E2F1: Cause and Consequence of DNA Replication Stress

In mammalian cells, cell cycle entry occurs in response to the correct stimuli and is promoted by the transcriptional activity of E2F family members. E2F proteins regulate the transcription of S phase cyclins and genes required for DNA replication, DNA repair, and apoptosis. The activity of E2F1, the archetypal and most heavily studied E2F family member, is tightly controlled by the DNA damage checkpoints to modulate cell cycle progression and initiate programmed cell death, when required. Altered tumor suppressor and oncogenic signaling pathways often result in direct or indirect interference with E2F1 regulation to ensure higher rates of cell proliferation independently of external cues. Despite a clear link between dysregulated E2F1 activity and cancer progression, literature on the contribution of E2F1 to DNA replication stress phenotypes is somewhat scarce. This review discusses how dysfunctional tumor suppressor and oncogenic signaling pathways promote the disruption of E2F1 transcription and hence of its transcriptional targets, and how such events have the potential to drive DNA replication stress. In addition to the involvement of E2F1 upstream of DNA replication stress, this manuscript also considers the role of E2F1 as a downstream effector of the response to this type of cellular stress. Lastly, the review introduces some reflections on how E2F1 activity is integrated with checkpoint control through post-translational regulation, and proposes an exploitable tumor weakness based on this axis.

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Tolerance of DNA Replication Stress Is Promoted by Fumarate Through Modulation of Histone Demethylation and Enhancement of Replicative Intermediate Processing in Saccharomyces cerevisiae

Genetics ◽

10.1534/genetics.119.302238 ◽

2019 ◽

Vol 212 (3) ◽

pp. 631-654 ◽

Cited By ~ 1

Author(s):

Faeze Saatchi ◽

Ann L. Kirchmaier

Keyword(s):

Saccharomyces Cerevisiae ◽

Dna Replication ◽

Mammalian Cells ◽

Cell Cancer ◽

Replication Stress ◽

Histone Demethylase ◽

Loss Of Function ◽

Cycle Enzyme ◽

Link Type ◽

Dna Replication Stress

Fumarase is a well-characterized TCA cycle enzyme that catalyzes the reversible conversion of fumarate to malate. In mammals, fumarase acts as a tumor suppressor, and loss-of-function mutations in the FH gene in hereditary leiomyomatosis and renal cell cancer result in the accumulation of intracellular fumarate—an inhibitor of α-ketoglutarate-dependent dioxygenases. Fumarase promotes DNA repair by nonhomologous end joining in mammalian cells through interaction with the histone variant H2A.Z, and inhibition of KDM2B, a H3 K36-specific histone demethylase. Here, we report that Saccharomyces cerevisiae fumarase, Fum1p, acts as a response factor during DNA replication stress, and fumarate enhances survival of yeast lacking Htz1p (H2A.Z in mammals). We observed that exposure to DNA replication stress led to upregulation as well as nuclear enrichment of Fum1p, and raising levels of fumarate in cells via deletion of FUM1 or addition of exogenous fumarate suppressed the sensitivity to DNA replication stress of htz1Δ mutants. This suppression was independent of modulating nucleotide pool levels. Rather, our results are consistent with fumarate conferring resistance to DNA replication stress in htz1Δ mutants by inhibiting the H3 K4-specific histone demethylase Jhd2p, and increasing H3 K4 methylation. Although the timing of checkpoint activation and deactivation remained largely unaffected by fumarate, sensors and mediators of the DNA replication checkpoint were required for fumarate-dependent resistance to replication stress in the htz1Δ mutants. Together, our findings imply metabolic enzymes and metabolites aid in processing replicative intermediates by affecting chromatin modification states, thereby promoting genome integrity.

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Gad8 Protein Is Found in the Nucleus Where It Interacts with the MluI Cell Cycle Box-binding Factor (MBF) Transcriptional Complex to Regulate the Response to DNA Replication Stress

Journal of Biological Chemistry ◽

10.1074/jbc.m115.705251 ◽

2016 ◽

Vol 291 (17) ◽

pp. 9371-9381 ◽

Cited By ~ 15

Author(s):

Adiel Cohen ◽

Martin Kupiec ◽

Ronit Weisman

Keyword(s):

Cell Cycle ◽

Dna Replication ◽

Replication Stress ◽

Binding Factor ◽

Dna Replication Stress ◽

Transcriptional Complex

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Budding yeast Dma1 and Dma2 participate in regulation of Swe1 levels and localization

