Study of the onset of gametogenesis at the beginning of puberty

2020 Fiscal Year Final Research Report

• Project/Area Number: 16H02514
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Morphology/Structure
• Research Institution: Nagoya University
• Principal Investigator: TANAKA MINORU 名古屋大学, 理学研究科, 教授 (80202175)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Keywords: 性決定 / 配偶子形成 / 性転換 / メダカ

Outline of Final Research Achievements

A series of studies have successfully revealed the presence of factors that regulate initiation of spermatogenesis at the timing of secondary sex characteristics. These include lhx8b and figla, which have been recognized as folliculogenic factors in mammals, and fbxo47, a component of ubiquitin ligase complex, and function downstream of sexual switch gene of germ cells, foxl3. Loss of these factors allowed spermatogenesis before onset of secondary sex characteristics. Regulations of chromosomal structures and membrane trafficking are involved in this mechanism. In addition, we are getting evidences that these factors are under control of somatic signal downstream of dmrt1.
The initiation of gametogenesis has been studied in terms of endocrinological regulation in the brain. However, these studies, for the first time, reveal that the initiation of spermatogenesis is associated with the mechanism of sex differentiation in the gonad.

Free Research Field

生殖生物学

Academic Significance and Societal Importance of the Research Achievements

配偶子形成開始は脳ホルモンによる第二次性徴制御の研究がほとんどであり、その明確な開始機構は未だ不明であった。今回の一連の研究により、配偶子形成開始が生殖腺の性決定分化と関わることが分子レベルで初めて示され、脳ホルモン以外の分子機構の存在を初めて明らかにした。
研究はメダカを用いて行われたが、同定された因子は脊椎動物に共通であり、哺乳類生殖腺でも発現が報告されている。第二次性徴は社会的医学的にさまざまな問題を包含する現象である。この研究は第二次性徴研究の新たな分野を拓き、人間を含めた哺乳類の第二次性徴そして配偶子形成の理解を前進させる成果と理解する。