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PLoS Negl Trop Dis
2014 Aug 28;88:e3085. doi: 10.1371/journal.pntd.0003085.
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A single crossing-over event in voltage-sensitive Na+ channel genes may cause critical failure of dengue mosquito control by insecticides.
Hirata K
,
Komagata O
,
Itokawa K
,
Yamamoto A
,
Tomita T
,
Kasai S
.
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The voltage-sensitive sodium (Na+) channel (Vssc) is the target site of pyrethroid insecticides. Pest insects develop resistance to this class of insecticide by acquisition of one or multiple amino acid substitution(s) in this channel. In Southeast Asia, two major Vssc types confer pyrethroid resistance in the dengue mosquito vector Aedes aegypti, namely, S989P+V1016G and F1534C. We expressed several types of Vssc in Xenopus oocytes and examined the effect of amino acid substitutions in Vssc on pyrethroid susceptibilities. S989P+V1016G and F1534C haplotypes reduced the channel sensitivity to permethrin by 100- and 25-fold, respectively, while S989P+V1016G+F1534C triple mutations reduced the channel sensitivity to permethrin by 1100-fold. S989P+V1016G and F1534C haplotypes reduced the channel sensitivity to deltamethrin by 10- and 1-fold (no reduction), respectively, but S989P+V1016G+F1534C triple mutations reduced the channel sensitivity to deltamethrin by 90-fold. These results imply that pyrethroid insecticides are highly likely to lose their effectiveness against A. aegypti if such a Vssc haplotype emerges as the result of a single crossing-over event; thus, this may cause failure to control this key mosquito vector. Here, we strongly emphasize the importance of monitoring the occurrence of triple mutations in Vssc in the field population of A. aegypti.
Figure 2. Structural and functional properties of Aedes aegypti Vsscs expressed in Xenopus oocytes.(A) The cloned AaNavS2 (wild-type) channel was expressed in Xenopus oocytes and a Na+ current trace was recorded. (B) The Na+ current was blocked by the application of 10 nM tetrodotoxin, verifying that this was a Na+ current. (C) Normalized voltage-conductance and inactivation curves of AaNavS2. The peak current was plotted against the depolarizing voltage (solid circles). The peak current amplitude was plotted as a function of the pre-pulse potential (triangles). Error bars indicate standard errors for 7–9 oocytes (D–I). Na+ current-voltage curves for 6 Vssc types. Error bars indicate standard errors for 7–9 oocytes. Reversal potentials were: (D) wild-type (+35 mV); (E) V1016G single mutation (+35 mV); (F) F1534C single mutation (+35 mV); (G) S989P single mutation (+35 mV); (H) S989P+V1016G double mutation (+25 mV); and (I) S989P+V1016G+F1534C triple mutation (+20 mV).
Figure 3. Pyrethroid-induced tail currents from oocytes injected with various types of Vssc.(A, G) AaNavS2 (wild-type); (B, H) AaNavR6 (V1016G); (C, I) AaNavR7 (F1534C); (D, J), AaNavR8 (S989P); (E, K), AaNavR9 (S989P+V1016G); (F, L) AaNavR10 (S989P+V1016G+F1534C) in the absence (control) or presence of 100 nM permethrin (A–F) or 100 nM deltamethrin (G–L).
Figure 4. Sensitivity of Aedes aegypti Vsscs to permethrin and deltamethrin.The percentages of modified channels were plotted against different concentrations of permethrin (A) and deltamethrin (B), and fitted to a four-parameter logistic equation. Error bars indicate standard errors for 4–8 oocytes. The percentages of modified channels were significantly different between AaNavR6 (V1016G) and AaNavR9 (S989P+V1016G) at deltamethrin concentration of 1.0 µM (P = 0.0091 by Tukey-Kramer test) in Figure 4B.
