The Caenorhabditis elegans unc-17 gene: a putative vesicular acetylcholine transporter.

Mutations in the unc-17 gene of the nematode Caenorhabditis elegans produce deficits in neuromuscular function. This gene was cloned and complementary DNAs were sequenced. On the basis of sequence similarity to mammalian vesicular transporters of biogenic amines and of localization to synaptic vesicles of cholinergic neurons in C. elegans, unc-17 likely encodes the vesicular transporter of acetylcholine. Mutations that eliminated all unc-17 gene function were lethal, suggesting that the acetylcholine transporter is essential. Molecular analysis of unc-17 mutations will allow the correlation of specific parts of the gene (and the protein) with observed functional defects. The mutants will also be useful for the isolation of extragenic suppressors, which could identify genes encoding proteins that interact with UNC-17.