Characteristics of 17β-hydroxysteroid dehydrogenase 8 and its potential role in gonad of Zhikong scallop Chlamys farreri.
17β-Hydroxysteroid dehydrogenases (17β-HSDs) are important enzymes catalyzing steroids biosynthesis and metabolism in vertebrates. Although studies indicate steroids play a potential role in reproduction of molluscs, little is known about the presence and function of 17β-HSDs in molluscs. In the present study, a full-length cDNA encoding 17β-HSD type 8 (17β-HSD8) was identified in the Zhikong scallop Chlamys farreri, which is 1104bp in length with an open reading frame of 759bp encoding a protein of 252 amino acids. Phylogenetic analysis revealed that the C. farreri 17β-HSD8 (Cf-17β-HSD8) belongs to the short chain dehydrogenase/reductase family (SDR) and shares high homology with other 17β-HSD8 homologues. Catalytic activity assay in vitro demonstrated that the refolded Cf-17β-HSD8 expressed in Escherichia coli could effectively convert estradiol-17β (E2) to estrone (E1), and weakly catalyze the conversion of testosterone (T) to androstenedione (A) in the presence of NAD(+). The Cf-17β-HSD8 mRNA was ubiquitously expressed in all tissues analyzed, including gonads. The expression levels of Cf-17β-HSD8 mRNA and protein increased with gametogenesis in both ovary and testis, and were significantly higher in testis than in ovary at growing stage and mature stage. Moreover, results of in situ hybridization and immunohistochemistry revealed that the mRNA and protein of Cf-17β-HSD8 were expressed in follicle cells and gametes at all stages except spermatozoa. Our findings suggest that Cf-17β-HSD8 may play an important role in regulating gametogenesis through modulating E2 levels in gonad of C. farreri.
Key Laboratory of Marine Genetics and Breeding, Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, PR China.
Jianguo
J
Liu
Key Laboratory of Marine Genetics and Breeding, Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, PR China. Electronic address: zzfp107@ouc.edu.cn.
Zhifeng
Z
Zhang
Key Laboratory of Marine Genetics and Breeding, Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, PR China.
Xiaoshi
X
Ma
Key Laboratory of Marine Genetics and Breeding, Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, PR China.
Shaoshuai
S
Liang
Key Laboratory of Marine Genetics and Breeding, Ministry of Education, College of Marine Life Sciences, Ocean University of China, Qingdao 266003, PR China.
Dandan
D
Yang
D015067:17-Hydroxysteroid Dehydrogenases / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D004958:Estradiol / Q000737:chemistry; D005260:Female; D005718:Gametogenesis; D015870:Gene Expression; D015971:Gene Expression Regulation, Enzymologic; D008297:Male; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010053:Ovary / Q000201:enzymology; D010084:Oxidation-Reduction; D049897:Pectinidae / Q000201:enzymology*; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D013737:Testis / Q000201:enzymology
D004958:Estradiol; D015067:17-Hydroxysteroid Dehydrogenases; C044256:3 (or 17)-beta-hydroxysteroid dehydrogenase
17β-Hydroxysteroid dehydrogenase 8 (17β-HSD8); Chlamys farreri; Estradiol-17β; Gametogenesis; Gonad; Steroid