title: Choline acetyltransferase-deficient mutants of the nematode Caenorhabditis elegans.
abstract: We have identified five independent allelic mutations, defining the gene cha-1, that result in decreased choline acetyltransferase (ChAT) activity in Caenorhabditis elegans. Four of the mutant alleles, when homozygous, lead to ChAT reductions of greater than 98%, as well as recessive phenotypes of uncoordinated behavior, small size, slow growth and resistance to cholinesterase inhibitors. Animals homozygous for the fifth allele retain approximately 10% of the wild-type enzyme level; purified enzyme from this mutant has altered Km values for both choline and acetyl-CoA and is more thermolabile than the wild-type enzyme. These qualitative alterations, together with gene dosage data, argue that cha-1 is the structural gene for ChAT. cha-1 has been mapped to the left arm of linkage group IV and is within 0.02 map unit of the gene unc-17, mutant alleles of which lead to all of the phenotypes of cha-1 mutants except for the ChAT deficiency. Extensive complementation studies of cha-1 and unc-17 alleles reveal a complex complementation pattern, suggesting that both loci may be part of a single complex gene.
mesh_terms: D000483:Alleles; D000818:Animals; D002107:Caenorhabditis / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development; D002795:Choline O-Acetyltransferase / Q000235:genetics*; D002872:Chromosome Deletion; D008040:Genetic Linkage; D005838:Genotype; D009154:Mutation; D010641:Phenotype
chemical_list: D002795:Choline O-Acetyltransferase