title: Dbeta3, an atypical nicotinic acetylcholine receptor subunit from Drosophila : molecular cloning, heterologous expression and coassembly.
abstract: Insect nicotinic acetylcholine receptors (nAChRs) play a central role in mediating neuronal synaptic transmission and are the target sites for the increasingly important group of neonicotinoid insecticides. Six nicotinic acetylcholine receptor (nAChR) subunits (four alpha-type and two beta-type) have been cloned previously from the model insect species Drosophila melanogaster. Despite extensive efforts, it has not been possible to generate functional recombinant nAChRs by heterologous expression of any combination of these six subunits. It has, however, been possible to express functional hybrid receptors when Drosophila alpha subunits are co-expressed with vertebrate beta subunits. This has led to the assumption that successful heterologous expression might require an, as yet, uncloned beta-type insect subunit. Examination of the recently completed Drosophila genomic sequence data has identified a novel putative nAChR beta-type subunit. Here we report the molecular cloning, heterologous expression and characterization of this putative Drosophila nAChR subunit (Dbeta3). Phylogenetic comparisons with other ligand-gated ion channel subunit sequences support its classification as a nAChR subunit but show it to be a distantly related member of this neurotransmitter receptor subunit family. Evidence that the Dbeta3 subunit is able to coassemble with other Drosophila nAChR subunits and contribute to recombinant nAChRs has been obtained by both radioligand binding and coimmunoprecipitation studies in transfected Drosophila S2 cells.
authors.affiliation: Department of Pharmacology, University College London, London, UK.
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Lansdell
authors.forename: Neil S
authors.initials: NS
authors.lastname: Millar
mesh_terms: D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D029721:Drosophila Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D004331:Drosophila melanogaster; D015870:Gene Expression; D008024:Ligands; D008969:Molecular Sequence Data; D010802:Phylogeny; D011233:Precipitin Tests; D011485:Protein Binding / Q000502:physiology; D021122:Protein Subunits; D011869:Radioligand Assay; D011978:Receptors, Nicotinic / Q000096:biosynthesis* / Q000737:chemistry / Q000235:genetics*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014162:Transfection
chemical_list: D029721:Drosophila Proteins; D008024:Ligands; D021122:Protein Subunits; D011978:Receptors, Nicotinic; C559460:nAChRbeta3 protein, Drosophila; C113681:nicotinic acetylcholine receptor alpha-subunits, Drosophila