Researcher Database

Researcher Profile and Settings

Master

Affiliation (Master)

  • Faculty of Fisheries Sciences Marine Life Science Marine Biotechnology and Microbiology

Affiliation (Master)

  • Faculty of Fisheries Sciences Marine Life Science Marine Biotechnology and Microbiology

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Profile and Settings

Affiliation

  • Hokkaido University, Faculty of Fisheries Sciences Division of Marine Life Science

Profile and Settings

  • Name (Japanese)

    Nagata
  • Name (Kana)

    Jun
  • Name

    202001015621294940

Affiliation

  • Hokkaido University, Faculty of Fisheries Sciences Division of Marine Life Science

Achievement

Research Areas

  • Life sciences / Aquaculture

Research Experience

  • 2022/04 - Today Hokkaido University Faculty of Fisheries Sciences Division of Marine Life Science
  • 2020/04 - 2022/03 Local Independent Administrative Agency Hokkaido Research Organization
  • 2019/04 - 2020/03 北海道大学 大学院水産科学院 学術研究員

Education

  • 2016/04 - 2019/03  北海道大学
  • 2014/04 - 2016/03  北海道大学
  • 2010/04 - 2014/03  Hokkaido University  School of Fisheries Sciences

Published Papers

  • Jun Nagata, Katsuki Takita, Hisae Kasai
    Aquaculture 741158 - 741158 0044-8486 2024/06 [Refereed][Not invited]
  • Efficacy of egg disinfection by povidone-iodine solutions for inactivation of causative agent of bacterial kidney disease (Renibacterium salmoninarum) in vitro
    Jun Nagata, Sayo Morimoto, Makoto Ameno, Keito Yamaguchi, Ken-ichi Watanabe, Dominic K. Bagenda, Hisae Kasai
    fish pathology(accepted) 2024 [Refereed]
  • Pathogenicity and tumorigenicity of Oncorhynchus masou virus (OMV) isolated from cultured coho salmon Oncorhynchus kisutch in Hokkaido, Japan
    勝又義友, 水野伸也, 永田淳, 笠井久会
    水産増殖 2023/12 [Refereed]
  • Yo Yamaguchi, Jin Namgung, Jun Nagata, Takuma Kawasaki, Akihiko Hara, Takashi Todo, Naoshi Hiramatsu
    Gene 147093 - 147093 0378-1119 2022/12 [Refereed]
  • Yo Yamaguchi, Jun Nagata, Osamu Nishimiya, Takuma Kawasaki, Naoshi Hiramatsu, Takashi Todo
    Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 261 111055 - 111055 1095-6433 2021/11 
    Fundamental knowledge on the regulation of reproduction by gonadotropins (Gths) is quite limited in viviparous fishes. In the present study, we performed molecular cloning and characterization of cDNAs encoding two Gth subunits (fshb and lhb) from the pituitaries of viviparous white-edged rockfish, Sebastes taczanowskii; expression profiles of both gene transcripts were elucidated in the pituitaries of reproductive males and females which were kept in a captive environment. The cloned fshb and lhb fragments exhibited high sequence identities with corresponding β-subunit sequences from black rockfish, S. schlegelii. Notably, the fshb of white-edged rockfish appeared to lack a putative N-glycosylation site, whereas lhb conserved it. Expression of fshb and lhb transcripts in the rockfish pituitaries largely changed in synchrony but for minor exceptions. In males, levels of both transcripts increased with progression of spermatogenesis, although the peak for fshb (October) appeared slightly earlier than that for lhb (November). In females, both gene transcripts exhibited synchronous bimodal changes. High expression of fshb and lhb transcripts in the female pituitary during the gestation period, followed by the drastic decrease at parturition, suggest their possible involvement in regulation of gestation of this species. The knowledge gained for Sebastes in this study superimposes fundamental information necessary for further physiological understanding of viviparity in teleost fish.
  • Jun Nagata, Satoru Wada, Osamu Nishimiya, Meiqin Wu, Yuji Mushirobira, Yo Yamaguchi, Takanori Yokono, Takuma Kawasaki, Takahiro Matsubara, Takashi Todo, Akihiko Hara, Naoshi Hiramatsu
    Zoological Science 38 (5) 451 - 458 0289-0003 2021/10/01 
    Viviparous fish, including white-edged rockfish (Sebastes taczanowskii), accumulate substantial yolk mass in the oocytes however, the details of the molecular mechanisms underlying yolk formation are not yet fully understood, especially concerning multiplicity in the yolk precursor vitellogenin (Vtg). The present study aimed to reveal the hepatic transcriptional profiles of multiple vtg gene transcripts (vtgAa, vtgAb, vtgC) during the reproductive cycle in captive female white-edged rockfish reared in an aquarium under natural photo-Thermal conditions. The serum estradiol-17ß concentration and the hepatic transcript levels of all vtg subtypes increased with the progress of vitellogenesis both levels decreased at the beginning of oocyte maturation and remained low during the gestation period. Considering the similarity in the transcriptional profiles of vtg subtypes between Sebastes and Oncorhynchus, along with the differences between Sebastes and Morone, it is suggested that the transcription patterns of multiple vtg genes relate to neither their reproductive modes (viviparity versus oviparity) nor to teleost phylogeny.
