title: RNAi validation of resistance genes and their interactions in the highly DDT-resistant 91-R strain of Drosophila melanogaster.
abstract: 4,4'-dichlorodiphenyltrichloroethane (DDT) has been re-recommended by the World Health Organization for malaria mosquito control. Previous DDT use has resulted in resistance, and with continued use resistance will increase in terms of level and extent. Drosophila melanogaster is a model dipteran that has many available genetic tools, numerous studies done on insecticide resistance mechanisms, and is related to malaria mosquitoes allowing for extrapolation. The 91-R strain of D. melanogaster is highly resistant to DDT (>1500-fold), however, there is no mechanistic scheme that accounts for this level of resistance. Recently, reduced penetration, increased detoxification, and direct excretion have been identified as resistance mechanisms in the 91-R strain. Their interactions, however, remain unclear. Use of UAS-RNAi transgenic lines of D. melanogaster allowed for the targeted knockdown of genes putatively involved in DDT resistance and has validated the role of several cuticular proteins (Cyp4g1 and Lcp1), cytochrome P450 monooxygenases (Cyp6g1 and Cyp12d1), and ATP binding cassette transporters (Mdr50, Mdr65, and Mrp1) involved in DDT resistance. Further, increased sensitivity to DDT in the 91-R strain after intra-abdominal dsRNA injection for Mdr50, Mdr65, and Mrp1 was determined by a DDT contact bioassay, directly implicating these genes in DDT efflux and resistance.
authors.affiliation: Molecular and Cellular Biology Program, University of Massachusetts, Amherst, MA, United States.
authors.forename: Kyle J
authors.initials: KJ
authors.lastname: Gellatly
authors.affiliation: Department of Biological Sciences and Environmental Sciences Program, Southern Illinois University-Edwardsville, Edwardsville, IL 62026, United States.
authors.forename: Kyong Sup
authors.initials: KS
authors.lastname: Yoon
authors.affiliation: Department of Veterinary & Animal Sciences, University of Massachusetts, Amherst, MA 01003, United States.
authors.forename: Jeffery J
authors.initials: JJ
authors.lastname: Doherty
authors.affiliation: Department of Entomology & Integrative Biology, University of Illinois, Urbana-Champaign, IL 61801, United States.
authors.forename: Weilin
authors.initials: W
authors.lastname: Sun
authors.affiliation: Department of Entomology & Integrative Biology, University of Illinois, Urbana-Champaign, IL 61801, United States.
authors.forename: Barry R
authors.initials: BR
authors.lastname: Pittendrigh
authors.affiliation: Molecular and Cellular Biology Program, University of Massachusetts, Amherst, MA, United States; Department of Veterinary & Animal Sciences, University of Massachusetts, Amherst, MA 01003, United States. Electronic address: jclark@vasci.umass.edu.
authors.forename: J Marshall
authors.initials: JM
authors.lastname: Clark
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D000818:Animals; D030801:Animals, Genetically Modified; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics; D003634:DDT / Q000494:pharmacology*; D029721:Drosophila Proteins / Q000235:genetics*; D004331:Drosophila melanogaster / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D005260:Female; D006838:Hydrocarbons / Q000378:metabolism; D007305:Insecticide Resistance / Q000235:genetics*; D007306:Insecticides / Q000494:pharmacology*; D008297:Male; D034622:RNA Interference
chemical_list: D018528:ATP-Binding Cassette Transporters; D029721:Drosophila Proteins; D006838:Hydrocarbons; D007306:Insecticides; D003577:Cytochrome P-450 Enzyme System; D003634:DDT
keywords: ABC transporters; Cuticular hydrocarbons; DDT resistance; Drosophila melanogaster; P450s; Resistance; UAS-RNAi