Molecular identification of steroidogenesis-related genes in scallops and their potential roles in gametogenesis

In this study, we characterized several steroidogenesis-related genes in M. yessoensis and proposed a putative biosynthetic pathway for sex steroids that is similar to that of vertebrates. Specifically, we identified several steroidogenesis-related gene sequences that encode steroid metabolizing enzymes: StAR-related lipid transfer (START) protein, 17α-hydroxylase, 17,20-lyase (cyp17a), 17β-hydroxysteroid dehydrogenase (hsd17b), and 3β-hydroxysteroid dehydrogenase (hsd3b). We sampled adult scallops throughout their reproductive phase to compare their degree of maturation with their intensity of mRNA expression. Semi-quantitative RT-PCR analysis revealed a ubiquitous expression of transcripts for steroid metabolizing enzymes (i.e., star, cyp17a, hsd17b, and hsd3b) in peripheral and gonadal tissues. Real-time PCR analysis revealed a high level of expression of star3 and cyp17a genes in gonadal tissues at the early stage of cell differentiation in scallops. Interestingly, mRNA expression of hsd3b and hsd17b genes showed a synchronous pattern related to degree of gonad maturity. These results indicate that both hsd3b and hsd17b genes are likely involved in steroidogenesis in scallops. We therefore believe that these steroid-metabolizing enzymes allow scallops to endogenously produce sex steroids to regulate reproductive events.Graphical Abstract
Source: The Journal of Steroid Biochemistry and Molecular Biology - Category: Biochemistry Source Type: research