Cloning, heterologous expression and co-assembly of Mpβ1, a nicotinic acetylcholine receptor subunit from the aphid Myzus persicae

Nicotinic acetylcholine receptors (nAChRs) play a major role in excitatory synaptic transmission in insects and are also the target site for chloronicotinyl insecticides such as imidacloprid. Here we report the cloning and characterization of a novel nAChR beta subunit, Mp beta 1, from the aphid Myzus persicae, an economically important pest species. Sequence analysis has identified an open reading frame of 509 amino acids with features typical of nAChR subunits. The Mp beta 1 gene is expressed as a single major transcript of 4.6 kb, considerably larger than the predicted length of the Mp beta 1 open reading frame (1527 bp). By heterologous expression in Drosophila S2 cells, the Mp beta 1 subunit has been shown to coassemble with the previously cloned nAChR subunits Mp alpha 1 and Mp alpha 2. In contrast, no co-assembly of Mp beta 1 could be detected with either Mp alpha 3 or Mp alpha 4. With the aim of gaining a clearer insight into the influence of subunit composition upon assembly, the ability of NI. persicae nAChR subunits to co-assemble with vertebrate nAChR su bu nits has also been examined. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.