title: Molecular cloning and expression of an abundant rabbit ovarian protein with 20 alpha-hydroxysteroid dehydrogenase activity.
abstract: An abundant 37-kDa protein, which comprises up to 30% of the soluble proteins of the ovary, has been found to have 20 alpha-hydroxysteroid dehydrogenase (20 alpha HSD) activity. The steroidogenic enzyme 20 alpha HSD regulates the conversion of progesterone to 20 alpha-hydroxyprogesterone in many mammalian species. Complimentary DNA clones encoding a unique and abundant 20 alpha HSD were isolated from a mature rabbit ovary library using guinea pig antisera generated to the purified 37-kDa protein and from a 5' EcoRI fragment from the initial positive clone. A full-length cDNA clone of 1217 basepairs encoding a 323-amino acid protein with an estimated mol wt of 37 kilodaltons was obtained. Amino acid sequence data indicate a similarity to human chlordecone reductase, bovine lung prostaglandin F synthase, human aldose reductase, human aldehyde reductase, and frog lens rho-crystallin, placing rabbit ovarian 20 alpha HSD in the aldo-keto reductase family of proteins. Northern blot analysis demonstrated a 1.2-kilobase mRNA in the interstitial tissue of mature rabbit ovaries and, to a lesser extent, in corpora luteal tissue. 20 alpha HSD was expressed in bacteria as a recombinant protein and was shown to possess enzymatic activity, preferring NADP as a cofactor. These studies demonstrate that an abundant ovarian protein belonging to the superfamily of NADP-dependent aldo-keto reductases has 20 alpha HSD activity. This is the first example of an abundant crystallin-related protein with known enzymatic activity in a tissue other than the lens.
authors.affiliation: Department of Cell Biology, Baylor College of Medicine Houston, Texas 77030.
authors.forename: W R
authors.initials: WR
authors.lastname: Lacy
authors.forename: K J
authors.initials: KJ
authors.lastname: Washenick
authors.forename: R G
authors.initials: RG
authors.lastname: Cook
authors.forename: B S
authors.initials: BS
authors.lastname: Dunbar
mesh_terms: D015089:20-Hydroxysteroid Dehydrogenases / Q000096:biosynthesis / Q000235:genetics* / Q000302:isolation & purification; D043607:20-alpha-Hydroxysteroid Dehydrogenase; D000595:Amino Acid Sequence; D000818:Animals; D001001:Anura; D001483:Base Sequence; D002417:Cattle; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D004790:Enzyme Induction; D005260:Female; D006801:Humans; D008969:Molecular Sequence Data; D005810:Multigene Family; D010053:Ovary / Q000201:enzymology*; D010088:Oxidoreductases / Q000235:genetics; D011817:Rabbits / Q000378:metabolism*; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D017386:Sequence Homology, Amino Acid
chemical_list: D011993:Recombinant Fusion Proteins; D004247:DNA; D010088:Oxidoreductases; D015089:20-Hydroxysteroid Dehydrogenases; D043607:20-alpha-Hydroxysteroid Dehydrogenase