Worm Breeder's Gazette 11(2): 43
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
About 25 neurons, many of which have been identified, stain with an antibody against the neuropeptide FMRFamide [see WBG 9(3):110]. The onset of FMRFamide-like expression in these neurons, as determined immunocytochemically, appears to be developmentally regulated. The first visible staining occurs in the nerve ring of young L1 animals. Shortly afterwards in L1, the cell bodies of about 8 neurons in the nerve ring region and anterior ventral cord processes become visible. During L2, about 13 cell bodies can be seen around the nerve ring, and ventral cord processes now extend to the tail. The posterior cells DVB and PVT, a dorsal process, and lateral processes begin to stain during mid to late L2. A few additional neurons around the nerve ring first become immunoreactive during L3 or L4. The VC cell bodies become visible during early adulthood. All neurons continue to express the peptide into adulthood, and no neuron is stained in larval animals that is not present in adult animals. We have recently isolated a cDNA encoding multiple FMRFamide-like peptides. Degenerate oligonucleotides against Phe-Met-Arg-Phe-Gly-Lys( Arg) were used to screen Stuart Kim's cDNA library; 16 hybridizing clones were selected. Because neuropeptides are synthesized as part of a large precursor polypeptide that is posttranslationally cleaved to yield many smaller peptides, we examined Sau3A restriction digests of the cDNA clones, and selected a clone that showed multiple hybridizing bands, as would be expected if several copies of FMRFamide are present in the precursor gene. This clone was subcloned and sequenced (shown below). The deduced amino acid sequence of the translation product reveals 8 potential neuropeptide sequences. Each of these peptide sequences is flanked by possible endoproteolytic cleavage sites (single, double, or triple basic residues), and ends with a C-terminal Gly, a potential amide donor. Seven of the peptides terminate with the sequence -Pro-Asn-Phe-Leu-Arg-Phe-Gly and extend 0- 4 residues towards the N-terminus by one of 5 separate sequences. These FMRFamide-like peptides would be recognized by the FMRFamide antiserum, and are likely to account for some, if not all, of the immunoreactivity seen. We are currently using the cDNA fragment as a probe to screen the MRC and MIT cosmid libraries to find the gene and position it on the physical and genetic maps. [See Figure 1]