通常論文]
  • NKG2DリガンドH60b、H60cの機能解析
    吉田 繁, 富居 一範, 大塚 紀幸, 外丸 詩野, 笠原 正典 日本病理学会会誌 97 (1) 203 -203 2008年03月 [査読無し][通常論文]
  • マウスH60ファミリーの異なる発現パターンとNKG2Dへの結合親和性を持つ二つの新しいNKG2Dリガンド(Two Novel NKG2D Ligands of the Mouse H60 Family with Differential Expression Patterns and Binding Affinities to NKG2D)
    吉田 繁, 高田 明生, 富居 一範, 宮武 由甲子, 外丸 詩野, 笠原 正典 日本癌学会総会記事 66回 41 -41 2007年08月 [査読無し][通常論文]
  • 新しいマウスNKG2Dリガンドの同定と解析
    吉田 繁, 富居 一範, 高田 明生, 宮武 由甲子, 鈴木 昭, 石津 明洋, 外丸 詩野, 笠原 正典 日本病理学会会誌 96 (1) 205 -205 2007年02月 [査読無し][通常論文]
  • 生殖細胞特異的に発現する新規MHC class I様分子の解析
    富居 一範, 吉田 繁, 宮武 由甲子, 高田 明生, 鈴木 昭, 石津 明洋, 外丸 詩野, 笠原 正典 日本病理学会会誌 96 (1) 206 -206 2007年02月 [査読無し][通常論文]
  • Micronodular thymoma with lymphoid hyperplasia(MNT)の一例
    古西 崇寛, 山田 綾子, 富居 一範, 鈴木 昭, 外丸 詩野, 石津 明洋, 笠原 正典 日本病理学会会誌 96 (1) 355 -355 2007年02月 [査読無し][通常論文]
  • NK細胞とMHC受容体 新たなマウスNKG2D ligand様分子の同定とその機能に関する解析
    富居 一範, 吉田 繁, 宮武 由甲子, 鈴木 昭, 石津 明洋, 外丸 詩野, 笠原 正典 日本免疫学会総会・学術集会記録 36 253 -253 2006年11月 [査読無し][通常論文]
  • 梶川瑞穂, 笠原正典 Annual Review 免疫 2006 30 -38 2005年12月10日 [査読無し][通常論文]
  • DNAアレイ法を用いた子宮頸癌症例のHPVジェノタイピング
    道又 理恵, 尾川 直樹, 石津 明洋, 渡利 英道, 鈴木 昭, 外丸 詩野, 櫻木 範明, 笠原 正典, 吉木 敬 日本癌学会総会記事 64回 93 -93 2005年09月 [査読無し][通常論文]
  • 笠原正典, 梶川瑞穂, 渡辺豊, 馬場智久 日本病理学会会誌 94 (1) 223 2005年03月18日 [査読無し][通常論文]
  • 笠原正典, 梶川瑞穂, 渡辺豊 日本分子生物学会年会プログラム・講演要旨集 27th 353 2004年11月25日 [査読無し][通常論文]
  • Polyploid origin of the human genome.
    In: D. N. Cooper (ed.): Nature Encyclopedia of the Human Genome, Vol. 4, Nature Publishing Group, Macmillan Publishers Ltd., London 614-618 2003年 [査読無し][通常論文]
  • Polyploid origin of the human genome.
    In: D. N. Cooper(ed. ): Encyclopedia of the Humun Genome, in press, Nature Publishing Group, Macmillan,London 2003年 [査読無し][通常論文]
  • M Kasahara, Y Watanabe, M Sumasu, T Nagata PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 99 (21) 13687 -13692 2002年10月 [査読無し][通常論文]
     
    Some members of the major histocompatibility complex (MHC) class I gene family are encoded outside the MHC. Here we describe a family of mouse class I-like genes mapping to the vicinity of the leukocyte receptor complex (LRC) on chromosome 7. This family, which we call Mill (MHC class I-like located near the LRC), has two members designated Mill1 and Mill2. Both genes are predicted to encode membrane glycoproteins with domain organization essentially similar to that of MHC class I heavy chains. The following features of Mill are noteworthy. (i) The deduced MILL proteins lack most of the residues known to be involved in the docking of peptides in classical MHC class I molecules. (it) Among the known members of the class I gene family, MILL1 and MILL2 are related most closely to MICA/MICB encoded in the human MHC. (fit) Unlike all other known members of the class I gene family, Mill1 and Mill2 have an exon between those coding for the signal peptide and the oil domain. (iv) Mill1 has a more restricted expression profile than Mill2. (v) The gene orthologous to Mill1 or Mill2 apparently is absent in the human. (vi) Mill1 and Mill2 show a limited degree of polymorphism in laboratory mice. The observation that the Mill family is related most closely to the MIC family, together with its apparent absence in the human, suggests its involvement in innate immunity.
  • Dev. Comp. Immunol. 26 (735-750) 2002年 [査読無し][通常論文]
  • Comparative genomics of the major histocompatibility complex : Glimpses into the evolution of the adaptive immune system.(共著)
    Immunity 15 (351-362) 2001年 [査読無し][通常論文]
  • Evidence that human epididymal protein ARP plays a role in gamete fusion through complementary sites on the surface of the human egg.(共著)
    Biol. Reprod. 65 (1000-1005) 2001年 [査読無し][通常論文]
  • A half-type ABC transporter TAPL is highly conserved between rodent and man, and the human gene is not responsive to interferon-γ in contrast to TAP1 and TAP2.(共著)
    J. Biochem. 128 711 -718 2000年 [査読無し][通常論文]
  • The MHC paralogous group : Listing of members and a brief overview. PP. in : Major Histocompatibility Complex : Evolution, Structure, and Function
    Springer-Verlagt Tokyo-Berlin-Heidelberg-New York 27-44 2000年 [査読無し][通常論文]
  • Major Histocompatibility Complex : Evolution, Structure, and Function
    Springer-Verlag, Tokyo-Berlin-Heidelberg-New York 2000年 [査読無し][通常論文]
  • Genome dynamics of the major histocompatibility complex: insights from genome paralogy
    M Kasahara IMMUNOGENETICS 50 (3-4) 134 -145 1999年11月 [査読無し][通常論文]
     
    It has recently become apparent that the human genome contains at least three regions that are paralogous to the major histocompatibility complex (MHC). The number of gene families with copies in the MHC and these paralogous regions is increasing steadily as genome analysis progresses. This review presents the updated listing of the human gene families that constitute the MHC paralogous group. When genes with multiple copies within the MHC, such as class I and class II genes, are counted as single entities, nearly one-third of the genes residing in the HLA complex have paralogous copies in at least one of the three paralogous regions. The review also discusses the long-term genome dynamics of the MHC, taking into account the rapidly accumulating information on the genomic organizations of the MHCs in various model organisms.
  • Two ancient allelic lineages at the single classical class I locus in the Xenopus MHC
    MF Flajnik, Y Ohta, AS Greenberg, L Salter-Cid, A Carrizosa, L Du Pasquier, M Kasahara JOURNAL OF IMMUNOLOGY 163 (7) 3826 -3833 1999年10月 [査読無し][通常論文]
     
    Unlike all other vertebrates examined to date, there is only one detectable class I locus in the Xenopus MWC. On the bases of a nearly ubiquitous and high tissue expression, extensive polymorphism and MHC linkage, this gene is of the classical or class Ia type. Sequencing analysis of class Ia cDNAs encoded by eight defined MHC haplotypes reveals two very old allelic lineages that perhaps emerged when humans and mice diverged from a common ancestor up to 100 million years ago. The unprecedented age of these lineages suggests that different class Ia genes from ancestors of the laboratory model Xenopus laevis are now expressed as alleles in this species. The lineages are best defined by their cytoplasmic and alpha 2 peptide-binding domains, and there are highly diverse alleles (defined by the al peptide-binding domain) in each lineage. Surprisingly, the alpha 3 domains are homogenized in both lineages, suggesting that interallelic gene conversion/recombination maintains the high sequence similarity.
  • J. Biol. Chem. 274 38211 -38215 1999年 [査読無し][通常論文]
  • Proteasomes and antigen presentation : biochemisty and genetics
    Recent Res. Dev. Immunol. 1 321 -337 1999年 [査読無し][通常論文]
  • Molecular biology of sperm maturation - New strategies for male contraception.
    Male Contraception : Present and Future, WHO, Geneva 103-123 1999年 [査読無し][通常論文]
  • M Kasahara IMMUNOLOGICAL REVIEWS 166 159 -175 1998年12月 [査読無し][通常論文]
     
    During the last decade, our understanding of the immune system of ectothermic vertebrates has advanced significantly It is now clear that all jawed vertebrates are equipped with the adaptive immune system characterized by the MHC molecules and the rearranging receptors. In contrast, there is no molecular evidence that suggests the existence of adaptive immunity in jawless vertebrates. How did the adaptive immune system emerge? Our recent work suggests that one of die driving forces that enabled the emergence of the adaptive immune system was one or more genome-nide or large-scale chromosomal duplications presumed to have taken place in a common ancestor of jawed vertebrates.
  • Y Suto, Y Ishikawa, M Kasahara, F Kasai, T Yabe, T Akaza, T Juji IMMUNOGENETICS 48 (4) 235 -241 1998年09月 [査読無し][通常論文]
     
    Human chromosome 19q13.4 has recently been revealed to be a remarkable region harboring multiple receptor genes of the immunoglobulin (Ig) superfamily differentially expressed on hematopoietic cell lineages. Over the past few years, more than 50 cDNAs have been cloned for the natural killer cell inhibitory receptor (KIR) gene family, which possess two or three Ig-like domains in the extracellular region. In this study, using two genomic DNA probes containing intron sequences of genes corresponding to the two- and three-domain types, we applied two-color-fluorescence in situ hybridization on stretched DNA fiber preparations (fiber-FISH). As a result, 11 positions homologous to KIR genes were found as a cluster within a range of approximately 120 kilobases on a chromatin fiber from human chromosome 19.
  • Characterization of the mouse PA28 activator complex gene family: Complete organizations of the three member genes and a physical map of the similar to 150-kb region containing the alpha- and beta-subunit genes
    K Kohda, T Ishibashi, N Shimbara, K Tanaka, Y Matsuda, M Kasahara JOURNAL OF IMMUNOLOGY 160 (10) 4923 -4935 1998年05月 [査読無し][通常論文]
     
    The proteasome is a multisubunit protease responsible for the generation of peptides loaded onto MHC class I molecules. Recent evidence indicates that binding of an IFN-gamma-inducible PA28 activator complex to the 20S proteasome enhances the generation of class I binding peptides, The alpha- and beta-subunits, which constitute the PA28 activator complex in the form of an (alpha beta)(3) heterohexamer, show significant amino acid sequence similarity to a protein, designated Ki or the gamma-subunit, that is capable of binding to the 20S proteasome, In this study, we describe the complete nucleotide sequences of the mouse genes, Psme1, Psme2, and Psme3, coding for the alpha-, beta-, and gamma-subunits, respectively. The overall exon-intron organizations of the three Psme genes are virtually identical, thus providing evidence that they are descended from a single ancestral gene. The promoter regions of the Psme1 and Psme2 genes contain sequence moths that qualify as IFN-stimulated response elements, consistent with the observation that their expression is induced strongly by IFN-gamma. The Psme1 and Psme2 genes are located similar to 6 kb apart with their 3'-ends pointing toward each other on bands C2 to D1 of mouse chromosome 14, supporting the idea that they emerged by tandem duplication.
  • K Kohda, Y Matsuda, T Ishibashi, K Tanaka, M Kasahara IMMUNOGENETICS 47 (1) 77 -87 1997年12月 [査読無し][通常論文]
     
    The proteasome is a multi-subunit protease responsible for the production of peptides presented by major histocompatibility complex class I molecules. Accumulated evidence indicates that, upon stimulation with interferon-gamma (IFN-gamma), three beta-type subunits, designated LMP2, LMP7, and PSMB10, are incorporated into the 20S proteasome by displacing the housekeeping beta-type subunits designated pSMB6, PSMB5, and PSMB7, respectively. These changes in the subunit composition appear to facilitate class I-mediated antigen presentation, presumably by altering the cleavage specificities of the proteasome. In the present study, we determined the organization of the mouse gene Psmb5, coding for the PSMB5 subunit. Psmb5 is made up of three exons, spanning similar to 5 kilobases. Its exon-intron organization differs radically from those of the other IFN-gamma-regulated. beta-type subunit genes including Lmp7 with which Psmb5 is believed to share an immediate common ancestor. The structure of the mouse Psmb5 gene is identical to that of its recently characterized human counterpart. Thus, the unique organization of the gene coding for the PSMB5 subunit appears to have been established before mammalian radiation. As well as the Psmb5 gene, the mouse genome contains a processed pseudogene designated Psmb5-ps. Interspecific backcross mapping showed that Psmb5 maps close to the Gtrgal2 locus on chromosome 14 and that Psmb5-ps is located in the vicinity of the Psme3 locus on chromosome 11. These results were confirmed by fluorescent in situ hybridization analysis that localized Psmb5 to band C2 to proximal D1 of chromosome 14 and Psmb5-ps to band D of chromosome 11.
  • The mouse genes encoding the third pair of beta-type proteasome subunits regulated reciprocally by IFN-gamma - Structural comparison, chromosomal localization, and analysis of the promoter
    M Hayashi, T Ishibashi, K Tanaka, M Kasahara JOURNAL OF IMMUNOLOGY 159 (6) 2760 -2770 1997年09月 [査読無し][通常論文]
     
