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 indepen dently isolated cs-Unc mutants were alleles of three X-linked Unc muta nts that exhibited the ''kinker'' phenotype. The remaining four isolat es identified new mutants that exhibited ''kinker,'' ''coiler,'' or se vere paralytic phenotypes. The temperature-sensitive period (TSP) for each gene was determined. As a homozygous or heterozygous dominant, un c-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 thermolab ility of the unc-125 gene product indicated that it may function in a multicomponent process involved in neuro-excitation.