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A human gene encoding morphine modulating peptides related to NPFF and FMRFamide
S J Perry1, E Yi-Kung Huang, D Cronk
1Sussex Centre for Neuroscience, University of Sussex, Brighton, UK.
Abstract:
FMRFamide-related peptides have been isolated from both invertebrates and vertebrates and exhibit a wide range of biological effects in rats. We show here that in humans 2 FMRFamide-related peptides are encoded by a single gene expressed as a spliced mRNA. The larger predicted peptide (AGEGLNSQFWSLAAPQRFamide) differs from the peptide isolated from bovines (AGEGLSSPFWSLAAPQRFamide) by the substitutions of 2 amino acids. The shorter predicted peptide (NPSF, SQAFLFQPQRFamide) is 3 amino acids longer than the bovine 8 amino-acid NPFF (FLFQPQRFamide) or the human NPFF peptide isolated from serum [5], suggesting that the encoded protein is subject to cleavage by a tripeptidyl peptidase or by a novel processing mechanism. On rat spinal cord, the larger peptide is indistinguishable in activity from the equivalent bovine peptide whereas the smaller extended peptide is inactive.
Insights
Two human FMRFamide-related peptides are encoded by one gene. The larger peptide shows similar activity to bovine forms in rats, while the smaller peptide is inactive, suggesting novel processing mechanisms.
Area of Science:
- Neuroscience
- Molecular Biology
- Biochemistry
Background:
- FMRFamide-related peptides (FaRPs) are found in diverse species, exhibiting varied biological roles.
- Previous research identified FaRPs in invertebrates and vertebrates, with known effects in rats.
Purpose of the Study:
- To investigate the genetic encoding and processing of FMRFamide-related peptides in humans.
- To compare the biological activity of human FaRPs with their bovine counterparts in a rat model.
Main Methods:
- Analysis of gene expression and mRNA splicing for human FaRPs.
- Peptide prediction based on genetic sequences.
- In vivo bioassays on rat spinal cord to assess peptide activity.
Main Results:
- A single human gene encodes two distinct FMRFamide-related peptides via alternative splicing.
- The larger human peptide (AGEGLNSQFWSLAAPQRFamide) differs by two amino acids from the bovine equivalent.
- The smaller human peptide (SQAFLFQPQRFamide) is longer than known bovine or human NPFF peptides and demonstrated inactivity on rat spinal cord.
- The larger peptide exhibited comparable activity to bovine FaRPs on rat spinal cord.
Conclusions:
- Human FMRFamide-related peptides are derived from a single gene with differential processing.
- The distinct processing of the smaller peptide suggests a novel mechanism, potentially involving tripeptidyl peptidase activity.
- The larger peptide retains biological activity similar to bovine analogs, while the smaller peptide appears inactive in the tested model.