House-fly cytochrome P450 CYP6D1: 5 ' flanking sequences and comparison ofalleles

CYP6D1 is a cytochrome P450 found in the house fly, Musca domestica. Expres sion is greater in pyrethroid-resistant vs. -susceptible strains and can be induced by phenobarbital in adult susceptible flies. CYP6D1 is expressed o nly in adult flies. To gain information about possible regulatory elements involved in CYP6D1 expression, and to confirm the gene sequence that was pr eviously determined by polymerase chain reaction (PCR), we screened a house -fly library prepared with genomic DNA from the pyrethroid-resistant LPR st rain. A CYP6D1v1 clone was isolated and sequenced. This clone contained 887 nucleotides 5' to the open reading frame and a previously unknown 2.4-kb i ntron. Using polymerase chain reaction with primers based on the CYP6D1v1 a llele, the sequences 5' to the ORF were obtained from five pyrethroid susce ptible strains. The transcription initiation site (TIS) was identified at t he same position in LPR and two susceptible strains (86 nucleotides upstrea m from the translation start site). A comparison of the 5' flanking sequenc es revealed a high degree of similarity for most regions, although differen ces in the sequences were identified. The possible roles of these sequence differences in regulation of CYP6D1 expression are discussed. (C) 1999 Else vier Science B.V. All rights reserved.