title: DDT resistance in Drosophila correlates with Cyp6g1 over-expression and confers cross-resistance to the neonicotinoid imidacloprid.
abstract: Mutagenesis can be used as a means of predicting likely mechanisms of resistance to novel classes of insecticides. We used chemical mutagenesis in Drosophila to screen for mutants that had become resistant to imidacloprid, a neonicotinoid insecticide. Here we report the isolation of two new dominant imidacloprid-resistant mutants. By recombinational mapping we show that these map to the same location as Rst(2)DDT. Furthermore, we show that pre-existing Rst(2)DDT alleles in turn confer cross-resistance to imidacloprid. In order to localize the Rst(2)DDT gene more precisely, we mapped resistance to both DDT and imidacloprid with respect to P-element markers whose genomic location is known. By screening for recombinants between these P-elements and resistance we localized the gene between 48D5-6 and 48F3-6 on the polytene chromosome map. The genomic sequence in this interval shows a cluster of cytochrome P450 genes, one of which, Cyp6g1, is over-expressed in all resistant strains examined. We are now testing the hypothesis that resistance to both compounds is associated with over-expression of this P450 gene.
authors.affiliation: Department of Biology and Biochemistry, University of Bath, Bath, BA2 7AY, UK.
authors.forename: P
authors.initials: P
authors.lastname: Daborn
authors.forename: S
authors.initials: S
authors.lastname: Boundy
authors.forename: J
authors.initials: J
authors.lastname: Yen
authors.forename: B
authors.initials: B
authors.lastname: Pittendrigh
authors.forename: R
authors.initials: R
authors.lastname: ffrench-Constant
mesh_terms: D000818:Animals; D002874:Chromosome Mapping; D003433:Crosses, Genetic; D003577:Cytochrome P-450 Enzyme System / Q000096:biosynthesis / Q000235:genetics*; D003634:DDT / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D029721:Drosophila Proteins / Q000096:biosynthesis / Q000235:genetics*; D004331:Drosophila melanogaster / Q000187:drug effects* / Q000235:genetics; D004351:Drug Resistance / Q000235:genetics; D005799:Genes, Dominant; D007093:Imidazoles / Q000494:pharmacology*; D007306:Insecticides / Q000494:pharmacology*; D000073943:Neonicotinoids; D009574:Nitro Compounds; D010944:Plants; D011994:Recombinant Proteins / Q000096:biosynthesis
chemical_list: D029721:Drosophila Proteins; D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; D011994:Recombinant Proteins; C082359:imidacloprid; D003577:Cytochrome P-450 Enzyme System; D003634:DDT; C446928:Cyp6g1 protein, Drosophila