Expression and regulation of CYP6D3 in the house fly, Musca domestica (L.)

Recently, a new cytochrome P450 gene, CYP6D3, was identified from house fly . CYP6D3 was found upstream of a related gene (CYP6D1) on autosome 1. CYP6D 3 cDNA sequences were obtained and compared from insecticide resistant (LPR ) and susceptible (CS and Edinburgh) strains. Although each strain had a di fferent CYP6D3 allele, the deduced amino acid sequences revealed no consist ent differences between the susceptible and resistant strains. There was ap proximately 12-fold more CYP6D3 mRNA detected in adult LPR flies compared t o CS, and the elevated level of expression in LPR was not due to gene ampli fication. Northern blots indicate expression of CYP6D3 mRNA is developmenta lly regulated with no expression in eggs, yet it is readily detectable in l arvae as well as male and female adults. Phenobarbital is a well studied in ducer of P450s in insects and it induced expression of CYP6D3 mRNA in both the CS (16-fold) and LPR (1.6 fold) strains. The CYP6D3 5 ' flanking region s were sequenced from the resistant and susceptible strains. Possible regul atory sequences within this region are discussed. (C) 2001 Elsevier Science Ltd. All rights reserved.