Researcher basic information

• (BLANK), Hokkaido University

• https://researchmap.jp/read0074110?lang=en

• https://jglobal.jst.go.jp/detail?JGLOBAL_ID=200901033482069243
• http://rep-dev.s2.weblife.me/index.html

• 200901033482069243

• Life Science, Cell biology
• Life Science, Molecular biology
• Life Science, Morphology and anatomical structure

• Bachelor's degree program, School of Science
• Master's degree program, Graduate School of Life Science
• Doctoral (PhD) degree program, Graduate School of Life Science

Research activity information

• Optochemical elucidation of a critical role of the incomplete spindle assembly checkpoint in zebrafish development.
  Akira Matsura; Miyu Hosono; Kazuya Matsuo; Nobuyuki Tamaoki; Tomoya Kotani; Ryota Uehara
  Communications biology, 23 Mar. 2026, [Peer-reviewed], [International Magazine]
  English, Scientific journal, Early animal embryos must balance the efficiency with the accuracy of mitotic control. However, the extent of mitotic errors that can be safely endured at different stages of development is unclear. In this study, using a recently developed photoswitchable CENP-E inhibitor, we introduce transient mitotic errors at various developmental windows and systematically address their organismal effects. Upon CENP-E inhibition in the pre-gastrula period, embryos suffer gradual aggravation of developmental defects as the duration of the inhibition extends. Conversely, embryos tolerate several hours of consecutive CENP-E inhibition in the gastrula period, frequently achieving full development. Live imaging reveals that chromosome misalignment caused by CENP-E inhibition results in a modest mitotic delay in the gastrula, but not in the early pre-gastrula period, suggesting the gradual functionalization of the spindle assembly checkpoint (SAC) at this stage. This mitotic delay helps alleviate, though not perfectly resolve, polar chromosome misalignment before anaphase onset. Importantly, pharmacological suppression of SAC renders gastrula embryos inviable upon CENP-E inhibition. Therefore, despite its leaky nature, the embryonic SAC contributes to partial mitotic error correction, which proves essential to manage consecutive mitotic perturbations. Our results demonstrate the power of optochemical approaches in understanding the robust control of dynamic processes in development.
• Revealing a critical role of the incomplete spindle assembly checkpoint in zebrafish development through an optochemical approach
  Ryota Uehara; Akira Matsura; Miyu Hosono; Kazuya Mastuo; Nobuyuki Tamaoki; Tomoya Kotani
  Springer Science and Business Media LLC, 30 Jul. 2025
  Abstract

  Early animal embryos must balance the efficiency with the accuracy of mitotic control. However, the extent of mitotic errors that can be safely endured at different stages of development is unclear. In this study, using a recently developed photoswitchable CENP-E inhibitor, we introduced transient mitotic errors at various developmental windows and systematically addressed their organismal effects. Upon CENP-E inhibition in the pre-gastrula period, embryos suffered gradual aggravation of developmental defects as the duration of the inhibition extended. Conversely, embryos tolerated several hours of consecutive CENP-E inhibition in the gastrula period, frequently achieving full development. Live imaging revealed that chromosome misalignment caused by CENP-E inhibition resulted in a modest mitotic delay in the gastrula, but not in the early pre-gastrula period, suggesting the functionalization of the spindle assembly checkpoint (SAC) at this stage. This mitotic delay helped alleviate, though not perfectly resolve, polar chromosome misalignment before anaphase onset. Importantly, pharmacological suppression of SAC rendered gastrula embryos inviable upon CENP-E inhibition. Therefore, despite its leaky nature, the embryonic SAC contributed to partial mitotic error correction, which proved essential to manage consecutive mitotic perturbations. Our results demonstrate the power of optochemical approaches in understanding the robust control of dynamic processes in development.

• Comprehensive analysis of mRNA 3' ends during early zebrafish development reveals dynamics of 3'UTR changes on a genome-wide scale.
  Ludivine Fierro; Anna Ishii; Haruka Aoyama; Toshihiro Arae; Yukako Chiba; Tomoya Kotani
  FEBS letters, 01 Jul. 2025, [International Magazine]
  English, Scientific journal, Eggs accumulate more than 10 000 mRNAs, from which proteins are synthesized constitutively or in a temporally controlled manner. Although changes in the translation state of these mRNAs are crucial for early development, how embryos orchestrate them remains unclear. Here, we investigated changes in mRNA 3' untranslated regions (UTRs) using 3' end-RNA sequencing of zebrafish embryos and computational methods. Consistent with our previous finding that pou5f3 mRNA is shortened at the 3'UTR during early development, thousands of mRNAs showed shortening of the 3'UTRs. Moreover, we found that most mRNAs in embryos contained several different 3' ends and their proportion was dynamically changed. These changes were coupled with protein synthesis. Our results reveal genome-wide 3'-end dynamics in the regulation of biological processes.
• Haploidy-linked cell proliferation defects limit larval growth in zebrafish.
  Kan Yaguchi; Daiki Saito; Triveni Menon; Akira Matsura; Miyu Hosono; Takeomi Mizutani; Tomoya Kotani; Sreelaja Nair; Ryota Uehara
  Open biology, 14, 10, 240126, 240126, Oct. 2024, [International Magazine]
  English, Scientific journal, Haploid larvae in non-mammalian vertebrates are lethal, with characteristic organ growth retardation collectively called 'haploid syndrome'. In contrast to mammals, whose haploid intolerance is attributed to imprinting misregulation, the cellular principle of haploidy-linked defects in non-mammalian vertebrates remains unknown. Here, we investigated cellular defects that disrupt the ontogeny of gynogenetic haploid zebrafish larvae. Unlike diploid control larvae, haploid larvae manifested unscheduled cell death at the organogenesis stage, attributed to haploidy-linked p53 upregulation. Moreover, we found that haploid larvae specifically suffered the gradual aggravation of mitotic spindle monopolarization during 1-3 days post-fertilization, causing spindle assembly checkpoint-mediated mitotic arrest throughout the entire body. High-resolution imaging revealed that this mitotic defect accompanied the haploidy-linked centrosome loss occurring concomitantly with the gradual decrease in larval cell size. Either resolution of mitotic arrest or depletion of p53 partially improved organ growth in haploid larvae. Based on these results, we propose that haploidy-linked mitotic defects and cell death are parts of critical cellular causes shared among vertebrates that limit the larval growth in the haploid state, contributing to an evolutionary constraint on allowable ploidy status in the vertebrate life cycle.
• High-sensitivity whole-mount in situ Hybridization of Mouse Oocytes and Embryos Visualizes the Super-resolution Structures and Distributions of mRNA Molecules
  Takahiro Sanada; Tomoya Kotani
  Biological Procedures Online, 26, 1, Springer Science and Business Media LLC, 10 Jul. 2024, [Peer-reviewed]
  Scientific journal, Abstract
  
