scholarly journals The chromatin-remodeling factor CHD4 coordinates signaling and repair after DNA damage

2010 ◽  
Vol 190 (5) ◽  
pp. 731-740 ◽  
Author(s):  
Dorthe Helena Larsen ◽  
Catherine Poinsignon ◽  
Thorkell Gudjonsson ◽  
Christoffel Dinant ◽  
Mark R. Payne ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Dna Repair ◽  
Chromatin Remodeling ◽  
Cell Cycle Progression ◽  
Clonogenic Survival ◽  
Dna Double Strand Breaks ◽  
Checkpoint Signaling ◽  
Strand Breaks ◽  
Delay Cell

In response to ionizing radiation (IR), cells delay cell cycle progression and activate DNA repair. Both processes are vital for genome integrity, but the mechanisms involved in their coordination are not fully understood. In a mass spectrometry screen, we identified the adenosine triphosphate–dependent chromatin-remodeling protein CHD4 (chromodomain helicase DNA-binding protein 4) as a factor that becomes transiently immobilized on chromatin after IR. Knockdown of CHD4 triggers enhanced Cdc25A degradation and p21Cip1 accumulation, which lead to more pronounced cyclin-dependent kinase inhibition and extended cell cycle delay. At DNA double-strand breaks, depletion of CHD4 disrupts the chromatin response at the level of the RNF168 ubiquitin ligase, which in turn impairs local ubiquitylation and BRCA1 assembly. These cell cycle and chromatin defects are accompanied by elevated spontaneous and IR-induced DNA breakage, reduced efficiency of DNA repair, and decreased clonogenic survival. Thus, CHD4 emerges as a novel genome caretaker and a factor that facilitates both checkpoint signaling and repair events after DNA damage.

scholarly journals ATM prevents DSB formation by coordinating SSB repair and cell cycle progression

2015 ◽  
Vol 112 (13) ◽  
pp. 3997-4002 ◽  
Author(s):  
Svetlana V. Khoronenkova ◽  
Grigory L. Dianov
Keyword(s):  
Cell Cycle ◽  
Dna Replication ◽  
Ataxia Telangiectasia ◽  
Cell Cycle Progression ◽  
Dna Double Strand Breaks ◽  
Cycle Progression ◽  
Strand Breaks ◽  
Delay Cell ◽  
Single Strand Breaks ◽  
Dna Instability

DNA single-strand breaks (SSBs) arise as a consequence of spontaneous DNA instability and are also formed as DNA repair intermediates. Their repair is critical because they otherwise terminate gene transcription and generate toxic DNA double-strand breaks (DSBs) on replication. To prevent the formation of DSBs, SSB repair must be completed before DNA replication. To accomplish this, cells should be able to detect unrepaired SSBs, and then delay cell cycle progression to allow more time for repair; however, to date there is no evidence supporting the coordination of SSB repair and replication in human cells. Here we report that ataxia-telangiectasia mutated kinase (ATM) plays a major role in restricting the replication of SSB-containing DNA and thus prevents DSB formation. We show that ATM is activated by SSBs and coordinates their repair with DNA replication. SSB-mediated ATM activation is followed by a G1 cell cycle delay that allows more time for repair and thus prevents the replication of damaged DNA and DSB accrual. These findings establish an unanticipated role for ATM in the signaling of DNA SSBs and provide important insight into the molecular defects leading to genetic instability in patients with ataxia-telangiectasia.

scholarly journals Retention but Not Recruitment of Crb2 at Double-Strand Breaks Requires Rad1 and Rad3 Complexes

2003 ◽  
Vol 23 (17) ◽  
pp. 6150-6158 ◽  
Author(s):  
Li-Lin Du ◽  
Toru M. Nakamura ◽  
Bettina A. Moser ◽  
Paul Russell
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Double Strand Breaks ◽  
Live Cells ◽  
Adapter Protein ◽  
Wild Type ◽  
Dna Double Strand Breaks ◽  
Checkpoint Signaling ◽  
Strand Breaks ◽  
Checkpoint Protein

ABSTRACT The fission yeast checkpoint protein Crb2, related to budding yeast Rad9 and human 53BP1 and BRCA1, has been suggested to act as an adapter protein facilitating the phosphorylation of specific substrates by Rad3-Rad26 kinase. To further understand its role in checkpoint signaling, we examined its localization in live cells by using fluorescence microscopy. In response to DNA damage, Crb2 localizes to distinct nuclear foci, which represent sites of DNA double-strand breaks (DSBs). Crb2 colocalizes with Rad22 at persistent foci, suggesting that Crb2 is retained at sites of DNA damage during repair. Damage-induced Crb2 foci still form in cells defective in Rad1, Rad3, and Rad17 complexes, but these foci do not persist as long as in wild-type cells. Our results suggest that Crb2 functions at the sites of DNA damage, and its regulated persistent localization at damage sites may be involved in facilitating DNA repair and/or maintaining the checkpoint arrest while DNA repair is under way.

