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.

摘要: Structures of cDNA clones encoding three members the rat 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase (3 beta-HSD) family were characterized. To search for potential new types beta-HSD, I and II beta-HSD cDNAs used as probes to screen a genomic DNA library. Among isolated, one encodes novel predicted isoenzyme, chronologically designated type IV. The corresponding full-length was thereafter isolated by selective polymerase chain reaction amplification from ovary day-15 placenta libraries. IV 372-amino acid protein 41,854 daltons, which shares 90.9, 87.9, 78.8% sequence identity with I, II, III proteins, respectively. Ribonuclease protection assay reveals that is sole mRNA species detectable in skin represents predominant while being also and, lower degree, adrenal gland. Transient expression SW-13 cells indicates activity similar beta-HSD. presence multiple genes should permit differential tissue-specific regulation this rate-limiting enzymatic essential biosynthesis all classes steroid hormones both classical steroidogenic intracrine peripheral tissues.