Effect of a neuropeptide gene on behavioral states in Caenorhabditis elegans egg-laying.
Egg-laying behavior in the nematode Caenorhabditis elegans involves fluctuation between alternative behavioral states: an inactive state, during which eggs are retained in the uterus, and an active state, during which eggs are laid in bursts. We have found that the flp-1 gene, which encodes a group of structurally related neuropeptides, functions specifically to promote the switch from the inactive to the active egg-laying state. Recessive mutations in flp-1 caused a significant increase in the duration of the inactive phase, yet egg-laying within the active phase was normal. This pattern resembled that previously observed in mutants defective in the biosynthesis of serotonin, a neuromodulator implicated in induction of the active phase. Although flp-1 mutants were sensitive to stimulation of egg-laying by serotonin, the magnitude of their serotonin response was abnormally low. Thus, the flp-1-encoded peptides and serotonin function most likely function in concert to facilitate the onset of the active egg-laying phase. Interestingly, we observed that flp-1 is necessary for animals to down-regulate their rate of egg-laying in the absence of food. Because flp-1 is known to be expressed in interneurons that are postsynaptic to a variety of chemosensory cells, the FLP-1 peptides may function to regulate the activity of the egg-laying circuitry in response to sensory cues.
Waggoner
L E
LE
Department of Biology, University of California, San Diego, California 92093-0349, USA.
Hardaker
L A
LA
Golik
S
S
Schafer
W R
WR
D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins; D005260:Female; D015801:Helminth Proteins / Q000235:genetics / Q000502:physiology*; D009479:Neuropeptides / Q000235:genetics / Q000502:physiology*; D010058:Oviposition / Q000235:genetics / Q000502:physiology; D010641:Phenotype; D012701:Serotonin / Q000502:physiology
D029742:Caenorhabditis elegans Proteins; C114560:Flp-1 protein, C elegans; D015801:Helminth Proteins; D009479:Neuropeptides; D012701:Serotonin