Cytochrome P450s and their functions in permethrin resistance in the house fly, Musca domestica

Cytochrome P450-mediated detoxification is one of the most important mechanisms involved in insecticide resistance. With the availability of the whole transcriptome sequence from house flies, we are now able to characterize the expression profiles of P450s and their functions in insecticide resistant house flies. In the current study, the expression profiles of a total of 87 P450 genes were compared in different house fly strains with different levels of insecticide resistance. Thirteen P450 genes were co-up-regulated in highly permethrin resistant ALHF strain. Genetic linkage analysis with house fly lines obtaining different autosomal combinations from ALHF revealed that the expression of these up-regulated P450 genes mainly controlled by co-regulation of factors among multiple autosomes, especially autosomes 1, 2 and 5, strongly demonstrating that regulatory cascades are involved in the regulation of resistance P450 gene expression. Functional study of the transgenic lines of Drosophila melanogaster with the house fly up-regulated P450 genes revealed that these house fly P450 genes were able to confer the tolerance of D. melanogaster to permethrin, suggesting the importance of these genes in resistance. Taken together, these results indicate that multiple up-regulated P450 genes are co-responsible for detoxification of insecticides and insecticide selection.