Fig. 5

Diagram of the WT and − 55 bp mutant locust LmigOr35 pre-mRNA splicing process. a In the WT locust, the branch site attacks the 5′ splice site and the lariat structure is formed. Then, 3’ OH of exon 3 attacks the 3′ splice site by separating intron 3 from exon 4 and combining exon 3 with exon 4. Therefore, intron 3 of LmigOr35 is cut from the pre-mRNA, and exons 3 and 4 combine with each other. b In the − 55 bp mutant locust, the lariat structure is normally formed, but the 3′ splice site is disrupted due to the deletion of 55 bp nucleotides. Therefore, 3’ OH of exon 3 attacks the next 3′ splice site located at the boundary of intron 4 and exon 5. Intron 3, exon 4, and intron 4 are cut from the pre-mRNA, and exon 3 combines with exon 5. Exon 4 is skipped during the pre-mRNA splicing. A: the branch site, it locates in the 18–25 bp upstream of the 3′ splice site and not includes in the 55 bp deleted nucleotides