    Proteasomes are the multisubunit protease involved in the generation of peptides presented by MHC class I molecules. When cells are stimulated with IFN-gamma, two MHC-encoded subunits, low M-r polypeptide 2 (LMP2) and LMP7, are incorporated into the proteasomal complex by displacing the housekeeping subunits, designated Y and X, respectively. Recent evidence indicates that besides the LMP2/Y and LMP7/X subunits, there is another pair of structurally similar beta-type subunits, designated MECL1 and Z, whose expression is regulated reciprocally by IFN-gamma. In the present study we determined the genomic organizations of the mouse genes, Psmb10 and Psmb7, that encode the MECL1 and Z subunits, respectively. Although the two genes differ >10-fold in size, they both have eight exons, with the exon-intron boundaries located precisely at the equivalent positions. The organization of the Psmb10 and Psmb7 genes differs from those of the genes encoding the other two pairs of IFN-gamma-regulated subunits. Thus, comparison of the gene structures supports the idea that Psmb10 and Psmb7 arose by duplication from an immediate common ancestor. The promoter region of the Psmb10 gene contains two IFN-stimulated response elements, the functionality of which was confirmed by in vitro mutagenesis. The mouse Psmb10 gene maps to chromosome 8, thus outside the MHC like its human counterpart. Besides the Psmb7 gene previously mapped to chromosome 2, a truncated processed pseudogene, designated Psmb7-ps, was identified and mapped to chromosome X.
  • E Kandil, K Kohda, T Ishibashi, K Tanaka, M Kasahara IMMUNOGENETICS 46 (4) 337 -344 1997年08月 [査読無し][通常論文]
     
    The 20S proteasome is a multi-subunit protease responsible for the production of peptides presented by major histocompatibility complex (MHC) class I molecules. Recent evidence indicates that an interferon-gamma (IFN-gamma)-inducible PA28 activator complex enhances the generation of class I binding peptides by altering the cleavage pattern of the proteasome. In the present study, we determined the primary structures of the mouse PA28 alpha- and beta-subunits. The deduced amino acid sequences of the alpha- and beta-subunits were 49% identical. We also determined the primary structure of the mouse PA28 gamma-subunit (Ki antigen), a protein of unknown function structurally related to the alpha- and beta-subunits. The amino acid sequence identity of the gamma-subunit to the alpha- and beta-subunits was 40% and 32%, respectively. Interspecific backcross mapping showed that the mouse genes coding for the alpha- and beta-subunits (designated Pslne1 and Psme2, respectively) are tightly linked and map close to the Atp5g1 locus on chromosome 14. Thus, unlike the LMP2 and LMP7 subunits, the IFN-gamma-inducible subunits of PA28 are encoded outside the MHC. The gene coding for the gamma-subunit (designated Psme3) was mapped to the vicinity of the Brca1 locus on chromosome 11. A computer search of the DNA databases identified a gamma-subunit-like protein in ticks and Caenorhabditis elegans, the organisms with no adaptive immune system. It appears that the IFN-gamma-inducible alpha- and beta-subunits emerged by gene duplication from a gamma-subunit-like precursor.
  • New insights into the genomic organization and origin of the major histocompatibility complex: Role of chromosomal (genome) duplication in the emergence of the adaptive immune system
    M Kasahara HEREDITAS 127 (1-2) 59 -65 1997年 [査読無し][通常論文]
     
    Recently, it became clear that the human and mouse genomes contain at least three regions paralogous to the major histocompatibility complex (MHC) region. This observation led us to the proposal that the MHC region emerged as a result of chromosomal duplication that took place at an early stage of vertebrate evolution. Here I briefly review this proposal. Accumulating evidence indicates that (a) genome-wide duplication(s) took place close to the origins of vertebrates. Taking this and others into account, I suggest that the duplication(s) involving the MHC region probably took place as a part of the genome-wide duplication(s). The human T cell receptor (TCR) and immunoglobulin (Ig) genes also appear to be located on paralogous chromosomal segments. These findings raise the possibility that the genome-wide duplication provided a major impetus not only to the emergence of the full-fledged MHC system, but also to the appearance of other key molecules of the adaptive immune system such as TCR and Ig.
  • Isolation of low molecular mass polypeptide complementary DNA clones from primitive vertebrates - Implications for the origin of MHC class I-restricted antigen presentation
    E Kandil, C Namikawa, M Nonaka, AS Greenberg, MF Flajnik, T Ishibashi, M Kasahara JOURNAL OF IMMUNOLOGY 156 (11) 4245 -4253 1996年06月 [査読無し][通常論文]
     
    Proteasomes are the multisubunit proteases thought to be involved in the generation of peptides presented by MHC class I molecules. When cells are stimulated with IFN-gamma, two MHC-encoded subunits, LMP2 and LMP7, are incorporated into the proteasomal complex, presumably by displacing the housekeeping subunits, designated Y and X, respectively, These changes in the subunit composition appear to facilitate class I-mediated Ag presentation, presumably by altering the cleavage specificities of the proteasome, Here we show that the cartilaginous fish, the most primitive class of vertebrates in which the MHC has been identified, have both LMP7 and X genes, Interestingly, nurse sharks, a member of the cartilaginous fish, appear to have two LMP7 genes, one encoding a typical LMP7 subunit and the other encoding a less typical one. In contrast, only cDNA clones with residues characteristic of X were identified in hagfishes and lampreys, the two extant members of the jawless fish in which no MHC has been identified, Pairwise amino acid sequence comparison and phylogenetic tree analysis showed that the subunits encoded by these clones were nearly equidistant from LMP7 and X, suggesting that the LMP7 gene might have emerged after the appearance of the jawless fish. Sequence comparison of the LMP7 and X/X-like subunits isolated from various vertebrate species showed that, unlike the X/X-like subunit, the LMP7 subunit displays a striking interspecies sequence variability in the vicinity of its catalytic site.
  • M Hayashi, S Fujimoto, H Takano, T Ushiki, K Abe, H Ishikura, MC Yoshida, C Kirchhoff, T Ishibashi, M Kasahara GENOMICS 32 (3) 367 -374 1996年03月 [査読無し][通常論文]
     
    Acidic epididymal glycoprotein (AEG), thus far identified only in rodents, is one of the sperm surface proteins involved in the fusion of the sperm and egg plasma membranes. In the present study, we describe the isolation and characterization of cDNA encoding a human glycoprotein related to AEG. Although this protein, designated ARP (AEG-related protein), is not the ortholog of rodent AEG, it resembles AEG in that it is an epididymal secretory glycoprotein that binds to the postacrosomal region of the sperm head. The fact that no AEG mRNA can be detected in the human epididymis suggests that ARP might be the functional counterpart of rodent AEG. The gene encoding ARP (AEGL1) was mapped by fluorescence in situ hybridization to 6p21.1-p21.2. This result indicates that AEGL1 and the mouse gene for AEG are located in the chromosomal segments with conserved syntenies. (C) 1996 Academic Press, Inc.
  • Origin and evolution of the class I gene family : Why are some of the mammalian class I genes encoded outside the major histocompatibility complex? Rebuttal to the commentary by Drs. Ahouse and Simister.
    Res. Immunol. 147 353 1996年 [査読無し][通常論文]
  • The human gene encoding the heavy chain of the major histocompatibility complex class I-like Fc receptor (FCGRT) maps to 19q13.3
    E Kandil, M Egashira, O Miyosi, N Niikawa, T Ishibashi, M Kasahara CYTOGENETICS AND CELL GENETICS 73 (1-2) 97 -98 1996年 [査読無し][通常論文]
     
    FcRn is an Fc receptor that structurally resembles the major histocompatibility complex class I molecule. In this study, we isolated the human gene encoding the heavy chain of FcRn (FCGRT) and mapped it by fluorescence in situ hybridization to chromosome band 19q13.3. Thus, like its mouse counterpart, the human FCGRT gene is located outside the major histocompatibility complex.
  • EXON-INTRON ORGANIZATION OF XENOPUS MHC CLASS-II BETA-CHAIN GENES
    F KOBARI, K SATO, BP SHUM, S TOCHINAI, M KATAGIRI, T ISHIBASHI, L DUPASQUIER, MF FLAJNIK, M KASAHARA IMMUNOGENETICS 42 (5) 376 -385 1995年09月 [査読無し][通常論文]
     
    The amphibian Xenopus laevis is the most primitive vertebrate in which the major histocompatibility complex (MHC) has been defined at the biochemical, functional, and molecular genetic levels. We previously described the isolation and characterization of cDNA clones encoding X. laevis MHC class II beta chains. In the present study, genomic clones encoding class II beta chains were isolated from X. laevis homozygous for the MHC f haplotype, Three class II beta chain genes, designated Xela-DAB, Xela-DBB, and Xela-DCB, were identified. Sequence analysis of these genes showed that Xela-DBB and Xela-DCB correspond to the previously characterized cDNA clones F3 and F8, respectively, whereas Xela-DAB encodes a third, hitherto unidentified class II beta chain of the MHC f haplotype. As a representative of X. laevis class II beta chain genes, the Xela-DAB gene underwent detailed structural analysis. In addition, the nucleotide sequence of Xela-DABf cDNA clones was determined. The Xela-DAB gene is made up of at least six exons, with an exon-intron organization similar to that of a typical mammalian class II beta chain gene. The 5'-flanking region of the Xela-DAB gene contains transcriptional control elements known as X1, X2, and Y, but lacks typical TATA or CCAAT boxes. A notable feature of the X, laevis class II beta chain genes is that the sizes of the introns are larger than those of their mammalian counterparts. As assessed by northern blot analysis, the three class II beta chain genes had similar expression patterns, with the highest level of transcription detected in the intestine. Identification of the Xela-DAB, -DBB, and -DCB genes is consistent with our previous observations, which suggested that the MHC of the tetraploid frog X. laevis is diploidized at the genomic level and contains three class II beta chain genes per haplotype that cross-hybridize to one another under reduced stringency conditions.
  • STRUCTURAL AND PHYLOGENETIC ANALYSIS OF THE MHC CLASS I-LIKE FC RECEPTOR GENE
    E KANDIL, M NOGUCHI, T ISHIBASHI, M KASAHARA JOURNAL OF IMMUNOLOGY 154 (11) 5907 -5918 1995年06月 [査読無し][通常論文]
     
    The intestinal epithelium of neonatal mice and rats expresses an Fc receptor that mediates selective uptake of IgG in mothers' milk. This receptor (FcRn), which helps newborn animals to acquire passive immunity, is an MHC class I-like heterodimer made up of a heavy chain and beta(2)-microglobulin. In the present study, we determined the genomic structure of a mouse gene (Fcm) encoding the heavy chain of FcRn. The overall exon-intron organization of the Fcrn gene was similar to that of the MHC class I gene, thus providing structural evidence that Fcrn is a bona fide class I gene. The 5'-flanking region of the Fcrn gene contained the binding motifs for two cytokine-inducible transcription factors, NF-IL6 and NF1. However, regulatory elements found in MHC class I genes (enhancer A, enhancer B, and the IFN response element) were absent. Phylogenetic tree analysis suggested that, like the MICA, AZGP1, and CD1 genes, the Fcrn gene diverged from MHC class I genes after the emergence of amphibians but before the split of placental and marsupial mammals. Consistent with this result, Southern blot analysis with a mouse Fcrn cDNA probe detected cross-hybridizing bands in various mammalian species and chickens. Sequence analysis of the Fcrn gene isolated from eight mouse strains showed that the membrane-distal domain of FcRn has at least three amino acid variants. The fact that Fcrn is a single copy gene indicates that it is expressed in both the neonatal intestine and the fetal yolk sac.
  • M NOGUCHI, A KITABATAKE, T ISHIBASHI, M KASAHARA IMMUNOGENETICS 42 (1) 72 -74 1995年05月 [査読無し][通常論文]
  • M KASAHARA, M HAYASHI, MC YOSHIDA, JH NADEAU, S FUJIMOTO, T ISHIBASHI MAMMALIAN GENOME 6 (1) 52 -54 1995年01月 [査読無し][通常論文]
  • Evolution of the major histocompatibility complex : A current overview.
    Transplant Immunol. 3 1 -20 1995年 [査読無し][通常論文]
  • HSP70 genes and linked to the Xenopus major histocompatibility complex.
    Immunogenetics 39,1-7 1994年 [査読無し][通常論文]
  • Isolation of classical MHC class I cDNA from an amphibian : Evidence for only one class I locus in the Xenopus MHC.
    J. Immunol. 151,5376-5386 1993年 [査読無し][通常論文]
  • Evolution of the MHC : Isolation of class II β-chain cDNA clones from the amphibian Xenopus laevis.
    J. Immunol 150,2831-2843 1993年 [査読無し][通常論文]
  • M KASAHARA, D KLEIN, VINCEK, V, DE SARAPATA, J KLEIN GENOMICS 14 (2) 340 -349 1992年10月 [査読無し][通常論文]
  • VINCEK, V, D KLEIN, F FIGUEROA, HAUPTFELD, V, M KASAHARA, C OHUIGIN, B MACH, J KLEIN IMMUNOGENETICS 35 (4) 263 -271 1992年03月 [査読無し][通常論文]
     
