DNA Double-Strand Break Formation Induced by Replication Arrest Depend On Artemis.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1097-1097
Author(s):  
Masatoshi Takagi ◽  
Junya Unno ◽  
Thoru Kiyono ◽  
Fumiko Honda ◽  
Hirobumi Teraoka ◽  
...  
Keyword(s):  
Cellular Response ◽  
Replication Fork ◽  
Conflicts Of Interest ◽  
Strand Break ◽  
Dna Lesions ◽  
Myelogenous Leukemia ◽  
Dependent Manner ◽  
Single Stranded Dna ◽  
Replication Fork Stalling ◽  
Fork Stalling

Abstract Abstract 1097 Poster Board I-119 Hydroxyurea (HU) is an antineoplastic drug used in hematological malignancies, specifically polycythemia vera, essential thrombocytosis or chronic myelogenous leukemia. HU targets cells that are actively replicating DNA by inhibit ing ribonucleotide reductase, which causes an imbalance in the deoxynucleotide triphosphate pool. Stalled replication forks lead to the production of single-stranded DNA (ssDNA), which in some cases is converted to DSBs by unknown mechanisms, an event that is termed replication fork collapse. however, the precise mechanism for DSB induction and the cellular response to persistent replication fork stalling are not fully understood. We show that DSBs are generated in an Artemis nuclease-dependent manner following prolonged stalling caused by exposure to HU, with subsequent activation of the ataxia-telangiectasia mutated (ATM) signaling pathway. DNA-dependent protein kinase (DNA-PK) activity, a prerequisite for the endonuclease activity of Artemis, is also required for DSB generation and subsequent ATM activation. Our findings indicate a novel function of Artemis as a molecular switch that converts single-stranded DNA lesions into DSBs, thereby activating an ATM-dependent fail-safe mechanism following prolonged replication fork stalling. Disclosures No relevant conflicts of interest to declare.

scholarly journals Managing Single-Stranded DNA during Replication Stress in Fission Yeast

2021 ◽  
Author(s):  
Sarah A. Sabatinos ◽  
Susan L. Forsburg
Keyword(s):  
Cellular Response ◽  
Replication Fork ◽  
Genome Instability ◽  
Replication Stress ◽  
S Phase ◽  
Single Stranded Dna ◽  
Replication Checkpoint ◽  
Primary Signal ◽  
Fork Stalling ◽  
Chromosome Integrity

Replication fork stalling generates a variety of responses, most of which cause an increase in single-stranded DNA. ssDNA is a primary signal of replication distress that activates cellular checkpoints. It is also a potential source of genome instability and a substrate for mutation and recombination. Therefore, managing ssDNA levels is crucial to chromosome integrity. Limited ssDNA accumulation occurs in wild-type cells under stress. In contrast, cells lacking the replication checkpoint cannot arrest forks properly and accumulate large amounts of ssDNA. This likely occurs when the replication fork polymerase and helicase units are uncoupled. Some cells with mutations in the replication helicase (mcm-ts) mimic checkpoint-deficient cells, and accumulate extensive areas of ssDNA to trigger the G2-checkpoint. Another category of helicase mutant (mcm4-degron) causes fork stalling in early S-phase due to immediate loss of helicase function. Intriguingly, cells realize that ssDNA is present, but fail to detect that they accumulate ssDNA, and continue to divide. Thus, the cellular response to replication stalling depends on checkpoint activity and the time that replication stress occurs in S-phase. In this review we describe the signs, signals, and symptoms of replication arrest from an ssDNA perspective. We explore the possible mechanisms for these effects. We also advise the need for caution when detecting and interpreting data related to the accumulation of ssDNA.

scholarly journals Phosphorylation of Rad55 on Serines 2, 8, and 14 Is Required for Efficient Homologous Recombination in the Recovery of Stalled Replication Forks

2006 ◽  
Vol 26 (22) ◽  
pp. 8396-8409 ◽  
Author(s):  
Kristina Herzberg ◽  
Vladimir I. Bashkirov ◽  
Michael Rolfsmeier ◽  
Edwin Haghnazari ◽  
W. Hayes McDonald ◽  
...  
Keyword(s):  
Dna Damage ◽  
Homologous Recombination ◽  
Cellular Response ◽  
Replication Fork ◽  
Normal Growth ◽  
Genotoxic Stress ◽  
Replication Forks ◽  
Replication Fork Stalling ◽  
Fork Stalling ◽  
Stalled Replication Forks

