The neuropeptide gene
flp-1 is one of at least 20 genes encoding FMRFamide-related neuropeptides (FaRPs) in the nematode Caenorhabditis elegans .
flp-1 can be alternatively spliced to produce two transcripts, which encode seven distinct FaRPs, six of which have been biochemically isolated from C. elegans (Rosoff et al, 1992). The NY2009 strain of C. elegans carries a construct containing a
flp-1 cDNA under the control of an inducible heatshock protein (
hsp16) promoter (Phsp::
flp-1 ). Heatshock of these animals induces overexpression of
flp-1 and results in a locomotory defect characterized by sluggish movement and a flattened waveform (Nelson et al, 1998). The transgene is inserted into chromosome IV. We have chemically mutagenized these worms to isolate a mutation that suppresses the sluggish phenotype induced by overexpression of
flp-1 . 624 haploid genomes have thus far been screened. Two individuals from the same haploid parent suppress the sluggish phenotype. These animals both contain the same allele (
yn7 ), and have been designated NY44 and NY44A. The suppressor mutation is on chromosome IV. Animals have a defecation phenotype independent of their suppression of
flp-1 overexpression-induced sluggishness. The defecation cycle period of
yn7 animals (NY44, 103.3+/-6.1 seconds; n=12) is significantly longer than that of wildtype (5.4+/-2.7 seconds; n=15; P<0.05). Wildtype defecation period (77.2+/-3.9 seconds; n=15) is lengthened at 16degC, but this is not true for the suppressor allele (NY44, 102.2+/-1.7 seconds; n=12). NY44 and NY44A defecation periods are significantly different from wildtype at all temperatures (P<0.05). This suppressor mutation may affect a gene that acts downstream of
flp-1 , such as a protease, receptor or signaling molecule. Alternatively, it may affect one of the other flp genes in C. elegans . Nelson, L.S., Rosoff, M.L. & Li, C. Science 281 1686-1690 (1998). Rosoff, M.L., Burglin, T.R. & Li, C. Journal of Neuroscience 12 2356-2361 (1992).