A Mechanism for Controlled Breakage of Under-replicated Chromosomes during Mitosis

Duda, Heike; Arter, Meret; Gloggnitzer, Jiradet; Teloni, Federico; Wild, Philipp S.; Blanco, Miguel; Altmeyer, Matthias; Matos, Joao

doi:10.1016/j.devcel.2016.11.017

Cited by 109 publications

(158 citation statements)

References 54 publications

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“…However, if these nucleases become prematurely activated in S phase due to increased CDK activity, they could process stalled replication forks into DSBs. This is observed when the G2/M checkpoint kinase WEE1 is inhibited in S phase 130,131 and may also be the case in ATR-deficient cells. Of course, some structure-specific nucleases, such as the EME2—MUS81 endonuclease complex, are active in S phase and promote restart of stalled replication forks 132 .…”

Section: Atr Functions During Dna Replicationmentioning

confidence: 89%

The essential kinase ATR: ensuring faithful duplication of a challenging genome

Saldivar

Chen

Cimprich

2017

Nat Rev Mol Cell Biol

611

645

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One way to preserve a rare book is to lock it away from all potential sources of damage. Of course, an inaccessible book is also of little use, and the paper and ink will continue to degrade with age in any case. Like a book, the information stored in our DNA needs to be read, but it is also subject to continuous assault. In this review, we examine how the replication stress response that is controlled by the kinase ataxia telangiectasia and Rad3-related (ATR) senses and resolves threats to DNA integrity so the DNA remains available to read in all of our cells. We discuss the multiple data that have revealed an elegant yet increasingly complex mechanism of ATR activation. These involve a core set of components that recruit ATR to stressed replication forks, stimulate kinase activity and amplify ATR signaling. We focus on the activities of ATR in control of cell cycle checkpoints, origin firing and replication fork stability, and how proper regulation of these processes is crucial to ensure faithful duplication of a challenging genome.

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Section: Atr Functions During Dna Replicationmentioning

confidence: 89%

The essential kinase ATR: ensuring faithful duplication of a challenging genome

Saldivar

Chen

Cimprich

2017

Nat Rev Mol Cell Biol

611

645

View full text Add to dashboard Cite

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“…Intriguingly, the N-terminal DNA-binding region of MUS81 also mediates the interaction with SLX4 (Duda et al., 2016, Fekairi et al., 2009, Nair et al., 2014). Although the interplay between these protein-DNA and protein-protein interactions remains to be elucidated, we hypothesize that steric constraints would prevent the MUS81 N-HhH from binding simultaneously to SLX4 and its DNA substrate.…”

Section: Discussionmentioning

confidence: 99%

The SMX DNA Repair Tri-nuclease

et al. 2017

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SummaryThe efficient removal of replication and recombination intermediates is essential for the maintenance of genome stability. Resolution of these potentially toxic structures requires the MUS81-EME1 endonuclease, which is activated at prometaphase by formation of the SMX tri-nuclease containing three DNA repair structure-selective endonucleases: SLX1-SLX4, MUS81-EME1, and XPF-ERCC1. Here we show that SMX tri-nuclease is more active than the three individual nucleases, efficiently cleaving replication forks and recombination intermediates. Within SMX, SLX4 co-ordinates the SLX1 and MUS81-EME1 nucleases for Holliday junction resolution, in a reaction stimulated by XPF-ERCC1. SMX formation activates MUS81-EME1 for replication fork and flap structure cleavage by relaxing substrate specificity. Activation involves MUS81’s conserved N-terminal HhH domain, which mediates incision site selection and SLX4 binding. Cell cycle-dependent formation and activation of this tri-nuclease complex provides a unique mechanism by which cells ensure chromosome segregation and preserve genome integrity.

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“…Although high Cdk levels are compatible with bulk DNA replication in fission yeast (2), chromatin replication is inhibited in Xenopus mitotic extracts (15). Perhaps the replication of specific genomic regions must be paused during metaphase to prevent damage and chromosome pulverization (16,17). Our data indicate that regions under-replicated in metaphase have one last opportunity to complete their replication before cytokinesis when Cdk levels fall below a critical threshold during mitotic exit.Why do yeast not complete replication prior to mitosis?…”

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confidence: 88%

Budding yeast complete DNA replication after chromosome segregation begins

Ivanova

Maier

Missarova

et al. 2018

Preprint

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To faithfully transmit genetic information, cells must replicate their entire genome before division. This is thought to be ensured by the temporal separation of replication and chromosome segregation. Here we show that in a substantial fraction of unperturbed yeast cells, DNA replication finishes during anaphase, late in mitosis. High cyclin-Cdk activity inhibits replication in metaphase, and the decrease in cyclin-Cdk activity during mitotic exit allows DNA replication to finish at difficult-to-replicate regions. Replication during late mitosis correlates with elevated mutation rates, including copy number variation. Thus, yeast cells temporally overlap replication and chromosome segregation during normal growth, possibly allowing cells to maximize population-level growth rate while simultaneously exploring greater genetic space. Main text:Eukaryotic cells must complete DNA replication before chromosome segregation in order to maintain genomic stability. Complete replication is thought to be ensured by the temporal separation of DNA synthesis (S-phase) from mitosis (M-phase) (1).The ordering of S and M phases is established by increasing levels of cyclindependent kinase (Cdk) activity during the cell cycle (2) and is enforced by checkpoints that inhibit chromosome segregation when cells are exposed to severe replication stress (3). However, some yeast mutants, and cancer cells exposed to mild DNA replication stress, perform DNA synthesis in mitosis and possibly even in the subsequent G1 (4, 5), suggesting that DNA synthesis and mitosis may not be fully incompatible. Supporting this view, several lines of evidence suggest that budding yeast lack a checkpoint to detect if DNA replication has completed before entry into mitosis (6-10). Thus, to what extent eukaryotic cells temporally separate DNA synthesis and segregation under physiological conditions remains an open question. 3To directly test if DNA synthesis occurs during mitosis in unstressed cells we arrested yeast in metaphase via depletion of the anaphase promoting complex activator Cdc20 and measured incorporation of the nucleotide analogue 5-ethynyl-2'-deoxyuridine (EdU) as cells were, or were not, released into a G1 arrest. Cells held in metaphase showed no nuclear EdU signal after a 60-minute pulse, whereas cells released from metaphase into G1 arrest incorporated EdU into the nucleus (Fig.1A, S1A). EdU incorporation was higher in G1 than in metaphase cells in both DAPI-rich and DAPI-poor nuclear regions, which contained the nucleolar marker Net1 (Fig. S1B). Freely-cycling unstressed cells showed significant nuclear EdU incorporation in late mitosis and G1, whereas mitotic cells with actively segregating nuclei did not ( Fig. S2). Further, 45% of log-phase cells entered anaphase with single-stranded DNA, detected as Replication Protein A (RPA) foci (Rfa2-GFP) (Fig. S3). These observations suggest that metaphase is refractive to nuclear DNA synthesis, but that some DNA synthesis occurs between metaphase and the following G1 in freely cycling, unstre...

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A Mechanism for Controlled Breakage of Under-replicated Chromosomes during Mitosis

Cited by 109 publications

References 54 publications

The essential kinase ATR: ensuring faithful duplication of a challenging genome

The essential kinase ATR: ensuring faithful duplication of a challenging genome

The SMX DNA Repair Tri-nuclease

Budding yeast complete DNA replication after chromosome segregation begins

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