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The nicotinic acetylcholine receptor subunit Mdα6 from Musca domestica is diversified via post‐transcriptional modification
Author(s) -
Gao J.R.,
Deacutis J. M.,
Scott J. G.
Publication year - 2007
Publication title -
insect molecular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.955
H-Index - 93
eISSN - 1365-2583
pISSN - 0962-1075
DOI - 10.1111/j.1365-2583.2007.00730.x
Subject(s) - spinosad , biology , drosophila melanogaster , untranslated region , genetics , open reading frame , alternative splicing , microbiology and biotechnology , exon , musca , gene isoform , mutation , gene , messenger rna , peptide sequence , botany , pesticide , larva , agronomy
Recent studies showed that deletion of a nicotinic acetylcholine receptor (nAChR) subunit gene, Dα6 in Drosophila melanogaster results in a strain that is resistant to spinosad, indicating that Dα6 is important for the toxic action of this insecticide. To determine if spinosad resistance in house flies was due to a mutation(s) of Mdα6 (the orthologue of Dα6 from house flies), cDNAs were cloned and characterized from an insecticide‐susceptible and a spinosad‐resistant strain of the house fly, Musca domestica . The cDNAs contain a 1470‐bp open reading frame encoding 490 amino acid residues, 415‐bp 5′ untranslated region (UTR) and a polymorphic 3′‐UTR of ∼371 bp. The predicted mature protein possesses 468 amino acid residues, has the typical features of a nAChR α subunit and is 97% identical to Dα6 . Quantitative real‐time PCR analysis revealed that Mdα6 was expressed in the head and the thorax at 1300‐ and 26‐fold higher levels, respectively, than in the abdomen. There was no difference in the expression level of Mdα6 between spinosad‐resistant and susceptible strains. Ten isoforms arising from alternative splicing were characterized, with isoform II being most common. A‐to‐I RNA editing was examined and found at 12 sites: editing at 11 of these sites resulted in an amino acid substitution. Mdα6 is linked to autosome 1 (spinosad resistance was previously shown to be linked to autosome 1). Single nucleotide polymorphisms, alternative splicing, mRNA levels and A‐to‐I RNA editing were compared between head and thorax and between insecticide‐susceptible and spinosad‐resistant strains. These comparisons indicate that Mdα6 is not responsible for spinosad resistance in house flies.