    The human HLA-DR3 haplotype consists of two functional genes (DRB1*03 and DRB3*01) and one pseudogene (DRB2), arranged in the order DRB1... DRB2...DRB3 on the chromosome. To shed light on the origin of the haplotype, we sequenced 1480 nucleotides of the HLA-DRB2 gene and long stretches of two other genes, Gogo-DRB2 from a gorilla, "Sylvia" and Patr-DRB2 from a chimpanzee, "Hugo". All three sequences (HLA-DRB2, Gogo-DRB2, Patr-DRB2) are pseudogenes. The HLA-DRB2 and Gogo-DRB2 pseudogenes lack exon 2 and contain a twenty-nucleotide deletion in exon 3, which destroys the correct translational reading frame and obliterates the highly conserved cysteine residue at position 173. The Patr-DRB2 pseudogene lacks exons 1 and 2; it does not contain the twenty-nucleotide deletion, but does contain a characteristic duplication of that part of exon 6 which codes for the last four amino acid residues of the cytoplasmic region. When the nucleotide sequences of these three genes are compared to those of all other known DRB genes, the HLA-DRB2 is seen as most closely related to Gogo-DRB2, indicating orthologous relationship between the two sequences. The Patr-DRB2 gene is more distantly related to these two DRB2 genes and whether it is orthologous to them is uncertain. The three genes are in turn most closely related to HLA-DRBVI (the pseudogene of the DR2 haplotype) and Patr-DRB6 (another pseudogene of the Hugo haplotype), followed by HLA-DRB4 (the functional but nonpolymorphic gene of the DR4 halotype). These relationships suggest that these six genes evolved from a common ancestor which existed before the separation of the human, gorilla, and chimpanzee lineages. The DRB2 and DRB6 have apparently been pseudogenes for at least six million years (myr). In the human and the gorilla haplotype, the DRB2 pseudogene is flanked on each side by what appear to be related genes. Apparently, the DR3 haplotype has existed in its present form for more than six myr.
  • 1,25-DIHYDROXYVITAMIN-D3 DOWN-REGULATION OF HLA-DR ON HUMAN PERIPHERAL-BLOOD MONOCYTES
    N TOKUDA, N MIZUKI, M KASAHARA, RB LEVY IMMUNOLOGY 75 (2) 349 -354 1992年02月 [査読無し][通常論文]
     
    The regulatory activity of 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) on human leucocyte antigen (HLA)-DR (MHC class II) antigen expression in monocytes from normal human peripheral blood was examined. Using forward light and side scatter by flow cytometry most cells within the discrete monocyte area expressed high levels of HLA-DR antigens following 4-day culture in medium alone (culture-enhanced HLA-DR) and expression was further up-regulated in the presence of interferon-gamma (IFN-gamma) (IFN-gamma-enhanced HLA-DR). Treatment with 1,25-(OH)2D3 markedly inhibited both culture and IFN-gamma-enhanced HLA-DR but not HLA-ABC (MHC class I). This 1,25-(OH)2D3 inhibition was as effective as PGE2 and hydrocortisone. To ascertain if HLA-DR was specifically down-regulated on monocytes, the effect of vitamin D3 analogues in CD33+ cells was examined. Incubation of the CD33+ cells with 1,25-(OH)2D3, 24-25-(OH)2D3 and 25-OHD3 resulted in dose-dependent inhibition of culture-enhanced HLA-DR parallelling the vitamin D3-receptor affinities of these compounds. Northern analysis also demonstrated that 1,25-(OH)2D3 treatment markedly decreased both expression of culture-enhanced and IFN-gamma-enhanced HLA-DR-beta chain messanger RNA (mRNA) in monocyte-enriched populations. In total, our findings are consistent with the proposal that vitamin D3 analogues can contribute to down-regulating immune responses as a consequence of inhibiting class II expression.
  • Mol.Immunol. 29 (9) 1157 -1158 1992年 [査読無し][通常論文]
  • Mouse submandibular glands express an androgen-regulated gene encoding an acidic epididymal glycoproteinlike molecule.
    Mol. Cell. Endocrinol. 89 25 -32 1992年 [査読無し][通常論文]
  • The mouse male germ cell-specific gene Tpx-1 : Molecular structure, mode of expression in spermatogenesis, and dsequence similarity to two non-mammalian genes.
    Mammalian Genome 3 1992年 [査読無し][通常論文]
  • GORILLA MAJOR HISTOCOMPATIBILITY COMPLEX-DRB PSEUDOGENE ORTHOLOGOUS TO HLA-DRBVIII
    D KLEIN, VINCEK, V, M KASAHARA, C SCHONBACH, C OHUIGIN, J KLEIN HUMAN IMMUNOLOGY 32 (3) 211 -220 1991年11月 [査読無し][通常論文]
     
    The HLA-DR4 haplotype consists of four DRB genes: DRB1*04, DRBVII, DRBVIII, and DRB4*01, arranged in this order on the chromosome. The DRB1 and DRB4 genes code for beta-chains of the alpha-beta heterodimers expressed on the cell surface and bearing the HLA-DR4 and HLA-DRw53 determinants, respectively; the DRBVII and DRBVIII are pseudogenes. We found and sequenced a gene closely related to HLA-DRBVIII in the genome of the lowland gorilla "Sylvia." We designate this gene Gogo-DRB8. The close relationship between the two genes is indicated by the overall sequence similarity, the absence of recognizable exons 1 and 2 in both genes, the presence of two Alu repeats at corresponding positions, and high sequence similarity between corresponding repeats. The comparison with an outgroup (tamarin) gene and the functional counterparts of the DRB8 gene indicate that DRB8 emerged between 18 and 26 million years ago and became inactivated at the same time as or shortly after its creation. Hence DRB8 has probably existed as a pseudogene since the divergence of apes from Old World monkeys more than 20 million years ago.
  • M KASAHARA, E SEBOUN, M FELLOUS, JH NADEAU IMMUNOGENETICS 34 (2) 132 -135 1991年08月 [査読無し][通常論文]
  • PHYLOGENY OF PRIMATE MAJOR HISTOCOMPATIBILITY COMPLEX DRB ALLELES
    J KLEIN, M KASAHARA, J GUTKNECHT, C SCHONBACH HUMAN IMMUNOLOGY 31 (1) 28 -33 1991年05月 [査読無し][通常論文]
  • Frozen haplotypes in Mhc evolution.
    Molecular Evolution of the Major Histocompatibility Complex, NATO ASI series H. Spriger-Verlag, Berlin-Heidelberg 59 261 -286 1991年 [査読無し][通常論文]
  • Molecular clining of nurse shark cDNAs with high sequence similarity to nucleoside diphosphate kinase genes.
    Molecular Evolution of the Major Histocompatibility Complex, NATO ASI series H. Spriger-Verlag, Berlin-Heidelberg 59 491 -499 1991年 [査読無し][通常論文]
  • Major Histocompatibility Complex : Lessons in evolution
    Immunogenetics of the Major Histocompatibility Complex, VCH Publishers, New York 13-38 1991年 [査読無し][通常論文]
  • Immunogenetics 33 295 -300 1991年 [査読無し][通常論文]
  • The role of tumor derived cytokines on the immune system of mice bearing a mammary adenocarcinoma.
    J. Immunol. 146 1991年 [査読無し][通常論文]
  • M KASAHARA, E MATSUMURA, G WEBB, PG BOARD, F FIGUEROA, J KLEIN GENOMICS 8 (1) 90 -96 1990年09月 [査読無し][通常論文]
  • Do we come from Adam and Eve? What does the study of the major histocompatibility complex tell us about our origin?
    Molecular Evolution, UCLA Symp. Mol. Cell. Biol., New Series, A.R. Liss, New York 22 1 -12 1990年 [査読無し][通常論文]
  • Origin and function of major histocompatibility complex polymorphism.
    1939-1989: Fifty Years Progress in Allergy, Chem. Immunol. (formerly, Progress in Allergy) Karger, Basel 49 35 -50 1990年 [査読無し][通常論文]
  • Evolution of the class II major histocompatibility complex alleles in higher primates.
    Immunol. Rev. 113 1990年 [査読無し][通常論文]
  • VINCEK, V, H KAWAGUCHI, K MIZUNO, Z ZALESKARUTCZYNSKA, M KASAHARA, J FOREJT, F FIGUEROA, J KLEIN GENOMICS 5 (4) 773 -786 1989年11月 [査読無し][通常論文]
  • M KASAHARA, D KLEIN, J KLEIN IMMUNOGENETICS 30 (1) 66 -68 1989年07月 [査読無し][通常論文]
  • Shared class II MHC polymorphisms between humans and chimpanzees.
    Human Immunol. 22 107 -121 1989年 [査読無し][通常論文]
  • Immunogenetics 29 1989年 [査読無し][通常論文]
  • Is there a t complex in man?
    Early Pregnancy Loss Mechanisms and Treatment, The Royak College of Obstericians and Gynecologists, London 269-274 1988年 [査読無し][通常論文]
  • PROBING MOUSE ORIGINS WITH RANDOM DNA PROBES
    J KLEIN, VINCEK, V, M KASAHARA, F FIGUEROA CURRENT TOPICS IN MICROBIOLOGY AND IMMUNOLOGY 137 55 -63 1988年 [査読無し][通常論文]
  • Mapping of the Sod-2 locus into the t complex on mouse chromosome 17.
    Immunogenetics 28 569 -579 1988年 [査読無し][通常論文]
  • NUCLEOTIDE-SEQUENCE ANALYSIS OF CLASS-II GENES BORNE BY MOUSE T-CHROMOSOMES
    M GOLUBIC, O BUDIMIR, R SCHOEPFER, M KASAHARA, WE MAYER, F FIGUEROA, J KLEIN GENETICAL RESEARCH 50 (2) 137 -146 1987年10月 [査読無し][通常論文]
  • NUCLEOTIDE-SEQUENCE ANALYSIS OF CLASS-II GENES BORNE BY MOUSE T-CHROMOSOMES
    M GOLUBIC, O BUDIMIR, R SCHOEPFER, M KASAHARA, WE MAYER, F FIGUEROA, J KLEIN GENETICAL RESEARCH 50 (2) 137 -146 1987年10月 [査読無し][通常論文]
  • T NAKAYAMA, K OGASAWARA, H IKEDA, H KUNIKANE, M KASAHARA, N ISHIKAWA, Y FUKASAWA, S HAWKIN, H KOJIMA, A WAKISAKA, M AIZAWA HUMAN IMMUNOLOGY 19 (2) 117 -126 1987年06月 [査読無し][通常論文]
  • MOLECULAR-CLONING OF A TESTIS-SPECIFIC GENE FROM MOUSE CHROMOSOME-17
    M KASAHARA, F FIGUEROA, J KLEIN TRANSPLANTATION PROCEEDINGS 19 (1) 815 -816 1987年02月 [査読無し][通常論文]
  • Cloning of a tesitis-specific gene located between Qa-2 and Upg-1 on mouse chromosome 17.
    H-2 Antigens: Genes, Moleules, and Function, NATO ASI Series A. Plenum Press, New York 144 321 -325 1987年 [査読無し][通常論文]
  • N ISHIKAWA, H KOJIMA, T NAKAYAMA, H KUNIKANE, S HAWKIN, Y FUKASAWA, H IKEDA, K OGASAWARA, M KASAHARA, Y TAJIMA, Y KAKUTA, A WAKISAKA, M AIZAWA IMMUNOGENETICS 26 (3) 143 -149 1987年 [査読無し][通常論文]
  • A STUDY ON CLASS-II ANTIGENS INVOLVED IN THE T-CELL PROLIFERATIVE RESPONSES TO PPD USING CROSS-REACTING MONOCLONAL-ANTIBODIES IN HUMAN AND MURINE SYSTEM
    K OGASAWARA, H KOJIMA, H IKEDA, N ISHIKAWA, M KASAHARA, Y FUKASAWA, T NATORI, A WAKISAKA, Y KIKUCHI, M AIZAWA, K IWABUCHI, M OGASAWARA, M NOGUCHI, L GENG, K MORIKAWA, K ONOE IMMUNOBIOLOGY 171 (1-2) 112 -124 1986年03月 [査読無し][通常論文]
  • The Wild Mouse in Immunology
    Curr. Top. Microbiol. Immunol. Springer-Verlag, Berlin-Heidelberg-New York-Tokyo 127 239 -246 1986年 [査読無し][通常論文]
  • M KASAHARA, STOJLKOVIC, I, WE MAYER, Z DEMBIC, F FIGUEROA, J KLEIN IMMUNOGENETICS 24 (5) 324 -327 1986年 [査読無し][通常論文]
  • A MONOCLONAL-ANTIBODY RECOGNIZING A POLYMORPHIC DETERMINANT ON HLA-DR ANTIGENS EXCEPT DR-7 AND DRW9
    K OGASAWARA, M KASAHARA, T NAKAYAMA, N ISHIKAWA, H KUNIKANE, S HAWKIN, H KOJIMA, H IKEDA, A WAKISAKA, Y KIKUCHI, M AIZAWA TISSUE ANTIGENS 26 (5) 344 -347 1985年 [査読無し][通常論文]
  • POLYMORPHIC REGIONS OF HLA-DR AND HLA-DQ ANTIGENS DEMONSTRATED BY N-TERMINAL AMINO-ACID SEQUENCE-ANALYSIS
    T ENDO, F OBATA, M IGARASHI, F OTANI, M KASAHARA, M KATAGIRI, N KASHIWAGI TRANSPLANTATION PROCEEDINGS 17 (1) 707 -709 1985年 [査読無し][通常論文]
  • Demonstration of structural polymorphism among MB3 light chains by two-dimensional gel electrophoresis.
    J. Immunol. 134 417 -422 1985年 [査読無し][通常論文]
  • PARTIAL N-TERMINAL SEQUENCE-ANALYSIS OF HUMAN CLASS-II MOLECULES EXPRESSING THE DQW3 DETERMINANT
    F OBATA, T ENDO, M YOSHII, F OTANI, M IGARASHI, T TAKENOUCHI, H IKEDA, K OGASAWARA, M KASAHARA, A WAKISAKA, M AIZAWA, N KASHIWAGI HUMAN IMMUNOLOGY 14 (1) 19 -27 1985年 [査読無し][通常論文]
  • ELECTROPHORETIC ANALYSIS OF HLA-DR2 MOLECULES ISOLATED FROM HLA-DW2 AND HLA-DW12 CELL-LINES
    T TAKENOUCHI, M KASAHARA, K OGASAWARA, H IKEDA, N ISHIKAWA, S HAWKIN, A WAKISAKA, M AIZAWA JOURNAL OF IMMUNOGENETICS 12 (1) 65 -69 1985年 [査読無し][通常論文]
  • Molecular and functional analysis of class II molecules characterisitc to HLA-Dw2 and HLA-Dw12.
    Histocompatibility Testing Springer-Verlag, Berlin-Heidelberg-New York-Tokyo 504-508 1984年 [査読無し][通常論文]
  • Three monoclonal antibodies apecific for human call II antigns detect RT1B-linked polymorphims in rat B cells.
    J. Immunogenet. 11 255 -258 1984年 [査読無し][通常論文]
  • INHIBITION OF AUTOLOGOUS MIXED LYMPHOCYTE-REACTION BY MONOCLONAL-ANTIBODIES SPECIFIC FOR THE BETA-CHAIN OF HLA-DR ANTIGENS
    M KASAHARA, H IKEDA, K OGASAWARA, N ISHIKAWA, T OKUYAMA, Y FUKASAWA, H KOJIMA, H KUNIKANE, S HAWKIN, T OHHASHI, T NATORI, A WAKISAKA, Y KIKUCHI, M AIZAWA IMMUNOLOGY 53 (1) 79 -86 1984年 [査読無し][通常論文]
  • Evidence for polymorphism of MB3 antigens among three HLA-D clusters associated with HLA-DR4.
    Immunogenetics 19 381 -390 1984年 [査読無し][通常論文]
  • IMMUNOCHEMICAL EVIDENCE FOR MULTIPLE BETA-UNITS OF THE CLASS-II MOLECULE IN THE RAT
    T NATORI, T OHHASHI, T INOMATA, Y FUJIMOTO, Y ISHIDA, M KASAHARA, M AIZAWA JOURNAL OF IMMUNOGENETICS 10 (6) 439 -452 1983年 [査読無し][通常論文]
  • Serologic dissection of HLA-D specificities by the use of monoclonal antibodies. II. Distinction between HLA-Dw2 and HLA-Dw12.
    Immunogenetics 18 525 -536 1983年 [査読無し][通常論文]
  • SEROLOGIC DISSECTION OF HLA-D SPECIFICITIES BY THE USE OF MONOCLONAL-ANTIBODIES
    M KASAHARA, T TAKENOUCHI, K OGASAWARA, H IKEDA, T OKUYAMA, N ISHIKAWA, J MORIUCHI, A WAKISAKA, Y KIKUCHI, M AIZAWA, T KANEKO, N KASHIWAGI, Y NISHIMURA, T SASAZUKI IMMUNOGENETICS 17 (5) 485 -495 1983年 [査読無し][通常論文]
  • A monoclonal antibody that detects a polymorphic determinant common to HLA-DR1 and 2.
    Tissue Antigens 21 105 -113 1983年 [査読無し][通常論文]
  • ROLE OF HLA IN IGA NEPHROPATHY
    M KASAHARA, K HAMADA, T OKUYAMA, N ISHIKAWA, K OGASAWARA, H IKEDA, T TAKENOUCHI, A WAKISAKA, M AIZAWA, Y KATAOKA, R MIYAMOTO, M KOHARA, S NAITO, N KASHIWAGI, Y HIKI CLINICAL IMMUNOLOGY AND IMMUNOPATHOLOGY 25 (2) 189 -195 1982年 [査読無し][通常論文]
  • THE HETEROGENEITY OF ANTIGEN DRW8
    Y NAKAI, M KASAHARA, J MORIUCHI, K MASUDA, A WAKISAKA, M AIZAWA, K ITAKURA TRANSPLANTATION PROCEEDINGS 13 (4) 1996 -1999 1981年 [査読無し][通常論文]

