Molecular characterization and functional analysis of cyp11a and cyp11b in black rockfish (Sebastes schlegelii).

The cyp11 includes cyp11a and cyp11b in most of mammals and teleost, encoded cholesterol side chain lyase and 11β-hydroxylase, respectively. It is essential in steroid hormone synthesis. However, studies on the regulation of cyp11 is limited, especially teleost. In this study, the sequence of cyp11a and cyp11b of black rockfish was cloned and showed high homology with other teleost counterparts by phylogenetic analysis. The expression of cyp11a and cyp11b exhibited a clear sexually dimorphic pattern, with a higher expression level observed in testis than that in ovary. During embryonic and sexual differentiation stage (40dph, 80dph, 190dph, 360dph, 720dph), expression of cyp11a was observed earlier than cyp11b. In situ hybridization results showed that cyp11a and cyp11b were mainly expressed in oocytes of the ovary, sertoli cells and spermatocytes of the testis. In order to explore the distinct roles of cyp11a and cyp11b on the sexual differentiation, estrogen and androgens were used to stimulate the primary testicular and ovarian cells. The expression of cyp11a and cyp11b were observed at different dose of 17α-methyltestosterone (17α-MT) and 17β-estradiol (E2). The results showed cyp11a was significantly increased at 10-6 mol/ml of 17α-MT and 10-8 mol/ml of E2 in ovary and 10-10 mol/ml of 17α-MT and E2 in testis, while cyp11b was significantly decreased after 17α-MT and E2 treatment. These results indicated that cyp11a and cyp11b likely to have different functions, and also implied cyp11a and cyp11b have crucial roles in the differentiation of gonads and the synthesis of steroids in the black rockfish. This article is protected by copyright. All rights reserved.