ABSTRACT DNA damage checkpoints coordinate the cellular response to genotoxic stress and arrest the cell cycle in response to DNA damage and replication fork stalling. Homologous recombination is a ubiquitous pathway for the repair of DNA double-stranded breaks and other checkpoint-inducing lesions. Moreover, homologous recombination is involved in postreplicative tolerance of DNA damage and the recovery of DNA replication after replication fork stalling. Here, we show that the phosphorylation on serines 2, 8, and 14 (S2,8,14) of the Rad55 protein is specifically required for survival as well as for normal growth under genome-wide genotoxic stress. Rad55 is a Rad51 paralog in Saccharomyces cerevisiae and functions in the assembly of the Rad51 filament, a central intermediate in recombinational DNA repair. Phosphorylation-defective rad55-S2,8,14A mutants display a very slow traversal of S phase under DNA-damaging conditions, which is likely due to the slower recovery of stalled replication forks or the slower repair of replication-associated DNA damage. These results suggest that Rad55-S2,8,14 phosphorylation activates recombinational repair, allowing for faster recovery after genotoxic stress.

scholarly journals Managing Single-Stranded DNA during Replication Stress in Fission Yeast

2021 ◽  
Author(s):  
Sarah A. Sabatinos ◽  
Susan L. Forsburg
Keyword(s):  
Cellular Response ◽  
Replication Fork ◽  
Genome Instability ◽  
Replication Stress ◽  
S Phase ◽  
Single Stranded Dna ◽  
Replication Checkpoint ◽  
Primary Signal ◽  
Fork Stalling ◽  
Chromosome Integrity

Replication fork stalling generates a variety of responses, most of which cause an increase in single-stranded DNA. ssDNA is a primary signal of replication distress that activates cellular checkpoints. It is also a potential source of genome instability and a substrate for mutation and recombination. Therefore, managing ssDNA levels is crucial to chromosome integrity. Limited ssDNA accumulation occurs in wild-type cells under stress. In contrast, cells lacking the replication checkpoint cannot arrest forks properly and accumulate large amounts of ssDNA. This likely occurs when the replication fork polymerase and helicase units are uncoupled. Some cells with mutations in the replication helicase (mcm-ts) mimic checkpoint-deficient cells, and accumulate extensive areas of ssDNA to trigger the G2-checkpoint. Another category of helicase mutant (mcm4-degron) causes fork stalling in early S-phase due to immediate loss of helicase function. Intriguingly, cells realize that ssDNA is present, but fail to detect that they accumulate ssDNA, and continue to divide. Thus, the cellular response to replication stalling depends on checkpoint activity and the time that replication stress occurs in S-phase. In this review we describe the signs, signals, and symptoms of replication arrest from an ssDNA perspective. We explore the possible mechanisms for these effects. We also advise the need for caution when detecting and interpreting data related to the accumulation of ssDNA.

scholarly journals The human Shu complex functions with PDS5B and SPIDR to promote homologous recombination

2019 ◽  
Vol 47 (19) ◽  
pp. 10151-10165 ◽  
Author(s):  
Julieta Martino ◽  
Gregory J Brunette ◽  
Jonathan Barroso-González ◽  
Tatiana N Moiseeva ◽  
Chelsea M Smith ◽  
...  
Keyword(s):  
Dna Repair ◽  
Homologous Recombination ◽  
Replication Fork ◽  
Complex Function ◽  
Strand Break ◽  
Sister Chromatid Exchanges ◽  
Complex Functions ◽  
Replication Fork Stalling ◽  
Fork Stalling ◽  
Chromatid Exchanges

AbstractRAD51 plays a central role in homologous recombination during double-strand break repair and in replication fork dynamics. Misregulation of RAD51 is associated with genetic instability and cancer. RAD51 is regulated by many accessory proteins including the highly conserved Shu complex. Here, we report the function of the human Shu complex during replication to regulate RAD51 recruitment to DNA repair foci and, secondly, during replication fork restart following replication fork stalling. Deletion of the Shu complex members, SWS1 and SWSAP1, using CRISPR/Cas9, renders cells specifically sensitive to the replication fork stalling and collapse caused by methyl methanesulfonate and mitomycin C exposure, a delayed and reduced RAD51 response, and fewer sister chromatid exchanges. Our additional analysis identified SPIDR and PDS5B as novel Shu complex interacting partners and genetically function in the same pathway upon DNA damage. Collectively, our study uncovers a protein complex, which consists of SWS1, SWSAP1, SPIDR and PDS5B, involved in DNA repair and provides insight into Shu complex function and composition.

