关键词: 福建牡蛎, 3β-HSD基因, 生殖, 内分泌, Crassostrea angulata, 3β-HSD, reproduction, endocrine

Abstract: Crassostrea angulata is a major commercial species for the shellfish aquaculture in southern China. To investigate the reproductive endocrinology of mollusc，we studied genes encoding enzymes involved in steroid metabolism in C. angulata by molecular biology technology. A full - length cDNA (1 444 bp) encoding a peptide of 356 amino acids of 3-beta-hydroxysteroid dehydrogenase (3p - HSD) from C. angulata was obtained and the similarities of its deduced amino acid sequence to these of other molluscan species were analyzed. 3β-HSD mRNA transcripts was expressed in most tissues of oyster，at highest levels in gonad (P<0. 05 ) . The mRNA transcript of 3/3 - HSD increased from initiation stage to ripeness stages (P<0.05 )，and then the expression level decreased dramatically after partially spent ( P< 0. 05 ). The results elucidated the potential role of 3β- HSD in the steroid genesis mechanism of C. angulata. Furthermore, results obtained from in situ hybridization indicated that 3β- HSD mRNA signals were detected in the follicle cell of ovary. Combining the results of the in situ hybridization and qRT-PCR，it suggested that 3β - HSD might play an important role in the regulation of gonad development basing on steroido genesis mechanism in C. angulata