DNA replication in the fission yeast: robustness in the face of uncertainty

AbstractTypically cells replicate their genome only once per division cycle, but under some circumstances, both natural and unnatural, cells synthesize an overabundance of DNA, either in a disorganized fashion (‘over-replication’) or by a systematic doubling of chromosome number (‘endoreplication’). These variations on the theme of DNA replication and division have been studied in strains of fission yeast, Schizosaccharomyces pombe, carrying mutations that interfere with the function of mitotic cyclin-dependent kinase (Cdk1:Cdc13) without impeding the roles of DNA-replication licensing factor (Cdc18) and S-phase cyclin-dependent kinase (Cdk1:Cig2). Some of these mutations support endoreplication, and some over-replication. In this paper, we propose a dynamical model of the interactions among the proteins governing DNA replication and cell division in fission yeast. By computational simulations of the mathematical model, we account for the observed phenotypes of these re-replicating mutants, and by theoretical analysis of the dynamical system, we provide insight into the molecular distinctions between over-replicating and endoreplicating cells. In case of induced over-production of regulatory proteins, our model predicts that cells first switch from normal mitotic cell cycles to growth-controlled endoreplication, and ultimately to disorganized over-replication, parallel to the slow increase of protein to very high levels.

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DNA Replication Checkpoint Control Mediated by the Spindle Checkpoint Protein Mad2p in Fission Yeast

Journal of Biological Chemistry ◽

10.1074/jbc.m403231200 ◽

2004 ◽

Vol 279 (45) ◽

pp. 47372-47378 ◽

Cited By ~ 22

Author(s):

Izumi Sugimoto ◽

Hiroshi Murakami ◽

Yuko Tonami ◽

Akihiko Moriyama ◽

Makoto Nakanishi

Keyword(s):

Dna Replication ◽

Fission Yeast ◽

Spindle Checkpoint ◽

Checkpoint Control ◽

Replication Checkpoint ◽

Checkpoint Protein ◽

Dna Replication Checkpoint

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Microscopy Techniques to Examine DNA Replication in Fission Yeast

Methods in Molecular Biology - DNA Replication ◽

10.1007/978-1-60327-815-7_26 ◽

2009 ◽

pp. 463-482 ◽

Cited By ~ 7

Author(s):

Marc D. Green ◽

Sarah A. Sabatinos ◽

Susan L. Forsburg

Keyword(s):

Dna Replication ◽

Fission Yeast ◽

Microscopy Techniques

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Essential role of human CDT1 in DNA replication and chromatin licensing

Journal of Cell Science ◽

10.1242/jcs.115.7.1435 ◽

2002 ◽

Vol 115 (7) ◽

pp. 1435-1440 ◽

Cited By ~ 2

Author(s):

Mickael Rialland ◽

Francesco Sola ◽

Corrado Santocanale

Keyword(s):

Cell Cycle ◽

Dna Replication ◽

Complex Formation ◽

Fission Yeast ◽

Origin Recognition Complex ◽

Essential Role ◽

Large Body ◽

Transformed Cells ◽

Minichromosome Maintenance

Formation of pre-replicative complexes at origins is an early cell cycle event essential for DNA duplication. A large body of evidence supports the notion that Cdc6 protein, through its interaction with the origin recognition complex, is required for pre-replicative complex assembly by loading minichromosome maintenance proteins onto DNA. In fission yeast and Xenopus, this reaction known as the licensing of chromatin for DNA replication also requires the newly identified Cdt1 protein. We studied the role of hCdt1 protein in the duplication of the human genome by antibody microinjection experiments and analyzed its expression during the cell cycle in human non-transformed cells. We show that hCdt1 is essential for DNA replication in intact human cells, that it executes its function in a window of the cell cycle overlapping with pre-replicative complex formation and that it is necessary for the loading of minichromosome maintenance proteins onto chromatin. Intriguingly, we observed that hCdt1 protein, in contrast to other licensing factors, is already present in serum-deprived G0 arrested cells and its levels increase only marginally upon re-entry in the cell cycle.

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Threonine-11, Phosphorylated by Rad3 and ATM In Vitro, Is Required for Activation of Fission Yeast Checkpoint Kinase Cds1

Molecular and Cellular Biology ◽

10.1128/mcb.21.10.3398-3404.2001 ◽

2001 ◽

Vol 21 (10) ◽

pp. 3398-3404 ◽

Cited By ~ 36

Author(s):

Katsunori Tanaka ◽

Michael N. Boddy ◽

Xiao-Bo Chen ◽

Clare H. McGowan ◽

Paul Russell

Keyword(s):

Dna Damage ◽

Dna Replication ◽

Fission Yeast ◽

Ataxia Telangiectasia ◽

Null Mutant ◽

Ataxia Telangiectasia Mutated ◽

Tolerance Mechanisms ◽

Checkpoint Kinase ◽

And Function

ABSTRACT Fission yeast Cds1 is phosphorylated and activated when DNA replication is interrupted by nucleotide starvation or DNA damage. Cds1 enforces the S-M checkpoint that couples mitosis (M) to the completion of DNA synthesis (S). Cds1 also controls replicational stress tolerance mechanisms. Cds1 is regulated by a group of proteins that includes Rad3, a kinase related to human checkpoint kinase ATM (ataxia telangiectasia mutated). ATM phosphorylates serine or threonine followed by glutamine (SQ or TQ). Here we show that in vitro, Rad3 and ATM phosphorylate the N-terminal domain of Cds1 at the motif T11Q12. Substitution of threonine-11 with alanine (T11A) abolished Cds1 activation that occurs when DNA replication is inhibited by hydroxyurea (HU) treatment. Thecds1-T11A mutant was profoundly sensitive to HU, although not quite as sensitive as a cds1− null mutant. Cds1T11A was unable to enforce the S-M checkpoint. These results strongly suggest that Rad3-dependent phosphorylation of Cds1 at threonine-11 is required for Cds1 activation and function.

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