  Mammalian oocytes accumulate more than ten thousand mRNAs, of which three to four thousand mRNAs are translationally repressed. The timings and sites of translational activation of these dormant mRNAs are crucial for promoting oocyte maturation and embryonic development. How these mRNAs are accumulated and distributed in oocytes is therefore a fundamental issue to be explored. A method that enables visualization of mRNA molecules with high resolution in a simple manner would be valuable for understanding how oocytes accumulate and regulate the dormant mRNAs. We have developed a highly sensitive whole-mount in situ hybridization method using in vitro-synthesized RNA probes and the tyramide signal amplification (TSA) system optimized for mouse oocytes and embryos. By using this method, Pou5f1/Oct4, Emi2, and cyclin B1 mRNAs were detected in immature oocytes and 2-cell stage embryos. Confocal microscopy showed that these mRNAs formed granular structures in the oocyte cytoplasm. The structures of Pou5f1/Oct4 and cyclin B1 mRNAs persisted in 2-cell stage embryos. Pou5f1/Oct4 RNA granules exhibited a solid-like property in immature oocytes and became liquid-like droplets in 2-cell stage embryos. Double-staining of cyclin B1 mRNA with Emi2 or Pou5f1/Oct4 mRNA revealed that these mRNAs were distributed as different RNA granules without overlapping each other and that the size of cyclin B1 RNA granules tended to be larger than that of Emi2 RNA granules. The structures and distribution patterns of these mRNAs were further analyzed by N-SIM super-resolution microscopy. This analysis revealed that the large-sized RNA granules consist of many small-sized granules, suggesting the accumulation and regulation of dormant mRNAs as basal-sized RNA granules. The method established in this study can easily visualize the structure and distribution of mRNAs accumulated in mammalian oocytes and embryos with high sensitivity and super-resolution. This method is useful for investigating the cellular and molecular mechanisms of translational control of mRNAs by which maturation and early developmental processes are promoted.
• Visualizing the translational activation of a particular mRNA in zebrafish embryos using in situ hybridization and proximity ligation assay.
  Keisuke Sato; Tomoya Kotani
  STAR protocols, 5, 2, 102951, 102951, 15 Mar. 2024, [Peer-reviewed], [International Magazine]
  English, Scientific journal, Fertilized eggs initiate translation of stored mRNAs in spatially and temporally controlled manners. Here, we present a protocol for visualizing spatial and temporal translation in zebrafish embryos by fluorescence in situ hybridization and proximity ligation assay. We describe steps for labeling newly synthesized proteins and mRNA, visualizing mRNA translation and mRNA, sample mounting, and observation. Coupling detection of mRNA molecules with their translation sites is useful for understanding the molecular and cellular mechanisms that drive embryo development. For complete details on the use and execution of this protocol, please refer to Sato et al.1 and Takada et al.2.
• Mature mRNA processing that deletes 3′ end sequences directs translational activation and embryonic development
  Yuki Takada; Ludivine Fierro; Keisuke Sato; Takahiro Sanada; Anna Ishii; Takehiro Yamamoto; Tomoya Kotani
  Science Advances, 9, 47, American Association for the Advancement of Science (AAAS), 24 Nov. 2023, [Peer-reviewed]
  Scientific journal, Eggs accumulate thousands of translationally repressed mRNAs that are translated into proteins after fertilization to direct diverse developmental processes. However, molecular mechanisms underlying the translation of stored mRNAs after fertilization remain unclear. Here, we report a previously unknown RNA processing of 3′ end sequences of mature mRNAs that activates the translation of stored mRNAs. Specifically, 9 to 72 nucleotides at the 3′ ends of zebrafish pou5f3 and mouse Pou5f1 mRNAs were deleted in the early stages of development. Reporter assays illustrated the effective translation of the truncated forms of mRNAs. Moreover, promotion and inhibition of the shortening of 3′ ends accelerated and attenuated Pou5f3 accumulation, respectively, resulting in defective development. Identification of proteins binding to unprocessed and/or processed mRNAs revealed that mRNA shortening acts as molecular switches. Comprehensive analysis revealed that >250 mRNAs underwent this processing. Therefore, our results provide a molecular principle that triggers the translational activation and directs development.
