S-phase DNA damage checkpoint in budding yeast (original) (raw)
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Perspectives on the DNA damage and replication checkpoint responses in Saccharomyces cerevisiae
DNA Repair, 2009
The DNA damage and replication checkpoints are believed to primarily slow the progression of the cell cycle to allow DNA repair to occur. Here we summarize known aspects of the Saccharomyces cerevisiae checkpoints including how these responses are integrated into downstream effects on the cell cycle, chromatin, DNA repair, and cytoplasmic targets. Analysis of the transcriptional response demonstrates that it is far more complex and less relevant to the repair of DNA damage than the bacterial SOS response. We also address more speculative questions regarding potential roles of the checkpoint during the normal S-phase and how current evidence hints at a checkpoint activation mechanism mediated by positive feedback that amplifies initial damage signals above a minimium threshold.
Checkpoint Control of DNA Repair in Yeast
2021
Budding yeast has been a model organism for understanding how DNA damage is repaired and how cells minimize genetic instability caused by arresting or delaying the cell cycle at well-defined checkpoints. However, many DNA damage insults are tolerated by mechanisms that can both be error-prone and error-free. The mechanisms that tolerate DNA damage and promote cell division are less well-understood. This review summarizes current information known about the checkpoint response to agents that elicit both the G2/M checkpoint and the intra-S phase checkpoint and how cells adapt to unrepaired DNA damage. Tolerance to particular bulky DNA adducts and radiomimetic agents are discussed, as well as possible mechanisms that may control phosphatases that deactivate phosphorylated proteins.
The yeast DNA damage checkpoint proteins control a cytoplasmic response to DNA damage
Proceedings of the National Academy of Sciences, 2007
A single HO endonuclease-induced double-strand break (DSB) is sufficient to activate the DNA damage checkpoint and cause Saccharomyces cells to arrest at G 2 /M for 12–14 h, after which cells adapt to the presence of the DSB and resume cell cycle progression. The checkpoint signal leading to G 2 /M arrest was previously shown to be nuclear-limited. Cells lacking ATR-like Mec1 exhibit no DSB-induced cell cycle delay; however, cells lacking Mec1's downstream protein kinase targets, Rad53 or Chk1, still have substantial G 2 /M delay, as do cells lacking securin, Pds1. This delay is eliminated only in the triple mutant chk1 Δ rad53 Δ pds1 Δ, suggesting that Rad53 and Chk1 control targets other than the stability of securin in enforcing checkpoint-mediated cell cycle arrest. The G 2 /M arrest in rad53 Δ and chk1 Δ revealed a unique cytoplasmic phenotype in which there are frequent dynein-dependent excursions of the nucleus through the bud neck, without entering anaphase. Such excursi...
The DNA Damage Checkpoint Signal in Budding Yeast Is Nuclear Limited
Molecular Cell, 2000
and of several key components is regulated; for example, in Department of Genetics mammalian cells Cdk1 is prevented from entering the Stanford University nucleus in response to DNA damage by a 14-3-3 protein Stanford, California 94305 (Jin et al., 1998; Chan et al., 1999). In fission yeast, † Rosenstiel Center and although Cdk1 seems to be predominantly nuclear at Department of Biology all times, the localization of its activating phosphatase, Brandeis University Cdc25, changes in response to DNA damage, becoming Waltham, Massachusetts 02454 cytoplasmic (Furnari et al., 1999). These observations suggest that control of the entry into mitosis after DNA damage might require transmission of the DNA damage Summary signal to the cytoplasmic compartment, although they could also be explained by a nuclear-limited active ex-The nature of the DNA damage-induced checkpoint port of a key mitotic component from the nucleus. signal that causes the arrest of cells prior to mitosis In the budding yeast Saccharomyces cerevisiae, inis unknown. To determine if this signal is transmitted hibitory phosphorylation of Cdc28p, the homolog of Cdk1, does not play a role in cell cycle arrest after DNA through the cytoplasm or is confined to the nucleus, damage (Amon et al., 1992; Sorger and Murray, 1992).
DNA damage checkpoint in budding yeast
The EMBO …, 1998
Checkpoints are genetically controlled surveillance mechanisms that ensure the interdependency of cell-cycle events (for reviews see Hartwell and Weinert, 1989; Murray, 1992; Elledge, 1996; Paulovich et al., 1997; Weinert, 1998). Both intrinsic and extrinsic checkpoints can ...
Coordination of DNA damage tolerance mechanisms with cell cycle progression in fission yeast
Cell cycle (Georgetown, Tex.), 2015
DNA damage tolerance (DDT) mechanisms allow cells to synthesize a new DNA strand when the template is damaged. Many mutations resulting from DNA damage in eukaryotes are generated during DDT when cells use the mutagenic translesion polymerases, Rev1 and Polζ, rather than mechanisms with higher fidelity. The coordination among DDT mechanisms is not well understood. We used live-cell imaging to study the function of DDT mechanisms throughout the cell cycle of the fission yeast Schizosaccharomyces pombe. We report that checkpoint-dependent mitotic delay provides a cellular mechanism to ensure the completion of high fidelity DDT, largely by homology-directed repair (HDR). DDT by mutagenic polymerases is suppressed during the checkpoint delay by a mechanism dependent on Rad51 recombinase. When cells pass the G2/M checkpoint and can no longer delay mitosis, they completely lose the capacity for HDR and simultaneously exhibit a requirement for Rev1 and Polζ. Thus, DDT is coordinated with t...