特許

受賞

  • 2017年 北海道知事賞
     
    受賞者: 笠原 正典
  • 2017年 北海道医師会賞
     
    受賞者: 笠原 正典
  • 2014年 日本病理学会 日本病理学賞
     
    受賞者: 笠原 正典
  • 2007年 日本比較免疫学会 古田賞
     
    受賞者: 笠原 正典

共同研究・競争的資金等の研究課題

  • NKG2Dリガンドの病態における役割
    文部科学省:科学研究費補助金(基盤研究(B))
    研究期間 : 2015年 -2017年 
    代表者 : 笠原 正典
  • 文部科学省:科学研究費補助金(挑戦的萌芽研究)
    研究期間 : 2013年 -2014年 
    代表者 : 笠原 正典
  • 文部科学省:科学研究費補助金(新学術領域研究(研究領域提案型))
    研究期間 : 2013年 -2014年 
    代表者 : 笠原 正典
  • 文部科学省:科学研究費補助金(基盤研究(B))
    研究期間 : 2012年 -2014年 
    代表者 : 笠原 正典
  • 文部科学省:科学研究費補助金(挑戦的萌芽研究)
    研究期間 : 2011年 -2011年 
    代表者 : 笠原 正典
  • 文部科学省:科学研究費補助金(特定領域研究)
    研究期間 : 2010年 -2011年 
    代表者 : 笠原 正典, 尾瀬 農之
     
    獲得免疫系と、それを支えるリンパ球は長い間、有顎類に固有であると考えられてきた。ところが、leucine-rich repeatモジュールを組み換えることにより10^<10>を超える多様性を生み出す抗原レセプター(可変的リンパ球レセプター、variable lymphocyte receptor、以下VLR)が無顎類ヤツメウナギで発見されるに及んで、この考えは根底から覆されるに至った。先に、われわれはVLRにAとBが存在することを示したが、最近、VLRAとBはそれぞれT、B様のリンパ球に発現され、Aは膜結合型レセプターとして、Bは抗体として機能することが示された。以上から、無顎類の段階で、細胞性免疫、液性免疫を担うリンパ球のサブセットがすでに存在することが明らかになった。今回、我々は第3のVLRを発見し、それをVLRCと命名した。本年度の研究により、1)VLRCは遺伝子再構成能力をもち、そのLRRドメインはVLRA,VLRBに匹敵する多様性を有していること、2)ただし、LRRCT領域の多様性は比較的低く、超可変領域に突起様の構造を形成できないこと、3)VLRCはVLA+細胞、VLRB+細胞とは別のリンパ球サブセットに発現されていること、4)VLRCはVLRAのように膜結合型レセプターとして機能している可能性が高いことなどが明らかになった。したがって、有顎類に3種のリンパ球サブ...
  • 文部科学省:科学研究費補助金(基盤研究(B))
    研究期間 : 2009年 -2011年 
    代表者 : 笠原 正典, 富居 一範, 大塚 紀幸
     
    NKG2Dはナチュラルキラー細胞(NK細胞)、CD8+T細胞(キラーT細胞)、γ/δT細胞に発現される活性化レセプターである。本レセプターに対するリガンド(以下、NKG2Dリガンド)は正常細胞には発現していないが、がん化、ウイルス感染、創傷などのストレスによって発現が誘導される。NKG2Dにリガンドが結合すると、NK細胞、CD8+T細胞等は活性化され、がん細胞、ウイルス感染細胞を破壊する。本研究では、NKG2Dリガンドの構造・機能・発現調節機構を詳細に解析するとともに、マウスにおける疾患モデルとヒト疾患を対象にNKG2Dリガンドの病態発生に果たす役割を解析することを目的とした。本年度は当研究室で同定されたマウスNKG2DリガンドであるH60c(histocompatibility-60c)に焦点を当てて解析し、以下の成果を得た。1.H60cは細胞外領域にα1,α2ドメインを有するMHCクラスI様分子である。2.H60cを発現する細胞はNK細胞に感受性になる。3.正常マウスの組織では、皮膚、女性生殖器粘膜をはじめとする体表面でH60c遺伝子の高い発現が確認された。H60cは皮膚・粘膜をはじめとする体表面で危険信号として機能するリガンドである可能性が示唆される。4.H60cとNKG2Dとの結合を阻害するH60c特異的モノクロナル抗体を作成した。現在、H60c分子の免疫監視における...
  • 文部科学省:科学研究費補助金(挑戦的萌芽研究)
    研究期間 : 2009年 -2010年 
    代表者 : 笠原 正典
     
    免疫グロブリンはアミノ酸一残基の違いをも識別できる卓越した抗原認識分子であり、臨床検査試薬、実験試薬あるいは医薬として広く用いられている。最近、最も原始的な脊椎動物である円口類(ヤツメウナギ、メクラウナギ)において、免疫グロブリンに匹敵する特異性と、それを凌駕する結合親和性、安定性をもった抗原認識分子variable lymphocyte receptor(VLR:可変性リンパ球レセプター)が発見された。VLRはleucine-rich repeatモジュールを組み合わせることによって多様性を生み出す。本計画では、VLRを免疫グロブリンの代替試薬として利用する可能性を探ることを目的とした。従来、VLRにはVLRA、VLRBの2種が存在することが知られていた。最近、Cooperらにより、分泌型の抗体として機能するのはVLRBであり、VLRAはT細胞受容体のように分泌されないことが示された。われわれは、今回、VLRA、VLRBとは異なる新しいVLR遺伝子を同定し、それをVLRCと命名した。VLRCは遺伝子再構成によりVLRA,VLRB遺伝子に匹敵する多様性を生み出すが、LRRCT領域の多様性はVLRA、VLRBのそれに較べ軽度である。また、VLRCに特異的な抗体を用いた解析により、VLRCはVLRBのように抗体として分泌されるのではなく、VLRAのように膜結合型受容体として機能す...
  • 文部科学省:科学研究費補助金(特定領域研究)
    研究期間 : 2008年 -2009年 
    代表者 : 笠原 正典
     
    本研究では、1)無顎類(メクラウナギ、ヤツメウナギ)に焦点を当てて、MHC(主要組織適合遺伝子複合体)パラロジー群の解析をおこなうことにより、2回のゲノム重複が系統発生のどの段階で起きたのかを実験的に推定するとともに、2)無顎類白血球cDNAライブラリーのEST解析によって同定されたvariable lymphocyte receptor(VLR)遺伝子群について詳細な解析をおこない、以下の成果を得た。1.MHCアンカー遺伝子をコードするBACクローンをメクラウナギから単離し、BACクローンを用いたfluorescence in situ hybridizationをおこなった。その結果、メクラウナギ・ゲノムには少なくとも2個のMHCパラロガス領域が存在することが示唆された。2.ヤツメウナギにはleucine rich repeatモジュールを再構成することによって、免疫グロブリンに匹敵する多様性を生み出す抗原レセプター遺伝子VLRが存在する。VLRにはVLRA、VLRBの2種の遺伝子が存在し、それぞれT細胞、B細胞と類似したリンパ球様細胞に発現されていることが知られていた。われわれは、今回、VLRA、VLRBのいずれとも異なる新しいVLR遺伝子を同定し、VLRCと命名した。VLRCは遺伝子再構成によりVLRA、VLRB遺伝子に匹敵する多様性を形成するが、LRRCT領域の多様...
  • 文部科学省:科学研究費補助金(基盤研究(B))
    研究期間 : 2007年 -2008年 
    代表者 : 笠原 正典, 外丸 詩野, 富居 一範
     
    NKG2Dリガンドはがん化やウイルス感染に伴って、細胞表面に発現される主要組織適合遺伝子複合体クラスI様分子であり、免疫系に異常細胞の存在を知らせる危険信号の働きをしている。本研究では、我々が同定した2個の新規リガンドを中心として、NKG2Dリガンドの構造、機能、病態における役割を解析した
  • 文部科学省:科学研究費補助金(萌芽研究)
    研究期間 : 2007年 -2008年 
    代表者 : 笠原 正典
     
