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

Abstract

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 (Cynoglossus semilaevis). However, the role of hsc genes in responding to high temperature and affecting sex determination/differentiation remains unclear. Here, by using C. semilaevis as model, we identified hsc70 and hsc70-like. hsc70 was abundant in the gonads with a testicular-higher expression at all gonadal development stages except for 6 months post fertilization (mpf). Intriguingly, hsc70-like 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 hsc70/hsc70-like between sexes. The dual-luciferase assay results also suggested that these genes can respond to high temperature rapidly in vitro. Heat treatment of C. semilaevis testis cells overexpressed with hsc70/hsc70-like could affect the expression of sex-related genes sox9a and cyp19a1a. Our results indicated that hsc70 and hsc70-like were key regulators linking external high-temperature signals with sex differentiation in vivo and provide a new idea for understanding the mechanism by which high temperature affects sex determination/differentiation in teleosts.

Transcriptome Analysis Revealed the Early Heat Stress Response in the Brain of Chinese Tongue Sole (Cynoglossus semilaevis)

“…The PPI analysis and heat map analysis revealed that numerous genes linked to the HSP family were present in females at first 1 h to 2 h, including hsp70, hspa5, hspa41, hspb6, and hsp90. The HSP family's expression, including hsp70 and hsp90, which are modulated under high temperatures has also been reported in various other species [74][75][76][77][78][79]. Moreover, it has been reported that hsp70 and hsp90 interact with the steroid hormone receptors to allow efficient hormone binding [80,81].…”

The Role of Z Chromosome Localization Gene psmd9 in Spermatogenesis of Cynoglossus semilaevis

“…The testicular cell line of C. semilaevis originated from the researchers’ laboratory and was cultured in L15 compound medium at 24 °C [ 41 ]. Taking an empty plasmid as the control group, Lipofectamine 3000 Reagent (Thermo Fisher, Invitrogen, Carlsbad, CA, USA) was used to transfect the recombinant plasmid into 6-well plates.…”