EGL-36 SHAW CHANNELS REGULATE C-ELEGANS EGG-LAYING MUSCLE-ACTIVITY

The C. elegans egl-36 gene encodes a Shaw-type potassium channel that regulates egg-laying behavior. Gain of function [egl-36(gf)] and domin ant negative [egl-36(dn)] mutations in egl-36 cause reciprocal defects in egg laying. An egl-36::gfp reporter is expressed in the egg-laying muscles and in a few other tissues. Expression of an egl-36(gf) cDNA in the egg-laying muscles causes behavioral defects similar to those o bserved in egl-36(gf) mutants. Gain of function EGL-36 subunits form c hannels that are active at more negative potentials than wild-type cha nnels. The egl-36(gf) alleles correspond to missense mutations in an a mino terminal subunit assembly domain (E138K) and in the S6 transmembr ane domain (P435S), neither of which were previously implicated in the voltage dependence of channel activation. Altogether, these results s uggest that EGL-36 channels regulate the excitability of the egg-layin g muscles.