Molecular evidence for dual pyrethroid-receptor sites on a mosquito sodium channel.

Abstract

Pyrethroid insecticides are widely used as one of the most effective control measures in the global fight against agricultural arthropod pests and mosquito-borne diseases, including malaria and dengue. They exert toxic effects by altering the function of voltage-gated sodium channels, which are essential for proper electrical signaling in the nervous system. A major threat to the sustained use of pyrethroids for vector control is the emergence of mosquito resistance to pyrethroids worldwide. Here, we report the successful expression of a sodium channel, AaNav1-1, from Aedes aegypti in Xenopus oocytes, and the functional examination of nine sodium channel mutations that are associated with pyrethroid resistance in various Ae. aegypti and Anopheles gambiae populations around the world. Our analysis shows that five of the nine mutations reduce AaNav1-1 sensitivity to pyrethroids. Computer modeling and further mutational analysis revealed a surprising finding: Although two of the five confirmed mutations map to a previously proposed pyrethroid-receptor site in the house fly sodium channel, the other three mutations are mapped to a second receptor site. Discovery of this second putative receptor site provides a dual-receptor paradigm that could explain much of the molecular mechanisms of pyrethroid action and resistance as well as the high selectivity of pyrethroids on insect vs. mammalian sodium channels. Results from this study could impact future prediction and monitoring of pyrethroid resistance in mosquitoes and other arthropod pests and disease vectors.

• Authors: Yuzhe Du, Yoshiko Nomura, Gul Satar, Zhaonong Hu, Ralf Nauen, Sheng Yang He, Boris S Zhorov, Ke Dong
• Journal: Proceedings of the National Academy of Sciences of the United States of America (Proc Natl Acad Sci U S A) Vol. 110 Issue 29 Pg. 11785-90 (Jul 16 2013) ISSN: 1091-6490 [Electronic] United States
• PMID: 23821746 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Pyrethrins
• Sodium Channels

Topics

• Aedes (genetics)
• Analysis of Variance
• Animals
• Anopheles (genetics)
• Base Sequence
• Computer Simulation
• Insecticide Resistance (genetics)
• Models, Biological
• Molecular Sequence Data
• Mutagenesis, Site-Directed
• Mutation (genetics)
• Oocytes (metabolism)
• Pyrethrins (metabolism, toxicity)
• Sequence Analysis, DNA
• Sodium Channels (genetics, metabolism)
• Xenopus