Figure 9. Nicrophorus allatostatin CCC gene.

(A) Schematic representation of the allatostatin CCC gene in Nicrophorus. Boxes indicate exons and horizontal lines introns. The first exon (white) is untranslated, the second (yellow) codes for the signal peptide and few additional amino acid residues. The last coding exon has two acceptor splice sites. (B) When the first acceptor splice site is used the mRNA is larger and leads to the production of an mRNA that contains coding sequences for two allatostatin CCC-like peptides, however, an in-frame stop codon prevents translation of the second one. When the second acceptor splice site is used, it is the second allatostatin CCC peptide that will be produced. (C) The last amino acid residues coded by the two types of mRNA. Convertase cleavage sites and C-terminal dibasic amino acid residues that will be removed by carboxypeptidases are highlighted. The Aleochara gene has a very similar structure, although the untranslated first exon could not be identified. Note that the sequences of these peptides are fairly similar between the two species, and that in both cases the peptides produced from the first transcript lack the C-terminal dibasic amino acid residues that are typically present in allatostatin CCC peptides (Veenstra, 2016b).