2022 Fiscal Year Final Research Report

Dissecting molecular mechanisms of gonadal sexual plasticity by combining experimental fish models with single-cell analysis

Research Project

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Project/Area Number	19H03049
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Review Section	Basic Section 40040:Aquatic life science-related
Research Institution	Kyushu University
Principal Investigator	Ohta Kohei 九州大学, 農学研究院, 教授 (10585764)
Co-Investigator(Kenkyū-buntansha)	荻野由紀子九州大学, 農学研究院, 准教授 (00404343) Chakraborty Tapas 九州大学, 農学研究院, 助教 (70715440) Mohapatra Sipra 九州大学, 農学研究院, 学術研究員 (80715441)
Project Period (FY)	2019-04-01 – 2022-03-31
Keywords	性的可塑性 / 生殖幹細胞 / 魚類 / 性転換 / シングルセル解析
Outline of Final Research Achievements	To understand the molecular and cellular mechanisms of gonadal sexual plasticity, we investigated the germ line stem cells (GSCs) and undifferentiated somatic cells (SSCs) in the gonad of a sex-changing fish. These GSCs and SSCs have been suggested to be the origin of testicular tissue during sex change from female to male. In this study, we performed single-cell RNA-seq analysis of GSCs and SSCs. As a result, we revealed the heterogeneity of GSCs and SSCs, respectively, and clarified the change in their gene expression patterns during gonadal sex change. More interestingly, we also found that SSCs switch the pattern of differentiation between ovarian somatic cells and testicular somatic cells. On the other hand, using gonochoristic fish, the involvement of oct4 gene in the maintenance of GSCs was demonstrated. Moreover, the result of in vitro culture experiment suggests the differences in sexual plasticity of gonadal somatic cells among fish species.
Free Research Field	魚類生殖学
Academic Significance and Societal Importance of the Research Achievements	性転換魚のモデル系などを用いて魚類生殖腺の性的可塑性のメカニズムを解析した結果、卵巣から精巣への転換に伴う生殖幹細胞の連続的な遺伝子発現変化を明らかにするとともに、未分化体細胞が卵巣型から精巣型へと分化パターンを切りかえることを初めて見出した。また、生殖幹細胞で発現するoct4遺伝子が幹細胞性の維持に関与すること、魚種間で生殖腺体細胞の性的可塑性に違いがあることなどを解明した。今後、これらの成果をもとに、生殖腺全体や個体での性を統御する機構へと理解を深めることが可能となり、脊椎動物一般の性的可塑性の分子・細胞機構の研究に貢献するとともに、水産における新たな性統御法の開発にも繋がると期待される。