CHARACTERIZATION OF VOLTAGE-SENSITIVE SODIUM-CHANNEL GENE CODING SEQUENCES FROM INSECTICIDE-SUSCEPTIBLE AND KNOCKDOWN-RESISTANT HOUSE-FLY STRAINS

The kdr insecticide resistance trait of the house by (Musca domestica L.), which confers reduced neuronal sensitivity to DDT and pyrethroid insecticides, was previously shown to exhibit tight genetic linkage to restriction fragment length polymorphism markers lying within a volta ge-sensitive sodium channel gene that is homologous to the para gene o f Drosophila melanogaster. In the present study, the 6315 nucleotide c oding sequences of this voltage-sensitive sodium channel gene from ins ecticide-susceptible (NAIDM strain) and kdr (538ge strain) house flies were determined by automated direct DNA sequencing of PCR fragments o btained by amplification on first strand cDNA from adult heads. The de duced 2105-residue amino acid sequence from each strain exhibited over all structure and organization typical of sodium channel a subunit gen es and was 90.0% identical to that of the D. melanogaster para gene pr oduct, We did not detect any splice variants among voltage-sensitive s odium channel cDNAs obtained from adult house fly head preparations, C omparison of the coding sequence of the voltage-sensitive sodium chann el gene of the kdr house fly strain to that of the NAIDM strain reveal ed 12 amino acid differences in the 538ge strain, The significance of these polymorphisms as candidate resistance-conferring mutations is di scussed, Copyright (C) 1996 Published by Elsevier Science Ltd.