scholarly journals Dephosphorylation of γH2A by Glc7/Protein Phosphatase 1 Promotes Recovery from Inhibition of DNA Replication

2009 ◽  
Vol 30 (1) ◽  
pp. 131-145 ◽  
Author(s):  
Marco Bazzi ◽  
Davide Mantiero ◽  
Camilla Trovesi ◽  
Giovanna Lucchini ◽  
Maria Pia Longhese
Keyword(s):  
Dna Replication ◽  
Protein Phosphatase ◽  
Replication Fork ◽  
Strand Break ◽  
Protein Phosphatase 1 ◽  
Synthesis Inhibitor ◽  
Replication Fork Stalling ◽  
Fork Stalling

ABSTRACT Replication fork stalling caused by deoxynucleotide depletion triggers Rad53 phosphorylation and subsequent checkpoint activation, which in turn play a crucial role in maintaining functional DNA replication forks. How cells regulate checkpoint deactivation after inhibition of DNA replication is poorly understood. Here, we show that the budding yeast protein phosphatase Glc7/protein phosphatase 1 (PP1) promotes disappearance of phosphorylated Rad53 and recovery from replication fork stalling caused by the deoxynucleoside triphosphate (dNTP) synthesis inhibitor hydroxyurea (HU). Glc7 is also required for recovery from a double-strand break-induced checkpoint, while it is dispensable for checkpoint inactivation during methylmethane sulfonate exposure, which instead requires the protein phosphatases Pph3, Ptc2, and Ptc3. Furthermore, Glc7 counteracts in vivo histone H2A phosphorylation on serine 129 (γH2A) and dephosphorylates γH2A in vitro. Finally, the replication recovery defects of HU-treated glc7 mutants are partially rescued by Rad53 inactivation or lack of γH2A formation, and the latter also counteracts hyperphosphorylated Rad53 accumulation. We therefore propose that Glc7 activity promotes recovery from replication fork stalling caused by dNTP depletion and that γH2A dephosphorylation is a critical Glc7 function in this process.

scholarly journals Tracking of controlled Escherichia coli replication fork stalling and restart at repressor-bound DNA in vivo

2006 ◽  
Vol 25 (11) ◽  
pp. 2596-2604 ◽  
Author(s):  
Christophe Possoz ◽  
Sergio R Filipe ◽  
Ian Grainge ◽  
David J Sherratt
Keyword(s):  
Escherichia Coli ◽  
Replication Fork ◽  
Replication Fork Stalling ◽  
Fork Stalling

scholarly journals Evidence for DNA-PK-dependent and -independent DNA double-strand break repair pathways in mammalian cells as a function of the cell cycle.

1997 ◽  
Vol 17 (3) ◽  
pp. 1425-1433 ◽  
Author(s):  
S E Lee ◽  
R A Mitchell ◽  
A Cheng ◽  
E A Hendrickson
Keyword(s):  
Cell Cycle ◽  
Mammalian Cells ◽  
Cellular Response ◽  
Strand Break ◽  
S Phase ◽  
Dependent Manner ◽  
Severe Combined Immune Deficiency ◽  
Dsb Repair ◽  
G2 Checkpoint ◽  
G2 Phase

Mice homozygous for the scid (severe combined immune deficiency) mutation are defective in the repair of DNA double-strand breaks (DSBs) and are consequently very X-ray sensitive and defective in the lymphoid V(D)J recombination process. Recently, a strong candidate for the scid gene has been identified as the catalytic subunit of the DNA-dependent protein kinase (DNA-PK) complex. Here, we show that the activity of the DNA-PK complex is regulated in a cell cycle-dependent manner, with peaks of activity found at the G1/early S phase and again at the G2 phase in wild-type cells. Interestingly, only the deficit of the G1/early S phase DNA-PK activity correlated with an increased hypersensitivity to X-irradiation and a DNA DSB repair deficit in synchronized scid pre-B cells. Finally, we demonstrate that the DNA-PK activity found at the G2 phase may be required for exit from a DNA damage-induced G2 checkpoint arrest. These observations suggest the presence of two pathways (DNA-PK-dependent and -independent) of illegitimate mammalian DNA DSB repair and two distinct roles (DNA DSB repair and G2 checkpoint traversal) for DNA-PK in the cellular response to ionizing radiation.

scholarly journals Phosphorylated Rad18 directs DNA Polymerase η to sites of stalled replication

