Baxter G D, Barker S C
Department of Parasitology, University of Queensland, Brisbane, Australia.
Insect Biochem Mol Biol. 1998 Aug;28(8):581-9. doi: 10.1016/s0965-1748(98)00034-4.
Acetylcholinesterase is the target of organophosphate and carbamate pesticides. Organophosphate resistance is widespread in the cattle tick, Boophilus microplus, in Australia. We have isolated a cDNA of acetylcholinesterase from B. microplus and show that it would encode a protein 62 kDa in size. The predicted amino acid sequence contains all the residues characteristic of an acetylcholinesterase. Alternative splicing of the transcript was detected at both the 5' and 3' ends. Alternative splicing at the 5' end would result in two proteins differing by six amino acids. This is the first report of alternative splicing of the N-terminal coding region in a cholinesterase. No point mutations were detected in the acetylcholinesterase gene from organophosphate resistant strains of B. microplus. Alternative explanations for resistance to organophosphates in B. microplus are discussed.
乙酰胆碱酯酶是有机磷和氨基甲酸酯类杀虫剂的作用靶点。在澳大利亚，牛蜱微小牛蜱对有机磷产生抗性的情况很普遍。我们从微小牛蜱中分离出了乙酰胆碱酯酶的cDNA，并表明它编码的蛋白质大小为62 kDa。预测的氨基酸序列包含乙酰胆碱酯酶的所有特征性残基。在转录本的5'端和3'端均检测到可变剪接。5'端的可变剪接会产生两种相差六个氨基酸的蛋白质。这是胆碱酯酶N端编码区可变剪接的首次报道。在微小牛蜱的有机磷抗性品系的乙酰胆碱酯酶基因中未检测到点突变。文中讨论了微小牛蜱对有机磷产生抗性的其他解释。
