Taylor-Wells Jennina, Hawkins Joseph, Colombo Claudia, Bermudez Isabel, Jones Andrew K
Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Headington, Oxford OX3 0BP, UK.
Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Headington, Oxford OX3 0BP, UK.
Neurotoxicology. 2017 May;60:207-213. doi: 10.1016/j.neuro.2016.06.007. Epub 2016 Jun 8.
The insect GABA receptor, RDL (resistance to dieldrin), plays central roles in neuronal signalling and is the target of several classes of insecticides. To study the GABA receptor from an important pollinator species, we cloned Rdl cDNA from the honey bee, Apis mellifera. Three Rdl variants were identified, arising from differential use of splice acceptor sites in the large intracellular loop between transmembrane regions 3 and 4. These variants were renamed from previously, as Amel_RDLvar1, Amel_RDLvar2 and Amel_RDLvar3. When expressed in Xenopus laevis oocytes, the three variants showed no difference in sensitivity to the agonist, GABA, with ECs of 29μM, 20μM and 29μM respectively. Also, the potencies of the antagonists, fipronil and imidacloprid, were similar on all three variants. Fipronil IC values were 0.18μM, 0.31μM and 0.20μM whereas 100μM imidacloprid reduced the GABA response by 17%, 24% and 31%. The possibility that differential splicing of the RDL intracellular loop may represent a species-specific mechanism leading to insensitivity to insecticides is discussed.
昆虫γ-氨基丁酸（GABA）受体RDL（对狄氏剂耐药）在神经元信号传导中起核心作用，并且是几类杀虫剂的作用靶点。为了研究一种重要传粉物种的GABA受体，我们从蜜蜂（西方蜜蜂）中克隆了Rdl cDNA。我们鉴定出了三种Rdl变体，它们源于跨膜区域3和4之间大的细胞内环中剪接受体位点的不同使用情况。这些变体从之前的名称重新命名为Amel_RDLvar1、Amel_RDLvar2和Amel_RDLvar3。当在非洲爪蟾卵母细胞中表达时，这三种变体对激动剂GABA的敏感性没有差异，其半数有效浓度（EC）分别为29μM、20μM和29μM。此外，拮抗剂氟虫腈和吡虫啉对这三种变体的效力相似。氟虫腈的半数抑制浓度（IC）值分别为0.18μM、0.31μM和0.20μM，而100μM吡虫啉使GABA反应分别降低了17%、24%和31%。本文讨论了RDL细胞内环的可变剪接可能代表一种导致对杀虫剂不敏感的物种特异性机制的可能性。
