scholarly journals ZNF365 promotes stalled replication forks recovery to maintain genome stability

Cell Cycle ◽  
2013 ◽  
Vol 12 (17) ◽  
pp. 2817-2828 ◽  
Author(s):  
Yuqing Zhang ◽  
Eumni Park ◽  
Christopher Kim ◽  
Ji-hye Paik
Keyword(s):  
Genome Stability ◽  
Replication Forks ◽  
Stalled Replication Forks ◽  
Maintain Genome Stability

scholarly journals Exo1 phosphorylation inhibits exonuclease activity and prevents fork collapse in rad53 mutants independently of the 14-3-3 proteins

2020 ◽  
Vol 48 (6) ◽  
pp. 3053-3070
Author(s):  
Esther C Morafraile ◽  
Alberto Bugallo ◽  
Raquel Carreira ◽  
María Fernández ◽  
Cristina Martín-Castellanos ◽  
...  
Keyword(s):  
Genome Stability ◽  
Nuclease Activity ◽  
S Phase ◽  
Exonuclease Activity ◽  
Replication Forks ◽  
Post Translational Modifications ◽  
Replicative Stress ◽  
Stalled Replication Forks ◽  
Maintain Genome Stability ◽  
Specific Contribution

Abstract The S phase checkpoint is crucial to maintain genome stability under conditions that threaten DNA replication. One of its critical functions is to prevent Exo1-dependent fork degradation, and Exo1 is phosphorylated in response to different genotoxic agents. Exo1 seemed to be regulated by several post-translational modifications in the presence of replicative stress, but the specific contribution of checkpoint-dependent phosphorylation to Exo1 control and fork stability is not clear. We show here that Exo1 phosphorylation is Dun1-independent and Rad53-dependent in response to DNA damage or dNTP depletion, and in both situations Exo1 is similarly phosphorylated at multiple sites. To investigate the correlation between Exo1 phosphorylation and fork stability, we have generated phospho-mimic exo1 alleles that rescue fork collapse in rad53 mutants as efficiently as exo1-nuclease dead mutants or the absence of Exo1, arguing that Rad53-dependent phosphorylation is the mayor requirement to preserve fork stability. We have also shown that this rescue is Bmh1–2 independent, arguing that the 14-3-3 proteins are dispensable for fork stabilization, at least when Exo1 is downregulated. Importantly, our results indicated that phosphorylation specifically inhibits the 5' to 3'exo-nuclease activity, suggesting that this activity of Exo1 and not the flap-endonuclease, is the enzymatic activity responsible of the collapse of stalled replication forks in checkpoint mutants.

scholarly journals Tim–Tipin dysfunction creates an indispensible reliance on the ATR–Chk1 pathway for continued DNA synthesis

2009 ◽  
Vol 187 (1) ◽  
pp. 15-23 ◽  
Author(s):  
Kevin D. Smith ◽  
Michael A. Fu ◽  
Eric J. Brown
Keyword(s):  
Dna Synthesis ◽  
Genome Stability ◽  
Double Strand Breaks ◽  
Dna Unwinding ◽  
Replication Forks ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Nucleotide Incorporation ◽  
Pathway Activation ◽  
Maintain Genome Stability

The Tim (Timeless)–Tipin complex has been proposed to maintain genome stability by facilitating ATR-mediated Chk1 activation. However, as a replisome component, Tim–Tipin has also been suggested to couple DNA unwinding to synthesis, an activity expected to suppress single-stranded DNA (ssDNA) accumulation and limit ATR–Chk1 pathway engagement. We now demonstrate that Tim–Tipin depletion is sufficient to increase ssDNA accumulation at replication forks and stimulate ATR activity during otherwise unperturbed DNA replication. Notably, suppression of the ATR–Chk1 pathway in Tim–Tipin-deficient cells completely abrogates nucleotide incorporation in S phase, indicating that the ATR-dependent response to Tim–Tipin depletion is indispensible for continued DNA synthesis. Replication failure in ATR/Tim-deficient cells is strongly associated with synergistic increases in H2AX phosphorylation and DNA double-strand breaks, suggesting that ATR pathway activation preserves fork stability in instances of Tim–Tipin dysfunction. Together, these experiments indicate that the Tim–Tipin complex stabilizes replication forks both by preventing the accumulation of ssDNA upstream of ATR–Chk1 function and by facilitating phosphorylation of Chk1 by ATR.

scholarly journals ING2 controls the progression of DNA replication forks to maintain genome stability

