Hid-1 encodes a novel highly conserved protein with many potential transmembrane domains identified by Ailion and Thomas (Genetics165, 127-44, 2003). Different alleles for Hid-1 mutant have pleiotropic phenotypes: form dauers constitutively (Daf-c) at 27, have uncoordinated movement, do not move well in response to touch and present defects in defecation. We isolated
js828, a novel allele of
hid-1 in a screen for mutants mislocalizing a GFP-tagged version of the rab effector rabphilin. By further characterizing
hid-1 phenotypes, we found that
hid-1 mutants were resistant to the acetylcholinesterase inhibitor aldicarb, suggesting that they have defects in acetylcholine transmission. To gain further insight regarding to the sites of function of
hid-1, RNAi by bacterial feeding was performed. This technique doesnt affect neuronal genes. RNAi of
hid-1 gene could phenocopy the defecation defects, but not the uncoordinated phenotypes of
hid-1 alleles suggesting that
hid-1 operates from the intestine to control defecation. The phenotypes of
hid-1 mutants are similar to those identified previously in mutants of presynaptic genes operating in the Rab pathway, such as
aex-3 (rab GDP/GTP exchange factor),
cab-1 (
aex-3 binding protein) and
aex-6. Recently in this lab
aex-3 has been shown regulate
aex-6 (encoding RAB-27) in addition to Rab3 (Nonet lab, unpublished results). To investigate whether
hid-1 interacts with other genes in the Rab27 pathway,
aex-3 (
js815) and
aex-6 (
sa24) animals were exposed to dsRNA targeting
hid-1. The double mutants:
hid-1(RNAi);
aex-3(
js815) and
hid-1(RNAi);
aex-6(
sa24) exhibited defecation cycle defects more severe than either single mutant, suggesting that
hid-1 regulates the defecation motor program in part independently of
aex-3 and
aex-6. Finally the expression pattern of
hid-1::gfp fusion gene, which was capable of rescuing the uncoordinated movement and constipated phenotypes, was observed predominantly in nervous system and intestine. All of these findings suggest that
hid-1 is a new regulatory component for synaptic vesicle release.