title: The generation and genetic analysis of suppressors of lethal mutations in the Caenorhabditis elegans rol-3(V) gene.
abstract: The Caenorhabditis elegans rol-3(e754) mutation is a member of a general class of mutations affecting gross morphology, presumably through disruption of the nematode cuticle. Adult worms homozygous for rol-3(e754) exhibit rotation about their long axis associated with a left-hand twisted cuticle, musculature, gut and ventral nerve cord. Our laboratory previously isolated 12 recessive lethal alleles of rol-3. All these lethal alleles cause an arrest in development at either early or mid-larval stages, suggesting that the rol-3 gene product performs an essential developmental function. Furthermore, through the use of the heterochronic mutants lin-14 and lin-29, we have established that the expression of rol-3(e754)'s adult specific visible function is not dependent on the presence of an adult cuticle. In an attempt to understand rol-3's developmental role we sought to identify other genes whose products interact with that of rol-3. Toward this end, we generated eight EMS induced and two gamma irradiation-induced recessive suppressors of the temperature sensitive (ts) mid-larval lethal phenotype of rol-3(s1040ts). These suppressors define two complementation groups srl-1 II and srl-2 III; and, while they suppress the rol-3(s1040) lethality, they do not suppress the adult specific visible rolling phenotype. Furthermore, there is a complex genetic interaction between srl-2 and srl-1 such that srl-2(s2506) fails to complement all srl alleles tested. These results suggest that srl-1 and srl-2 may share a common function and, thus, possibly constitute members of the same gene family. Mutations in both srl-1 and srl-2 produce no obvious hermaphrodite phenotypes in the absence of rol-3(s1040ts); however, males homozygous for either srl-1 or srl-2 display aberrant tail morphology. We present evidence suggesting that the members of srl-2 are not allele specific with respect to their suppression of rol-3 lethality, and that rol-3 may act in some way to influence proper posterior morphogenesis. Finally, based on our genetic analysis of rol-3 and the srl mutations, we present a model whereby the wild-type products of the srl loci act in a concerted manner to negatively regulate the rol-3 gene.
authors.affiliation: Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada.
authors.forename: W B
authors.initials: WB
authors.lastname: Barbazuk
authors.forename: R C
authors.initials: RC
authors.lastname: Johnsen
authors.forename: D L
authors.initials: DL
authors.lastname: Baillie
mesh_terms: D000483:Alleles; D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000254:growth & development; D002874:Chromosome Mapping; D012734:Disorders of Sex Development / Q000235:genetics; D005260:Female; D005804:Genes, Lethal; D016153:Genes, Suppressor; D005816:Genetic Complementation Test; D008040:Genetic Linkage; D005819:Genetic Markers; D006720:Homozygote; D008297:Male; D016296:Mutagenesis; D010641:Phenotype; D013696:Temperature
chemical_list: D005819:Genetic Markers