Cloning and expression analysis of a new member of the cytochrome P450, CYP2A15 from the Chinese hamster, encoding testosterone 7 alpha-hydroxylase

We cloned a new cytochrome P450 cDNA encoding testosterone 7 alpha-hydroxyl ase in the Chinese hamster, designated CYP2A15 which shares significant ami no acid sequence homology with members of the CYP2A subfamily. The CYP2A15 cDNA was isolated by screening a liver cDNA library and the sequence contai ns an open reading frame of 1482 nucleotides encoding a polypeptide of 493 amino acids with a calculated molecular mass of 56,295 Da. This is flanked by a 5'-untranslated region of 2 bp and a 3' untranslated region of 191 bp including the poly(A) tail. We determined the catalytic activity of CYP2A15 using microsomes obtained by transient expression of its cDNA in transfect ed COS-7 cells. The heterologously expressed CYP2A15 was found to hydroxyla te testosterone at position 7 alpha in a reconstituted system. RT-PCR exper iments revealed that the mRNA of CYP2A15 was expressed in liver, but not de tected in kidney, lung, or small intestine. The expression of CYP2A15 mRNA was slightly induced by treatment with either rifampicin or 3-methylcholant hrene. (C) 1999 Academic Press.