title: Splice form variant and amino acid changes in MDR49 confers DDT resistance in transgenic Drosophila.
abstract: The ATP-binding cassette (ABC) transporters represent a superfamily of proteins that have important physiological roles in both prokaryotes and eukaryotes. In insects, ABC transporters have previously been implicated in insecticide resistance. The 91-R strain of Drosophila melanogaster has been intensely selected with DDT over six decades. A recent selective sweeps analysis of 91-R implicated the potential role of MDR49, an ABC transporter, in DDT resistance, however, to date the details of how MDR49 may play a role in resistance have not been elucidated. In this study, we investigated the impact of structural changes and an alternative splicing event in MDR49 on DDT-resistance in 91-R, as compared to the DDT susceptible strain 91-C. We observed three amino acid differences in MDR49 when 91-R was compared with 91-C, and only one isoform (MDR49B) was implicated in DDT resistance. A transgenic Drosophila strain containing the 91-R-MDR49B isoform had a significantly higher LD50 value as compared to the 91-C-MDR49B isoform at the early time points (6 h to 12 h) during DDT exposure. Our data support the hypothesis that the MDR49B isoform, with three amino acid mutations, plays a role in the early aspects of DDT resistance in 91-R.
authors.affiliation: Department of Entomology, University of Illinois at Urbana-Champaign, Illinois, 61801, USA.
authors.forename: Keon Mook
authors.initials: KM
authors.lastname: Seong
authors.affiliation: Department of Entomology, University of Illinois at Urbana-Champaign, Illinois, 61801, USA.
authors.forename: Weilin
authors.initials: W
authors.lastname: Sun
authors.affiliation: Department of Veterinary &Animal Science, University of Massachusetts, Amherst, MA, 01003, USA.
authors.forename: John M
authors.initials: JM
authors.lastname: Clark
authors.affiliation: Department of Entomology, University of Illinois at Urbana-Champaign, Illinois, 61801, USA.
authors.forename: Barry R
authors.initials: BR
authors.lastname: Pittendrigh
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B / Q000235:genetics*; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000235:genetics*; D000818:Animals; D030801:Animals, Genetically Modified; D003634:DDT / Q000494:pharmacology*; D029721:Drosophila Proteins / Q000235:genetics*; D004331:Drosophila melanogaster / Q000187:drug effects / Q000235:genetics*; D007305:Insecticide Resistance; D009154:Mutation; D016366:Open Reading Frames; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D017423:Sequence Analysis, RNA / Q000379:methods
chemical_list: D018435:ATP Binding Cassette Transporter, Subfamily B; D000596:Amino Acids; D029721:Drosophila Proteins; D020033:Protein Isoforms; C069935:mdr49 protein, Drosophila; D003634:DDT