High NaCl causes Mre11 to leave the nucleus, disrupting DNA damage signaling and repair

2003 ◽  
Vol 285 (2) ◽  
pp. F266-F274 ◽  
Author(s):  
Natalia I. Dmitrieva ◽  
Dmitry V. Bulavin ◽  
Maurice B. Burg
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Dna Repair ◽  
Cell Cycle Arrest ◽  
Dna Damage Response ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Cycle Arrest ◽  
Damage Response

High NaCl causes DNA double-strand breaks and cell cycle arrest, but the mechanism of its genotoxicity has been unclear. In this study, we describe a novel mechanism that contributes to this genotoxicity. The Mre11 exonuclease complex is a central component of DNA damage response. This complex assembles at sites of DNA damage, where it processes DNA ends for subsequent activation of repair and initiates cell cycle checkpoints. However, this does not occur with DNA damage caused by high NaCl. Rather, following high NaCl, Mre11 exits from the nucleus, DNA double-strand breaks accumulate in the S and G2 phases of the cell cycle, and DNA repair is inhibited. Furthermore, the exclusion of Mre11 from the nucleus by high NaCl persists following UV or ionizing radiation, also preventing DNA repair in response to those stresses, as evidenced by absence of H2AX phosphorylation at places of DNA damage and by impaired repair of damaged reporter plasmids. Activation of chk1 by phosphorylation on Ser345 generally is required for DNA damage-induced cell cycle arrest. However, chk1 does not become phosphorylated during high NaCl-induced cell cycle arrest. Also, high NaCl prevents ionizing and UV radiation-induced phosphorylation of chk1, but cell cycle arrest still occurs, indicating the existence of alternative mechanisms for the S and G2/M delays. DNA breaks that occur normally during processes such as DNA replication and transcription, as well as damages to DNA induced by genotoxic stresses, ordinarily are rapidly repaired. We propose that inhibition of this repair by high NaCl results in accumulation of DNA damage, accounting for the genotoxicity of high NaCl, and that cell cycle delay induced by high NaCl slows accumulation of DNA damage until the DNA damage-response network can be reactivated.

scholarly journals Mitotic progression following DNA damage enables pattern recognition within micronuclei

2017 ◽  
Author(s):  
Shane M Harding ◽  
Joseph L Benci ◽  
Jerome Irianto ◽  
Dennis E Discher ◽  
Andy J Minn ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Pattern Recognition ◽  
Dna Damage ◽  
Immune Checkpoint ◽  
Cell Cycle Progression ◽  
Immune Checkpoint Blockade ◽  
Checkpoint Blockade ◽  
Dna Double Strand Breaks ◽  
Strand Breaks

Inflammatory gene expression following genotoxic cancer therapy is well documented, yet the events underlying its induction remain poorly understood. Inflammatory cytokines modify the tumor microenvironment by recruiting immune cells and are critical for both local and systemic (abscopal) tumor responses to radiotherapy1. An enigmatic feature of this phenomenon is its delayed onset (days), in contrast to the acute DNA damage responses that occur in minutes to hours. Such dichotomous kinetics implicate additional rate limiting steps that are essential for DNA-damage induced inflammation. Here, we show that cell cycle progression through mitosis following DNA double-strand breaks (DSBs) leads to the formation of micronuclei, which precede activation of inflammatory signaling and are a repository for the pattern recognition receptor cGAS. Inhibiting progression through mitosis or loss of pattern recognition by cGAS-STING impaired interferon signaling and prevented the regression of abscopal tumors in the context of ionizing radiation and immune checkpoint blockade in vivo. These findings implicate temporal modulation of the cell cycle as an important consideration in the context of therapeutic strategies that combine genotoxic agents with immune checkpoint blockade.

scholarly journals Direct Regulation of DNA Repair by E2F and RB in Mammals and Plants: Core Function or Convergent Evolution?