Molecular Biology of the Cell ◽

10.1091/mbc.e11-02-0127 ◽

2011 ◽

Vol 22 (13) ◽

pp. 2185-2197 ◽

Cited By ~ 18

Author(s):

Erica Raspelli ◽

Corinne Cassani ◽

Giovanna Lucchini ◽

Roberta Fraschini

Keyword(s):

Cell Cycle ◽

Dna Replication ◽

Budding Yeast ◽

Cell Cycle Control ◽

Replication Stress ◽

Down Regulation ◽

Evolutionarily Conserved ◽

Dna Replication Stress ◽

Morphogenesis Checkpoint ◽

The One

Timely down-regulation of the evolutionarily conserved protein kinase Swe1 plays an important role in cell cycle control, as Swe1 can block nuclear division through inhibitory phosphorylation of the catalytic subunit of cyclin-dependent kinase. In particular, Swe1 degradation is important for budding yeast cell survival in case of DNA replication stress, whereas it is inhibited by the morphogenesis checkpoint in response to alterations in actin cytoskeleton or septin structure. We show that the lack of the Dma1 and Dma2 ubiquitin ligases, which moderately affects Swe1 localization and degradation during an unperturbed cell cycle with no apparent phenotypic effects, is toxic for cells that are partially defective in Swe1 down-regulation. Moreover, Swe1 is stabilized, restrained at the bud neck, and hyperphosphorylated in dma1Δ dma2Δ cells subjected to DNA replication stress, indicating that the mechanism stabilizing Swe1 under these conditions is different from the one triggered by the morphogenesis checkpoint. Finally, the Dma proteins are required for proper Swe1 ubiquitylation. Taken together, the data highlight a previously unknown role of these proteins in the complex regulation of Swe1 and suggest that they might contribute to control, directly or indirectly, Swe1 ubiquitylation.

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Protein phosphatase 2A (PP2A) promotes anaphase entry after DNA replication stress in budding yeast

Molecular Biology of the Cell ◽

10.1091/mbc.e21-04-0222 ◽

2021 ◽

Author(s):

Cory Haluska ◽

Fengzhi Jin ◽

Yanchang Wang

Keyword(s):

Cell Cycle ◽

Dna Replication ◽

Dna Synthesis ◽

Protein Phosphatase ◽

Budding Yeast ◽

Replication Stress ◽

S Phase ◽

Viability Loss ◽

Phosphatase 2A ◽

Dna Replication Stress

DNA replication stress activates the S-phase checkpoint that arrests the cell cycle, but it is poorly understood how cells recover from this arrest. Cyclin-dependent kinase (CDK) and Protein Phosphatase 2A (PP2A) are key cell cycle regulators, and Cdc55 is a regulatory subunit of PP2A in budding yeast. We found that yeast cells lacking functional PP2ACdc55 showed slow growth in the presence of hydroxyurea (HU), a DNA synthesis inhibitor, without obvious viability loss. Moreover, PP2A mutants exhibited delayed anaphase entry and sustained levels of anaphase inhibitor Pds1 after HU treatment. A DNA damage checkpoint Chk1 phosphorylates and stabilizes Pds1. We showed that chk1Δ and mutation of the Chk1 phosphorylation sites in Pds1 largely restored efficient anaphase entry in PP2A mutants after HU treatment. In addition, deletion of SWE1 that encodes the inhibitory kinase for CDK or mutation of the Swe1 phosphorylation site in CDK ( cdc28F19) also suppressed the anaphase entry delay in PP2A mutants after HU treatment. Our genetic data suggest that Swe1/CDK acts upstream of Pds1. Surprisingly, cdc55Δ showed significant suppression to the viability loss of S-phase checkpoint mutants during DNA synthesis block. Together, our results uncover a PP2A-Swe1-CDK-Chk1-Pds1 axis that promotes recovery from DNA replication stress.

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Centrosome impairment causes DNA replication stress through MLK3/MK2 signaling and R-loop formation

10.1101/2020.01.09.898684 ◽

2020 ◽

Author(s):

Zainab Tayeh ◽

Kim Stegmann ◽

Antonia Kleeberg ◽

Mascha Friedrich ◽

Josephine Ann Mun Yee Choo ◽

...

