Identification of genes required for spermatogonial stem cell differentiation

• Project/Area Number: 17K15549
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: General anatomy (including histology/embryology)
• Research Institution: Yokohama City University
• Principal Investigator: Tomizawa Shinichi 横浜市立大学, 医学部, 助教 (00704628)
• Project Period (FY): 2017-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000); Fiscal Year 2018: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000); Fiscal Year 2017: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
• Keywords: エピジェネティクス / 生殖細胞 / 幹細胞 / 発生 / 精子幹細胞 / 精子形成 / 分化 / クロマチン / 遺伝子 / ゲノム / 細胞・組織 / 発現制御 / 解剖学

Outline of Final Research Achievements

In this study, we performed genome-wide transcriptome and epigenome analyses to understand the proliferation and differentiation mechanisms of spermatogonial stem cells (SSCs) in mammals. We collected mouse SSCs and progenitor spermatonia from mouse testis and analysed mRNA and DNA methylation status at the single cell level (M&T-seq). We found that SSCs are potentially heterogeneous with subpopulations showing different transcription and methylation status. Furthermore, from histological and histone modification analyses, we found that a histone methyltransferase Kmt2b plays an essential role for SSC differentiation.

Academic Significance and Societal Importance of the Research Achievements

本研究は、正常な精子形成に欠かせない精子幹細胞の増殖・分化を司る分子機構を明らかにするものである。本研究の成果から、精子幹細胞集団の遺伝子発現制御機構に関する重要な知見が得られたと共に、ヒストン修飾酵素の一つであるKmt2bが精子形成に必要な多くの遺伝子の発現を制御し、精子幹細胞分化において重要な役割を担うことが示された。これらは、原因が明らかでない男性不妊症の研究に対して有用な情報を提供すると同時に、組織幹細胞研究分野の今後の発展に貢献することが期待できる。

Research Products

• [Journal Article] Kmt2b conveys monovalent and bivalent H3K4me3 in spermatogonial stem cells at germline and embryonic promoters (2018)
  • Author(s): Tomizawa S, Kobayashi Y, Shirakawa T, Watanabe K, Mizoguchi K, Hoshi I, Nakajima K, Nakabayashi J, Singh S, Dahl A, Alexopoulou D, Seki M, Suzuki Y, Royo H, Peters6, A. H.F.M, Anastassiadis K, Stewart A.F. and Ohbo K
  • Journal Title: Development Volume: 145 Issue: 23
  • DOI: 10.1242/dev.169102
  • Peer Reviewed / Int'l Joint Research
• [Presentation] エピジェネティック機構を介した精子発生制御メカニズム (2019)
  • Author(s): 小林裕貴、尾野道男、溝口敬太、夏目幸治、富澤信一、河越龍方、水木信久、小倉淳郎、大保和之
  • Organizer: 第124回日本解剖学会総会全国学術集会
• [Presentation] Kmt2b is required for spermatogenic programs through both bivalent and monovalent priming of the spermatogonial stem cell epigenome. (2017)
  • Author(s): Tomizawa S, Kobayashi Y, Shirakawa T, Hoshi I, Nakajima K, Royo H, Nakamura Y, Peters AHFM, Anastassiadis K, Stewart AF, Yoshida S, Ohbo K
  • Organizer: The International Research Symposium on Regulation of Germ Cell Development in vivo and in vitro
  • Int'l Joint Research
• [Presentation] Kmt2b is required for spermatogenesis through both bivalent and monovalent priming of the spermatogonial stem cell epigenome. (2017)
  • Author(s): Tomizawa S, Kobayashi Y, Shirakawa T, Hoshi I, Nakajima K, Royo H, Peters AHFM, Anastassiadis K, Stewart AF, Ohbo K
  • Organizer: EMBO conference: Nuclear structure and dynamics
  • Int'l Joint Research
• [Remarks] 横浜市立大学医学部組織学
  • URL: http://www-user.yokohama-cu.ac.jp/~finemorp/