    無顎類(メクラウナギ,ヤツメウナギ)の抗原レセプターであるvariable lymphocyte receptor (VLR) は,免疫グロブリンやT細胞レセプターと異なり,leucine-rich repeats (LRR) をモジュールとして遺伝子再構成を行うことにより,10^<14>にも及ぶ多様性を作り出し,高い親和性と特異性をもって抗原に結合する.この事実は,無顎類には有顎類のそれとは原理的に異なる抗原特異的な生体識別機構が存在することを示唆しており,興味深い.本研究では,VLRが抗原を特異的に認識することに着目して、VLRのLRRモジュールを利用して,抗体の代用となる抗原認識試薬の開発を目指すことを最終的な目的としている.本年度は,飼育可能で入手しやすいヤツメウナギのVLRシステムの詳細な解析を行った.その結果,ヤツメウナギには従来から知られていたVLRA,VLRB遺伝子のほかに,VLRCと命名した第3のVLR遺伝子が存在することを見出した.VLRC遺伝子は,1) VLRB遺伝子の発現を誘導する抗原刺激を与えても発現が誘導されない,2) LRRCT領域における多様性が乏しい,などの特徴を有している.さらに,種々のヒト細胞株,アロ血球,糖鎖抗原で免疫したヤツメウナギから白血球を分離し,cDNAを作成し,ファージディスプレイライブラリーを作成した.現在,パンニングにより...
  • 文部科学省:科学研究費補助金(基盤研究(C))
    研究期間 : 2007年 -2008年 
    代表者 : 石黒 信久, 遠藤 理香, 有賀 正, 笠原 正典
     
    ヒトボカウイルス(Human bocavirus ; HBoV)は2005年にスウェーデンの研究者により発見されたウイルスである。まず最初に本研究ではバキュロウイルス・昆虫細胞発現系を用いた抗HBoV IgG抗体の測定方法を確立した。4名の呼吸器感染症の小児患者の回復期血清中の抗HBoV IgG抗体の上昇を認めるとともに、鼻咽頭ぬぐい液と血清からHBoVゲノムを検出した。年齢層別の抗HBoV IgG抗体陽性率をみると、6-8か月の抗体陽性率は最低であるが、その後上昇して6歳以降のほとんど全ての人が抗HBoV抗体を保有していることがわかった。これらのことから、HBoVは呼吸器感染症に関連する重要なウイルスであると推定された。
  • 文部科学省:科学研究費補助金(特定領域研究)
    研究期間 : 2006年 -2007年 
    代表者 : 笠原 正典
     
    本研究では,1)無顎類(メクラウナギ、ヤツメウナギ)に焦点を当てて,MHC(主要組織適合遺伝子複合体)パラロガス群の解析をおこなうことにより,2回のゲノム重複が系統発生のどの段階で起きたのかを実験的に確定するとともに,2)無顎類白血球cDNAライブラリーのEST解析によって同定されたvariable lymphocyte receptor遺伝子群について詳細な解析をおこなった。その結果,以下の成果を得た。1.MHCアンカー遺伝子をコードするBACクローンをメクラウナギから単離し、BACクローンを用いたfluorescence in situ hybridizationをおこなった。その結果,メクラウナギ・ゲノムには少なくとも2個のMHCパラロガス領域が存在することを示唆する結果を得た。2.ヤツメウナギにはleucine rich repeatsの再構成によって、著しい多様性を生み出す抗原レセプター遺伝子VLRが3個存在することを示した。VLR-Cと命名した第3のVLR遺伝子は今回初めて同定されたものである。3.ヤツメウナギVLR-B特異的モノクロナル抗体を作成した。4.クラウナギVLR-A,-B分子(VLR-B 2分子種,VLR-A 1分子種)を大腸菌で発現させることによって,組み換え蛋白質を得て,VLR-A, -Bモノマーの結晶構造を決定した(韓国Jie-Oh Lee准教授...
  • 文部科学省:科学研究費補助金(特定領域研究)
    研究期間 : 2005年 -2006年 
    代表者 : 笠原 正典, 石津 明洋, 外丸 詩野
     
    NKG2Dリガンドは癌細胞やウイルス感染細胞などで発現されるストレス誘導性のMHCクラスI様分子であり,NK細胞,CD8_+T細胞による免疫監視において重要な役割を果たしている.マウスでは,既知のリガンドとして,RAE-1α,-β,-γ,-δ,-ε,H60(Histocompatibility-60),MULT-1が知られている.本年度は,ヒトのNKG2Dリガンド分子の一つであるMICA-MICB分子と最も近縁なマウスのMHCクラスI様分子MILL(MHCclass I-like located near the leukocyte recptor complex)がNKG2Dのリガンドとして機能するか否かを検討するとともに,新しいマウスNKG2Dリガンドの同定を試みた.その結果,MILLは配列的にはNKG2Dのリガンドとして機能することが予想されたにもかかわらず,NKG2D-Ig融合タンパク質と結合しないことが示された.さらに,MILLはβ2ミクログロブリンと会合するGPIアンカー型タンパク質であり,この点でもMICA・MICB分子とは異なっていることが判明した.この結果を受けて新しいマウスNKG2Dリガンドを探索した結果,2個のMHCクラスI様分子がNKG2Dリガンドとして同定された.これらのNKG2Dリガンドは既知のリガンドの中ではH60と最も相似性が高かったため,H6...
  • 文部科学省:科学研究費補助金(特定領域研究)
    研究期間 : 2005年 -2005年 
    代表者 : 笠原 正典
     
    われわれは、HLA(MHC)領域とパラロガスな領域がヒトゲノムに3箇所存在することを発見し、これらのパラロガス領域とHLA領域の原型が脊椎動物進化の初期におきたと想定される2回の大規模な染色体重複(おそらくはゲノム重複)によって形成された可能性が高いことを示してきた。しかしながら、パラロガス領域を生み出した重複の性質、回数、時期に関しては十分な理解が得られていないのが現状である。そこで、本研究では、系統発生的に2度の重複の直前、直後に位置すると考えられる無顎類(特に、ヌタヌナギEptatretus burgeri)に焦点を当てて研究を進め、以下の成果を得た。1.ヌタウナギ・ゲノムに存在するMHCパラロガス領域を同定することを目的として、MHCアンカー遺伝子をコードするBACクローンを単離した。また、BACクローンを用いたfluorescence in situ hybridization法の開発をおこなった。2.免疫グロブリンやT細胞抗原レセプターの祖先と推測されるVドメインを有するpaired Ig-like receptor遺伝子群をヌタヌナギで同定し、APAR(agnathan paired receptors resembling antigen receptors)と命名、その構造解析をおこなった。3.leucine rich repeatsの再構成によって、著しい...
  • 文部科学省:科学研究費補助金(特定領域研究)
    研究期間 : 2004年 -2004年 
    代表者 : 笠原 正典
     
    われわれは、HLA(MHC)領域とパラロガスな領域がヒトゲノムに3箇所存在することを発見し、これらのパラロガス領域とHLA領域の原型が脊椎動物進化の初期におきたと想定される2回の大規模な染色体重複(おそらくはゲノム重複)によって形成された可能性が高いことを示してきた。しかしながら、パラロガス領域を生み出した重複の性質、回数、時期に関しては十分な理解が得られていないのが現状である。そこで、本研究では、系統発生的に2度の重複の直前、直後に位置すると考えられる無顎類(特に、ヌタヌナギ)に焦点を当てて研究を進め、以下の成果を得た。1)哺乳類とほぼ同じゲノムサイズをもつと推定されるヌタウナギのゲノムを3倍カバーするBACライブラリー(平均インサート長約100kb)を作製した。2)上記BACライブラリー(3倍ゲノムカバレッジ分)のスクリーニングを行い、7個のMHC前駆領域をカバーするBACクローンを同定し、その塩基配列を決定した。3)ヌタウナギ白血球由来cDNAライブラリーのランダム・シークエンスを行い、約12,000クローンの5'-end,3'-endの塩基配列を決定した。4)免疫グロブリンやT細胞抗原レセプターの祖先と推測されるVドメインを有するpaired Ig-like receptor遺伝子群をヌタヌナギで同定し、APAR(agnathan paired receptors r...
  • 文部科学省:科学研究費補助金(基盤研究(B))
    研究期間 : 2002年 -2004年 
    代表者 : 笠原 正典
     
    本研究では、免疫遺伝学、構造生物学、比較ゲノム学、免疫生物学など幅広い視点から、ナチュラルキラー(NK)レセプターならびにNKレセプターと相互作用するMHCクラスI分子の構造・機能・進化を解析し、以下の成果を得た。1.ヒトの主要なNKレセプターであるKIR (killer immunoglobulin-like receptor)遺伝子群はLRC (leukocyte receptor complex)領域に存在するが、第7染色体に位置するマウスのLRC領域にはKIRと相同な遺伝子群は存在しない。このため、マウスにはKIR相同遺伝子は存在しないというのが定説であった。われわれは、マウスのX染色体上にKIRと相同な遺伝子(Kirl : Kir-likeと命名)が2コピー存在することを明らかにした。2.マウスLRC領域には、IgA Fc receptor遺伝子(Fcar)が欠損していることを明らかにするとともに、ラットとマウスではLRCのゲノム構造が大幅に異なっていることを示した。3.げっ歯類以外の哺乳類では、KIRがNKレセプターとして使われているというのがこれまでの通説であったが、ウマではC型レクチン様分子であるLY49がNKレセプターとして使われていることを強く示唆する結果を得た。4.無顎類ヌタウナギにおいて抗原レセプターと類似したVドメインを有するpaired Ig-li...
  • 文部科学省:科学研究費補助金(特定領域研究)
    研究期間 : 2003年 -2003年 
    代表者 : 笠原 正典
     
    われわれは、HLA (MHC)領域とパラロガスな領域がヒトゲノムに3箇所存在することを発見し、これらのパラロガス領域とHLA領域の原型が脊椎動物進化の初期におきたと想定される2回の大規模な染色体重複(おそらくはゲノム重複)によって形成された可能性が高いことを示してきた。今日では、本パラロガス群はヒトゲノムで同定された数多くのパラロガス領域のプロトタイプとしての地位を確立しつつある。しかしながら、パラロガス領域を生み出した重複の性質、回数、時期に関しては十分な理解が得られていないのが現状である。そこで、本研究では、系統発生的に2度の重複の直前、直後に位置すると考えられる無顎類(特に、ヌタヌナギ)に焦点を当てて研究を進め、以下の成果を得た。1)哺乳類とほぼ同じゲノムサイズをもつと推定されるヌタウナギのゲノムを3倍カバーするBACライブラリー(平均インサート長約100kb)を作製した。2)上記BACライブラリー(3倍ゲノムカバレッジ分)のスクリーニングを行い、7個のMHC前駆領域をカバーするBACクローンを同定し、その塩基配列を決定した。3)ヌタウナギ白血球由来cDNAライブラリーのランダム・シークエンスを行い、約12,000クローンの5'-end,3'-endの塩基配列を決定した。4)MHCパラロガス群に属するホヤ遺伝子を体系的に同定し、染色体重複後に生じたゲノム構造の変化を解析...
  • 文部科学省:科学研究費補助金(特定領域研究)
    研究期間 : 2003年 -2003年 
    代表者 : 笠原 正典
     
    本研究では、マウスの新しいMHCクラスI様分子群MILLの構造と機能を解明することを目的とした。MILL分子群に関しては、われわれのこれまでの研究により以下の点があきらかにされている(Proc.Natl.Acad.Sci.USA 99: 13687,2002)。1)MILL分子には、MILL1,MILL2と名づけられた二つのメンバーが存在する。2)両分子ともMHC領域ではなく、第7染色体上のleukocyte receptor complex近傍でコードされている。3)既知のクラス1様分子の中で、MILLはヒトMHCでコードされるMICA・MICB分子と最も高い配列相似(アミノ酸レベルで約40%の相同性)を示す。4)MILLは正常組織にはほとんど発現されていないが、がん細胞株では高発現される傾向がある。上記の成果を踏まえて、本研究では、1)MILL分子の基本的な性状を解析すること、2)MILL分子と相互作用する分子を同定すること、を主要な具体的目標とした。主な研究成果は以下のとおりである。1)MILLクラスI分子はMICA/B分子と最も近縁なクラスI分子であるが、MICA/B分子とは異なったクラスI分子であり、NKG2Dとの結合能をもたない。2)MILL分子はベータ2ミクログロブリンと会合する可能性が高い。3)MILL分子は、TAP欠損株においても細胞表面に発現されるので、ペ...
  • 文部科学省:科学研究費補助金(特定領域研究)
    研究期間 : 2002年 -2002年 
    代表者 : 笠原 正典
     
    われわれは、HLA(MHC)領域とパラロガスな領域がヒトゲノムに3箇所存在することを発見し、これらのパラロガス領域とHLA領域の原型が脊椎動物進化の初期におきたと想定される2回の大規模な染色体重複(おそらくはゲノム重複)によって形成された可能性が高いことを示してきた。今日では、本パラロガス群はヒトゲノムで同定された数多くのパラロガス領域のプロトタイプとしての地位を確立しつつある。しかしながら、1)パラロガス領域を生み出した重複の性質、回数、時期、2)重複ののちにゲノムに生じた変化、に関しては十分な理解が得られていないのが現状である。そこで、本研究では、1)系統発生的に2度の重複の直前、直後に位置すると考えられる無顎類(特に、ヌタヌナギ)に焦点を当てて、MHCパラロガス群のBACクローンを用いた解析を行うとともに、2)ゲノム解析が終了しつつあるヒトおよびマウスを対象として、重複後に生じたゲノム構造の変化を明らかにすることを目的として研究を遂行し、以下の成果を得た。1)哺乳類とほぼ同じゲノムサイズをもっと推定されるヌタウナギのゲノムを3倍カバーするBACライブラリー(平均インサート長約100kb)を作製した。2)上記BACライブラリー(3倍ゲノムカバレッジ分)のスクリーニングを行い、7個のMHC前駆領域をカバーするBACクローンを同定し、その塩基配列を決定した。3)ヌタウナギ白血...
  • 文部科学省:科学研究費補助金(特定領域研究(C))
    研究期間 : 2001年 -2001年 
    代表者 : 笠原 正典
     