• Identification of embryonic RNA granules that act as sites of mRNA translation after changing their physical properties.
  Keisuke Sato; Moeko Sakai; Anna Ishii; Kaori Maehata; Yuki Takada; Kyota Yasuda; Tomoya Kotani
  iScience, 25, 6, 104344, 104344, 17 Jun. 2022, [Peer-reviewed], [International Magazine]
  English, Scientific journal, Fertilized eggs begin to translate mRNAs at appropriate times and placements to control development, but how the translation is regulated remains unclear. Here, we found that pou5f3 mRNA encoding a transcriptional factor essential for development formed granules in a dormant state in zebrafish oocytes. Although the number of pou5f3 granules remained constant, Pou5f3 protein accumulated after fertilization. Intriguingly, signals of newly synthesized peptides and a ribosomal protein became colocalized with pou5f3 granules after fertilization and, moreover, nascent Pou5f3 was shown to be synthesized in the granules. This functional change was accompanied by changes in the state and internal structure of granules. Dissolution of the granules reduced the rate of protein synthesis. Similarly, nanog and sox19b mRNAs in zebrafish and Pou5f1/Oct4 mRNA in mouse assembled into granules. Our results reveal that subcellular compartments, termed embryonic RNA granules, function as activation sites of translation after changing physical properties for directing vertebrate development.
• Tdrd3 regulates the progression of meiosis II through translational control of Emi2 mRNA in mouse oocytes
  Natsumi Takei; Keisuke Sato; Yuki Takada; Rajan Iyyappan; Andrej Susor; Takehiro Yamamoto; Tomoya Kotani
  Current Research in Cell Biology, 100009, 100009, Elsevier {BV}, Jun. 2021, [Peer-reviewed]
  Scientific journal
• A Testis-Specific Long Noncoding RNA, Start, Is a Regulator of Steroidogenesis in Mouse Leydig Cells.
  Kai Otsuka; Shin Matsubara; Akira Shiraishi; Natsumi Takei; Yui Satoh; Miho Terao; Shuji Takada; Tomoya Kotani; Honoo Satake; Atsushi P Kimura
  Frontiers in endocrinology, 12, 665874, 665874, 2021, [Peer-reviewed], [International Magazine]
  English, Scientific journal, The testis expresses many long noncoding RNAs (lncRNAs), but their functions and overview of lncRNA variety are not well understood. The mouse Prss/Tessp locus contains six serine protease genes and two lncRNAs that have been suggested to play important roles in spermatogenesis. Here, we found a novel testis-specific lncRNA, Start (Steroidogenesis activating lncRNA in testis), in this locus. Start is 1822 nucleotides in length and was found to be localized mostly in the cytosol of germ cells and Leydig cells, although nuclear localization was also observed. Start-knockout (KO) mice generated by the CRISPR/Cas9 system were fertile and showed no morphological abnormality in adults. However, in adult Start-KO testes, RNA-seq and qRT-PCR analyses revealed an increase in the expression of steroidogenic genes such as Star and Hsd3b1, while ELISA analysis revealed that the testosterone levels in serum and testis were significantly low. Interestingly, at 8 days postpartum, both steroidogenic gene expression and testosterone level were decreased in Start-KO mice. Since overexpression of Start in two Leydig-derived cell lines resulted in elevation of the expression of steroidogenic genes including Star and Hsd3b1, Start is likely to be involved in their upregulation. The increase in expression of steroidogenic genes in adult Start-KO testes might be caused by a secondary effect via the androgen receptor autocrine pathway or the hypothalamus-pituitary-gonadal axis. Additionally, we observed a reduced number of Leydig cells at 8 days postpartum. Collectively, our results strongly suggest that Start is a regulator of steroidogenesis in Leydig cells. The current study provides an insight into the overall picture of the function of testis lncRNAs.
• Changes in subcellular structures and states of Pumilio1 regulate the translation of target Mad2 and Cyclin B1 mRNAs.
  Natsumi Takei; Yuki Takada; Shohei Kawamura; Keisuke Sato; Atsushi Saitoh; Jenny Bormann; Wai Shan Yuen; John Carroll; Tomoya Kotani
  Journal of cell science, 04 Nov. 2020, [Peer-reviewed], [International Magazine]