EMBO Reports ◽  
2009 ◽  
Vol 10 (10) ◽  
pp. 1168-1174 ◽  
Author(s):  
Delphine Larrieu ◽  
Damien Ythier ◽  
Romuald Binet ◽  
Christian Brambilla ◽  
Elisabeth Brambilla ◽  
...  
Keyword(s):  
Dna Replication ◽  
Genome Stability ◽  
Replication Forks ◽  
Maintain Genome Stability

scholarly journals Functional cross talk between the Fanconi anemia and ATRX/DAXX histone chaperone pathways promotes replication fork recovery

2019 ◽  
Vol 29 (7) ◽  
pp. 1083-1095 ◽  
Author(s):  
Maya Raghunandan ◽  
Jung Eun Yeo ◽  
Ryan Walter ◽  
Kai Saito ◽  
Adam J Harvey ◽  
...  
Keyword(s):  
Fanconi Anemia ◽  
Replication Fork ◽  
Genome Stability ◽  
Chromosome Instability ◽  
Histone H3 ◽  
Underlying Mechanism ◽  
Replication Forks ◽  
Death Domain ◽  
Origin Firing ◽  
Stalled Replication Forks

Abstract Fanconi anemia (FA) is a chromosome instability syndrome characterized by increased cancer predisposition. Specifically, the FA pathway functions to protect genome stability during DNA replication. The central FA pathway protein, FANCD2, locates to stalled replication forks and recruits homologous recombination (HR) factors such as CtBP interacting protein (CtIP) to promote replication fork restart while suppressing new origin firing. Here, we identify alpha-thalassemia retardation syndrome X-linked (ATRX) as a novel physical and functional interaction partner of FANCD2. ATRX is a chromatin remodeler that forms a complex with Death domain-associated protein 6 (DAXX) to deposit the histone variant H3.3 into specific genomic regions. Intriguingly, ATRX was recently implicated in replication fork recovery; however, the underlying mechanism(s) remained incompletely understood. Our findings demonstrate that ATRX forms a constitutive protein complex with FANCD2 and protects FANCD2 from proteasomal degradation. ATRX and FANCD2 localize to stalled replication forks where they cooperate to recruit CtIP and promote MRE11 exonuclease-dependent fork restart while suppressing the firing of new replication origins. Remarkably, replication restart requires the concerted histone H3 chaperone activities of ATRX/DAXX and FANCD2, demonstrating that coordinated histone H3 variant deposition is a crucial event during the reinitiation of replicative DNA synthesis. Lastly, ATRX also cooperates with FANCD2 to promote the HR-dependent repair of directly induced DNA double-stranded breaks. We propose that ATRX is a novel functional partner of FANCD2 to promote histone deposition-dependent HR mechanisms in S-phase.

scholarly journals Rif1 inhibits replication fork progression and controls DNA copy number in Drosophila

2018 ◽  
Author(s):  
Alexander Munden ◽  
Zhan Rong ◽  
Rama Gangula ◽  
Simon Mallal ◽  
Jared T. Nordman
Keyword(s):  
Copy Number ◽  
Replication Fork ◽  
Genome Stability ◽  
Replication Timing ◽  
Physical Interaction ◽  
Dependent Manner ◽  
Replication Forks ◽  
Dna Copy Number ◽  
Replication Fork Progression ◽  
Maintain Genome Stability

ABSTRACTControl of DNA copy number is essential to maintain genome stability and ensure proper cell and tissue function. In Drosophila polyploid cells, the SNF2-domain-containing SUUR protein inhibits replication fork progression within specific regions of the genome to promote DNA underreplication. While dissecting the function of SUUR’s SNF2 domain, we identified a physical interaction between SUUR and Rif1. Rif1 has many roles in DNA metabolism and regulates the replication timing program. We demonstrate that repression of DNA replication is dependent on Rif1. Rif1 localizes to active replication forks in an SUUR-dependent manner and directly regulates replication fork progression. Importantly, SUUR associates with replication forks in the absence of Rif1, indicating that Rif1 acts downstream of SUUR to inhibit fork progression. Our findings uncover an unrecognized function of the Rif1 protein as a regulator of replication fork progression.

scholarly journals SDE2 Integrates into the TIMELESS-TIPIN Complex to Protect Stalled Replication Forks

2020 ◽  
Author(s):  
Julie Rageul ◽  
Jennifer J. Park ◽  
Ping Ping Zeng ◽  
Eun-A Lee ◽  
Jihyeon Yang ◽  
...  
Keyword(s):  
Dna Replication ◽  
Replication Fork ◽  
Genome Stability ◽  
Essential Role ◽  
Replication Stress ◽  
Replication Forks ◽  
Genomic Integrity ◽  
Fork Protection Complex ◽  
Stalled Replication Forks ◽  
Stalled Fork

