| First Author | Rheault P | Year | 1999 |
| Journal | Biochim Biophys Acta | Volume | 1447 |
| Issue | 1 | Pages | 17-24 |
| PubMed ID | 10500239 | Mgi Jnum | J:57835 |
| Mgi Id | MGI:1345863 | Doi | 10.1016/s0167-4781(99)00106-2 |
| Citation | Rheault P, et al. (1999) Structure and activity of the murine type 5 17beta-hydroxysteroid dehydrogenase gene(1). Biochim Biophys Acta 1447(1):17-24 |
| abstractText | 17beta-Hydroxysteroid dehydrogenases (17beta-HSDs) play a crucial role in the control of active sex steroid intracellular levels. Seven types of 17beta-HSD have been described. In this study, we report the cloning and characterization of the mouse type 5 17beta-HSD belonging to the aldo-keto reductase superfamily, in contrast with types 1, 2, 3, 4, 6, and 7 17beta-HSD which belong to the short-chain alcohol dehydrogenase family. The gene spans 16 kb and contains 9 exons separated by 8 introns. Primer extension analysis identified a major transcription start site beginning 50 nucleotides upstream from the ATG initiation codon. Northern blot analysis showed a high mRNA expression level in the liver and a weaker signal in the kidney. To determine more precisely the substrate specificity of the enzyme, we established a stable cell line expressing mouse type 5 17beta-HSD in transformed human embryonic kidney (293) cells. The transfected cell line preferentially catalyzes the transformation of 4-androstenedione (4-dione) and androstanedione (A-dione) into testosterone (T) and dihydrotestosterone (DHT), respectively. This data is somewhat in contradiction with a previous study that described the enzyme as estradiol 17beta-dehydrogenase. Our results indicate that the rate of transformation of estradiol (E(2)) to estrone (E(1)) represents only 1% of the rate of transformation of 4-dione to T. Mouse type 5 17beta-HSD shares 76% amino acid sequence identity with human type 5 17beta-HSD; 71%, 76%, 76% with rat 3alpha-HSD and human types 1 and 3 3alpha-HSDs, respectively; and 71%, 69% and 77% with mouse, rat and human 20 alpha-HSD, respectively. |