  English, Scientific journal, Temporal and spatial control of mRNA translation has emerged as a major mechanism for promoting diverse biological processes. However, the molecular nature of temporal and spatial control of translation remains unclear. In oocytes, many mRNAs are deposited as a translationally repressed form and are translated at appropriate timings to promote the progression of meiosis and development. Here, we show that changes in subcellular structures and states of the RNA-binding protein Pumilio1 regulate the translation of target mRNAs and progression of oocyte maturation. Pumilio1 was shown to bind to Mad2 and Cyclin B1 mRNAs, assemble highly clustered aggregates, and surround Mad2 and Cyclin B1 RNA granules in mouse oocytes. These Pumilio1 aggregates were dissolved prior to the translational activation of target mRNAs possibly by phosphorylation. Stabilization of Pumilio1 aggregates prevented the translational activation of target mRNAs and progression of oocyte maturation. Together, our results provide an aggregation-dissolution model for the temporal and spatial control of translation.
• Posttranscriptional regulation of maternal Pou5f1/Oct4 during mouse oogenesis and early embryogenesis.
  Yuki Takada; Rajan Iyyappan; Andrej Susor; Tomoya Kotani
  Histochemistry and cell biology, 15 Sep. 2020, [Peer-reviewed], [International Magazine]
  English, Scientific journal, Protein syntheses at appropriate timings are important for promoting diverse biological processes and are controlled at the levels of transcription and translation. Pou5f1/Oct4 is a transcription factor that is essential for vertebrate embryonic development. However, the precise timings when the mRNA and protein of Pou5f1/Oct4 are expressed during oogenesis and early stages of embryogenesis remain unclear. We analyzed the expression patterns of mRNA and protein of Pou5f1/Oct4 in mouse oocytes and embryos by using a highly sensitive in situ hybridization method and a monoclonal antibody specific to Pou5f1/Oct4, respectively. Pou5f1/Oct4 mRNA was detected in growing oocytes from the primary follicle stage to the fully grown GV stage during oogenesis. In contrast, Pou5f1/Oct4 protein was undetectable during oogenesis, oocyte maturation and the first cleavage stage but subsequently became detectable in the nuclei of early 2-cell-stage embryos. Pou5f1/Oct4 protein at this stage was synthesized from maternal mRNAs stored in oocytes. The amount of Pou5f1/Oct4 mRNA in the polysomal fraction was small in GV-stage oocytes but was significantly increased in fertilized eggs. Taken together, our results indicate that the synthesis of Pou5f1/Oct4 protein during oogenesis and early stages of embryogenesis is controlled at the level of translation and suggest that precise control of the amount of this protein by translational regulation is important for oocyte development and early embryonic development.
• Vitrification-induced activation of lysosomal cathepsin B perturbs spindle assembly checkpoint function in mouse oocytes.
  Ahmed Z Balboula; Karen Schindler; Tomoya Kotani; Manabu Kawahara; Masashi Takahashi
  Molecular human reproduction, 26, 9, 689, 701, 01 Sep. 2020, [Peer-reviewed], [International Magazine]
  English, Scientific journal, As the age of child-bearing increases and correlates with infertility, cryopreservation of female gametes is becoming common-place in ART. However, the developmental competence of vitrified oocytes has remained low. The underlying mechanisms responsible for reduced oocyte quality post-vitrification are largely unknown. Mouse cumulus-oocyte complexes were vitrified using a cryoloop technique and a mixture of dimethylsulphoxide, ethylene glycol and trehalose as cryoprotectants. Fresh and vitrified/thawed oocytes were compared for chromosome alignment, spindle morphology, kinetochore-microtubule attachments, spindle assembly checkpoint (SAC) and aneuploidy. Although the majority of vitrified oocytes extruded the first polar body (PB), they had a significant increase of chromosome misalignment, abnormal spindle formation and aneuploidy at metaphase II. In contrast to controls, vitrified oocytes extruded the first PB in the presence of nocodazole and etoposide, which should induce metaphase I arrest in a SAC-dependent manner. The fluorescence intensity of mitotic arrest deficient 2 (MAD2), an essential SAC protein, at kinetochores was reduced in vitrified oocytes, indicating that the SAC is weakened after vitrification/thawing. Furthermore, we found that vitrification-associated stress disrupted lysosomal function and stimulated cathepsin B activity, with a subsequent activation of caspase 3. MAD2 localization and SAC function in vitrified oocytes were restored upon treatment with a cathepsin B or a caspase 3 inhibitor. This study was conducted using mouse oocytes, therefore confirming these results in human oocytes is a prerequisite before applying these findings in IVF clinics. Here, we uncovered underlying molecular pathways that contribute to an understanding of how vitrification compromises oocyte quality. Regulating these pathways will be a step toward improving oocyte quality post vitrification and potentially increasing the efficiency of the vitrification program.