Genes & Development, 1994
In eukaryotes a cell-cycle control termed a checkpoint causes arrest in the S or G2 phases when chromosomes are incompletely replicated or damaged. Previously, we showed in budding yeast that RAD9 and RAD17 are checkpoint genes required for arrest in the G2 phase after DNA damage. Here, we describe a genetic strategy that identified four additional checkpoint genes that act in two pathways. Both classes of genes are required for arrest in the G2 phase after DNA damage, and one class of genes is also required for arrest in S phase when DNA replication is incomplete. The Gz-specific genes include MEC3 (for mitosis entry checkpoint), RAD9, RAD17, and RAD24. The genes common to both S phase and G2 phase pathways are MECl and MEC2. The MEC2 gene proves to be identical to the RAD53 gene. Checkpoint mutants were identified by their interactions with a temperature-sensitive allele of the cell division cycle gene CDC13-, cdcl3 mutants arrested in G2 and survived at the restrictive temperature, whereas all cdcl3 checkpoint double mutants failed to arrest in G2 and died rapidly at the restrictive temperature. The cell-cycle roles of the RAD and MEC genes were examined by combination of rad and mec mutant alleles with 10 cdc mutant alleles that arrest in different stages of the cell cycle at the restrictive temperature and by the response of rad and mec mutant alleles to DNA damaging agents and to hydroxyurea, a drug that inhibits DNA replication. We conclude that the checkpoint in budding yeast consists of overlapping S-phase and G2-phase pathways that respond to incomplete DNA replication and/or DNA damage and cause arrest of cells before mitosis.
Nucleic Acids Research, 2014
DNA double-strand breaks (DSBs) can cause chromosomal rearrangements and extensive loss of heterozygosity (LOH), hallmarks of cancer cells. Yet, how such events are normally suppressed is unclear. Here we identify roles for the DNA damage checkpoint pathway in facilitating homologous recombination (HR) repair and suppressing extensive LOH and chromosomal rearrangements in response to a DSB. Accordingly, deletion of Rad3 ATR , Rad26 ATRIP , Crb2 53BP1 or Cdc25 overexpression leads to reduced HR and increased break-induced chromosome loss and rearrangements. We find the DNA damage checkpoint pathway facilitates HR, in part, by promoting break-induced Cdt2-dependent nucleotide synthesis. We also identify additional roles for Rad17, the 9-1-1 complex and Chk1 activation in facilitating break-induced extensive resection and chromosome loss, thereby suppressing extensive LOH. Loss of Rad17 or the 9-1-1 complex results in a striking increase in break-induced isochromosome formation and very low levels of chromosome loss, suggesting the 9-1-1 complex acts as a nuclease processivity factor to facilitate extensive resection. Further, our data suggest redundant roles for Rad3 ATR and Exo1 in facilitating extensive resection. We propose that the DNA damage checkpoint pathway coordinates re-section and nucleotide synthesis, thereby promoting efficient HR repair and genome stability.
Eukaryotic DNA damage checkpoint activation in response to double-strand breaks
Cellular and Molecular Life Sciences, 2012
Double-strand breaks (DSBs) are the most detrimental form of DNA damage. Failure to repair these cytotoxic lesions can result in genome rearrangements conducive to the development of many diseases, including cancer. The DNA damage response (DDR) ensures the rapid detection and repair of DSBs in order to maintain genome integrity. Central to the DDR are the DNA damage checkpoints. When activated by DNA damage, these sophisticated surveillance mechanisms induce transient cell cycle arrests, allowing sufficient time for DNA repair. Since the term ''checkpoint'' was coined over 20 years ago, our understanding of the molecular mechanisms governing the DNA damage checkpoint has advanced significantly. These pathways are highly conserved from yeast to humans. Thus, significant findings in yeast may be extrapolated to vertebrates, greatly facilitating the molecular dissection of these complex regulatory networks. This review focuses on the cellular response to DSBs in Saccharomyces cerevisiae, providing a comprehensive overview of how these signalling pathways function to orchestrate the cellular response to DNA damage and preserve genome stability in eukaryotic cells. Keywords Cancer Á Checkpoint Á DNA damage Á Double-strand break Á Yeast Á Genome instability Abbreviations ATM Ataxia telangiectasia mutated ATR ATM and Rad3-related ATRIP ATR interacting protein BRCT BRCA1 carboxyl terminal CAD Chk1 activation domain CDK Cyclin-dependent kinase DDK Dbf4-dependent kinase DDR DNA damage response DNA-PKcs DNA-dependent protein kinase catalytic subunit DSB Double-strand break GCRs Gross chromosomal rearrangements G1 Gap phase 1