Аннотация:To provide a basis for investigation of the molecular mechanisms underlying the hormonal regulation of steroid 17α-hydroxylase (P-45017α) activity in adrenal, ovary, and testis as well as human 17α-hydroxylase deficiency, we have isolated from a human fetal adrenal cDNA library a cDNA sequence complementary to the mRNA that encodes the human P-45017α enzyme. Of 75,000 colonies from the library that were screened by use of a nick-translated 5′-specific bovine P-45017α cDNA probe, 10 positive colonies were isolated and the clone with the longest insert (pcD-17αH) was selected for further characterization. pcD-17αH encodes the complete human P-45017α protein having approximately 78% homology at the nucleotide level and 71% homology at the amino acid level when the sequence of pcD-17αH is compared to the bovine P-45017α cDNA sequence. By transient expression of the human P-45017αcDNA clone in COS 1 cells, we have demonstrated that the17α-hydroxylase and 17,20 lyase activities reside within the same human P-45017α polypeptide chain. The insert was also used as a probe to investigate, by means of Southern blot analysis, possible alterations in the P-45017αgene sequence in DNA isolated from skin fibroblasts from three patients with clinically characterized 17α-hydroxylase deficiencies. No changes were detected in the DNA of any of the patients by this analysis.