Cancers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 934
Author(s):  
Swarnalatha Manickavinayaham ◽  
Briana K. Dennehey ◽  
David G. Johnson
Keyword(s):  
Cell Cycle ◽  
Dna Repair ◽  
Cell Cycle Progression ◽  
Mitotic Cell ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Expression Of Genes ◽  
Genes Encoding ◽  
E2f Transcription Factor ◽  
Dna End Resection

Members of the E2F transcription factor family regulate the expression of genes important for DNA replication and mitotic cell division in most eukaryotes. Homologs of the retinoblastoma (RB) tumor suppressor inhibit the activity of E2F factors, thus controlling cell cycle progression. Organisms such as budding and fission yeast have lost genes encoding E2F and RB, but have gained genes encoding other proteins that take on E2F and RB cell cycle-related functions. In addition to regulating cell proliferation, E2F and RB homologs have non-canonical functions outside the mitotic cell cycle in a variety of eukaryotes. For example, in both mammals and plants, E2F and RB homologs localize to DNA double-strand breaks (DSBs) and directly promote repair by homologous recombination (HR). Here, we discuss the parallels between mammalian E2F1 and RB and their Arabidopsis homologs, E2FA and RB-related (RBR), with respect to their recruitment to sites of DNA damage and how they help recruit repair factors important for DNA end resection. We also explore the question of whether this role in DNA repair is a conserved ancient function of the E2F and RB homologs in the last eukaryotic common ancestor or whether this function evolved independently in mammals and plants.

scholarly journals RepID-deficient cancer cells are sensitized to a drug targeting p97/VCP segregase

2021 ◽  
Author(s):  
Sang-Min Jang ◽  
Christophe E. Redon ◽  
Haiqing Fu ◽  
Fred E. Indig ◽  
Mirit I. Aladjem
Keyword(s):  
Dna Damage ◽  
Cancer Cells ◽  
Cell Sorting ◽  
Clonogenic Survival ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Ubiquitinated Proteins ◽  
Damage Response ◽  
Survival Assay

Abstract Background The p97/valosin-containing protein (VCP) complex is a crucial factor for the segregation of ubiquitinated proteins in the DNA damage response and repair pathway. Objective We investigated whether blocking the p97/VCP function can inhibit the proliferation of RepID-deficient cancer cells using immunofluorescence, clonogenic survival assay, fluorescence-activated cell sorting, and immunoblotting. Result p97/VCP was recruited to chromatin and colocalized with DNA double-strand breaks in RepID-deficient cancer cells that undergo spontaneous DNA damage. Inhibition of p97/VCP induced death of RepID-depleted cancer cells. This study highlights the potential of targeting p97/VCP complex as an anticancer therapeutic approach. Conclusion Our results show that RepID is required to prevent excessive DNA damage at the endogenous levels. Localization of p97/VCP to DSB sites was induced based on spontaneous DNA damage in RepID-depleted cancer cells. Anticancer drugs targeting p97/VCP may be highly potent in RepID-deficient cells. Therefore, we suggest that p97/VCP inhibitors synergize with RepID depletion to kill cancer cells.

scholarly journals Sae2 antagonizes Rad9 accumulation at DNA double-strand breaks to attenuate checkpoint signaling and facilitate end resection

2018 ◽  
Vol 115 (51) ◽  
pp. E11961-E11969 ◽  
Author(s):  
Tai-Yuan Yu ◽  
Michael T. Kimble ◽  
Lorraine S. Symington
Keyword(s):  
Dna Damage ◽  
Dna Damage Response ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Inhibitory Effects ◽  
Checkpoint Signaling ◽  
Synthetic Lethal ◽  
Strand Breaks ◽  
Damage Response ◽  
End Resection

The Mre11-Rad50-Xrs2NBS1 complex plays important roles in the DNA damage response by activating the Tel1ATM kinase and catalyzing 5′–3′ resection at DNA double-strand breaks (DSBs). To initiate resection, Mre11 endonuclease nicks the 5′ strands at DSB ends in a reaction stimulated by Sae2CtIP. Accordingly, Mre11-nuclease deficient (mre11-nd) and sae2Δ mutants are expected to exhibit similar phenotypes; however, we found several notable differences. First, sae2Δ cells exhibit greater sensitivity to genotoxins than mre11-nd cells. Second, sae2Δ is synthetic lethal with sgs1Δ, whereas the mre11-nd sgs1Δ mutant is viable. Third, Sae2 attenuates the Tel1-Rad53CHK2 checkpoint and antagonizes Rad953BP1 accumulation at DSBs independent of Mre11 nuclease. We show that Sae2 competes with other Tel1 substrates, thus reducing Rad9 binding to chromatin and to Rad53. We suggest that persistent Sae2 binding at DSBs in the mre11-nd mutant counteracts the inhibitory effects of Rad9 and Rad53 on Exo1 and Dna2-Sgs1–mediated resection, accounting for the different phenotypes conferred by mre11-nd and sae2Δ mutations. Collectively, these data show a resection initiation independent role for Sae2 at DSBs by modulating the DNA damage checkpoint.

