The neuropeptide gene nlp-3, together with serotonin, stimulates egg laying.

A) Overexpression of nlp-3, but not of four other neuropeptide genes, increased the rate of egg-laying behavior. Genomic clones for each neuropeptide gene, or the coinjection marker alone (control), were injected into C. elegans to generate high-copy extrachromosomal transgenes. For each gene, 250 freshly laid eggs (50 from each of five independent transgenic lines) were examined and the percent laid at early stages of development (eight cells or fewer) was determined. Only nlp-3 overexpression gave results significantly different from the control (p<0.05). B-C) Representative images of nlp-3 and tph-1; nlp-3 animals showing the average number of unlaid eggs, n = 30. D) Graph of the number of unlaid eggs for the strains indicated. Two independent deletion alleles of nlp-3 were used. n≥30 for each strain. Comparisons labeled n.s. showed no significant differences (p>0.05). All other pairwise comparisons were significantly different with p<0.033.