Effects of low salinity on epigenetic changes of growth hormone and growth hormone receptor in half smooth tongue sole (Cynoglossus semilaevis)

Abstract

Salinity is a crucial factor in marine teloest growth. Growth hormone (GH) and growth hormone receptor 1 (GHR1) are crucial regulators of somatic growth and development in teleosts, and may be involved in the mechanisms which drive growth sexual dimorphism in the half smooth tongue sole (Cynoglossus semilaevis). To evaluate the epigenetic changes of gh and ghr1 under low salinity stress, the gh and ghr1 proximal promoters were identified and the methylation levels of these genes in corresponding tissues were assayed. The results suggested that significant increasement of gh putative promoter methylation levels in pituitary was observed in females compared with males. However, there were no sex-specific epigenetic changes in ghr1 promoter. Meanwhile, the methylation level of gh putative promoter was negatively correlated with body weight as well as mRNA expression of gh in pituitary. Taken together, our data provide an epigenetic mechanism of explicating the sex duality in phenotypic plasticity of growth rate in male and female of C. semilaevis under different salinities.

Keywords

• Cynoglossus semilaevis
• Growth hormone
• Growth hormone receptor
• Methylation
• Low salinity