Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2001 Aug 30;1520(2):124-30.
doi: 10.1016/s0167-4781(01)00247-0.

Gene structure, chromosomal localization and analysis of 3-ketosteroid reductase activity of the human 3(alpha-->beta)-hydroxysteroid epimerase

X F Huang  1 , V Luu-The
Affiliations

Gene structure, chromosomal localization and analysis of 3-ketosteroid reductase activity of the human 3(alpha-->beta)-hydroxysteroid epimerase

X F Huang et al. Biochim Biophys Acta. .

Abstract

Following our previous characterization of the first human 3(alpha-->beta)hydroxysteroid epimerase (hHSE), we determined the genomic structure and chromosomal localization of the hHSE gene using fluorescent in situ hybridization (FISH) in this study. The gene spans 23 kb and contains five exons and four introns. FISH mapping assigned this gene to chromosome band 12q13. Primer extension analysis allowed the identification of a single transcription start site at 179 bp upstream from the ATG start codon. The 5'-flanking sequence lacks a typical TATA box in the proximal region of the transcription start site. However, analysis of the 2 kb promoter region revealed the presence of multiple potential transcription factor binding sites. Furthermore, we studied the 3-ketosteroid reductase activity demonstrated by hHSE in intact cells stably expressing the enzyme. It has been known that, in vitro, 3beta-hydroxysteroid dehydrogenase (3beta-HSD) shows both oxidative and reductive activity. Our results showed that hHSE catalyzes the reduction of 3-ketosteroids to form 3beta-hydroxysteroids while 3beta-HSD cannot catalyze this reaction in intact cells. However, hHSE showed 3-keto reductase activity in both microsomal fractions and intact cells. Since intact cells constitute a system which closely reflects in vivo intracellular conditions, we propose that hHSE might contribute to the cellular 3-ketosteroid reductase activity in the peripheral tissues.

PubMed Disclaimer

Similar articles

See all similar articles

Cited by

Publication types

LinkOut - more resources