2010 ◽  
Vol 191 (5) ◽  
pp. 953-966 ◽  
Author(s):  
Tovah A. Day ◽  
Komariah Palle ◽  
Laura R. Barkley ◽  
Naoko Kakusho ◽  
Ying Zou ◽  
...  
Keyword(s):  
Dna Polymerase ◽  
Replication Fork ◽  
Genome Stability ◽  
Nuclear Antigen ◽  
Binding Motif ◽  
Polymerase Eta ◽  
Cdc7 Kinase ◽  
Replication Fork Stalling ◽  
Fork Stalling ◽  
Y Family

The E3 ubiquitin ligase Rad18 guides DNA Polymerase eta (Polη) to sites of replication fork stalling and mono-ubiquitinates proliferating cell nuclear antigen (PCNA) to facilitate binding of Y family trans-lesion synthesis (TLS) DNA polymerases during TLS. However, it is unclear exactly how Rad18 is regulated in response to DNA damage and how Rad18 activity is coordinated with progression through different phases of the cell cycle. Here we identify Rad18 as a novel substrate of the essential protein kinase Cdc7 (also termed Dbf4/Drf1-dependent Cdc7 kinase [DDK]). A serine cluster in the Polη-binding motif of Rad18 is phosphorylated by DDK. Efficient association of Rad18 with Polη is dependent on DDK and is necessary for redistribution of Polη to sites of replication fork stalling. This is the first demonstration of Rad18 regulation by direct phosphorylation and provides a novel mechanism for integration of S phase progression with postreplication DNA repair to maintain genome stability.

scholarly journals Oligodeoxynucleotide Binding to (CTG) · (CAG) Microsatellite Repeats Inhibits Replication Fork Stalling, Hairpin Formation, and Genome Instability

2012 ◽  
Vol 33 (3) ◽  
pp. 571-581 ◽  
Author(s):  
Guoqi Liu ◽  
Xiaomi Chen ◽  
Michael Leffak
Keyword(s):  
Replication Fork ◽  
Trinucleotide Repeat ◽  
Cell Model ◽  
Replication Stress ◽  
Dna Hairpin ◽  
Replication Fork Stalling ◽  
Fork Stalling ◽  
Hairpin Formation ◽  
Lagging Strand

ABSTRACT(CTG)n· (CAG)ntrinucleotide repeat (TNR) expansion in the 3′ untranslated region of the dystrophia myotonica protein kinase (DMPK) gene causes myotonic dystrophy type 1. However, a direct link between TNR instability, the formation of noncanonical (CTG)n· (CAG)nstructures, and replication stress has not been demonstrated. In a human cell model, we found that (CTG)45· (CAG)45causes local replication fork stalling, DNA hairpin formation, and TNR instability. Oligodeoxynucleotides (ODNs) complementary to the (CTG)45· (CAG)45lagging-strand template eliminated DNA hairpin formation on leading- and lagging-strand templates and relieved fork stalling. Prolonged cell culture, emetine inhibition of lagging-strand synthesis, or slowing of DNA synthesis by low-dose aphidicolin induced (CTG)45· (CAG)45expansions and contractions. ODNs targeting the lagging-strand template blocked the time-dependent or emetine-induced instability but did not eliminate aphidicolin-induced instability. These results show directly that TNR replication stalling, replication stress, hairpin formation, and instability are mechanistically linkedin vivo.

scholarly journals New Faces of old Friends: Emerging new Roles of RNA-Binding Proteins in the DNA Double-Strand Break Response

2021 ◽  
Vol 8 ◽  
Author(s):  
Julie A. Klaric ◽  
Stas Wüst ◽  
Stephanie Panier
Keyword(s):  
Cellular Response ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Genome Instability ◽  
Strand Break ◽  
Dna Lesions ◽  
Cell Cycle Checkpoints ◽  
Dna Double Strand Breaks ◽  
Dna Strand

DNA double-strand breaks (DSBs) are highly cytotoxic DNA lesions. To protect genomic stability and ensure cell homeostasis, cells mount a complex signaling-based response that not only coordinates the repair of the broken DNA strand but also activates cell cycle checkpoints and, if necessary, induces cell death. The last decade has seen a flurry of studies that have identified RNA-binding proteins (RBPs) as novel regulators of the DSB response. While many of these RBPs have well-characterized roles in gene expression, it is becoming increasingly clear that they also have non-canonical functions in the DSB response that go well beyond transcription, splicing and mRNA processing. Here, we review the current understanding of how RBPs are integrated into the cellular response to DSBs and describe how these proteins directly participate in signal transduction, amplification and repair at damaged chromatin. In addition, we discuss the implications of an RBP-mediated DSB response for genome instability and age-associated diseases such as cancer and neurodegeneration.

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