Figure 1.

RNA alternative splicing of the chh gene in the shore crab Carcinus maenas. C. maenas chh gene is a 4-exon gene. The long-splice form (CHH-L mRNA) consists of exon I, II, III, and IV, and the short-splice form (CHH mRNA) consists of exon I, II, and IV. The first 2 exons (exon I and II), which encode the signal peptide, the precursor-related peptide (PRP), and the first 40 residues of the mature peptide, are common to the two splice forms. The remaining sequence of the CHH-L and CHH mature peptide is encoded by exon III and IV, respectively. Note that both exon III and IV have a stop codon. The dashed line marks the splice site.