• Function of leukaemia inhibitory factor in spermatogenesis of a teleost fish, the medaka Oryzias latipes.
  Satoh R; Bando H; Sakai N; Kotani T; Yamashita M
  Zygote (Cambridge, England), 27, 6, 423, 431, Dec. 2019, [Peer-reviewed]
• A novel testis-specific long noncoding RNA, Tesra, activates the Prss42/Tessp-2 gene during mouse spermatogenesis.
  Satoh Y; Takei N; Kawamura S; Takahashi N; Kotani T; Kimura AP
  Biology of reproduction, 100, 3, 833, 848, Mar. 2019, [Peer-reviewed]
• Pumilio1 phosphorylation precedes translational activation of its target mRNA in zebrafish oocytes.
  Saitoh A; Takada Y; Horie M; Kotani T
  Zygote (Cambridge, England), 1, 9, Oct. 2018, [Peer-reviewed]
• High-Sensitivity and High-Resolution in Situ Hybridization of Coding and Long Non-coding RNAs in Vertebrate Ovaries and Testes
  Natsumi Takei; Takuma Nakamura; Shohei Kawamura; Yuki Takada; Yui Satoh; Atsushi P. Kimura; Tomoya Kotani
  Biological Procedures Online, 20, 1, 6, BioMed Central Ltd., 01 Mar. 2018, [Peer-reviewed]
  English, Scientific journal
• Regulation of translationally repressed mRNAs in zebrafish and mouse Oocytes
  Tomoya Kotani; Kaori Maehata; Natsumi Takei
  Results and Problems in Cell Differentiation, 63, 297, 324, Springer Verlag, 2017, [Peer-reviewed], [Invited]
  English, In book
• Formation of mos RNA granules in the zebrafish oocyte that differ from cyclin B1 RNA granules in distribution, density and regulation
  Mayu Horie; Tomoya Kotani
  EUROPEAN JOURNAL OF CELL BIOLOGY, 95, 12, 563, 573, Dec. 2016, [Peer-reviewed]
  English, Scientific journal
• A Genomic Region Transcribed Into a Long Noncoding RNA Interacts With the Prss42/Tessp-2 Promoter in Spermatocytes During Mouse Spermatogenesis, and Its Flanking Sequences Can Function as Enhancers
  Ryoma Yoneda; Yui Satoh; Ikuya Yoshida; Shohei Kawamura; Tomoya Kotani; Atsushi P. Kimura
  MOLECULAR REPRODUCTION AND DEVELOPMENT, 83, 6, 541, 557, Jun. 2016, [Peer-reviewed]
  English, Scientific journal
• Real-Time Imaging of Actin Filaments in the Zebrafish Oocyte and Embryo
  Yumiko Nukada; Mayu Horie; Akimasa Fukui; Tomoya Kotani; Masakane Yamashita
  CYTOSKELETON, 72, 9, 491, 501, Sep. 2015, [Peer-reviewed]
  English, Scientific journal
• Possible involvement of insulin-like growth factor 2 mRNA-binding protein 3 in zebrafish oocyte maturation as a novel cyclin B1 mRNA-binding protein that represses the translation in immature oocytes
  Kazuki Takahashi; Tomoya Kotani; Yoshinao Katsu; Masakane Yamashita
  BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS, 448, 1, 22, 27, May 2014, [Peer-reviewed]
  English, Scientific journal
• A cis-acting element in the coding region of cyclin B1 mRNA couples subcellular localization to translational timing
  Kyota Yasuda; Tomoya Kotani; Masakane Yamashita
  DEVELOPMENTAL BIOLOGY, 382, 2, 517, 529, Oct. 2013, [Peer-reviewed]
  English, Scientific journal
• Cyclin B1 mRNA translation is temporally controlled through formation and disassembly of RNA granules
  Tomoya Kotani; Kyota Yasuda; Ryoma Ota; Masakane Yamashita
  Journal of Cell Biology, 202, 7, 1041, 1055, 7, 2013, [Peer-reviewed]
  English, Scientific journal
• PROTEIN KINASE A ACTIVITY AND HEDGEHOG SIGNALING PATHWAY
  Tomoya Kotani
  VITAMINS AND HORMONES: HEDGEHOG SIGNALING, 88, 273, 291, 2012, [Peer-reviewed], [Invited]
  English, In book
• Possible Involvement of Nemo-like Kinase 1 in Xenopus Oocyte Maturation As a Kinase Responsible for Pumilio1, Pumilio2, and CPEB Phosphorylation
  Ryoma Ota; Tomoya Kotani; Masakane Yamashita
  BIOCHEMISTRY, 50, 25, 5648, 5659, Jun. 2011, [Peer-reviewed]
  English, Scientific journal
• Genetic visualization with an improved GCaMP calcium indicator reveals spatiotemporal activation of the spinal motor neurons in zebrafish
  Akira Muto; Masamichi Ohkura; Tomoya Kotani; Shin-ichi Higashijima; Junichi Nakai; Koichi Kawakami
  PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 108, 13, 5425, 5430, Mar. 2011, [Peer-reviewed]
  English, Scientific journal
• Biochemical Characterization of Pumilio1 and Pumilio2 in Xenopus Oocytes
  Ryoma Ota; Tomoya Kotani; Masakane Yamashita
  JOURNAL OF BIOLOGICAL CHEMISTRY, 286, 4, 2853, 2863, Jan. 2011, [Peer-reviewed]
  English, Scientific journal
