Functional co-expression of two insect nicotinic receptor subunits (Nlα3 and Nlα8) reveals the effects of a resistance-associated mutation (Nlα3Y¹⁵¹S) on neonicotinoid insecticides

• Published in: Journal of neurochemistry Vol. 110; no. 6; pp. 1855 - 1862
• Main Authors: Yixi, Zhang, Liu, Zewen, Han, Zhaojun, Song, Feng, Yao, Xiangmei, Shao, Ying, Li, Jian, Millar, Neil S
• Format: Journal Article
• Language: English
• Published: Oxford, UK Oxford, UK : Blackwell Publishing Ltd 01.09.2009; Blackwell Publishing Ltd; Wiley-Blackwell
• Subjects: Acetylcholine - pharmacology; Amino Acid Sequence; Animals; Biochemistry; Biological and medical sciences; Cell receptors; Cell structures and functions; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Dose-Response Relationship, Drug; Drosophila Proteins; Electric Stimulation; Fundamental and applied biological sciences. Psychology; Gene expression; Gene Expression - drug effects; Imidazoles - pharmacology; Immunoprecipitation - methods; Insecta; Insecticide Resistance - drug effects; Insecticide Resistance - genetics; Insecticides; Insecticides - pharmacology; Insects; Medical sciences; Membrane Potentials - drug effects; Membrane Potentials - genetics; Microinjections - methods; Molecular and cellular biology; Molecular Sequence Data; Monoamines receptors (catecholamine, serotonine, histamine, acetylcholine); Mutation; Neonicotinoids; Neurology; nicotinic acetylcholine receptor; Nilaparvata lugens; Nitro Compounds - pharmacology; Oocytes; Patch-Clamp Techniques; Point Mutation - physiology; Protein Subunits - genetics; Protein Subunits - metabolism; Receptors, Nicotinic - genetics; Receptors, Nicotinic - metabolism; resistance-associated mutation; subunit composition; Xenopus laevis; Insecta; resistance-associated mutation; Subunit; Resistance; Cholinergic receptor; Arthropoda; subunit composition; Neurotransmitter; Nilaparvata lugens; Acetylcholine; Mutation; Invertebrata; Nicotinic receptor; nicotinic acetylcholine receptor
• ISSN: 0022-3042; 1471-4159
• DOI: 10.1111/j.1471-4159.2009.06280.x

Neonicotinoid insecticides, such as imidacloprid, are selective agonists of insect nicotinic acetylcholine receptors (nAChRs) and are used extensively to control a variety of insect pest species. Previously, we have identified a nAChR point mutation (Y151S) associated with insecticide resistance in the brown planthopper Nilaparvata lugens. Although this mutation has been identified in two different N. lugens nAChR subunits (Nlα1 and Nlα3) because of difficulties in heterologous expression of Nlα3; its influence on agonist potency has been examined only in Nlα1-containing nAChRs. Here we describe the cloning of a novel nAChR subunit from N. lugens (Nlα8), together with evidence for its co-assembly with Nlα3 in native and recombinant nAChRs. This has, for the first time, enabled the functional effects of the Nlα3Y¹⁵¹S mutation to be examined. The Nlα3Y¹⁵¹S mutation has little effect on agonist potency of acetylcholine but has a dramatic effect on neonicotinoid insecticides (reducing Imax values and increasing EC₅₀ values). The apparent affinity of neonicotinoids was higher and the effect of the Y151S mutation on neonicotinoid agonist potency was more profound in Nlα3-containing, rather than Nlα1-containing nAChR. We conclude that Nlα3- and Nlα1-containing nAChRs may be representative of two distinct insect nAChR populations.