scholarly journals Recent advances in the nucleolar responses to DNA double-strand breaks

2020 ◽  
Vol 48 (17) ◽  
pp. 9449-9461
Author(s):  
Lea Milling Korsholm ◽  
Zita Gál ◽  
Blanca Nieto ◽  
Oliver Quevedo ◽  
Stavroula Boukoura ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Dna Damage Response ◽  
Ribosomal Dna ◽  
Repetitive Sequences ◽  
Dna Lesions ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Damage Response

Abstract DNA damage poses a serious threat to human health and cells therefore continuously monitor and repair DNA lesions across the genome. Ribosomal DNA is a genomic domain that represents a particular challenge due to repetitive sequences, high transcriptional activity and its localization in the nucleolus, where the accessibility of DNA repair factors is limited. Recent discoveries have significantly extended our understanding of how cells respond to DNA double-strand breaks (DSBs) in the nucleolus, and new kinases and multiple down-stream targets have been identified. Restructuring of the nucleolus can occur as a consequence of DSBs and new data point to an active regulation of this process, challenging previous views. Furthermore, new insights into coordination of cell cycle phases and ribosomal DNA repair argue against existing concepts. In addition, the importance of nucleolar-DNA damage response (n-DDR) mechanisms for maintenance of genome stability and the potential of such factors as anti-cancer targets is becoming apparent. This review will provide a detailed discussion of recent findings and their implications for our understanding of the n-DDR. The n-DDR shares features with the DNA damage response (DDR) elsewhere in the genome but is also emerging as an independent response unique to ribosomal DNA and the nucleolus.

Abstract C46: DNA damage-induced autophagy is required for efficient DNA repair and cell cycle progression

2012 ◽  
Vol 72 (4 Supplement) ◽  
pp. C46-C46
Author(s):  
Kamini Singh ◽  
Sayer R. Al-Harbi ◽  
Akwasi Agyeman ◽  
Janet A. Houghton ◽  
Warren D. Heston ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Dna Damage ◽  
Dna Repair ◽  
Cell Cycle Progression ◽  
Cycle Progression

scholarly journals Sustained CHK2 activity, but not ATM activity, is critical to maintain a G1 arrest after DNA damage in untransformed cells

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Iraia García-Santisteban ◽  
Alba Llopis ◽  
Lenno Krenning ◽  
Jon Vallejo-Rodríguez ◽  
Bram van den Broek ◽  
...  
Keyword(s):  
Dna Damage ◽  
Cell Cycle Progression ◽  
Double Strand Breaks ◽  
G1 Arrest ◽  
Dna Double Strand Breaks ◽  
Independent Manner ◽  
Cycle Progression ◽  
Strand Breaks ◽  
G1 Checkpoint ◽  
The Impact

Abstract Background The G1 checkpoint is a critical regulator of genomic stability in untransformed cells, preventing cell cycle progression after DNA damage. DNA double-strand breaks (DSBs) recruit and activate ATM, a kinase which in turn activates the CHK2 kinase to establish G1 arrest. While the onset of G1 arrest is well understood, the specific role that ATM and CHK2 play in regulating G1 checkpoint maintenance remains poorly characterized. Results Here we examine the impact of ATM and CHK2 activities on G1 checkpoint maintenance in untransformed cells after DNA damage caused by DSBs. We show that ATM becomes dispensable for G1 checkpoint maintenance as early as 1 h after DSB induction. In contrast, CHK2 kinase activity is necessary to maintain the G1 arrest, independently of ATM, ATR, and DNA-PKcs, implying that the G1 arrest is maintained in a lesion-independent manner. Sustained CHK2 activity is achieved through auto-activation and its acute inhibition enables cells to abrogate the G1-checkpoint and enter into S-phase. Accordingly, we show that CHK2 activity is lost in cells that recover from the G1 arrest, pointing to the involvement of a phosphatase with fast turnover. Conclusion Our data indicate that G1 checkpoint maintenance relies on CHK2 and that its negative regulation is crucial for G1 checkpoint recovery after DSB induction.

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