The <i>Schizosaccharomyces pombe cdc37</i> gene has been identified and was found to be essential for cell viability. To further study <i>S. pombe</i> Cdc37, a range of mutants were generated using both random and directed mutagenesis. Cdc37 temperature-sensitive mutant cells at the restrictive temperature stop dividing within a single cell cycle. Cdc37 protein levels were not changed at the non-permissive temperature in mutants, indicating that cell inviability arises from defective function of the mutant Cdc37 protein. Morphologically, temperature-sensitive mutant cells arrest with a uniform phenotype, being elongated, characteristic of the <i>cdc </i>phenotype. About 80% of these elongated cells contained a single nucleus with a 2C DNA content, indicating that <i>cdc37</i> temperature-sensitive mutants arrest in G2. The only exception was <i>cdc37-J</i>, where half the cells leaked through to mitosis after 8 hours at the restrictive temperature and displayed divided nuclei and septa, arresting with defects in cytokinesis. Characterisation of the <i>cdc37</i> temperature-sensitive mutants led to the identification of Cdc2 as a client protein and a principal candidate for the cause of the G2 cell cycle arrest. Cdc2 activity was dramatically reduced within one hour at the non-permissive temperature in <i>cdc37</i> temperature-sensitive mutants, but Cdc2 protein levels remained constant. Biochemical and genetic interactions between Cdc37 and Cdc2 were observed, supporting the idea of Cdc2 as a client of Cdc37. Cdc37 is believed to deliver client protein kinases to the co-chaperone Hsp90, forming a heterocomplex. A small fraction of total cellular Cdc37 in <i>s. pombe</i> forms a high molecular weight complex which also contains Hsp90, Cdc37 was found to biochemically and genetically interact with Hsp90, indicating these co-chaperones co-operate in <i>S. pombe.</i>
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:663097 |
| Date | January 2005 |
| Creators | Turnbull, Emma |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/14594 |
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