Expression data from wild type C. elegans and 5 osmotic stress resistant mutants exposed to hyper/isotonic environments

Adaptation of C. elegans to hypertonic environments involves the accumulation of the organic osmolyte glycerol via transcriptional upregulation of the glycerol biosynthestic enzyme gpdh-1. A number of mutants, termed osmotic stress resistant (osr) mutants, have been identified. osr mutants cause constitutive upregulation of gpdh-1 and confer extreme resistance to hypertonicity. We tested the hypothesis that osr mutants broadly activate a gene expression program normally activated by osmotic stress in wild type animals using Affymterix microarray analysis of the hypertonic stress response in wild type animals and of constituitive gene expression changes in five osr mutants. Young adult C. elegans were exposed to hypertonic growth plates for varying times prior to RNA extraction and hybridization on Affymetrix microarrays. Since we wished to separate direct response from secondary responses to osmotic stress, we collected worms following short term exposures to hypertonic conditions (15 minutes and 1 hour) and after long term exposure to hypertonic conditions (6 hours or a full generation of growth under hypertonic conditions). We also collected young adults from the osr mutants osm-7, osm-8, osm-11, dpy-9, and dpy-10 for microarray analysis. These mutants were grown under isotonic conditions to determine whether that constitutively activate genes normally regulated by hypertonic stress in wild type animals.