  • Jun Nagata, Yuji Mushirobira, Osamu Nishimiya, You Yamaguchi, Toshiaki Fujita, Naoshi Hiramatsu, Akihiko Hara, Takashi Todo
    General and Comparative Endocrinology 310 113812 - 113812 0016-6480 2021/09 
    Estradiol-17β (E2) regulates transcription of estrogen-responsive genes via estrogen receptors (Esr). In many teleost species, choriogenin (chg), vitellogenin (vtg) and esr genes are transactivated by E2 in the liver. This study aimed i) to compare expression properties of all subtypes of these genes (chg: chgHα, chgHβ, chgL; vtg: vtgAs, vtgC; esr: esr1a, esr1b, esr2a, esr2b) in response to estrogen stimulation, and ii) to confirm how each of four Esr subtypes is involved in the transcriptional regulation of these estrogen-responsive genes in cutthroat trout hepatocytes. In hepatocytes in primary culture, all chg and vtg subtype mRNA levels, and those of esr1a, were increased by E2 treatment (10−6 M) at 24 and 72 h post initiation (hpi), but esr1b, esr2a and esr2b mRNA levels were not. Treatment of hepatocytes with various concentrations of E2 (10−11–10−6 M) induced dose-dependent increases in the levels of all chg and vtg subtype mRNAs at 24 and 72 hpi. At both time points, the lowest dose that induced a significant increase in the expression levels of mRNAs (LOEC) for E2 differed among the genes; LOECs were estimated as 10−11 M for chgHα at 24 hpi, as 10−9 M for vtgC at 72 hpi, and as 10−10 M for other mRNAs at both 24 and 72 hpi. Meanwhile, the levels of esr1a mRNA exhibited a dose-dependent increase at 24 and 72 hpi, but the LOEC shifted from 10−9 M at 24 hpi to 10−7 M at 72 hpi because of a decrease in mRNA levels at treatment groups exposed to high concentrations of E2. All Esr subtypes transactivated chg, vtg and esr1a promoters in the presence of E2 in vitro. The activation levels indicated that promoter activity of chgHα ≥ vtgAs > chgHβ > chgL ≥ vtgC ≥ esr1a when mediated by Esr1a, chgHβ > chgHα > chgHL > vtgAs ≥ vtgC ≥ esr1a by Esr1b, chgHβ ≥ chgL > chgHα ≥ vtgAs > vtgC > esr1a by Esr2a, and chgHβ ≥ chgHα ≥ vtgAs > chgL ≥ vtgC > esr1a by Esr2b. Collectively, different Esr subtypes were distinctly different in their ability to transactivate estrogen-responsive target genes, resulting in differential expression of chg, vtg and esr1a genes in the estrogen-exposed hepatocytes.
  • Jin Namgung, Hiroko Mizuta, Yo Yamaguchi, Jun Nagata, Takashi Todo, Ozlem Yilmaz, Naoshi Hiramatsu
    Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology 257 110967 - 110967 1095-6433 2021/07 
    Recent studies of vitellogenesis engendered a novel model of teleost yolk formation in which multiple yolk precursors, vitellogenins (Vtgs), and their receptors (Vtgrs) interact to ensure proper yolk composition for embryonic development and larval growth. As a step toward verification of this concept, we examined the role of one candidate Vtgr, termed low-density lipoprotein receptor relative with eight ligand-binding repeat (Lr8), in the medaka, a representative teleost and established laboratory model. A homozygous lr8 knock out (lr8-KO) medaka was produced to perform reverse-genetic functional analyses. In ovaries of wild type (WT) medaka, Western blotting detected a putative Lr8 protein band at ~130 kDa, while immunohistochemistry detected the putative Lr8 signal at the periphery of the oocyte underneath the zona radiata. These signals disappeared in ovaries of the lr8-KO group. Offspring of lr8-KO medaka exhibited decreased survival rate compared to WT fish, but KO of lr8 was not 100% lethal. There was no significant difference in total yolk protein content or size of eggs between WT and lr8-KO fish. However, LC-MS/MS analyses revealed a remarkable decrease in the relative abundance of yolk proteins derived from VtgAb in lr8-KO eggs, in conjunction with a compensatory increase in proteins derived from VtgAa1. These findings strongly support the conclusion that Lr8 is an important receptor for VtgAb in medaka. The disruption of proper yolk composition by lr8-KO is possibly one cause of the low offspring survival.
  • Hisae Kasai, Jun Nagata
    Fish Pathology 55 (4) 111 - 116 0388-788X 2021/01/15
  • Jun Nagata, Sayo Morimoto, Dominic K. Bagenda, Hisae Kasai
    Fisheries Science [Springer Japan] 86 (5) 829 - 834 0919-9268 2020/09
  • 莚平 裕次, 川崎 琢真, 中田 訓彰, 竹中 映美, 永田 淳, 石田 良太郎, 山口 浩志, 佐藤 充, 東藤 孝, 平松 尚志
    水産増殖 = Aquaculture science 日本水産増殖学会 68 (1) 1 - 8 0371-4217 2020/04 [Refereed][Not invited]
  • Georgia Thomson-Laing, Erin L Damsteegt, Jun Nagata, Shigeho Ijiri, Shinji Adachi, Takashi Todo, Naoshi Hiramatsu, P Mark Lokman
    Biology of reproduction 100 (5) 1319 - 1332 2019/05/01 [Refereed][Not invited]
     
