Acetylcholine receptor molecules of the nematode Caenorhabditis elegans.

Receptors for acetylcholine are present in nematodes. Studies using physiological and biochemical methods have revealed the existence of nicotinic acetylcholine receptors with a novel pharmacology. Caenorhabditis elegans provides a particularly suitable organism with which to investigate such receptors using molecular genetic approaches. Mutants resistant to the cholinergic agonist (and anthelmintic drug) levamisole have permitted the isolation of a number of genes, including structural subunits of the nicotinic acetylcholine receptor. The only known viable mutants of nicotinic receptors are those of Caenorhabditis elegans. This organism offers the prospect of studying the developmental and regulatory effects of the loss of a single component of the receptor. Using Caenorhabditis elegans it is possible to select interesting phenotypic mutations by in vivo mutagenesis before determining the causative lesion. Resistance genes other than those encoding structural subunits are of particular interest, as they will encode additional polypeptides closely associated with nicotinic receptor function. Such proteins are often difficult or impossible to identify using conventional biochemical approaches, whereas genetic selection should permit their identification.