The Fission Yeast S-Phase Cyclin Cig2 Can Drive Mitosis
| Autor: | Nicholas Rhind, Mary T. Pickering, Daniel Keifenheim, Mira Magner |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Fission
Mitosis Cyclin B 03 medical and health sciences 0302 clinical medicine Cyclin-dependent kinase Phase (matter) Schizosaccharomyces Genetics Mitotic catastrophe 030304 developmental biology Cyclin Investigation 0303 health sciences biology Kinase Chemistry fungi Cell cycle biology.organism_classification Cyclin-Dependent Kinases Yeast Cell biology Schizosaccharomyces pombe biology.protein Phosphorylation Schizosaccharomyces pombe Proteins 030217 neurology & neurosurgery |
| Zdroj: | Genetics |
| DOI: | 10.1101/213330 |
| Popis: | Commitment to mitosis is regulated by cyclin-dependent kinase (CDK) activity. In the fission yeastSchizosaccharomyces pombe, the major B-type cyclin, Cdc13, is necessary and sufficient to drive mitotic entry. Furthermore, Cdc13 is also sufficient to drive S phase, demonstrating that a single cyclin can regulate alternating rounds of replication and mitosis and providing the foundation of the quantitative model of CDK function. It has been assumed that Cig2, a B-type cyclin expressed only during S-phase and incapable of driving mitosis in wild-type cells, was specialized for S-phase regulation. Here, we show that Cig2 is capable of driving mitosis. Cig2/CDK activity drives mitotic catastrophe—lethal mitosis in inviably small cells—in cells that lack CDK inhibition by tyrosine-phosphorylation. Moreover, Cig2/CDK can drive mitosis in the absence of Cdc13/CDK activity and constitutive expression of Cig2 can rescue loss of Cdc13 activity. These results demonstrate that in fission yeast, not only can the presumptive M-phase cyclin drive S phase, but the presumptive S-phase cyclin can drive M phase, further supporting the quantitative model of CDK function. Furthermore, these results provide an explanation, previously proposed on the basis of computational analyses, for the surprising observation that cells expressing a single-chain Cdc13-Cdc2 CDK do not require Y15 phosphorylation for viability. Their viability is due to the fact that in such cells, which lack Cig2/CDK complexes, Cdc13/CDK activity is unable to drive mitotic catastrophe. |
| Databáze: | OpenAIRE |
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