Figure 3

Editing of B. mori nAChR alpha6 splice forms (A) The structure and alternative splicing patterns of the alpha6 gene in the regions surrounding the alternative exons 3. Three main variants, depending on the alternative exon 3 versions: type I (alternative exon 3a), type II (alternative exon 3b), type III (alternative exons 3a and 3b). Boxes represent exons and the line represents introns. The black boxes represent constitutive exons and the open boxes represent exons that are duplicated in tandem. "*" represents the editing sites. The migration positions of PCR products corresponding to transcripts with one or two alternative duplicated exon variants are indicated with arrows. Primer1, 2, 3, 4, 5 refer to BmDa-5-4, BmDa-5-8, BmDa-5-9, BmDa-5-10, and BmDa-3-1, respectively (Table 1). (B) Analysis of alternative splicing in silkworm embryo, larvae, pupae, and adult using RT-PCR. 1, 2, 3, 4 indicated splice forms amplified using forward primer (primer1, or 2, or 3, or 4), and reverse primer (primer5), respectively. (C) Frequency of splice forms in silkworm embryo, larvae, pupae, and adult. RNA was isolated from each developmental stage and used for RT-PCR. The RT-PCR products were cloned and analyzed. 20 cDNA clones were sequenced for every stage. (D) Comparison of the editing levels (A/G signal) of sites in exon 4 among distinct splice forms. cDNA 1, 2, 3, 4 indicated splice forms in Figure 3B.