title: The identities of sym-2, sym-3 and sym-4, three genes that are synthetically lethal with mec-8 in Caenorhabditis elegans.
abstract: On the basis of synthetic lethality, five genes in Caenorhabditis elegans are known to be redundant with the mec-8 gene, which encodes a protein that contains two copies of an RNA recognition motif (RRM) and affects alternative RNA splicing. The molecular identities of two of the redundant genes, sym-1 and sym-5, were previously reported. The remaining three genes have now been cloned, and their synthetically lethal phenotypes with mec-8 are described in more detail. Animals homozygous for mec-8 and sym-2 loss-of-function mutations die during late embryogenesis. The SYM-2 predicted protein contains three RRMs; we propose that SYM-2 and MEC-8 can substitute for each other in promoting the maturation of the transcripts of a vital gene. Animals homozygous for mutations in mec-8 and in either sym-3 or sym-4 have the same striking defect: they arrest development just prior to or just after hatching with a pharynx that appears fully formed but is not properly attached to the body cuticle. sym-3 encodes a protein of unknown function with orthologs in Drosophila and mammals. sym-4 encodes a WD-repeat protein and may also have orthologs in Drosophila and mammals. We propose that SYM-3 and SYM-4 contribute to a common developmental pathway that is redundant with a MEC-8-dependent pathway.
authors.affiliation: Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota 55455, USA. jyochem@cbs.umn.edu
authors.forename: John
authors.initials: J
authors.lastname: Yochem
authors.forename: Leslie R
authors.initials: LR
authors.lastname: Bell
authors.forename: Robert K
authors.initials: RK
authors.lastname: Herman
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000378:metabolism; D029742:Caenorhabditis elegans Proteins / Q000235:genetics* / Q000378:metabolism; D005804:Genes, Lethal; D008969:Molecular Sequence Data; D010641:Phenotype; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA
chemical_list: D029742:Caenorhabditis elegans Proteins; D016601:RNA-Binding Proteins; C500275:SYM-2 protein, C elegans; C500277:SYM-3 protein, C elegans; C500279:SYM-4 protein, C elegans; C099356:mec-8 protein, C elegans