Synthetic viability genomic screening defines Sae2 function in DNA repair

Puddu, Fabio; Oelschlaegel, Tobias; Guerini, Ilaria; Geisler, Nicola J.; Niu, Hengyao; Herzog, Mareike; Salguero, Israel; Ochoa‐Montaño, Bernardo; Viré, Emmanuelle; Sung, Patrick; Adams, David J.; Keane, Thomas M.; Jackson, Stephen

doi:10.15252/embj.201590973

Cited by 42 publications

(51 citation statements)

References 54 publications

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“…10 a, b) 4 . In S. cerevisiae , failure to remove MRE11 from single-stranded DNA can lead to hypersensitivity to a variety of clastogens 34,35 . We therefore propose that deficiencies in PTIP, CHD4 and PARP1 could confer drug resistance in Brca -deficient cells by limiting the access of MRE11 to single strand DNA at stalled RFs.…”

Section: Discussionmentioning

confidence: 99%

Replication fork stability confers chemoresistance in BRCA-deficient cells

Chaudhuri

Callén

Ding

et al. 2016

Nature

769

851

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Brca1- and Brca2-deficient cells have reduced capacity to repair DNA double-strand breaks (DSBs) by homologous recombination (HR) and consequently are hypersensitive to DNA damaging agents, including cisplatin and poly(ADP-ribose) polymerase (PARP) inhibitors. Here we show that loss of the MLL3/4 complex protein, PTIP, protects Brca1/2-deficient cells from DNA damage and rescues the lethality of Brca2-deficient embryonic stem cells. However, PTIP deficiency does not restore HR activity at DSBs. Instead, its absence inhibits the recruitment of the MRE11 nuclease to stalled replication forks, which in turn protects nascent DNA strands from extensive degradation. More generally, acquisition of PARPi and cisplatin resistance is associated with replication fork (RF) protection in Brca2-deficient tumor cells that do not develop Brca2 reversion mutations. Disruption of multiple proteins, including PARP1 and CHD4, leads to the same end point of RF protection, highlighting the complexities by which tumor cells evade chemotherapeutic interventions and acquire drug resistance.

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Section: Discussionmentioning

confidence: 99%

Replication fork stability confers chemoresistance in BRCA-deficient cells

Chaudhuri

Callén

Ding

et al. 2016

Nature

769

851

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“…Regardless, the biochemistry for these regulating partners suggests changes in protein–DNA interaction stability and off rates. As described in the proposed model ( Figure 2 d ), Sae2 (CtIP in humans) may dislodge the yeast MRX complex (Mre11–Rad50–Xrs2, MRN in humans) from ssDNA ends after resection (104, 105). In the absence of Sae2, DSB repair is impaired due to prolonged MRX complex binding.…”

Section: Mrn and Double-strand Break Repairmentioning

confidence: 96%

The MRE11–RAD50–NBS1 Complex Conducts the Orchestration of Damage Signaling and Outcomes to Stress in DNA Replication and Repair

Syed

Tainer

2018

Annu. Rev. Biochem.

336

345

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Genomic instability in disease and its fidelity in health depend on the DNA damage response (DDR), regulated in part from the complex of meiotic recombination 11 homolog 1 (MRE11), ATP-binding cassette–ATPase (RAD50), and phosphopeptide-binding Nijmegen breakage syndrome protein 1 (NBS1). The MRE11–RAD50–NBS1 (MRN) complex forms a multifunctional DDR machine. Within its network assemblies, MRN is the core conductor for the initial and sustained responses to DNA double-strand breaks, stalled replication forks, dysfunctional telomeres, and viral DNA infection. MRN can interfere with cancer therapy and is an attractive target for precision medicine. Its conformations change the paradigm whereby kinases initiate damage sensing. Delineated results reveal kinase activation, posttranslational targeting, functional scaffolding, conformations storing binding energy and en-abling access, interactions with hub proteins such as replication protein A (RPA), and distinct networks at DNA breaks and forks. MRN biochemistry provides prototypic insights into how it initiates, implements, and regulates multifunctional responses to genomic stress.

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“…Sae2 is likely to have additional cellular functions because sae2Δ mutants exhibits higher sensitivity to DNA damaging agents than mre11-nd mutants, Mre11 persists at ends for longer in the absence of Sae2 than observed when the Mre11 nuclease is eliminated and the DNA damage checkpoint is hyper-activated in sae2Δ mutants (Lisby et al, 2004; Clerici et al, 2006; Mimitou and Symington, 2010). The prolonged Mre11 retention at ends and checkpoint deactivation defects of sae2Δ can be rescued by mutations in the N-terminal region of Mre11 that decrease DNA binding without affecting end resection, indicating that these defects are separable (Chen et al, 2015; Puddu et al, 2015). Although Sae2 and CtIP were reported to exhibit endonuclease activity in vitro (Lengsfeld et al, 2007; Makharashvili et al, 2014; Wang et al, 2014), the proteins lack homology to known nucleases and other groups have not found nuclease activity associated with highly purified Sae2 or Ctp1 (Cannavo and Cejka, 2014; Andres et al, 2015).…”

Section: Initiation Of End Resection By Mre11-rad50-xrs2/nbs1 and Sae2mentioning

confidence: 99%

Mechanism and regulation of DNA end resection in eukaryotes

Symington

2016

Critical Reviews in Biochemistry and Molecular Biology

356

402

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The repair of DNA double-strand breaks (DSBs) by homologous recombination (HR) is initiated by nucleolytic degradation of the 5′ terminated strands in a process termed end resection. End resection generates 3′ single-stranded DNA tails, substrates for Rad51 to catalyze homologous pairing and exchange of DNA strands, and for activation of the DNA damage checkpoint. The commonly accepted view is that end resection occurs by a two-step mechanism. In the first step, Sae2/CtIP activates the Mre11-Rad50-Xrs2/Nbs1 (MRX/N) complex to endonucleolytically cleave the 5′-terminated DNA strands close to break ends, and in the second step Exo1 and/or Dna2 nucleases extend the resected tracts to produce long 3′-ssDNA-tailed intermediates. Initiation of resection commits a cell to repair a DSB by HR because long ssDNA overhangs are poor substrates for non-homologous end joining (NHEJ). Thus, the initiation of end resection has emerged as a critical control point for repair pathway choice. Here, I review recent studies on the mechanism of end resection and how this process is regulated to ensure the most appropriate repair outcome.

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Synthetic viability genomic screening defines Sae2 function in DNA repair

Cited by 42 publications

References 54 publications

Replication fork stability confers chemoresistance in BRCA-deficient cells

Replication fork stability confers chemoresistance in BRCA-deficient cells

The MRE11–RAD50–NBS1 Complex Conducts the Orchestration of Damage Signaling and Outcomes to Stress in DNA Replication and Repair

Mechanism and regulation of DNA end resection in eukaryotes

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