• Transgenic zebrafish reveals novel mechanisms of translational control of cyclin B1 mRNA in oocytes
  Kyota Yasuda; Tomoya Kotani; Ryoma Ota; Masakane Yamashita
  DEVELOPMENTAL BIOLOGY, 348, 1, 76, 86, Dec. 2010, [Peer-reviewed]
  English, Scientific journal
• Visualization of spatially and temporally controlled translation by transgenesis
  Kotani Tomoya; Yasuda Kyota; Ota Ryoma; Yamashita Masakane
  GENES & GENETIC SYSTEMS, 85, 6, 416, 416, Dec. 2010, [Peer-reviewed]
  English
• Mys Protein Regulates Protein Kinase A Activity by Interacting with Regulatory Type I alpha Subunit during Vertebrate Development
  Tomoya Kotani; Shun-ichiro Iemura; Tohru Natsume; Koichi Kawakami; Masakane Yamashita
  JOURNAL OF BIOLOGICAL CHEMISTRY, 285, 7, 5106, 5116, Feb. 2010, [Peer-reviewed]
  English, Scientific journal
• Mys protein antagonizes Hedgehog signaling through activation of PKA during embryonic development
  Kotani Tomoya; Iemura Shun-ichiro; Natsume Tohru; Kawakami Koichi; Yamashita Masakane
  MECHANISMS OF DEVELOPMENT, 126, S324, Aug. 2009, [Peer-reviewed]
• Production of Transgenic Medaka Fish Carrying Fluorescent Nuclei and Chromosomes
  Toshiharu Iwai; Shinya Inoue; Tomoya Kotani; Masakane Yamashita
  ZOOLOGICAL SCIENCE, 26, 1, 9, 16, Jan. 2009, [Peer-reviewed]
  English, Scientific journal
• Possible Involvement of Phosphatidylinositol 3-Kinase, but Not Protein Kinase B or Glycogen Synthase Kinase 3 beta, in Progesterone-Induced Oocyte Maturation in the Japanese Brown Frog, Rana japonica
  Ryoma Ota; Kaori Suwa; Tomoya Kotani; Koich Mita; Masakane Yamashita
  ZOOLOGICAL SCIENCE, 25, 7, 773, 781, Jul. 2008, [Peer-reviewed]
  English, Scientific journal
• misty somites, a maternal effect gene identified by transposon-mediated insertional mutagenesis in zebrafish that is essential for the somite boundary maintenance
  Tomoya Kotani; Koichi Kawakami
  DEVELOPMENTAL BIOLOGY, 316, 2, 383, 396, Apr. 2008, [Peer-reviewed]
  English, Scientific journal
• Genetic dissection of neural circuits by Tol2 transposon-mediated Gal4 gene and enhancer trapping in zebrafish
  Kazuhide Asakawa; Maximiliano L. Suster; Kanta Mizusawa; Saori Nagayoshi; Tomoya Kotani; Akihiro Urasaki; Yasuyuki Kishimoto; Masahiko Hibi; Koichi Kawakami
  PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 105, 4, 1255, 1260, Jan. 2008, [Peer-reviewed]
  English, Scientific journal
• Transposon-mediated gene trapping in zebrafish
  Tomoya Kotani; Saori Nagayoshi; Akihiro Urasaki; Koichi Kawakami
  METHODS, 39, 3, 199, 206, Jul. 2006, [Peer-reviewed]
  English, Scientific journal
• Overexpression of truncated gamma-tubulins disrupts mitotic aster formation in Xenopus oocyte extracts
  T Kotani; M Yamashita
  BIOCHEMICAL JOURNAL, 389, 3, 611, 617, Aug. 2005, [Peer-reviewed]
  English, Scientific journal
• Behavior of gamma-tubulin during spindle formation in Xenopus oocytes: requirement of cytoplasmic dynein-dependent translocation
  T Kotani; M Yamashita
  ZYGOTE, 13, 3, 219, 226, Aug. 2005, [Peer-reviewed]
  English, Scientific journal
• [The transposon-mediated gene trap method in Zebrafish].
  Kotani T; Kawakami K
  Tanpakushitsu kakusan koso. Protein, nucleic acid, enzyme, 49, 13, 2111, 2116, Oct. 2004, [Peer-reviewed]
• Involvement of Xenopus Pumilio in the translational regulation that is specific to cyclin B1 mRNA during oocyte maturation
  S Nakahata; T Kotani; K Mita; T Kawasaki; Y Katsu; Y Nagahama; M Yamashita
  MECHANISMS OF DEVELOPMENT, 120, 8, 865, 880, Aug. 2003, [Peer-reviewed]
  English, Scientific journal
• Maturational factors as indicators of egg quality in Japanese eel, Anguilla japonica
  D. H.S. Shin; H. Matsubara; S. Kaneko; T. Kotani; M. Yamashita; S. Adachi; K. Yamauchi
  Fish Physiology and Biochemistry, 28, 1-4, 519, 520, 2003, [Peer-reviewed]
  English, Scientific journal
• Discrimination of the roles of MPF and MAP kinase in morphological changes that occur during oocyte maturation
  T Kotani; M Yamashita
  DEVELOPMENTAL BIOLOGY, 252, 2, 271, 286, Dec. 2002, [Peer-reviewed]
  English, Scientific journal
• Requirement of cyclin B2, but not cyclin B1, for bipolar spindle formation in frog (Rana japonica) oocytes
  T Kotani; N Yoshida; K Mita; M Yamashita
  MOLECULAR REPRODUCTION AND DEVELOPMENT, 59, 2, 199, 208, Jun. 2001, [Peer-reviewed]
  English, Scientific journal
• Dispersion of cyclin B mRNA aggregation is coupled with translational activation of the mRNA during zebrafish oocyte maturation
  T Kondo; T Kotani; M Yamashita
  DEVELOPMENTAL BIOLOGY, 229, 2, 421, 431, Jan. 2001, [Peer-reviewed]
  English, Scientific journal