    Estradiol-17β (E2) and 11-ketotestosterone (11KT) have been implicated in vitellogenesis and in regulating expression of the follicle-stimulating hormone receptor (fshr), respectively. To override the captivity-induced reproductive block in shortfinned eel, Anguilla australis, we hypothesized that in combination, 11KT and E2 would stimulate ovarian uptake of vitellogenin (Vtg). Early pubertal eels received hormone implants containing varying concentrations of E2 (0, 0.2, 2, 5 mg) with or without 11KT (1 mg). Vtg levels were determined in plasma, liver, and ovarian tissues by histological examination, qPCR, immunoblotting, or single radial immunodiffusion. The expression of gonadotropin-beta subunits and gonadotropin receptors in the pituitary and ovary, respectively, were analyzed to determine mechanisms by which steroid effects may be exerted. When administered alone, E2 increased hepatic production and plasma levels of Vtg. In contrast, 11KT decreased plasma levels of Vtg, seemingly reducing its production. Neither 11KT nor E2 could induce uptake of Vtg into oocytes, although E2 treatment appeared necessary for uptake to occur. This was the case despite 11KT dramatically increasing both oocyte size and fshr mRNA levels. Astonishingly, the uptake of Vtg was successfully induced by co-treatment with 11KT and E2, suggesting that 11KT might facilitate the incorporation of Vtg into the developing oocyte. These results highlight the potential of sex steroid co-treatment, an approach aimed at mimicking oogenesis in wild eels, to induce vitellogenesis, specifically ovarian yolk deposition, even in the absence of exogenous gonadotropin treatment.
  • Yuji Mushirobira, Osamu Nishimiya, Jun Nagata, Takashi Todo, Akihiko Hara, Benjamin J. Reading, Naoshi Hiramatsu
    GENERAL AND COMPARATIVE ENDOCRINOLOGY 267 157 - 166 0016-6480 2018/10 [Refereed][Not invited]
     
    Transcription of vitellogenin (vtg) genes are initiated when estradiol-17 beta (E-2)-estrogen receptor (ER) complexes bind estrogen response elements (ERE) located in the gene promoter region. Transcriptional regulation of dual vtg subtypes (major salmonid A-type vtg: vtgAs; minor C-type vtg: vtgC) by E-2 was investigated under co-expression of a potential major transcriptional factor, era1 , in cutthroat trout. Two forms of trout vtgAs promoters (1 and 2) and one vtgC promoter were sequenced. These promoters structurally differ based on the number of EREs present. The vtgAs promoter 1 exhibited the highest maximal transcriptional activity by in vitro gene reporter assays. The concentration of E-2 that induces 50% of gene reporter activity (half-maximal effective concentrations, EC50) was similar among all vtg promoters and also to the EC50 of E-2 administered to induce vtg transcription in vivo. This study revealed a difference in transcriptional properties of multiple vtg promoters for the first time in a salmonid species, providing the basis to understand mechanisms underlying regulation of vitellogenesis via dual vtg gene expression.
  • Nagata Jun, Todo Takashi, Hara Akihiko, Hiramatsu Naoshi, Kasai Kei, Mineno Kazuhiro, Fujisaki Yudai, Mushirobira Yuji, Namgung Jin, Takeda Yasutaka, Fujita Toshiaki, Kawasaki Takuma
    Aquaculture Science 水産増殖談話会 66 (4) 257 - 266 0371-4217 2018 [Refereed][Not invited]
     
