Increased DNA methylation levels of cyp19a1a 5’-flanking region during sex change in orange-spotted grouper, Epinephelus coioides

• Main Authors: Tseng, Peng-Wei, 曾鵬瑋
• Other Authors: Chang, Ching-Fong
• Format: Others
• Language: zh-TW
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/aguzz2

碩士 === 國立臺灣海洋大學 === 水產養殖學系 === 107 === Grouper is the protogynous teleost. 17α-methyltestosterone (MT) or aromatase inhibitor (AI) were induced female-to-male sex change in grouper. However, sex reversal was observed after withdrawal chemical administration. The Cyp19a1a catalyzes the conversion of androgens to estrogens. The transcription factor foxl2 and sf-1 has been characterized as an upstream regulator of a cyp19a1a that would activate cyp19a1a expression. In addition, the paralog of foxl2, foxl3, may involve in cyp19a1a regulation. To understand the potential role of epigenetics on sex change, the DNA methylation profile of cyp19a1a 5'-flanking region is used. DNA methylation typically acts to repress gene transcription. Our data showed the 5'-flanking regions of cyp19a1a had lower methylation levels and higher gene expression in ovary compared with the hypothalamus, liver and testis. Furthermore, methylation levels of cyp19a1a were significantly decreased in MT-induced female-to-male sex change. According to our bisulfite sequencing results, no differences were found in proto-male and MT-induced male and suspension cells and adhesive cells in ovary. Moreover, in situ hybridization shows that foxl3 is expressed in oogonia and spermatogonia but not somatic cells and other germ cells in both sexes. Taken together, our results demonstrate that hypermethylated 5'-flanking region of cyp19a1a is associated to male characteristic but not related to the sexual phase.