Isolation, characterization, and chromosomal mapping of mouse P450 17[alpha]-hydroxylase/C17-20 lyase

Abstract

Cytochrome P450 17[alpha]-hydroxylase/C17-20 lyase (P45017[alpha]) catalyzes the conversion of C-21 steroids to C-19 steroids in gonads. A full-length mouse cDNA encoding P45017[alpha] was isolated from a mouse Leydig cell library and characterized by restriction mapping and sequencing. The predieted amino acid sequence has 83% homology to rat, 66% homology to human, and 62% homology to bovine P45017[alpha] amino acid sequences. The protein is 507 amino acids in length, which is 1 amino acid shorter than the human protein and 2 amino acids shorter than the bovine protein. The structural gene encoding P45017[alpha] (Cyp17) was localized utilizing an interspecific testcross to mouse chromosome 19, distal to Got-1. Another cytochrome P450, P4502c (Cyp2c), also is located at the distal end of chromosome 19. CYP17, CYP2c, and GOT1 have been mapped to human chromosome 10, with CYP2C and GOT1 mapped to the distal region, q24.3 and q25.3, respectively. The data in the present study indicate conserved syntenic loci on mouse chromosome 19 and human chromosome 10 and predict that the structural gene encoding P45017[alpha] will be found distal to GOT1 on human chromosome 10.