Fission Yeast

Fission yeast (Schizosaccharomyces pombe) is an attractive organism for studying eukaryotic cell cycle controls, and a wealth of information has been accumulated about its physiology, genetics and molecular biology. Its cell cycle is controlled by a single CDK, namely Cdc2 (the protein encoded by the cdc2+ gene), in combination with three B-type cyclins (Cdc13, Cig1, and Cig2 ). The most important cyclin partner of Cdc2 protein is Cdc13. The complex of Cdc2 and Cdc13 (known as M-phase promoting factor, MPF) is absolutely essential to initiate mitosis, and in the absence of other cyclins, this complex can trigger S phase as well. Cdc13 level fluctuates dramatically during the cell cycle, reaching a maximum as cells enter mitosis, dropping precipitously as cells exit mitosis, and reappearing after S phase is initiated. The activity of Cig2-dependent kinase peaks at the G1/S transition, and it, together with Cdc13-dependent kinase, is responsible for S phase initiation during normal cell cycles. Cig1-dependent kinase peaks at M phase; its physiological role is not known. In addition to the three B-type cyclins, fission yeast has a CLN-type cyclin with unknown function, Puc1, whose concentration is roughly constant (small compared to Cdc13 level at mitosis) over the cell cycle.

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Our new project is to incorporate more molecular details into our earlier fission yeast models and be able to simulate the behavior of 58 different mutants.

People on this project:

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Attila Csikász-Nagy

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Béla Novák

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Ákos Sveiczer

Related publications:

Sveiczer, A., Tyson J.J., & Novak, B. (2004): Modelling the fission yeast cell cycle. Briefings in Functional Genomics and Proteomics .2, 298-307. PDF

Sveiczer, Á., Csikász-Nagy, A. & Novák, B. (2002): Morphogenetic checkpoint in fission yeast? Yes! Microbiology 148, 2270-2271 PDF

Sveiczer, A., Tyson, J. J., Novak, B.: A stochastic molecular model of the fission yeast cell cycle: role of the nucleocytoplasmic ratio in cycle time regulation. Biophysical Chemistry 92, 1-15 (2001) PDF

Csikász-Nagy A. (2001): Cell cycle controls in fission yeast cells. Caltech, USA, 27 March. PPS

Novak, B., Pataki, Zs., Ciliberto A. and Tyson, J. J. (2001) Mathematical model of the cell division cycle of fission yeast. Chaos, 11, 277-286 PDF

Sveiczer, Á., Csikász-Nagy, A., Gyorffy, B., Tyson, J. J., Novák, B.(2000) Modeling the fission yeast cell cycle: quantized cycle times in wee1- cdc25Δ mutant cells. Proc. Natl. Acad. Sci. USA, 97, 7865-7870 PDF

Sveiczer, A., Novak, B., Mitchison, J. M. (1999) Mitotic control in the absence of cdc25 mitotic inducer in fission yeast. Journal of Cell Science 112, 1085-1092  PDF

Novák, B., Csikász-Nagy, A., Gyorffy, B., Chen, K. & Tyson, J.J. (1998) Mathematical model of the fission yeast cell cycle with checkpoint controls at the G1/S, G2/M and metaphase/anaphase transitions Biophys. Chem. 72, 185-200 PDF

Mitchison, J. M., Sveiczer, A., Novak, B. (1998) Length growth in fission yeast: is growth exponential? - No. Microbiology 144, 265-266 PDF

Mitchison, J. M., Novak, B., Sveiczer, A. (1997) Size control in the cell cycle. Cell Biology International 21, 461-463

Novák, B. & Tyson, J.J. (1997): Modeling the control of DNA replication in fission yeast. Proc. Natl. Acad. Sci. USA 94: 9147-9152 PDF

Sveiczer, Á., Novák, B. & Mitchison, J.M. (1996): The size control of fission yeast revisited. J. Cell Sci. 109: 2947-2957 PDF

Sveiczer, Á., Novák, B. (1996) A stochastic model of the fission yeast cell cycle. ACH - Models in Chemistry 133, 299-311

Novák, B. & Tyson, J.J. (1995). Quantitative analysis of a molecular model of mitotic control in fission yeast. J. Theor. Biol. 173: 283-305. PDF

Novák, B., Sveiczer, Á. & Mitchison, J.M. (1993): CO2 production in cell-free extracts of fission yeast detects cell cycle changes. J. Cell Sci. 105: 529-531. PDF