Figure 1. Mutations of Aedes aegypti Vssc investigated in this study.(A) Schematic illustration of the locations of the Vssc mutations assessed. Positions are numbered according to the amino acid sequence of the most abundant splice variant of housefly Vssc (GenBank accession nos. AAB47604 and AAB47605). (B) Six Vssc types investigated in this study and the positions of primers used for site-directed mutagenesis are shown. Primer sequences are listed in Methods. AaNavS2 is the wild-type Vssc of which the cDNA was isolated from the insecticide-susceptible SMK strain.
Bezanilla,
Inactivation of the sodium channel. I. Sodium current experiments.
1977, Pubmed
Bezanilla,
Inactivation of the sodium channel. I. Sodium current experiments.
1977,
Pubmed
Burton,
Differential resistance of insect sodium channels with kdr mutations to deltamethrin, permethrin and DDT.
2011,
Pubmed
,
Xenbase
Davies,
DDT, pyrethrins, pyrethroids and insect sodium channels.
2007,
Pubmed
Du,
Molecular determinants on the insect sodium channel for the specific action of type II pyrethroid insecticides.
2009,
Pubmed
Du,
Molecular evidence for dual pyrethroid-receptor sites on a mosquito sodium channel.
2013,
Pubmed
,
Xenbase
Feng,
Cloning and functional analysis of TipE, a novel membrane protein that enhances Drosophila para sodium channel function.
1995,
Pubmed
,
Xenbase
Gubler,
Dengue and dengue hemorrhagic fever.
1998,
Pubmed
Harris,
Pyrethroid resistance in Aedes aegypti from Grand Cayman.
2010,
Pubmed
Hemingway,
The molecular basis of insecticide resistance in mosquitoes.
2004,
Pubmed
Ho,
Site-directed mutagenesis by overlap extension using the polymerase chain reaction.
1989,
Pubmed
Hu,
A sodium channel mutation identified in Aedes aegypti selectively reduces cockroach sodium channel sensitivity to type I, but not type II pyrethroids.
2011,
Pubmed
,
Xenbase
Huang,
Frequency of kdr gene in house fly field populations: correlation of pyrethroid resistance and kdr frequency.
2004,
Pubmed
Kasai,
First detection of a putative knockdown resistance gene in major mosquito vector, Aedes albopictus.
2011,
Pubmed
Kasai,
Mechanisms of pyrethroid resistance in the dengue mosquito vector, Aedes aegypti: target site insensitivity, penetration, and metabolism.
2014,
Pubmed
Kawada,
Widespread distribution of a newly found point mutation in voltage-gated sodium channel in pyrethroid-resistant Aedes aegypti populations in Vietnam.
2009,
Pubmed
Linss,
Distribution and dissemination of the Val1016Ile and Phe1534Cys Kdr mutations in Aedes aegypti Brazilian natural populations.
2014,
Pubmed
Marcombe,
Insecticide resistance in the dengue vector Aedes aegypti from Martinique: distribution, mechanisms and relations with environmental factors.
2012,
Pubmed
Saavedra-Rodriguez,
Quantitative trait loci mapping of genome regions controlling permethrin resistance in the mosquito Aedes aegypti.
2008,
Pubmed
Stenhouse,
Detection of the V1016G mutation in the voltage-gated sodium channel gene of Aedes aegypti (Diptera: Culicidae) by allele-specific PCR assay, and its distribution and effect on deltamethrin resistance in Thailand.
2013,
Pubmed
Tan,
Identification of amino acid residues in the insect sodium channel critical for pyrethroid binding.
2005,
Pubmed
,
Xenbase
Tan,
Novel sodium channel gene mutations in Blattella germanica reduce the sensitivity of expressed channels to deltamethrin.
2002,
Pubmed
,
Xenbase
Tatebayashi,
Differential mechanism of action of the pyrethroid tetramethrin on tetrodotoxin-sensitive and tetrodotoxin-resistant sodium channels.
1994,
Pubmed
Thackeray,
Conserved alternative splicing patterns and splicing signals in the Drosophila sodium channel gene para.
1995,
Pubmed
Vais,
Activation of Drosophila sodium channels promotes modification by deltamethrin. Reductions in affinity caused by knock-down resistance mutations.
2000,
Pubmed
,
Xenbase