Keyword(s):

Cell Cycle ◽

Dna Replication ◽

Replication Stress ◽

List Type ◽

Replication Forks ◽

Loop Formation ◽

Animal Cells ◽

Replication Fork Progression ◽

Primordial Dwarfism ◽

Dna Replication Stress

AbstractCentrosomes function as organizing centers of microtubules and support accurate mitosis in many animal cells. However, it remains to be explored whether and how centrosomes also facilitate the progression through different phases of the cell cycle. Here we show that impairing the composition of centrosomes, by depletion of centrosomal components or by inhibition of polo-like kinase 4 (PLK4), reduces the progression of DNA replication forks. This occurs even when the cell cycle is arrested before damaging the centrosomes, thus excluding mitotic failure as the source of replication stress. Mechanistically, the kinase MLK3 associates with centrosomes. When centrosomes are disintegrated, MLK3 activates the kinases p38 and MK2/MAPKAPK2. Transcription-dependent RNA:DNA hybrids (R-loops) are then causing DNA replication stress. Fibroblasts from patients with microcephalic primordial dwarfism (Seckel syndrome) harbouring defective centrosomes showed replication stress and diminished proliferation, which were each alleviated by inhibition of MK2. Thus, centrosomes not only facilitate mitosis, but their integrity is also supportive in DNA replication.HighlightsCentrosome defects cause replication stress independent of mitosis.MLK3, p38 and MK2 (alias MAPKAPK2) are signalling between centrosome defects and DNA replication stress through R-loop formation.Patient-derived cells with defective centrosomes display replication stress, whereas inhibition of MK2 restores their DNA replication fork progression and proliferation.Graphical abstract

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DNA replication stress induces deregulation of the cell cycle events in root meristems of Allium cepa

Annals of Botany ◽

10.1093/aob/mcs215 ◽

2012 ◽

Vol 110 (8) ◽

pp. 1581-1591 ◽

Cited By ~ 12

Author(s):

Aneta Żabka ◽

Justyna Teresa Polit ◽

Janusz Maszewski

Keyword(s):

Cell Cycle ◽

Dna Replication ◽

Allium Cepa ◽

Replication Stress ◽

Root Meristems ◽

Dna Replication Stress

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Role of a Candida albicans Nrm1/Whi5 homologue in cell cycle gene expression and DNA replication stress response

Molecular Microbiology ◽

10.1111/j.1365-2958.2012.08056.x ◽

2012 ◽

Vol 84 (4) ◽

pp. 778-794 ◽

Cited By ~ 17

Author(s):

Ayala Ofir ◽

Kay Hofmann ◽

Esther Weindling ◽

Tsvia Gildor ◽

Katherine S. Barker ◽

...

Keyword(s):

Gene Expression ◽

Cell Cycle ◽

Candida Albicans ◽

Dna Replication ◽

Stress Response ◽

Replication Stress ◽

Cell Cycle Gene ◽

Dna Replication Stress ◽

Cell Cycle Gene Expression

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LIM Protein Ajuba associates with the RPA complex through direct and cell cycle-dependent interaction with the RPA70 subunit

10.1101/177840 ◽

2017 ◽

Author(s):

Sandy Fowler ◽

Pascal Maguin ◽

Sampada Kalan ◽

Diego Loayza

Keyword(s):

Cell Cycle ◽

Dna Replication ◽

Genome Stability ◽

Replication Stress ◽

Cellular Transformation ◽

Early Event ◽

Lim Protein ◽

Show Evidence ◽

Dna Replication Stress ◽

Cycle Dependent

AbstractDNA damage response pathways are essential for genome stability and cell survival. Specifically, the ATR kinase is activated by DNA replication stress. An early event in this activation is the recruitment and phosphorylation of RPA, a single stranded DNA binding complex composed of three subunits, RPA70,RPA32 and RPA14. We have previously shown that the LIM protein Ajuba associates with RPA, and that depletion of Ajuba leads to potent activation of ATR. In this study, we show evidence that the Ajuba-RPA interaction occurs through direct protein contact with RPA70, and that their association is cell cycle-regulated and is reduced upon DNA replication stress. We propose a model in which Ajuba negatively regulates the ATR pathway by directly interacting with RPA70, thereby preventing an inappropriate ATR activation. Our results provide a framework to understand the mechanism of regulation of ATR in human cells, which is important to prevent cellular transformation and tumorigenesis.

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