Molecular mechanisms of environmental sex determination

2014 Fiscal Year Final Research Report

• Project/Area Number: 23370030
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Morphology/Structure
• Research Institution: Kumamoto University
• Principal Investigator: KITANO TAKESHI 熊本大学, 自然科学研究科, 准教授 (40336219)
• Project Period (FY): 2011-04-01 – 2015-03-31
• Keywords: 性決定 / 性分化 / コルチゾル / メダカ

Outline of Final Research Achievements

We have already reported that cortisol is deeply involved in temperature-dependent sex determination. Here, we first showed that exposure to high temperature (HT) or cortisol after hatching inhibited the expression of fshr and cyp19a1 mRNAs, and induced the expression of gsdf mRNA in XX gonads during gonadal sex differentiation. Next, we analyzed the phenotypes of FSHR-knockout, CYP19A1-knockout and GSDF-overexpressed transgenic medaka. As results, among these medaka lines only GSDF-overexpressed XX medaka were completely sex-reversed into phenotypic males. Furthermore, quantitative real-time PCR analysis showed that the overexpression suppressed the expression of fshr and cyp19a1 mRNAs in XX gonads during gonadal sex differentiation. These results strongly suggest that HT induces masculinization of XX medaka by elevation of cortisol levels, which, in turn, causes suppression of fshr and cyp19a1 expression while inducing gsdf expression in XX gonads.

Free Research Field

比較内分泌学