    われわれは、HLA(MHC)領域とパラロガスな領域がヒトゲノムに3箇所存在することを発見し、これらのパラロガス領域とHLA領域の原型が脊椎動物進化の初期におきたと想定される2回の大規模な染色体重複(おそらくはゲノム重複)によって形成された可能性が高いことを示してきた。今日では、本パラロガス群はヒトゲノムで同定された数多くのパラロガス領域のプロトタイプとしての地位を確立しつつある。しかしながら、1)パラロガス領域を生み出した重複の性質、回数、時期、2)重複ののちにゲノムに生じた変化、に関しては十分な理解が得られていないのが現状である。そこで、本研究では、1)系統発生的に2度の重複の直前、直後に位置すると考えられる無顎類(特に、ヌタヌナギ)に焦点を当てて、MHCパラロガス群のBACクローンを用いた解析を行うとともに、2)ゲノム解析が終了しつつあるヒトおよびマウスを対象として、重複後に生じたゲノム構造の変化を明らかにすることを目的として研究を遂行し、以下の成果を得た。1)哺乳類とほぼ同じゲノムサイズをもつと推定されるヌタウナギのゲノムを3倍カバーするBACライブラリー(平均インサート長約100kb)の作製に成功した。現在、ゲノムカバレッジを5倍まで増加させるべく、作製作業(3Dプール作製を含む)を継続中である。2)上記BACライブラリー(1倍ゲノムカバレッジ分)のスクリーニングを行...
  • 文部科学省:科学研究費補助金(特定領域研究(C))
    研究期間 : 2001年 -2001年 
    代表者 : 笠原 正典
     
    1.KIR遺伝子をもたないと考えられてきたマウスのゲノムに、ブラストサーチでヒトのKIRと最も高い相似性を示す免疫グロブリンドメイン2個を有する遺伝子をみいだした。高い配列相似性をもったESTクローンが存在することから、X染色体上に位置する本遺伝子はタンパク質をコードしている可能性が高いが、発現組織の違いからNKレセプターとして働いている可能性は低いことが示唆された。2.Ly94遺伝子を含むBACクローンに、Tnnt1(slow skeletal muscle troponin T)遺伝子、Tnni3(cardiac troponin I)遺伝子、Mbs85(myosin binding subunit 85)遺伝子、Flj20258遺伝子、Flj20510遺伝子、Gp6(platelet glycoprotein VI)遺伝子をみいだした。Tnni3,Tnnt1,Mbs85遺伝子はこの順に並んで存在し、また、Flj20510遺伝子とGp6遺伝子は並んで存在することが判った。ヒトでは、LY94遺伝子に隣接してFCAR(IgA Fc receptor)遺伝子が存在するが、本遺伝子と相同と考えられる配列はBACクローン中にみいだされなかった。Pir遺伝子を含むBAC contig中には少なくとも、3個のPirb遺伝子が存在した。これらの遺伝子は既知のPirb遺伝子と同様なエクソン...
  • 文部科学省:科学研究費補助金(基盤研究(B))
    研究期間 : 1999年 -2001年 
    代表者 : 笠原 正典
     
    1)IFN-γで発現が誘導される3個の20Sプロテアソーム・サブユニット遺伝子は、クラスI分子による抗原提示システムが誕生した際に、構成的に発現されるサブユニット遺伝子から遺伝子重複によって形成されたものであることを明らかにした。さらに、1)この重複は個々の遺伝子の重複ではなく、MHC領域を巻き込んだ少なくとも2回の染色体重複の一環として起きたものであること、2)上記の重複は脊椎動物進化の初期段階、具体的には有顎脊椎動物の共通祖先が出現するまでに起きたものであり、HMCの誕生に不可欠な役割を果たしたと考えられることを明らかにした。これら一連の研究に基づき、MHCのゲノム構造を理論的に説明する「HMCの染色体重複モデル」を提唱した。2)IFN-γによって制御されるプロテアソーム・サブユニット遺伝子群を129/SvJマウスから系統的にクローニングし、遺伝子構造と染色体局在を決定し、発現制御機構を解析した。具体的には、IFN-γによって発現が制御されることが知られている9個の遺伝子中、6個の遺伝子(20Sブロテアソーム・サブユニヅトMECL1、Z、XをコードするPsmb10、Psmb7、Psmb5遺伝子、およびプロテアソーム・アクチベータPA28α、PA28β、PA28γサブユニットをコードするPsme1、Psme2、Psme3遺伝子)の解析を行った。Psme1、Psme2、Psm...
  • 文部科学省:科学研究費補助金(国際学術研究, 基盤研究(B))
    研究期間 : 1998年 -2001年 
    代表者 : 笠原 正典, Kaufman Jame, Du Pasquier, Flajnik Mart
     
    ヒトやマウスがもつ精巧な自己・非自己識別システムは,長い時間をかけて行われた試行錯誤の結果,形成されたものであり,言うまでもなく「進化」の所産である.したがって,システムの全貌を総合的に理解するためには,ヒトやマウスのみを研究の対象としていたのでは不十分である.そこで,本研究では,ヒトから魚におよぶ脊椎動物を研究の対象として,自己・非自己識別システムの構造・機能,由来を探ることを目的とした.研究代表者は,プロテアソーム遺伝子群を解析することにより,主要組織適合遺伝子複合体(MHC)領域が大規模な染色体重複によって形成されたものであることをあきらかにした.MHC領域をまきこんだ染色体重複は今から4億年以上も前に,有顎脊椎動物の共通祖先に起こったものと想定され,ゲノム重複の一環として起こった可能性が強く示唆された.分担者の一人であるFlajnikはアフリカツメガエルMHCのゲノム構造の解析を推進するとともに,軟骨魚類で同定されたNAR遺伝子の多様性形成機構に関し新知見を得た.Du Pasquierは胸腺皮質リンパ球に特異的に発現される免疫グロブリン超遺伝子族CTXに関する研究を精力的に推進し,本超遺伝子族に属する多数の新規遺伝子をヒトにおいて同定した.また,同じく分担者の一人であるKaufmanはニワトリMHCの全塩基配列を決定し,ニワトリのMHCにはプロテアソーム遺伝子が存在し...
  • 文部科学省:科学研究費補助金(特定領域研究(A))
    研究期間 : 2000年 -2000年 
    代表者 : 笠原 正典
     
    本研究では,ゲノム重複によって形成されたと想定されるパラロガス領域の典型例と考えられるMHC(Major Histocompatibility Complex)パラロガス・グループに焦点を当てることにより,パラロガス領域を形成した重複の性質,回数,時期を解明することを目的とした.1.MHCパラロガス・グループを構成する新規ヒト遺伝子群の同定1)HLA領域に存在する全遺伝子の約3〜4分の1に相当すると考えられる37個の遺伝子がHLAとパラロガスな領域(9q33-q34,19p13.1-13.3,1q21-q25/p11-p32)のいずれかにコピーをもっていること(ただし,直列重複で生じた遺伝子を一つと数える),2)HLA領域内にはコピーをもたないが,9q33-q34,19p13.1-13.3,1q21-q25/p11-p32領域間でパラロガスなコピーを共有する遺伝子群が少なくとも50個存在することを示した.2.メクラウナギのゲノムに存在するMHCパラロガス領域数の同定MHCパラロガス・グループのメンバーである5個の遺伝子族をメクラウナギからクローニングした.これらの遺伝子族の大部分において2-3コピーのパラロガスコピーを同定することが可能であった.したがって,無顎類が誕生する前の段階ですでに一回のゲノム重複が起こった可能性が高いことが示唆された.最終的には,ゲノム・レベルでのク...
  • 文部科学省:科学研究費補助金(特定領域研究(C))
    研究期間 : 2000年 -2000年 
    代表者 : 笠原 正典
     
    ヌタウナギとヤツメウナギによって代表される無顎類は,系統発生上,脊椎動物に最も近い無脊椎動物である原索動物とヒトが属する有顎脊椎動物の中間に位置している.近年,われわれを含めた複数の研究グループにより,原索動物と無顎類の中間段階,および無顎類と有顎脊椎動物の中間段階で各1回のゲノム重複がおこった可能性が高いことが提唱されている.もし,この仮説が正しければ,グノム重複による遺伝子数の飛躍的な増加が原索動物から有顎脊椎動物への進化において,きわめて重要な役割を果たした可能性がある.本研究では,ヌタウナギcDNAクローンをランダムにシークエンシングすることにより,ゲノム重複仮説の妥当性を検証するとともに,系統発生上枢要な位置を占めているにもかかわらず,これまで十分に顧みられることのなかった無顎類から配列データを収集することを目的とした.(結果)メクラウナギの血球由来cDNAクローンをランダムに1000個シークエンスした.これらのクローンのうちで,有顎脊椎動物において複数のパラロガスコピーを有する遺伝子につき,分子系統解析をおこなった.さまざまな生物種からの配列情報が入手可能であり,分子系統解析が有用と考えられたのは,HMG(high mobility group)protein,SOS(son of sevenless),enolase,aldolaseなどの遺伝子群であった.これ...
  • 文部科学省:科学研究費補助金(特定領域研究(C))
    研究期間 : 2000年 -2000年 
    代表者 : 笠原 正典
     
    LRC(leukocyte receptor complex)として知られるヒト19q13.4領域には,NKリセプターとして機能するKIRの他に,KIRと類似した多くのIg様レセプター遺伝子(ILT,LAIRなど)が存在する.ILT,LAIRのなかには,MHCクラスI分子に結合する能力をもったものも存在することから,免疫制御において重要な役割を果たしている可能性がある.マウスでは,ILT,LAIRに相当する遺伝子群としてPIR-A,PIR-Bが同定されているが,KIRに相当する遺伝子はみいだされていない.したがって,ヒトとマウスのLRC領域には遺伝子構成という点で大きな差異が存在するものと予想される.そこで本研究では,BACクローンをもちいて,マウスLRC相当領域のゲノム構造を解明することを目的とした.(結果)1.Ly94遺伝子を含むBACクローンに,Tnnt1遺伝子,Tnni3遺伝子,Mbs85遺伝子,Flj20258遺伝子,Flj20510遺伝子,Gp6遺伝子を見出した.Tnni3,Tnnt1,Mbs85遺伝子はこの順に並んで存在し,また,Flj20510遺伝子とGp6遺伝子は並んで存在することが判った.ヒトでは,LY94遺伝子に隣接してFCAR遺伝子が存在するが,これまでのところ本遺伝子と相同と考えられる配列はBACクローン中に発見されていない.また,マウスのLy94遺...
  • 文部科学省:科学研究費補助金(特定領域研究(A))
    研究期間 : 1999年 -1999年 
    代表者 : 笠原 正典
     
    本研究では,1)MHCパラロガス・グループに属する新規遺伝子群を体系的に同定すること,2)系統発生的にMHCパラロガス領域を形成した重複の直前に位置すると考えられる無顎類(メクラウナギ)のゲノムに存在するMHCパラロガス領域数を同定することを目的とした.1.MHCパラロガス・グループに属するヒト遺伝子群の同定これまでに,約20の遺伝子群が,HLAとそのパラロガスな領域(ヒト染色体9q33-q34,19p13.1-13.3,1q21-q25/p11-p32領域)にコピーをもつことを示してきた.今回,新たにデータベースを検索することにより,1)HLA領域に存在する全遺伝子の約3〜4分の1に相当する37個の遺伝子が9q33-q34,19p13.1-13.3,1q21-q25/p11-p32領域のいずれかにパラロガスなコピーをもっていること,2)MHC領域内にはコピーをもたないが,9q33-q34,19p13.1-13.3,1q21-q25/p11-p32領域間でパラロガスなコピーを共有する遺伝子群が少なくとも50個存在することがあきらかになった.以上から,ほぼ90に近い多種多様な遺伝子族がMHCパラロガス群に属することが判明した.2.メクラウナギのゲノムに存在するMHCパラロガス領域数の同定MHCパラロガス・グループのメンバーであるPBX遺伝子をメクラウナギからクローニングした.ヒ...
  • 文部科学省:科学研究費補助金(重点領域研究, 特定領域研究(A))
    研究期間 : 1996年 -1999年 
    代表者 : 笹月 健彦, 西村 泰治, 西村 泰治, 菊谷 仁, 笠原 正典, 稲葉 カヨ, 吉開 泰信, 福井 宣規, 武田 俊一, 猪子 英俊
     
