A novel set of uncoordinated mutants in Caenorhabditis elegans uncovered by cold-sensitive mutations.

A set of uncoordinated (Unc) cold-sensitive (cs) mutants was isolated at a stringent condition of 11 degrees C. About half of the 13 independently isolated cs-Unc mutants were alleles of three X-linked Unc mutants that exhibited the "kinker" phenotype. The remaining four isolates identified new mutants that exhibited "kinker," "coiler," or severe paralytic phenotypes. The temperature-sensitive period (TSP) for each gene was determined. As a homozygous or heterozygous dominant, unc-125 exhibited a TSP throughout all stages of development. Its severe paralysis was immediately observed upon a shift down to 11 degrees C and reversed upon a shift up to 23 degrees C. The reversible thermolability of the unc-125 gene product indicated that it may function in a multicomponent process involved in neuro-excitation.