Identification of a novel gene family involved in osmotic stress response in Caenorhabditis elegans.
Organisms exposed to the damaging effects of high osmolarity accumulate solutes to increase cytoplasmic osmolarity. Yeast accumulates glycerol in response to osmotic stress, activated primarily by MAP kinase Hog1 signaling. A pathway regulated by protein kinase C (PKC1) also responds to changes in osmolarity and cell wall integrity. C. elegans accumulates glycerol when exposed to high osmolarity, but the molecular pathways responsible for this are not well understood. We report the identification of two genes, osm-7 and osm-11, which are related members of a novel gene family. Mutations in either gene lead to high internal levels of glycerol and cause an osmotic resistance phenotype (Osr). These mutants also have an altered defecation rhythm (Dec). Mutations in cuticle collagen genes dpy-2, dpy-7, and dpy-10 cause a similar Osr Dec phenotype. osm-7 is expressed in the hypodermis and may be secreted. We hypothesize that osm-7 and osm-11 interact with the cuticle, and disruption of the cuticle causes activation of signaling pathways that increase glycerol production. The phenotypes of osm-7 are not suppressed by mutations in MAP kinase or PKC pathways, suggesting that C. elegans uses signaling pathways different from yeast to mount a response to osmotic stress.
Wheeler
Jeanna M
JM
Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA.
Thomas
James H
JH
D000595:Amino Acid Sequence; D000818:Animals; D017173:Caenorhabditis elegans / Q000166:cytology / Q000235:genetics* / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics* / Q000502:physiology*; D002874:Chromosome Mapping; D002875:Chromosomes; D003360:Cosmids; D017353:Gene Deletion; D005786:Gene Expression Regulation; D017238:Genes, Helminth; D005990:Glycerol / Q000032:analysis / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009997:Osmotic Pressure; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism; D021382:Protein Sorting Signals; D017434:Protein Structure, Tertiary; D034622:RNA Interference; D017386:Sequence Homology, Amino Acid; D019076:Transgenes
D029742:Caenorhabditis elegans Proteins; D021382:Protein Sorting Signals; D049452:Green Fluorescent Proteins; D011493:Protein Kinase C; D020928:Mitogen-Activated Protein Kinases; D005990:Glycerol