In contrast, in bilaterian NPY/NPF genes the intron interrupts the coding sequence for NPY/NPF-type peptides between the second and third nucleotide of the codon for the arginine residue of the C-terminal RF or RY dipeptide and the position of this phase two intron in the reading frame is represented as −1. purpuratus) residue and the position of the intron in the reading frame is therefore represented as +1. In genes encoding echinoderm PrRP-like peptides the intron interrupts the coding sequence in the N-terminal or central region of the PrRP-like peptide, with the intron located between the first and second nucleotides of the codon (phase one intron) for an alanine ( A. The right side of the figure shows how an intron interrupts the coding sequence of the neuropeptides, but the position of the intron is different for echinoderm PrRP-like peptides and bilaterian NPY/NPF-type neuropeptides. The protein-coding exons are colour-coded to show regions that encode the N-terminal signal peptide (blue), the neuropeptide (red), monobasic or dibasic cleavage sites (green) and other regions of the precursor protein (grey). The left side of the figure shows schematic representations of the gene structures, with protein-coding exons shown as rectangles and introns shown as lines (with intron length stated underneath). The fragmentation table for this mass spectrum can be found in Figure 1-figure supplement 1-source data 1. The fragment match tolerance used for the search was 0.8 Da.
The peptide was identified with: Sequest HT (v1.17) XCorr: 4.27, Percolator q-Value: 0.0e0, Percolator PEP:1.6e-2.
#The missing link in evolution series
The b series of peptide fragment ions are shown in red, the y series in blue and additional identified peptide fragment ions in green. The peptide QDRSKAMQAERTGQLRRLNPRF, with Q1-Pyroglutamate (−17.02655 Da) and F22-amidated (−0.98402 Da), was observed at charge state +6, monoisotopic m/z 440.90631 Da with a precursor mass error of 0.12 ppm and with a retention time (RT) of 66.3484 min. This sequence has been deposited in GenBank under the accession number MK033631.1 ( B) Annotated mass spectrum showing the structure of a NPY/NPF/PrRP-like peptide isolated from an A.
rubens radial nerve cord transcriptome data is highlighted in black, but this is a synonymous substitution. A single nucleotide that differs from a contig sequence (1060225) identified from A. The cDNA was cloned in the vector pBluescript II SK (+) and the T3 and T7 primers were used for the sequencing. rubens radial nerve cord cDNA using primers corresponding to the sequences highlighted in yellow.
The predicted signal peptide is shown in blue, the predicted cleavage site is shown in green and the predicted neuropeptide is shown in red, with an N-terminal glutamine that is a potential substrate for pyroglutamation shown in purple and with a C-terminal glycine that is a potential substrate for amidation shown in orange. The cDNA sequence (lowercase) comprises an open reading frame of 324 bases that encode a 108-residue protein (uppercase). ( A) Sequence of a cDNA encoding the precursor of a NPY/NPF/PrRP-like peptide in A. Our findings indicate that PrRP-type and sNPF-type signalling systems are orthologous and originated as a paralog of NPY/NPF-type signalling in Urbilateria.Įchinoderm evolution evolutionary biology neuroscience prolactin releaasing peptide receptors short neuropeptide-f starfish. Furthermore, experimental studies revealed that the PrRP-type neuropeptide pQDRSKAMQAERTGQLRRLNPRF-NH 2 is a potent ligand for a sNPF/PrRP-type receptor in the starfish Asterias rubens. Analysis of transcriptome/genome sequence data revealed loss of NPY/NPF-type signalling, but orthologs of PrRP-type neuropeptides and sNPF/PrRP-type receptors were identified in echinoderms. Here we investigated the occurrence of NPY/NPF/PrRP/sNPF-related signalling systems in a deuterostome invertebrate phylum - the Echinodermata. Orthologs of vertebrate neuropeptide-Y (NPY) known as neuropeptide-F (NPF) have been identified in protostome invertebrates, whilst prolactin-releasing peptide (PrRP) and short neuropeptide-F (sNPF) have been identified as paralogs of NPY/NPF in vertebrates and protostomes, respectively. However, there are challenges associated with determination of orthology between neuropeptides in different taxa. Neuropeptide signalling systems comprising peptide ligands and cognate receptors are evolutionarily ancient regulators of physiology and behaviour.