Neuropeptides Gly-Asp-Pro-Phe-Leu-Arg-Phe-amide (GDPFLRFamide) and Ser-Asp-Pro-Phe-Leu-Arg-Phe-amide (SDPFLRFamide) are encoded by an exon 3' to Phe-Met-Arg-Phe-NH2 (FMRFamide) in the snail Lymnaea stagnalis.
Biochemical analysis has shown the pond snail Lymnaea stagnalis to contain 2 main classes of Phe-Met-Arg-Phe-NH2 (FMRFamide)-like neuropeptides: the tetrapeptides FMRFamide and Phe-Leu-Arg-Phe-NH2 (FLRFamide), and the heptapeptides Gly-Asp-Pro-Phe-Leu-Arg-Phe-NH2 (GDP-FLRFamide) and Ser-Asp-Pro-Phe-Leu-Arg-Phe-NH2 (SDPFFRFamide). By genomic mapping and DNA sequencing, we show here that the GDP/SDPFLRFamide coding region lies 3' to the FMRFamide coding region. The absence of an initiating start methionine and the presence of good-concensus 3' and 5' splice sites suggests that the GDP/SDPFLRFamide coding region makes up 1 exon of a larger gene. In addition to 7 copies of GDPFLRFamide and 6 copies of SDPFLRFamide, the exon encoding the heptapeptides also encodes 3 novel peptides, Glu-Phe-Phe-Pro-Leu-NH2 (EFFPLamide), Ser-Asp-Pro-Tyr-Leu-Phe-Arg-NH2 (SDPYLFRamide), and Ser-Asp-Pro-Phe-Phe-Arg-Phe-NH2 (SDPFFRFamide). In contrast to the tetrapeptide FMRFamide precursor protein, the GDP/SDPFLRFamide peptides are encoded contiguously, being separated only by single basic amino acids.
Saunders
S E
SE
Neuroscience Interdisciplinary Research Centre, University of Sussex, Falmer, Brighton, United Kingdom.
Bright
K
K
Kellett
E
E
Benjamin
P R
PR
Burke
J F
JF
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D005091:Exons; D019835:FMRFamide; D008195:Lymnaea / Q000235:genetics*; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000235:genetics*; D015345:Oligonucleotide Probes; D011487:Protein Conformation; D012326:RNA Splicing
D009479:Neuropeptides; D015345:Oligonucleotide Probes; C067840:GDPFLRFamide; C067845:SDPFLRFamide; D019835:FMRFamide