    MHCの構造と機能を解析して、その成果を免疫病の病因・病態の解明に資することを目的として研究を実施し、以下のような成果を得た。1)CLIP部分をランダム配列ペプチドに置換したインバリアント鎖ライブライーを作製し、HLA-DR遺伝子と共にCOS細胞に一過性発現させ、共培養したT細胞クローンの応答を検出することにより、T細胞クローンが認識するTCRリガンドを同定するシステムを構築した(西村)。2)未熟な樹状細胞は抗原ペプチド・MHCクラスII複合体を形成しないが、成熟刺激により速やかにこれを形成して、CD80等の共刺激分子と共に細胞表面に発現し、特異的T細胞を活性化する(稲葉)。3)Ly49C/I^+NK1.1^+γδT細胞細胞は胸腺内でMHCクラスI分子により分化の抑制を受ける。またinvariantVg6/Vd1鎖を発現するγδT細胞細胞は、Toll-like receptor-2を介して細菌成分に直接反応する(吉開)。4)HLA領域のマイクロサテライト多型を解析し、尋常性乾癬ではHLA-C遺伝子のテロメア側にある新規遺伝子が、またベーチェット病ではHLA-B51遺伝子そのものが疾患感受性遺伝子であることを示した(猪子)。5)HLA領域内の全遺伝子の1/3がHLAとパラロガスな3つの領域にパラロガスなコピーをもつ。Proteasome activatorγ遺伝子標的欠損マウス...
  • 文部科学省:科学研究費補助金(特定領域研究(A))
    研究期間 : 1998年 -1998年 
    代表者 : 笠原 正典
     
    (1) マウスのPA28α、PA28β、PA28γサブユニットをコードする遺伝子を単離し、全構造を決定した。その結果、3つのサブユニットをコードする遺伝子は11個のエクソンから成り、基本的に同一なエクソン・イントロン構造をもっていること、PA28α、PA28βサブユニットをコードする遺伝子は約6kb離れて、その3'-endを向き合うようにして第14染色体上に存在すること、PA28γサブユニット遺伝子は第11染色体のBrcal遺伝子近傍に位置していること、などが判明した。また、PA28α、PA28βサブユニット遺伝子のプロモータ領域には、機能的なISRE(interferon stimulated response element)が存在することをluciferase assayを用いて確認した。(2) IFN-γ誘導性のPA28サブユニット遺伝子は、MHCクラスI分子による抗原提示システムの誕生とともに誕生したものと推定される。この推定を実証するために、上記システムをもつ最も下等な生物であるサメと適応免疫系をもたないと想定されるメクラウナギを対象としてPA28遺伝子群の解析を行った。その結果、1)PA28αサブユニット遺伝子は予想どおりサメではじめて検出可能となること、2)PA28βサブユニット遺伝子はもっと後の段階でαサブユニット遺伝子が直列に重複した結果、誕生したものであ...
  • 文部科学省:科学研究費補助金(基盤研究(B))
    研究期間 : 1997年 -1998年 
    代表者 : 笠原 正典
     
    プロテアソームは,MHCクラスI分子によって提示されるペプチドを産生するプロテアーゼである.本課題では,クラスI分子による抗原提示を促進する機能をもつと想定されるIFN-γ誘導性プロテアソーム・サブユニットの構造・機能・起源を明らかにすることを目的として研究を推進し,以下の成果を得た.1) IFN-γ誘導性20Sプロテアソーム・サブユニット遺伝子の起源:MHCの染色体重複モデルの提唱IFN-γで発現が誘導される3個の20Sプロテアソーム・サブユニットは,クラスI分子による抗原提示システムが誕生した際に,構成的に発現されるサブユニット遺伝子が重複して形成されたものと考えられる.われわれは,1)この重複が,個々の遺伝子の重複ではなく,MHC領域を巻き込んだ染色体領域の重複の一環としておこったものであること,2)上記の重複は脊椎動物進化の初期段階,具体的には有顎脊椎動物の共通祖先におこったと考えられること,などを明らかにした.これら一連の研究により,MHCという遺伝領域のゲノム構成を理論的に説明する「MHCの染色体重複モデル」が提唱された.2) IFN-γによって制御されるプロテアソーム・サブユニット遺伝子群のクローニングとその構造解析IFN-γによって制御されるプロテアソーム・サブユニット遺伝子群を129/SvJマウスから系統的にクローニングすることにより,遺伝子構造と染色体局在...
  • 文部科学省:科学研究費補助金(萌芽的研究)
    研究期間 : 1997年 -1998年 
    代表者 : 笠原 正典
     
    常染色体劣性無精子症の原因候補遺伝子であるヒトのDAZLA(Deleted in Azoospermia-like autosomal)遺伝子を解析することにより以下の成果を得た.1. ヒトDAZLA遺伝子の構造・染色体局在の決定1)ヒトDAZLA遺伝子はY染色体でコードされるヒトDAZ遺伝子と同一のエクソン・イントロン構造を有していること,2)DAZLA遺伝子は第3染色体のバンドp25領域に存在すること,が明らかになった.2. ヒトDAZLAタンパク質に特異的な抗体の作製RNA結合タンパク質と考えられるDAZLA分子は,核,サイトゾル,あるいはその両方に存在する可能性がある.大腸菌で発現された組み換えヒトDAZLA分子でラビットを免疫することにより,DAZLAタンパク質に特異的な抗体を作製した.本抗体を用いてDAZLAタンパク質の細胞内局在を検討したところ,DAZLA分子は主としてサイトゾルに存在することがあきらかになった.DAZLA分子は主に精原細胞・精母細胞において発現されている.3. DAZ/DAZLA遺伝子の分岐年代の決定ヒトのゲノムにはY染色体でコードされるDAZ遺伝子と常染色体でコードされるDAZLA遺伝子の両方が存在するが,マウスのゲノムには常染色体でコードされるDazla遺伝子しか存在しない.本研究により,DAZは旧世界ザルと新世界ザルが分岐した後に前者の系...
  • 文部科学省:科学研究費補助金(国際学術研究)
    研究期間 : 1997年 -1997年 
    代表者 : 笠原 正典, Kaufman Jame, Du Pasquier, Flajnik Mart, Pasquier Lou
     
    ヒトやマウスがもつ精巧な自己・非自己識別システムは,長い時間をかけて行われた試行錯誤の結果,形成されたものであり,言うまでもなく「進化」の所産である.したがって,システムの全貌を総合的に理解するためには,ヒトやマウスのみを研究の対象としていたのでは不十分である.そこで,本研究では,ヒトから魚におよぶ脊椎動物を研究の対象として,自己・非自己識別システムの構造,機能,由来を探ることを目的とした.研究代表者は,プロテアソーム遺伝子群を解析することにより,ヒトの9q33-q34領域,マウスの第2染色体傍動原体領域に主要組織適合遺伝子複合体(MHC)様の遺伝領域が存在することを明らかにした.この遺伝領域とMHC,領域は抗原処理遺伝子(プロテアソームのbetaサブユニットをコードするLMP遺伝子とTAP遺伝子)の祖先遺伝子をまきこんだ染色体重複によって分岐・形成されたものと想定された.系統発生的な解析を行うことにより,この染色体重複は今から4億年以上も前に,有顎脊椎動物の共通祖先に起こったものであることが判明した.Flajnikは,ヒトやマウスではMHCクラスII遺伝子の近傍に存在するLMP,TAP遺伝子がアフリカツメガエルではクラスI遺伝子の近傍に位置していることを明らかにした.これから,アフリカツメガエルでは本来のMHCのゲノム構造が良く温存されているものと考えられた.Du Pasq...
  • 文部科学省:科学研究費補助金(重点領域研究)
    研究期間 : 1996年 -1996年 
    代表者 : 菊地 浩吉, 松浦 晃洋, 古川 圭子, 益子 高, 別宮 好文, 笠原 正典
     
    癌の特異的免疫治療を目指し、人癌特異抗原を同定し、その自家T細胞による免疫学的認識、拒絶の分子機構を明らかにし自家癌拒絶の誘導法の開発を試みた。1.癌患者リンパ球から、自家胃癌、膵癌、口腔癌特異的キラーT細胞クローンおよびヘルパーT細胞クローンを樹立し、癌抗原提示分子が各々、HLA-A31、-A24、-DR^*08032であることを証明した。自家胃癌に対するCTL誘導能を有する結合ペプチドの画分を精製し、抗原ペプチド分子の同定に成功した。2.ヒト胃癌、膵癌を特異的に障害するT細胞クローンの抗原レセプター遺伝子をT細胞株にトランスフェクトし、TCR分子の細胞表面発現を認め、更にこれが自家癌抗原を認識することを確かめた。3.原癌遺伝子(C-erbB-2)産物のKd拘束性ペプチド感作により特異的CTLを誘導できた。4.MC誘発肉腫CMS5に特異的なCTLcloneの認識する腫瘍抗原遺伝子を単離し、その産物が第136アミノ酸にK→Q変異を持つ変異型MAPkinase(ERK2)であることを明らかにした。5.イムノプロテアソームβサブユニット・ペアをコードする遺伝子を単離し、その構造、染色体居在を明らかにした。6.腫瘍細胞の臓器浸潤や血行性転位に関与する癌関連糖鎖を合成する糖転位酵素、シアリルトランスフェラーゼおよびフコシルトランスフェラーゼの発現をアンチセンスcDNA等を用い制御でき...
  • 文部科学省:科学研究費補助金(一般研究(C), 基盤研究(C))
    研究期間 : 1995年 -1996年 
    代表者 : 笠原 正典
     
    主要組織適合遺伝子複合体(MHC)クラスI分子には,抗原提示に主役を演じるクラスIa分子の他に,クラスIb分子と総称される多様な分子群が存在する(Transplant Immunol.3:1,1995;Res.Immunol.147:278,1996).IgGを胎盤・腸管において輸送するFcRn分子,糖脂質を抗原提示するCD1分子,機能不明のZn-α2 糖タンパク質分子,ヘマクロマトーシスの病因分子と想定されるHLA-H分子などが代表的なクラスIb分子である.本研究では,前三者のクラスIb分子を対象として,以下の成果を得た.1)マウスおよびヒトのFcRn分子をコードする遺伝子をクローニングし,その構造・染色体局在を決定した(J.Immunol.154:5907,1995;Cytogenet.Cell Genet.73:97,1996).2)ヒトCD1遺伝子の存在する領域とMHC領域が染色体重複によって形成されたことを明らかにした(Proc.Natl.Acad.Sci.USA 93:9096,1996;Trends in Genetics 13:in press,1997).3)マウスのZn-α2 糖タンパク質分子がMHC領域外でコードされていることを示した(Immunogenetics 42:72,1995).4)ヒトのCD1b分子を胸腺から精製し,CD1b分子に結合する内在...
  • 文部科学省:科学研究費補助金(重点領域研究)
    研究期間 : 1995年 -1995年 
    代表者 : 石橋 輝雄, 西野 秀明, 笠原 正典, 荒磯 恒久
     
    細胞の生命維持には膜タンパク質の働きが必須であるが、その活性は生体膜脂質が構成する周囲の微小環境により調節されている。生体膜は生理的条件下では液晶(Lα)二重層構造を有しているが、刺激によりその一部が非二重層構造をとり膜構築の乱れを生じ、膜タンパク質の高次構造や機能に重要な影響を与えるものと思われる。本研究では細胞内情報伝達のセカンドメッセンジャーとして重要なジアシルグリセロール(DAG)が生理的に生じ得る濃度で生体膜液晶相(Lα)を逆ヘキサゴナル相(HII)に誘導すること、および相転移初期に膜内側方圧が上昇することを見出し、又それらと膜結合酵素の関係を明らかにした。
  • 文部科学省:科学研究費補助金(重点領域研究)
    研究期間 : 1995年 -1995年 
    代表者 : 菊地 浩吉, 松浦 晃洋, 益子 高, 伊東 恭悟, 別宮 好文, 笠原 正典
     
    本研究は人癌とくにヒト固型癌の自家T細胞による免疫学的癌抗原認識、拒絶の分子機構を明らかにすることを目的とする。本年度の成果を要約する。1)日本人に多い胃癌・肺癌・食道癌の腫瘍細胞株を樹立するとともに、腫瘍内浸潤リンパ球からIL〜2にて、自家癌特異的キラーT細胞株およびヘルパーT細胞株を樹立した。癌抗原ペプチドの提示分子が、自己MHC分子であるHLA-A31,HLA-A2601であることが証明された。さらに、HLA分子結合ペプチド画分の精製に成功した。2)自家癌反抗性キラーT細胞株から、完全長のTCRα,TCRβ鎖cDNAクローンを単離し、シーケンスを決定、発現ベクターに組み込んだ。3)癌化に伴い発現する糖鎖抗原や癌細胞表面に多量に発現する癌遺伝子産物(c-erbB2)に対し、宿主抗癌免疫活性を誘導する方法を開発した。以上により、人癌の免疫遺伝子治療に向けた癌抗原ペプチドの同定法や癌特異的免疫能の移入について知見の集積がなされ、今後の展開の基礎が確立された。
  • 文部科学省:科学研究費補助金(国際学術研究)
    研究期間 : 1994年 -1995年 
    代表者 : 笠原 正典, Pasquier Lou, Klain Jan, Flajnik Mart, 石橋 輝雄, 佐藤 啓介, 片桐 一, 永田 三郎, 栃内 新
     
