Open AccessDrug-resistant Drosophila indicate glutamate-gated chloride channels are targets for the antiparasitics nodulisporic acid and ivermectin
Author(s) -
Nanci S. Kane,
Birgit Hirschberg,
Su Wen Qian,
David Hunt,
Brande S. Thomas,
Richard M. Brochu,
Steven W. Ludmerer,
Yi Zheng,
McHardy M. Smith,
Joseph P. Arena,
Charles J. Cohen,
Dennis M. Schmatz,
Jeffrey W. Warmke,
Doris Cully
Publication year - 2000
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.240464697
Subject(s) - chloride channel , biology , mutant , biochemistry , drosophila melanogaster , serine , wild type , glutamic acid , amino acid , microbiology and biotechnology , pharmacology , gene , enzyme
The fruit flyDrosophila melanogaster was used to examine the mode of action of the novel insecticide and acaricide nodulisporic acid. Flies resistant to nodulisporic acid were selected by stepwise increasing the dose of drug in the culture media. The resistant strain,glc1 , is at least 20-fold resistant to nodulisporic acid and 3-fold cross-resistant to the parasiticide ivermectin, and exhibited decreased brood size, decreased locomotion, and bang sensitivity. Binding assays usingglc1 head membranes showed a marked decrease in the affinity for nodulisporic acid and ivermectin. A combination of genetics and sequencing identified a proline to serine mutation (P299S) in the gene coding for the glutamate-gated chloride channel subunit DmGluClα. To examine the effect of this mutation on the biophysical properties of DmGluClα channels, it was introduced into a recombinant DmGluClα, and RNA encoding wild-type and mutant subunits was injected intoXenopus oocytes. Nodulisporic acid directly activated wild-type and mutant DmGluClα channels. However, mutant channels were ≈10-fold less sensitive to activation by nodulisporic acid, as well as ivermectin and the endogenous ligand glutamate, providing direct evidence that nodulisporic acid and ivermectin act on DmGluClα channels.