Pig testicular 20 beta-hydroxysteroid dehydrogenase exhibits carbonyl reductase-like structure and activity. cDNA cloning of pig testicular 20 beta-hydroxysteroid dehydrogenase.

cDNA inserts encoding 20 beta-hydroxysteroid dehydrogenase (EC 1.1.1.53) were, for the first time, isolated and cloned from a pig testis cDNA library using synthetic oligonucleotides deduced from the partially determined amino acid sequences. The cDNA contains an open reading frame predicted to encode 289 amino acid residues. Surprisingly, it has 85% amino acid homology to human carbonyl reductase. The purified enzyme exhibited carbonyl reductase activity. Adenine-rich sequence was located in the 3'-untranslated nine-rich sequence was located in the 3'-untranslated region, which may mean that the gene originates by retroposition. RNA transcripts of 1.3, 3, and 6 kilobases were detected in poly(A)+ RNA extracted from pig testis by Northern blot hybridization. The steady-state level of the RNA species increased to a maximum in testes from 10-day-old pigs, but rapidly declined thereafter to the same levels found in testes of mature animals.