Rainbow trout cytochrome P‐450c17 (17α‐hydroxylase/17,20‐lyase) cDNA cloning, enzymatic properties and temporal pattern of ovarian P‐450c17 mRNA expression during oogenesis

Abstract
A cDNA clone encoding cytochrome P‐450c17 (17α‐hydroxylase/17,20‐lyase) was isolated from a rainbow trout ovarian follicle cDNA library. The cDNA contained an open reading frame of 1,542 nucleotides encoding a protein of 514 amino acid residues. The amino acid sequence of trout P‐450c17 shows a much greater homology with chicken P‐450c17 than with that of human, bovine and rat. The trout P‐450c17 expressed in non‐steroidogenic mammalian COS‐1 cells showed both 17α‐hydroxylase and 17,20‐lyase activities. The cDNA only hybridized to a single species or mRNA (2.4 kb) isolated from rainbow trout ovaries; the 2.4 kb transcripts were abundant in trout ovaries during the later stages of oogenesis.