Molecular cloning and characterization of a novel human hydroxysteroid dehydrogenase-like 2 (HSDL2) cDNA from fetal brain.

Hydroxysteroid dehydrogenases (HSDs) are responsible for the biosynthesis of steroid hormones and play a crucial role in mammalian physiology and development. By large-scale sequencing analysis of a human fetal brain cDNA library, we isolated a novel human hydroxysteroid dehydrogenase-like cDNA (HSDL2). This cDNA is 3211 bp in length, encoding a 418-amino-acid polypeptide, which contains a typical motif for NAD(P)+-binding (TGxxxGxG), an SDR active site motif (S-Y-K) and a sterol carrier protein domain. HSDL2 shows high similarity with the homologues in the mouse and fruit fly. The HSDL2 gene is mapped to chromosome 9q32 and contains 11 exons. RT-PCR analysis shows that the HSDL2 gene is widely expressed in human tissues and the expression levels in liver, kidney, prostate, testis, and ovary are relatively high.