title: Three new classes of mutations in the Caenorhabditis elegans muscle gene sup-9.
abstract: We are studying five interacting genes involved in the regulation or coordination of muscle contraction in Caenorhabditis elegans. A distinctive "rubber-band" muscle-defective phenotype was previously shown to result from rare altered-function mutations in either of two of these genes, unc-93 and sup-10. null mutations in sup-9, sup-10, sup-18 or unc-93 act as essentially recessive suppressors of these rubber-band mutations. In this work, we identify three new classes of sup-9 alleles: altered-function rubber-band, partial loss-of-function and dominant-suppressor. The existence of rubber-band mutations in sup-9, sup-10 and unc-93 and the suppression of these mutations by null mutations in any of these three genes suggest that these proteins are required at the same step in muscle contraction. Moreover, allele-specific interactions shown by the partial loss-of-function mutations indicate that the products of these interacting genes may physically contact each other in a multiple subunit protein complex. Finally, the phenotypes of double rubber-band mutant combinations suggest that the rubber-band mutations affect a neurogenic rather than a myogenic input in excitation-contraction coupling in muscle.
authors.affiliation: Howard Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge 02139.
authors.forename: J Z
authors.initials: JZ
authors.lastname: Levin
authors.forename: H R
authors.initials: HR
authors.lastname: Horvitz
mesh_terms: D000483:Alleles; D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins; D005799:Genes, Dominant; D016153:Genes, Suppressor; D005816:Genetic Complementation Test; D005838:Genotype; D015801:Helminth Proteins / Q000235:genetics* / Q000378:metabolism; D008565:Membrane Proteins; D009119:Muscle Contraction; D009124:Muscle Proteins / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D010641:Phenotype
chemical_list: D029742:Caenorhabditis elegans Proteins; D015801:Helminth Proteins; D008565:Membrane Proteins; D009124:Muscle Proteins; C073904:unc-93 protein, C elegans