• 卵母細胞の成熟に必須の翻訳制御
  小谷 友也, 細胞, 53, 13, 830, 833, Nov. 2021
  (株)ニュー・サイエンス社, Japanese
• Disassembly of Emi2 RNA granules in meiosis II is coupled with translational activation of mRNA in mouse oocytes
  Natsumi Takei; Ahmed Balboula; Masashi Takahashi; Tomoya Kotani, MECHANISMS OF DEVELOPMENT, 145, S92, S93, Jul. 2017
  English, Summary international conference
• 顆粒の形成と消失を介した時期特異的なcyclin B1mRNA翻訳制御
  小谷友也; 安田恭大; 太田龍馬; 山下正兼, 日本分子生物学会年会プログラム・要旨集(Web), 36th, 3P-0680 (WEB ONLY), 2013
  Japanese
• 卵成熟過程でのゼブラフィッシュcyclin B1 mRNA翻訳制御に関する新規シス配列の同定
  安田恭大; 小谷友也; 山下正兼, 日本動物学会大会予稿集, 83rd, 132, 20 Aug. 2012
  Japanese
• Visualization of spatiotemporal activity of the spinal motor neurons in zebrafish with a genetically-encoded calcium indicator
  Masamichi Ohkura; Akira Muto; Tomoya Kotani; Shin-ichi Higashijima; Koichi Kawakami; Junichi Nakai, JOURNAL OF PHARMACOLOGICAL SCIENCES, 118, 94P, 94P, 2012
  English, Summary international conference
• 遺伝子導入による部位・時期特異的な翻訳の可視化
  小谷友也; 安田恭大; 太田龍馬; 山下正兼, 日本遺伝学会大会プログラム・予稿集, 82nd, 103, 07 Sep. 2010
  Japanese
• ゼブラフィッシュ卵成熟過程における時期特異的な翻訳の可視化
  小谷友也; 安田恭大; 太田龍馬; 山下正兼, 日本動物学会大会予稿集, 81st, 94, 20 Aug. 2010
  Japanese
• Hybrid MPF consisting of CDC2 and cyclin B derived from different species is responsible for abnormal embryonic development in inter-specific hybrids
  Konno Fumiko; Koya Emiko; Nakano Osamu; Oka Akie; Kotani Tomoya; Iwai Toshiharu; Mita Koichi; Yamashita Masakane, ZOOLOGICAL SCIENCE, 22, 12, 1458, Dec. 2005, [Peer-reviewed]
• Possible involvement of the signal transduction pathway mediated by PI3K/PKB in progesterone-induced oocyte maturation in Rana japonica
  Suwa Kaori; Kotani Tomoya; Mita Koichi; Yamashita Masakane, ZOOLOGICAL SCIENCE, 21, 12, 1289, Dec. 2004, [Peer-reviewed]
• ゼブラフィッシュの時空間特異的な遺伝子発現--トランスポゾンを用いた遺伝子トラップ法による研究 (特集 トランスポゾンによる進化,変異導入の生物学的意義)
  小谷 友也; 川上 浩一, 蛋白質核酸酵素, 49, 13, 2111, 2116, Oct. 2004
  共立出版, Japanese
• 雑種のはい発生異常は異種由来のCdc2・サイクリンBサブユニットからなるMPFに起因する
  古屋江美子; 中野治; 岡亜希恵; 小谷友也; 岩井俊治; 箕田康一; 山下正兼, 日本分子生物学会年会プログラム・講演要旨集, 26th, 755, 25 Nov. 2003
  Japanese
• Discrimination of the Roles of MPF and MAP kinase in Marphological Charges that Occur during Oocyte Maturation
  Developmental Biology, 252(2), 271-286, 2002
• Requirement of Cyclin B2, but not Cyclin B1, for Bipolar Spindle Formation in Frog (Rarq japonica) Oocyte
  Molecular Reproduction and Development, 59, 2, 199, 208, 2001
• アカガエル卵成熟過程におけるサイクリンB1とB2の機能差
  小谷友也; 吉田徳之; 箕田康一; 山下正兼, 日本発生生物学会大会発表要旨集, 33rd, 161, 2000
  Japanese

