Molecular cloning of cytochrome P450 aromatases in the protogynous wrasse, Halichoeres tenuispinis

P450 aromatase (P450arom, CYP19), a CYP19 gene product, is a member of the cytochrome P450 superfamily that catalyzes the formation of aromatic C18 estrogen from C19 androgen. To begin to understand the molecular mechanisms of P450 aromatase action in the protogynous wrasse, we isolated two cDNAs: one encoding CYP19a from ovary and the other encoding CYP19b from brain. The full-length cDNA of wrasse CYP19a, isolated from ovary cDNA library, is 2020 bp long and encodes 519 amino acids. The amino acid sequence of CYP19a has 62-83% identity with ovary-type aromatases of other teleosts. The full-length cDNA of wrasse CYP19b obtained using 5′ and 3′ RACE consists of 2666 bp, and its open reading frame encodes 496 amino acids. The deduced amino acid sequence has 62-83% identity with brain-type aromatases of other teleosts. Northern blot analysis identified a single 2.2-kb transcript in the ovary (CYP19a), and a single 2.6-kb transcript in the brain (CYP19b), suggesting that there are single forms of CYP19a and CYP19b, respectively, in the wrasse. RT-PCR assay showed that two CYP19 genes were expressed ubiquitously in various tissues, although each CYP19 subtype was expressed at highest level in the ovary and brain of the wrasse. These results suggest that CYP19 genes act in diverse tissue types, in addition to their effects on the physiological and reproductive functions of estrogen.