Ehs-1 is required for the expulsion step of the Caenorhabditis elegans defecation motor program
The Caenorhabditis elegans digestive motor program occurs at approximately 50 second intervals and consists of three contractions. The first contraction occurs in the posterior body wall muscle and is followed by a contraction of the anterior body wall muscle approximately 4 seconds later. Finally, waste is expelled via contraction of the enteric muscles. The later contractions are controlled by the release of neuropeptides from the intestine, which activate two GABAergic neurons. A genome-wide RNA interference (RNAi) screen identified EPS-15 homologous sequence 1 (ehs-1) as a candidate gene involved in defecation. Ehs-1 knockdown does not affect the first contraction or the timekeeping mechanisms. However, the expulsion step occurs in only 10.9% percent of cycles. Ehs-1 has previously been implicated in synaptic vesicle recycling in neurons, suggesting that the expulsion defect is due to defective GABA release from DVB. However, intestine-specific knockdown of ehs-1 results in a 92.3% reduction in expulsion, matching the expulsion frequency following systemic knockdown. Our findings suggest that intestinal expression of ehs-1 is also required for expulsion. We hypothesize that ehs-1 is needed for recycling of vesicles in both neurons and intestines.
Freeburg, Nelson, and Maureen Peters. 2014. "Ehs-1 is required for the expulsion step of the Caenorhabditis elegans defecation motor program." FASEB Journal 28(1): 1129.5.
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