FMRFamide-related peptides (FaRPs) are short neuropeptides that have been found throughout the animal kingdom. FaRPs have been shown to have many general functions, including neuromodulation. In C. elegans, at least 10% of the neurons are FMRFamide-like immunoreactive. To date, at least 17 genes,
flp-1 through
flp-17, encoding these peptides have been identified in C. elegans. Expression of these genes was confirmed by RT-PCR and DNA sequencing or by isolation of EST sequences. The
flp-3 gene of C. elegans encodes 9 copies of GTMRFamide-containing peptides.
flp-3 transcripts are expressed during all developmental stages and in adults, suggesting that
flp-3 functions throughout the life of C. elegans. To localize
flp-3 expression in C. elegans, gfp (green fluorescent protein) and lacZ reporter constructs under the control of the
flp-3 promoter were made. Transgenic animals expressing the
flp-3::gfp or
flp-3::lacZ fusion genes show that
flp-3 is strongly expressed in six neurons located in the head region and weakly in two neurons located in the head region and tail region. Identification of these cells is underway. A
flp-3 deletion strain was isolated by screening a C. elegans EMS-mutagenized library. The deletion removes 2.6 kbp, and includes the entire
flp-3 coding region. To remove any unlinked EMS mutations, the strain was backcrossed 12 times into a wild-type background. A homozygous
flp-3 deletion mutant was isolated and confirmed by PCR and Southern blot analysis. This deletion strain is being assayed for abnormal phenotypes, such as chemosensory, osmosensory, thermosensory, mechanosensory, and locomotory defects. To look at effects of overexpression of
flp-3 peptides, we are generating transgenic animals with the
flp-3 cDNA under control of a heat shock promoter or neural-specific promoter.