1. Structure and tissue-specific expression of a novel member of the rat 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase (3 beta-HSD) family. The exclusive 3 beta-HSD gene expression in the skin.
- Author
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Simard J, Couet J, Durocher F, Labrie Y, Sanchez R, Breton N, Turgeon C, and Labrie F
- Subjects
- Amino Acid Sequence, Animals, Base Sequence, Cloning, Molecular, DNA genetics, DNA isolation & purification, Female, Humans, Isoenzymes metabolism, Kinetics, Male, Molecular Sequence Data, Molecular Weight, Multienzyme Complexes metabolism, Oligodeoxyribonucleotides, Organ Specificity, Poly A genetics, Poly A isolation & purification, Progesterone Reductase metabolism, RNA genetics, RNA isolation & purification, RNA, Messenger, Rats, Rats, Sprague-Dawley, Recombinant Proteins biosynthesis, Recombinant Proteins metabolism, Restriction Mapping, Sequence Homology, Amino Acid, Species Specificity, Steroid Isomerases metabolism, Gene Expression Regulation, Enzymologic, Isoenzymes biosynthesis, Isoenzymes genetics, Multienzyme Complexes biosynthesis, Multienzyme Complexes genetics, Progesterone Reductase biosynthesis, Progesterone Reductase genetics, Skin enzymology, Steroid Isomerases biosynthesis, Steroid Isomerases genetics
- Abstract
Structures of cDNA clones encoding three members of the rat 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase (3 beta-HSD) family were characterized. To search for potential new types of 3 beta-HSD, rat types I and II 3 beta-HSD cDNAs were used as probes to screen a rat genomic DNA library. Among the clones isolated, one encodes a novel predicted rat 3 beta-HSD isoenzyme, chronologically designated type IV. The corresponding full-length cDNA was thereafter isolated by selective polymerase chain reaction amplification from rat ovary and day-15 placenta cDNA libraries. The rat type IV 3 beta-HSD cDNA encodes a predicted 372-amino acid protein of 41,854 daltons, which shares 90.9, 87.9, and 78.8% sequence identity with rat types I, II, and III proteins, respectively. Ribonuclease protection assay reveals that type IV 3 beta-HSD is the sole 3 beta-HSD mRNA species detectable in the skin and represents the predominant species in the placenta while being also detectable in the ovary and, to a lower degree, in the adrenal gland. Transient expression of type IV cDNA in SW-13 cells indicates 3 beta-HSD activity similar to that of rat type I 3 beta-HSD. The presence of multiple 3 beta-HSD genes should permit differential and tissue-specific regulation of this rate-limiting enzymatic activity essential in the biosynthesis of all classes of steroid hormones in both classical steroidogenic and intracrine peripheral tissues.
- Published
- 1993