The Role of the Heat Shock Cognate Protein 70 Genes in Sex Determination and Differentiation of Chinese Tongue Sole ().

Fish sex determination can be affected by environmental temperature. This process relies on temperature-sensitive proteins such as heat shock proteins (HSPs). Our previous work found that heat shock cognate proteins (HSCs) may participate in high-temperature associated sex reversal of Chinese tongue sole (). However, the role of genes in responding to high temperature and affecting sex determination/differentiation remains unclear. Here, by using as model, we identified and . was abundant in the gonads with a testicular-higher expression at all gonadal development stages except for 6 months post fertilization (mpf). Intriguingly, showed higher expression in testes from 6 mpf on. Both long-term heat treatment during the temperature-sensitive sex-determining period and short-term heat stress at the end of this period caused different expression of / between sexes. The dual-luciferase assay results also suggested that these genes can respond to high temperature rapidly . Heat treatment of testis cells overexpressed with / could affect the expression of sex-related genes and . Our results indicated that and were key regulators linking external high-temperature signals with sex differentiation and provide a new idea for understanding the mechanism by which high temperature affects sex determination/differentiation in teleosts.