title: Cloning, characterization, and expression analysis of a putative 17 beta-hydroxysteroid dehydrogenase 11 in the abalone, Haliotis diversicolor supertexta.
abstract: The 17-beta-hydroxysteroid dehydrogenases (17β-HSDs) are key enzymes for sex steroid biosynthesis. To date, relatively little is known about the presence and function of 17β-HSDs in marine gastropods. In the present study, a cDNA sequence encoding putative 17β-HSD type 11 (17β-HSD-11) was identified in marine abalone (Haliotis diversicolor supertexta). The full-length cDNA contains 1058bp, including an open reading frame (ORF) of 900bp that encodes a protein of 299 amino acids. Comparative structural analysis revealed that abalone 17β-HSD-11 shares relatively high homology with other 17b-HSD-11 hormologues, and a lesser degree of amino acid identity with other forms of 17b-HSD, especially in the functional domains, including the cofactor binding domain (TGxxxGxG) and catalytic site (YxxSK). Phylogenetic analysis showed that abalone 17β-HSD-11 belongs to the short-chain dehydrogenase/reductase (SDR) family. Functional analysis following transient transfection of the ORF into human embryonic kidney-293 (HEK-293) cells indicated that abalone 17β-HSD-11 has the ability to convert 5α-androstane-3α,17β-diol (3α-diol) to androsterone (A) and testosterone (T) to androstenedione (4A). Expression analysis in vivo demonstrated that abalone 17β-HSD-11 is differentially expressed during three stages (non-reproductive, reproductive, and post-reproductive). Taken together, these results indicate that ab-17β-HSD-11 is an SDR family member with a potential role in steroid regulation during the reproductive stage.
authors.affiliation: School of Life Sciences, Tsinghua University, Beijing, PR China.
authors.forename: Hong-ning
authors.initials: HN
authors.lastname: Zhai
authors.forename: Jin
authors.initials: J
authors.lastname: Zhou
authors.forename: Zhong-hua
authors.initials: ZH
authors.lastname: Cai
mesh_terms: D015067:17-Hydroxysteroid Dehydrogenases / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry; D049851:Gastropoda / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D016366:Open Reading Frames; D058974:Phylogeography; D014162:Transfection
chemical_list: D018076:DNA, Complementary; D015067:17-Hydroxysteroid Dehydrogenases