    本研究では、1)下等脊椎動物からMHC(主要組織適合遺伝子複合体)遺伝子をクローニングすることにより、MHC遺伝子の系統発生学的起源を明らかにすること、2)軟骨魚類から哺乳類におよぶ多様な生物種のMHC遺伝子を解析することにより、MHC遺伝子の長期進化を規定する一般的な法則を明らかにすること、を目的とした。まず第一番目の目的に関しては、軟骨魚類には、多型性に富んだ典型的なMHC遺伝子が存在することを明らかにした。しかし、それより下等な脊椎動物である無顎類からMHCクラスI,II遺伝子を分離しようとする試みは、現在のところすべて失敗に終わっている。したがって、無顎類にはMHC遺伝子は存在しないか、あるいは、存在するとしても他の脊椎動物のMHC遺伝子とはかなり配列が異なっているものと推定された。最近、我々は、軟骨魚類にはプロテアソームのサブユニットをコードするLMP7,LMPX両遺伝子が存在するのに対し、無顎類にはLMPX遺伝子しか存在しないことを示唆するデータを得た。これらの結果を総合すると、無顎類には典型的なMHC遺伝子が存在しない可能性が示唆された。また、MHC遺伝子の長期進化を規定する一般的な特徴として、以下の3点を同定した。1)MHC遺伝子では、種間配列保存の程度が低いにも関わらず、全体的なドメイン構造はよく保存されている。2)機能的に重要なMHC遺伝子の数はヒトからサ...
  • 文部科学省:科学研究費補助金(重点領域研究)
    研究期間 : 1994年 -1994年 
    代表者 : 石橋 輝雄, 西野 秀昭, 笠原 正典, 荒磯 恒久
     
    細胞の生命維持には膜タンパク質の働きが必須であるが、その活性は生体膜脂質が構成する周囲の微小環境により調節されている。生体膜は生理的条件下では液晶(Lα)二重層構造を有しているが、刺激によりその一部が非二重層構造をとり膜構築の乱れを生じ、膜タンパク質の高次構造や機能に重要な影響を与えるものと思われる。一方生体膜融合は細胞の食作用や分泌、シナプスに於ける神経伝達物質の放出など、生理機能に重要な役割をもつ。膜融合は二つの膜が接着し、膜脂質分子の再配列を経て膜が開裂する過程が含まれる。脂質膜分子の再配列機構は、膜融合が引き起こされる誘因によって大きく異なるが、膜構成成分にPE(phosphatidylathanolamine)、DG(diacylglycerol)やコレステロールなど極性頭部の小さい脂質を含む脂質二重層は、非二重相構造である逆ヘキサゴナル相を取り易いことから、逆ミセル形中間体(inverted micelle intermediate)を経て融合が進行するものと考えられる。本研究では細胞内情報伝達のセカンドメッセンジャーとして重要なDGと膜構成に必須なコレステロールが生体膜液晶相(Lα)の逆ヘキサゴナル相(H_)への相転移や膜リン脂質の分子運動にどの様な影響を与え、生体膜微細構造の調節に如何に関与するかを明らかにした。
  • 文部科学省:科学研究費補助金(重点領域研究)
    研究期間 : 1994年 -1994年 
    代表者 : 菊地 浩吉, 松浦 晃洋, 益子 高, 笠原 正典, 神奈木 玲児, 伊東 恭悟
     
    癌は遺伝子の病気であり、遺伝子変異に伴い細胞増殖や生存に有利な形質を獲得するとともに腫瘍抗原を発現するに到る。本研究は人癌とくにヒト固型癌の自家T細胞による免疫学的癌抗原認識、拒絶の分子機構を明らかにすることを目的とする。本年度の成果を要約する。1)日本人に多い胃癌・食堂癌の腫瘍内浸潤リンパ球からIL-2にて、自家癌特異的キラーT細胞株およびヘルパーT細胞株を樹立した。抗HLA抗体による阻害活性から、癌抗原ペプチドの提示分子が、自己MHC分子であるHLA-A31,HLA-12601であることが証明された。さらに、酸処理によるHLA分子結合ペプチド画分の精製に成功した。2)自家癌反応性キラーT細胞株のT細胞レセプターusageを検討し、TCRα,TCRβ鎖cDNAクローンを単離し、一次構造を決定した。3)癌細胞表面に多量に発現する癌遺伝子産物(c-erbB2)や癌化に伴い発現する糖鎖抗原に対し、宿主抗癌免疫活性を誘導する方法を開発した。以上により、人癌の免疫遺伝子治療に向けた癌抗原ペプチドの同定法や癌特異的免疫能の移入についての知見の集積がなされ、今後の展開の基礎が確立された。
  • 文部科学省:科学研究費補助金(一般研究(C))
    研究期間 : 1993年 -1994年 
    代表者 : 笠原 正典
     
    本研究では、1)下等脊椎動物からMHC主要組織適合遺伝子複合体)遺伝子をクローニングすることにより、MHC遺伝子の系統発生学的起源を明らかにすること、2)軟骨魚類から哺乳類におよぶ多様な生物種のMHC遺伝子を解析することにより、MHC遺伝子の長期進化を規定する一般的な法則を明らかにすること、を目的とした。まず第一番目の目的に関しては、軟骨魚類には、多型性に富んだ典型的なMHC遺伝子が存在することを明らかにした。しかし、それより下等な脊椎動物である無顎類からM HCクラスI、II遺伝子を分離しようとする試みは、現在のところすべて失敗に終わっている。したがって、無顎類にはMHC遺伝子は存在しないか、あるいは、存在するとしても他の脊椎動物のMHC遺伝子とはかなり配列が異なっているものと推定された。最近、我々は、軟骨魚類にはプロテアソームのサブユニットをコードするLMP7、LMPX両遺伝子が存在するのに対し、無顎類にはLMPX遺伝子しか存在しないことを示唆するデータを得た。これらの結果を総合すると、無顎類には典型的なMHC遺伝子が存在しない可能性が示唆された。また、MHC遺伝子の長期進化を規定する一般的な特徴として、以下の3点を同定した。1) MHC遺伝子では、種間配列保存の程度が低いにも関わらず、全体的なドメイン構造はよく保存されている。2) 機能的に重要なMHC遺伝子の数はヒトか...
  • 文部科学省:科学研究費補助金(総合研究(A))
    研究期間 : 1993年 -1994年 
    代表者 : 高畑 尚之, 堀 寛, 池村 淑道, 笠原 正典, 小幡 裕一, 笹月 健彦
     
    自己・非自己識別分子MHCの起源は、脊椎動物の出現時期とほぼ同一であることが明らかになった。橋本や笠原は、世界に先駆けて軟骨魚類のMHCの単離に成功し、その多様性のあり方が基本的には哺乳類のものと同じであることを示した。堀は魚類におけるMHCの遺伝子構成に注目し、3種のクラスII遺伝子群の存在を確認した。しかし、より下等な無鰐類からMHC遺伝子を単離する試みはすべて失敗に終わっていて、その他の知見と合わせMHC分子の出現が無鰐類の出現以降であったことが示唆された。以上は脊椎動物免疫系の起源が5億程前のカンブリア紀であり、このときMHCの他に免疫グロブリンやT細胞受容体分子なども同時に進化したことを示している。自己・非自己識別に重要な役割を担っている分子は古典的MHCであるが、機能が不明確な非古典的MHCも多数存在する。小幡、森脇と高畑はマウスの非古典的MHCであるTLに注目し、腸で強く発現することの生物的意義が特種な寄生体への対応であるという仮説をたてた。これを検証するためにTL特異的に結合するペプチドの単離を急いでいる。これは中枢免疫と局所免疫の関係など新しい問題を含んでいる。ヒトMHC(HLA)領域の遺伝的多様性と様々な疾患を明らかにするため、猪子、池村と笹月は4Mb領域の遺伝解析を進め、遺伝子密度、GC量、組換えホットスポット、DNAの複製点などの同定を行った。このこと...
  • 文部科学省:科学研究費補助金(重点領域研究)
    研究期間 : 1993年 -1993年 
    代表者 : 笠原 正典, 西野 秀昭, 石橋 輝雄
     
    1.TAP〔Transporter associated with antigen presentation〕分子はサイトゾルから小胞体内腔へペプチドを輸送することにより主要組織適合遺伝子複合体〔Major Histocompatibility Complex:MHC〕クラスI分子にペプチドを供給する。ラットではTAP遺伝子に多型が存在し、TAP遺伝子の多型によってMHCクラスI分子に結合するペプチドのレパトアが変化する。我々はヒトTAP〔TAP1,TAP2〕遺伝子に多型が存在するか否かを検討した。その結果、3個のTAP1アリルと5個のTAP2アリルの存在が確認された。しかし、アリル産物間のアミノ酸置換は1〜3個しかなく、しかも置換の大部分はペプチド輸送の特異性に影響を及ぼさないと思われるATP結合ドメインに位置していた。このことから、ヒトTAP遺伝子の多型によって疾患感受性が規定される可能性は低いことが示唆された。2.TAP遺伝子に機能的に意義のある(すなわち、MHCクラスI分子に結合するペプチドのレパトアを変化させるような)多型のある唯一の動物種であるラットのクラスI遺伝子には、低レベルの多型しか存在しない。一般的に、MHCクラスI遺伝子自体に多型の乏しい動物では、TAP遺伝子の多型によってMHCクラスI分子に結合するペプチドのレパトアの個体差が生み出されているのかも知れ...

教育活動情報

主要な担当授業

  • 研究発表技法Ⅰ
    開講年度 : 2018年
    課程区分 : 修士課程
    開講学部 : 医学院
  • 基本医学研究
    開講年度 : 2018年
    課程区分 : 修士課程
    開講学部 : 医学院
    キーワード : 病理学の基礎
  • 研究発表技法Ⅱ
    開講年度 : 2018年
    課程区分 : 修士課程
    開講学部 : 医学院
  • 基本医学総論
    開講年度 : 2018年
    課程区分 : 修士課程
    開講学部 : 医学院
    キーワード : 細胞と組織の基本的病的変化,疾患の種類と分類,疾患の病因と病態、がんプロフェッショナル
  • 研究発表技法Ⅰ
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 医学研究科
  • 医学総論
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 医学院
    キーワード : 疾患の分子機構、腫瘍病理学、医療と病理診断、がんプロフェッショナル
  • 研究発表技法Ⅱ
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 医学研究科
  • 基盤医学研究
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 医学院
    キーワード : 実験病理学、人体病理学
  • 基盤医学研究Ⅱ
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 医学研究科
  • 臨床病理学
    開講年度 : 2018年
    課程区分 : 学士課程
    開講学部 : 医学部
    キーワード : 臨床診断、病理診断、診断の根拠と鑑別診断、治療の評価
  • 基盤医学研究Ⅰ
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 医学研究科
  • 病理学
    開講年度 : 2018年
    課程区分 : 学士課程
    開講学部 : 医学部
    キーワード : 細胞と組織の基本的病的変化,疾患の種類と分類,疾患の病因と病態
  • 医学総論
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 医学研究科
  • 病理学演習
    開講年度 : 2018年
    課程区分 : 学士課程
    開講学部 : 医学部
    キーワード : 肉眼的病理診断、組織学的病理診断、最終診断、個体の総合的病態、ポスター/スライド発表
  • 研究発表技法Ⅰ
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 医学院
  • 病理学実習
    開講年度 : 2018年
    課程区分 : 学士課程
    開講学部 : 医学部
    キーワード : 組織病理、光学顕微鏡、バーチャルスライド、免疫染色、スケッチ
  • 研究発表技法Ⅱ
    開講年度 : 2018年
    課程区分 : 博士後期課程
    開講学部 : 医学院
  • 臨床病理学
    開講年度 : 2018年
    課程区分 : 学士課程
    開講学部 : 医学部

大学運営

学内役職歴

  • 2013年4月1日 - 2015年3月31日 医学部長
  • 2013年4月1日 - 2015年3月31日 教育研究評議会評議員
  • 2013年4月1日 - 2015年3月31日 大学院医学研究科長
  • 2015年4月1日 - 2017年3月31日 医学部長
  • 2015年4月1日 - 2017年3月31日 教育研究評議会評議員
  • 2015年4月1日 - 2017年3月31日 大学院医学研究科長
  • 2017年10月26日 - 2019年3月31日 経営戦略室室長代理
  • 2017年4月1日 - 2017年10月26日 企画・経営室室長
  • 2017年4月1日 -  技術支援本部長
  • 2017年4月1日 -  国際連携機構長
  • 2017年4月1日 -  国際連携研究教育局 副局長
  • 2017年4月1日 -  人材育成本部長
  • 2017年4月1日 -  大学力強化推進本部副本部長
  • 2019年4月1日 -  経営戦略室室長代理

委員歴

  • 2018年 - 現在   日本胸腺研究会   特別会員
  • 2013年 - 現在   日本組織適合性学会   理事
  • 2008年 - 現在   日本組織適合性学会   評議員
  • 1997年 - 現在   日本免疫学会   評議員   日本免疫学会
  • 1998年 - 2019年   日本生化学会   評議員   日本生化学会
  • 2018年 - 2018年   日本病理学会   総会会長
  • 2013年 - 2018年   日本胸腺研究会   監事
  • 2017年 - 2017年   日本比較免疫学会   学術集会会長
  • 2016年 - 2016年   日本組織適合性学会   学術集会会長
  • 2014年 - 2016年   日本癌学会   評議員
  • 2012年 - 2016年   日本病理学会   理事   日本病理学会
  • 2012年 - 2016年   日本比較免疫学会   会長
  • 2013年 - 2013年   日本胸腺研究会   会長
  • 2006年 - 2008年   日本学術会議   連携会員


Copyright © MEDIA FUSION Co.,Ltd. All rights reserved.