    Whole-mount immunostaining (WI) was used for identification of eggs of brown sole (Pseudopleuronectes herzensteini), sand flounder (Limanda punctatissima) and pointhead flounder (Cleisthenes pinetorum). Polyclonal antibodies were raised in rabbit against vitelline envelope (VE) of ovulated eggs of each flounder (a-brown sole VE, a-sand flounder VE and a-pointhead flounder VE). A WI method was first developed using the non-labeled primary a-VE antibodies in conjunction with a labeled-secondary antibody (2-step method). Another WI method using the labeled-primary a-VE anitbodies alone was developed (1-step method) in order to omit the use of the secondary antibody. When fertilized eggs of each species (2-24 hrs post-fertilization) were examined, both WI methods effectively stained the eggs in a species-specific manner. Immunological tools developed for identification of flounder eggs in this study will contribute to simplify fishery surveys of flounder species during their early life stages.
  • Nagata Jun, Mushirobira Yuji, Nishimiya Osamu, Fujita Toshiaki, Hiramatsu Naoshi, Hara Akihiko, Todo Takashi
    Aquaculture Science 水産増殖談話会 66 (2) 91 - 101 0371-4217 2018 [Refereed][Not invited]
     
    Choriogenin (Chg) and vitellogenin (Vtg) subtypes and estrogen receptor α1 (Erα1) are upregulated by estradiol-17β (E2) in the liver of female salmonids. The aim of this study was to examine the relationships among hepatic mRNA levels for chgs (chgHα; chgHβ; chgL), vtgs (vtgAs; vtgC), erα1 and serum E2 levels in female cutthroat trout (Oncorhynchus clarki) during a reproductive cycle. Levels of serum E2 and hepatic chg mRNAs, as well as hepatic vtg mRNAs, increased in correlation with the progress of vitellogenesis. In the ovulated fish, chg mRNA remained at high levels while serum E2 and vtg mRNA levels decreased. Hepatic erα1 mRNA levels exhibited a peak in August (at the beginning of vitellogenesis) before levels of E2, chg and vtg mRNAs start to increase. These results suggest that expression levels of chg, vtg and erα1 genes are potentially regulated through E2 stimulation by different mechanisms.
  • Hiroko Mizuta, Yuji Mushirobira, Jun Nagata, Takashi Todo, Akihiko Hara, Benjamin J. Reading, Craig V. Sullivan, Naoshi Hiramatsu
    COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR & INTEGRATIVE PHYSIOLOGY 212 24 - 34 1095-6433 2017/10 [Refereed][Not invited]
     
    To evaluate potential involvement of clathrin in endocytosis of vitellogenin (Vtg) by teleost oocytes, cDNAs encoding clathrin heavy chain (cltc) were cloned from ovaries of cutthroat trout. Quantitative PCR revealed three types of cltc (cltc-al, cltc-a2, cltc-b) to be expressed in 10 different tissues including the ovary. The cltc-al alone exhibited a significant decrease in ovarian expression during vitellogenesis; this was correlated with a corresponding decrease in transcripts encoding the major Vtg receptor (Vtgr). No development-related changes in ovarian cltc-a2 or cltc-b transcript levels were observed. In situ hybridization revealed a strong ctic signal in pre-vitellogenic oocytes, but not in vitellogenic oocytes. Western blotting using a rabbit antiserum (a-Cltc) raised against a recombinant Cltc preparation detected a polypeptide band with an apparent mass of similar to 170 kDa in vitellogenic ovary extracts. Immunohistochemistry using a-Cltc revealed Cltc to be uniformly distributed throughout the ooplasm of perinucleolus stage oocytes, translocated to the periphery of lipid droplet stage oocytes, and localized to the oolemma during vitellogenesis. These patterns of citc/Cltc distribution and abundance during oogenesis, which are identical to those previously reported for vtgr/Vtgr in this species, constitute the first empirical evidence that cltc-al/Cltc-al is involved in Vtg endocytosis via the Vtgr in teleost fish.

