Characterization of a novel cDNA sequence encoding invertebrate tachykinin-related peptides isolated from the echiuroid worm, Urechis unicinctus

Tachykinin is one of the most well-known bioactive peptides found in verteb rates, and tachykinin-related peptides have also been. isolated from variou s inverte-brate species. Urechistachykinin I (Leu-Arg-Gln-Ser-GIn-Phe-Val-G ly-Ser-Arg-NH2) and II (Ala-Ala-Gly-Met-Gly-Phe-Phe-Gly-Ala-Arg-NH2) were p urified from the ventral nerve cords of echiuroid worm, Urechis unicinctus. In the present study, we described the characterization of a novel cDNA en coding the urechistachykinin precursor. Amino acid sequence analysis of the deduced polypeptide revealed that the urechistachykinin precursor included seven structurally related peptides, unlike mammalian tachykinin precursor s which encode only one or two tachykinin peptides. This is the first ident ification of an invertebrate tachykinin-related peptide cDNA (C) 1999 Acade mic Press.