title: Ovarian 3 beta-hydroxysteroid dehydrogenase/delta 5-4-isomerase of rainbow trout: its cDNA cloning and properties of the enzyme expressed in a mammalian cell.
abstract: A cDNA clone encoding 3 beta-hydroxysteroid dehydrogenase delta 5-4-isomerase (3 beta-HSD) was isolated from a cDNA library of rainbow trout ovarian thecal cells. Southern hybridization analysis of trout genomic DNA with the cDNA suggested the presence of a single gene encoding 3 beta-HSD in the rainbow trout showing a total genomic size of less than 4 kilobases (kb). The cDNA hybridized to a species of mRNA isolated from rainbow trout ovaries; the 1.4 kb transcripts were most abundant in trout ovaries during the later stages of oogenesis. The trout 3 beta-HSD expressed in non-steroidogenic monkey kidney tumor (COS-1) cells showed a unique enzymatic 3 beta-HSD activity. Dehydroepiandrosterone was a more favoral substrate of the trout 3 beta-HSD than 1- alpha-hydroxypregnenolone. Interestingly, the trout 3 beta-HSD expressed in COS-1 cells exhibited minimal ability to convert pregnenolone to progesterone.
authors.affiliation: Laboratory of Reproductive Biology, National Institute for Basic Biology, Okazaki, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Sakai
authors.forename: M
authors.initials: M
authors.lastname: Tanaka
authors.forename: M
authors.initials: M
authors.lastname: Takahashi
authors.forename: S
authors.initials: S
authors.lastname: Fukada
authors.forename: J I
authors.initials: JI
authors.lastname: Mason
authors.forename: Y
authors.initials: Y
authors.lastname: Nagahama
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000235:genetics*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D005260:Female; D015870:Gene Expression; D005796:Genes; D008969:Molecular Sequence Data; D017686:Oncorhynchus mykiss / Q000235:genetics*; D010053:Ovary / Q000201:enzymology; D012333:RNA, Messenger / Q000235:genetics; D011994:Recombinant Proteins / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014162:Transfection
chemical_list: D012333:RNA, Messenger; D011994:Recombinant Proteins; D015096:3-Hydroxysteroid Dehydrogenases