The neuropeptide F (NPF) encoding gene from the cestode, Moniezia expansa

Neuropeptide F (NPF) is an abundantly expressed neuropeptide in platyhelmin th nervous systems, and exhibits a moderate, myogenic effect on muscle prep arations of parasitic flatworms. NPF displays structural similarities to pe ptides from molluscs and vertebrate members of the neuropeptide Y (NPY)-sup erfamily of peptides. NPY is one of the most abundant and highly conserved neuropeptides within vertebrates and similarities between the gene organiza tion of NPY, pancreatic polypeptide (PP) and peptide tyrosine tyrosine (PYY ), suggest a common evolutionary origin of this peptide family. Dual locali zation analyses coupled with confocal scanning laser microscopy revealed a close spatial relationship between NPF-containing nerves and muscle fibres in M. expansa. Molecular cloning techniques identified the M. expansa NPF ( mxNPF) precursor and characterized the isolated transcript which encodes an open reading frame of 57 amino acids. The transcript possesses a 17 amino acid signal peptide and the mature NPF sequence (39 amino acids) followed b y a carboxyterminal glycyl extension. Sequence analysis of genomic DNA iden tified a product which possessed a 54 base pair intron with consensus seque nces for 5' and 3' splice sites. The M. expansa npf gene possesses a phase 2 intron within the penultimate: arginyl residue, a characteristic feature of NPY superfamily peptide-genes. The intron-exon organization of the npf g ene, coupled with the abundant expression of NPF within the nervous systems of flatworms, suggests an early evolutionary origin for this peptide trans mitter family within the nervous systems of basal bilaterian metazoans.