Elucidation of sex differentiation mechanism by crosstalk between the sex determination cascade and the ecdysone signal

2019 Fiscal Year Final Research Report

• Project/Area Number: 17H03940
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Insect science
• Research Institution: The University of Tokyo
• Principal Investigator: Suzuki Masataka 東京大学, 大学院新領域創成科学研究科, 准教授 (30360572)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 性決定 / 性分化 / エクダイソン / doublesex / dmrt遺伝子 / Masculinizer / long-non-coding RNA

Outline of Final Research Achievements

The primary purpose of this research project is to elucidate whether ecdysone, which is known as a typical insect steroid hormone, is involved in the regulation of insect sex differentiation, and if so, what is its mechanism. The results obtained through this project revealed that the expression of dsx, the master regulator for insect sex differentiation, in testis increased in accordance with the concentration of ecdysone. Based on the results of expression site analysis by immunohistochemistry, phenotypic analysis by genome editing, and enhancer analysis, the maleness of internal reproductive organs cannot be explained only by dsx, and its cognate gene dmrt93B is required. Our results also suggested that dmrt93B may be responsible for the ecdysone-dependent regualtion of genes including dsx involved in the sexual development of testis and internal genitalia.

Free Research Field

分枝昆虫学

Academic Significance and Societal Importance of the Research Achievements

本研究では、内部生殖器の性分化がdsxだけでは説明できず、その同族遺伝子dmrt93Bが内部生殖器の雄化にとってより重要な働きをもつことを明らかにできた。これは、昆虫性分化のマスター制御因子であるとのこれまでの見解に一石を投じる発見と言える。dsxの精巣における発現がエクダイソン濃度依存的に上昇することを明らかにすると共に、この過程にdmrt93Bが関与するという新たな知見をもたらしたという点でも学術的価値が高い。また本研究では長年謎であった、雄化因子MASCがdsxの雄型アイソフォームの産生を制御する分子機構を解明し、性決定研究にブレークスルーをもたらしたという点で学術的意義が高いと言える。