ABSTRACTProtecting replication fork integrity during DNA replication is essential for maintaining genome stability. Here, we report that SDE2, a PCNA-associated protein, plays a key role in maintaining active replication and counteracting replication stress by regulating the replication fork protection complex (FPC). SDE2 directly interacts with the FPC component TIMELESS (TIM) and enhances TIM stability and its localization to replication forks, thereby aiding the coordination of replisome progression. Like TIM deficiency, knockdown of SDE2 leads to impaired fork progression and stalled fork recovery, along with a failure to activate CHK1 phosphorylation. Moreover, loss of SDE2 or TIM results in an excessive MRE11-dependent degradation of reversed forks. Together, our study uncovers an essential role for SDE2 in maintaining genomic integrity by stabilizing the FPC and describes a new role for TIM in protecting stalled replication forks. We propose that TIM-mediated fork protection may represent a way to cooperate with BRCA-dependent fork stabilization.

BAP1 promotes stalled fork restart and cell survival via INO80 in response to replication stress

2019 ◽  
Vol 476 (20) ◽  
pp. 3053-3066 ◽  
Author(s):  
Han-Sae Lee ◽  
Hye-Ran Seo ◽  
Shin-Ai Lee ◽  
Soohee Choi ◽  
Dongmin Kang ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Genome Stability ◽  
Genome Instability ◽  
Ectopic Expression ◽  
Replication Stress ◽  
Replication Forks ◽  
Suppressor Activity ◽  
Replication Fork Progression ◽  
Tumor Suppressor Activity ◽  
Stalled Replication Forks

Abstract The recovery from replication stress by restarting stalled forks to continue DNA synthesis is crucial for maintaining genome stability and thereby preventing diseases such as cancer. We previously showed that BRCA1-associated protein 1 (BAP1), a nuclear deubiquitinase with tumor suppressor activity, promotes replication fork progression by stabilizing the INO80 chromatin remodeler via deubiquitination and recruiting it to replication forks during normal DNA synthesis. However, whether BAP1 functions in DNA replication under stress conditions is unknown. Here, we show that BAP1 depletion reduces S-phase progression and DNA synthesis after treatment with hydroxyurea (HU). BAP1-depleted cells exhibit a defect in the restart of HU-induced stalled replication forks, which is recovered by the ectopic expression of INO80. Both BAP1 and INO80 bind chromatin at replication forks upon HU treatment. BAP1 depletion abrogates the binding of INO80 to replication forks and increases the formation of RAD51 foci following HU treatment. BAP1-depleted cells show hypersensitivity to HU treatment, which is rescued by INO80 expression. These results suggest that BAP1 promotes the restart of stress-induced stalled replication forks by recruiting INO80 to the stalled forks. This function of BAP1 in replication stress recovery may contribute to its ability to suppress genome instability and cancer development.

Succinylation at a key residue of FEN1 is involved in the DNA damage response to maintain genome stability

2020 ◽  
Vol 319 (4) ◽  
pp. C657-C666
Author(s):  
Rongyi Shi ◽  
Yiyi Wang ◽  
Ya Gao ◽  
Xiaoli Xu ◽  
Shuyu Mao ◽  
...  
Keyword(s):  
Dna Damage ◽  
Dna Replication ◽  
Replication Fork ◽  
Genome Stability ◽  
Damage Response ◽  
Dna Replication And Repair ◽  
Fork Stalling ◽  
Stalled Replication Forks ◽  
Maintain Genome Stability

Human flap endonuclease 1 (FEN1) is a structure-specific, multifunctional endonuclease essential for DNA replication and repair. Our previous study showed that in response to DNA damage, FEN1 interacts with the PCNA-like Rad9-Rad1-Hus1 complex instead of PCNA to engage in DNA repair activities, such as stalled DNA replication fork repair, and undergoes SUMOylation by SUMO-1. Here, we report that succinylation of FEN1 was stimulated in response to DNA replication fork-stalling agents, such as ultraviolet (UV) irradiation, hydroxyurea, camptothecin, and mitomycin C. K200 is a key succinylation site of FEN1 that is essential for gap endonuclease activity and could be suppressed by methylation and stimulated by phosphorylation to promote SUMO-1 modification. Succinylation at K200 of FEN1 promoted the interaction of FEN1 with the Rad9-Rad1-Hus1 complex to rescue stalled replication forks. Impairment of FEN1 succinylation led to the accumulation of DNA damage and heightened sensitivity to fork-stalling agents. Altogether, our findings suggest an important role of FEN1 succinylation in regulating its roles in DNA replication and repair, thus maintaining genome stability.

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