MISC

Presentations

  • イクラ味付け工程における塩・しょうゆ調味液処理がサケ科魚類病原体の生残性および感染性に及ぼす影響  [Not invited]
    永田 淳, 森本紗世, 笠井久会
    令和 2 年度日本魚病学会春季大会  2020/03
  • カットスロートトラウト肝臓で発現するエストロジェン応答性遺伝子のプロモーター解析  [Not invited]
    永田淳, 莚平裕次, 西宮攻, 藤田敏明, 平松尚志, 原彰彦, 東藤孝
    平成31年度日本水産学会春季大会  2019/03
  • Expression of estrogen responsive genes in primary cultured hepatocyte of cutthroat trout, Oncorhynchus clarki  [Not invited]
    Nagata J, Mushirobira Y, Nishimiya O, Fujita T, Hiramastsu N, Hara A, Todo T
    The 15th International Meeting on Reproductive Biology of Aquatic Animals of the East China Sea  2018/08
  • カットスロートトラウト初代培養肝細胞を用いたエストラジオール‐17β応答性遺伝子の発現解析  [Not invited]
    永田淳, 莚平裕次, 西宮攻, 藤田敏明, 平松尚志, 原彰彦, 東藤孝
    平成30年度日本水産学会春季大会  2018/03
  • The in vivo effects of estradiol and 11-ketotestosterone on vitellogenin physiology in shortfinned eel, Anguilla australis
    Thomson-Laing, G, Samsteegt, E.L, Nagata, J, Ijiri, S, Adachi, S, Todo, T, Hiramatsu, N, Lokman, P, M
    11th International Symposium on Reproductive Physiology of Fish  2018/03
  • ホールマウント免疫染色法による3種カレイ受精卵の種判別  [Not invited]
    笠井慶, 永田淳, 峯野博和, 藤崎雄大, 莚平裕次, 莚平裕次, 武田康孝, 藤田敏明, 東藤孝, 原彰彦, 平松尚志
    平成29年度日本水産学会北海道支部大会  2017/12
  • Changes in mRNA levels of estrogen responsive genes in the liver of cutthroat trout following estradiol-17beta injection.  [Not invited]
    Nagata J, Mushirobira Y, Hiramatsu N, Hara A, Todo T
    The 14th International Meeting on Reproductive Biology of Aquatic Animals of the East China Sea  2017/09
  • カットスロートトラウト雌の肝臓におけるエストラジオール‐17β応答性遺伝子の生殖周期に伴う発現変化  [Not invited]
    永田淳, 莚平裕次, 西宮攻, 平松尚志, 原彰彦, 東藤孝
    平成29年度日本水産学会春季大会  2017/03
  • Expression profiles of dual vitellogenin genes in the cutthroat trout (Onchorhychus clarki) following estradiol-17β administration.
    Mushirobira,Y, Nagata, J, Todo, T, Hara, A, Hiramatsu, N
    The 13th International Meeting on Reproductive Biology of Aquatic Animals of the East China Sea  2016/11
  • Differential responses of oogenesis-related genes to estradiol-17β in the liver of cutthroat trout, (Onchorhychus clarki)  [Not invited]
    Nagata, J, Mushirobira, Y, Hiramatsu, N, Hara, A, Todo, T
    The 13th International Meeting on Reproductive Biology of Aquatic Animals of the East China Sea  2016/11
  • カットスロートトラウト(Oncorhynchus clarki)における2型ビテロジェニンプロモーターの性状解析  [Not invited]
    莚平裕次, 西宮攻, 永田淳, 東藤孝, 原彰彦, 平松尚志
    平成28年日本水産学会春季大会  2016/03
  • Molecular characterization of dual vitellogenin gene promoters in the cutthroat trout (Oncorhynchus clarki)  [Not invited]
    Mushirobira, Y, Nishimiya, O, Nagata, J, Todo, T, Hara, A, Hiramatsu, N
    The 12th International Meeting on Reproductive Biology of Aquatic Animals of the East China Sea  2015
  • Analysis of lipid droplet formation in oocytes of the cutthroat trout, Oncorhynchus clarki in vitro
    Nagata, J, Mushirobira, Y, Hiramatsu, N, Hara, A, Todo, T
    The 12th International Meeting on Reproductive Biology of Aquatic Animals of the East China Sea  2015

Research Projects



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