• 生命システム科学基礎論, 2024年, 修士課程, 生命科学院
• 生殖発生機構学特論, 2024年, 修士課程, 生命科学院
• 細胞生物学概論, 2024年, 学士課程, 理学部
• 科学・技術の世界（1単位）, 2024年, 学士課程, 全学教育
• 生殖発生生物学Ⅱ, 2024年, 学士課程, 理学部
• ISP生物科学実習Ⅱ・a, 2024年, 学士課程, 理学部
• ISP生物科学実習Ⅱ・b, 2024年, 学士課程, 理学部
• 発生学実習, 2024年, 学士課程, 理学部
• 発生学実習, 2024年, 学士課程, 理学部
• 生物学Ⅰ, 2024年, 学士課程, 全学教育

• THE MOLECULAR BIOLOGY SOCIETY OF JAPAN
• 日本動物学会
• 日本発生生物学会

• Molecular mechanisms by which early developmental processes are temporally controlled
  Grants-in-Aid for Scientific Research
  01 Apr. 2025 - 31 Mar. 2027
  小谷 友也
  Japan Society for the Promotion of Science, Grant-in-Aid for Transformative Research Areas (A), Hokkaido University, 25H02435
• 新規RNAプロセシングと相転換による翻訳の時空間的制御システムの解明
  科学研究費助成事業
  01 Apr. 2024 - 31 Mar. 2027
  小谷 友也
  日本学術振興会, 基盤研究(B), 北海道大学, 24K01952
• A study to understand oogenesis and early development through phase transition of molecules
  Grants-in-Aid for Scientific Research
  30 Jun. 2023 - 31 Mar. 2026
  小谷 友也
  Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Research (Exploratory), Hokkaido University, 23K18104
• Analysis of temporal and spatial control of mRNA translation that is mediated by subcellular structures and novel RNA processing
  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)
  01 Apr. 2021 - 31 Mar. 2024
  小谷 友也; 山本 雄広
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Hokkaido University, 21H02398
• A novel screening for isolating maternal-effect mutants that contributes to understanding mechanisms underlying the birth of animals
  Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Research (Exploratory)
  28 Jun. 2019 - 31 Mar. 2022
  Kotani Tomoya
  The proper production of eggs is crucial for almost all animal to promote development, since eggs accumulate almost all factors that are required for promoting developmental processes. The aim of this study was to develop a novel screening that enable us to identify maternal-effect mutants in order to understand functions of transcripts stored in eggs. In this study, we effectively isolated females homozygous for the insertions and identified a maternal-effect mutant using a small scale fish maintenance systems.
  Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Research (Exploratory), Hokkaido University, 19K22376
• 卵形成から個体形成過程における翻訳の実態と役割の解明
  科学研究費補助金(基盤研究(C))
  2016 - 2018
  小谷 友也
  文部科学省, Principal investigator, Competitive research funding
• Molecular and functional analysis of translational machenary during oogenesis and development
  Grants-in-Aid for Scientific Research
  2013 - 2015
  Kotani Tomoya
  In this study, we aimed to elucidate molecular mechanisms of evolutionally conserved control of cyclin B1 mRNA translation to understand the nature of translational machineries by which special and temporal translation is regulated. First, we demonstrated that binding of Pumilio1 to cyclin B1 mRNA is essential for the RNA granule formation, which was found in vertebrate oocytes, and that this Pumilio1-mediated RNA granule formation is important for specially and temporally regulated translational activation of the mRNA. Then, we identified IMP3 protein as a novel factor binding to cycle B1 mRNA, providing novel insight into the translational regulation of the mRNA. Furthermore, we generated transgenic animals visualizing dynamics of actin filaments and obtained results supporting the notion that assembly and depolymerization of actin filaments are involved in the translational regulation.
  Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (C), Hokkaido University, Principal investigator, Competitive research funding, 25440001
• 成熟卵母細胞形成に必須の翻訳制御機構解析
  科学研究費補助金(特定領域研究)
  2011 - 2012
  小谷 友也
  すべての動物の卵母細胞は、第一減数分裂前期で分裂を停止しmRNAと蛋白質を蓄積する。十分に成長した卵母細胞(未成熟卵)はホルモン刺激を受けて卵成熟を起こし、減数分裂の再開と第二分裂中期での再停止を経て受精可能な成熟卵となる。卵成熟の開始にともない遺伝子の転写は抑制されるため、成熟卵となるすべての現象は卵母細胞に蓄積された田RNAと蛋白質の修飾で制御される。サイクリンB1蛋白質は、卵成熟を推進する卵成熟促進因子(MPF)の調節サブユニットで、その翻訳は正常な卵成熟の進行に必須である。本研究において、我々は脊椎動物に普遍的なサイクリンB1翻訳制御機構の解明を目指し、ゼブラフィッシュとマウスを用いて解析を行った。その結果、次の成果を得てきた。1)ゼブラフィッシュとマウスの未成熟卵において、翻訳が抑制されたサイクリンB1 mRNAはRNA顆粒を形成する。2)これらRNA顆粒は、卵成熟過程における翻訳の活性化に伴って消失する。3)RNA結合蛋白質PumilioはサイクリンB1 mRNAに結合し、顆粒の形成に関わる。4)サイクリンB1 mRNAの顆粒形成はアクテン繊維に依存する。5)顆粒を形成しないmRNAはその翻訳時期が早まる。本年度は新たに、RNA顆粒の安定化が翻訳に及ぼす影響を解析し、次の成果を得た。1)PumilioのN末端領域の過剰発現によって顆粒が安定化し、翻訳の活性化が阻害される。2)アクチン繊維の安定化によってRNA顆粒が安定化し、同じく翻訳の活性化が阻害される。これらの結果から、RNA顆粒の形成とその消失がサイクリンB1の翻訳時期の制御に重要であることが示された。これらの成果は、成熟卵形成に必須のサイクリンB1翻訳の新規分子機構を明らかにしたのみでなく、RNA顆粒の形成が翻訳の活性化時期の制御に関わることを初めて示したものである。
  文部科学省, 特定領域研究, 北海道大学, Principal investigator, Competitive research funding, 23013001
• Analysis of mechanisms of translational control using transgenes and visualization of the site and timing of translation
  Grants-in-Aid for Scientific Research
  2011 - 2012
  KOTANI Tomoya
  Localization and translational control of cytoplasmic mRNAs play key roles in the regulation of site and timing of gene expression. We analyzed molecular mechanisms by which localization and translational control of cyclin B1 mRNA deposited in oocytes are regulated using transgenes and real-time imaging of the site and timing of translation. In this study, we revealed that a cis-acting element consisting of 9 nucleotides sequences in the coding region is necessary for the regulation of both localization and translational control of the mRNA. Our results suggest a functional link between mRNA localization and translational control.
  Japan Society for the Promotion of Science, Grant-in-Aid for Young Scientists (B), Hokkaido University, Principal investigator, Competitive research funding, 23770196
• Elucidation of novel molecular mechanisms in protein transportation from ER to Golgi apparatus and their roles in development
  Grants-in-Aid for Scientific Research(若手研究(B))
  2009 - 2010
  Tomoya KOTANI
  We previously identified a novel gene misty somites (mys), which encodes Mys protein, and found that almost all vertebrate genomes contain the gene encoding Mys protein homolog. In this study, we newly produced antibodies recognizing carboxy-terminus of human Mys protein, a region highly conserved in vertebrate Mys protein homologs. Mys protein homologs were found to be expressed in human and mouse cultured cells and Xenopus embryos. We then examined the localization of Mys protein in human cultured cells using the newly produced antibody and found that Mys protein was localized in Golgi ap...
  Ministry of Education, Culture, Sports, Science and Technology, 若手研究(B), 北海道大学, Principal investigator, Competitive research funding, 21770066
• 蛋白質間相互作用を用いた細胞分裂分子制御機構の解析
  Competitive research funding
• Molecular mechanism of protein-protein interaction in mitosis
  Competitive research funding