Figure 4

Alternative splicing of Bombyx mori nAChRs. A) Comparison of corresponding exons of Bombyx and Drosophila nAChRs. LpE and LpB indicated are loops involved in acetylcholine binding. Two asterisks stand for Cys residues forming disulfide bond separated by 13 amino acid residues. TM2 and TM3 are transmembrane motifs engaged in forming the cation permeable channel. B) Phylogenetic relationship of Bmα8 exon 7s and their corresponding exons from Heliothis, Apis, Anopheles and Drosophila. Protein sequence of Dmα1 corresponding to Bmα8 exon 7s is included as an outgroup. Numbers at each node represent bootstrap values with 1,000 replicates. C) Four splicing patterns between exons 2 and 4 of Bombyx mori nAChR α 6.