Cloning of a novel cytochrome P450 (CYP4C15) differentially expressed in the steroidogenic glands of an arthropod

Biosynthesis of ecdysteroids, arthropod steroid molting hormones, proceeds from dietary cholesterol through a complex and still incompletely elucidate d pathway. Most of the known steps are catalyzed by cytochrome P450 enzymes (CYPs) but none of their genes has yet been identified. We have establishe d a cDNA library of crayfish steroidogenic glands (Y organs). A full length CYP-cDNA was characterized containing a 1539 bp open reading frame encodin g a predicted protein of 513 amino acid residues. This novel CYP was assign ed to the CYP4 family and designated CYP4C15. Northern blots demonstrated p redominant expression of this gene in the active molting glands, suggesting a role in ecdysteroid biosynthesis rather than detoxification. (C) 1999 Ac ademic Press.