Mutations in the clk-1 gene of Caenorhabditis elegans result in an average slowing down and deregulation of a variety of developmental and physiological processes. In addition, clk-1 mutants are defective in responding to temperature changes. For example, wild-type worms adjust their defecation cycle length after a temperature shift whereas the defecation cycle length of clk-1 mutants is unaffected by such a shift. To understand the basis of the clk-1 phenotype, a number of genetic screens have been carried out to isolate feature-specific suppressor mutations. dsc-3(qm179) and dsc-4(qm182) were isolated in this manner. It has previously been found that dsc-3(qm179) and dsc-4(qm182) strongly suppress the slow defecation phenotype of clk-1 mutants at 20°C, as well as after a temperature shift to 25°C. Molecular analysis of dsc-4, which encodes the microsomal triglyceride transfer protein, suggests that dsc genes affect lipid metabolism. We carried out a genetic screen for additional mutations that can suppress the slow defecation of clk-1 mutants after a temperature shift to 25°C and isolated two new suppressor mutations. Complementation tests as well as linkage analysis and mapping indicates that dsc-6(qm192) and dsc-7(qm193) define new dsc genes. We analyzed the phenotype of the new suppressor strains and have found that, like dsc-4(qm182), dsc-6(qm192) and dsc-7(qm193) can suppress a variety of clk-1 phenotypes. Based on additional phenotypic analyses of the new suppressor strains, including the determination of their sensitivity to exogenous cholesterol, we believe that, like dsc-4, dsc-6 and dsc-7 encode activities that affect lipid metabolism in worms.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.98781 |
| Date | January 2005 |
| Creators | Rodrigues, Tania, 1979- |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Department of Biology.) |
| Rights | © Tania Rodrigues, 2005 |
| Relation | alephsysno: 002494686, proquestno: AAIMR24782, Theses scanned by UMI/ProQuest. |
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