RPA antagonizes microhomology-mediated repair of DNA double-strand breaks

Deng, Sarah; Gibb, Bryan; Almeida, Mariana Justino de; Greene, Eric C.; Symington, Lorraine S.

doi:10.1038/nsmb.2786

Cited by 179 publications

(225 citation statements)

References 64 publications

(104 reference statements)

Supporting

Mentioning

201

Contrasting

Order By: Relevance

“…We also show that BRCA1 recruitment is dramatically affected. Since BRCA1 is acting with CtIP to activate long-term resection (Chen et al 2008), it is possible that DNA ends are not appropriately resected to create a proper template for recombination, and the short resection channels lesions to A-EJ as was proposed earlier (Zhang and Jasin 2011;Deng et al 2014). The fact that resection at the lamina is not as dramatically affected as late steps of HR might also suggest that nuclear position dictates the DNA repair pathway choice by regulating only the recruitment of late HR proteins to DSBs.…”

Section: Discussionmentioning

confidence: 98%

Nuclear position dictates DNA repair pathway choice

et al. 2014

View full text Add to dashboard Cite

Faithful DNA repair is essential to avoid chromosomal rearrangements and promote genome integrity. Nuclear organization has emerged as a key parameter in the formation of chromosomal translocations, yet little is known as to whether DNA repair can efficiently occur throughout the nucleus and whether it is affected by the location of the lesion. Here, we induce DNA double-strand breaks (DSBs) at different nuclear compartments and follow their fate. We demonstrate that DSBs induced at the nuclear membrane (but not at nuclear pores or nuclear interior) fail to rapidly activate the DNA damage response (DDR) and repair by homologous recombination (HR). Real-time and superresolution imaging reveal that DNA DSBs within lamina-associated domains do not migrate to more permissive environments for HR, like the nuclear pores or the nuclear interior, but instead are repaired in situ by alternative end-joining. Our results are consistent with a model in which nuclear position dictates the choice of DNA repair pathway, thus revealing a new level of regulation in DSB repair controlled by spatial organization of DNA within the nucleus.

show abstract

Section: Discussionmentioning

confidence: 98%

Nuclear position dictates DNA repair pathway choice

et al. 2014

View full text Add to dashboard Cite

show abstract

“…MMEJ is a distinct DSB repair pathway that operates in the presence of functional NHEJ and HR pathways (10,37). The genetic requirements of MMEJ are being studied in the model eukaryote Saccharomyces cerevisiae and involve components traditionally considered specific to the NHEJ (Pol λ) and HR (Rad1-Rad10, Rad59, and Mre11-Rad50-Xrs2) pathways (4,5,10,38).…”

mentioning

confidence: 99%

DNA polymerases δ and λ cooperate in repairing double-strand breaks by microhomology-mediated end-joining in Saccharomyces cerevisiae

Meyer

Heyer

2015

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Maintenance of genome stability is carried out by a suite of DNA repair pathways that ensure the repair of damaged DNA and faithful replication of the genome. Of particular importance are the repair pathways, which respond to DNA double-strand breaks (DSBs), and how the efficiency of repair is influenced by sequence homology. In this study, we developed a genetic assay in diploid Saccharomyces cerevisiae cells to analyze DSBs requiring microhomologies for repair, known as microhomology-mediated end-joining (MMEJ). MMEJ repair efficiency increased concomitant with microhomology length and decreased upon introduction of mismatches. The central proteins in homologous recombination (HR), Rad52 and Rad51, suppressed MMEJ in this system, suggesting a competition between HR and MMEJ for the repair of a DSB. Importantly, we found that DNA polymerase delta (Pol δ) is critical for MMEJ, independent of microhomology length and base-pairing continuity. MMEJ recombinants showed evidence that Pol δ proofreading function is active during MMEJ-mediated DSB repair. Furthermore, mutations in Pol δ and DNA polymerase 4 (Pol λ), the DNA polymerase previously implicated in MMEJ, cause a synergistic decrease in MMEJ repair. Pol λ showed faster kinetics associating with MMEJ substrates following DSB induction than Pol δ. The association of Pol δ depended on RAD1, which encodes the flap endonuclease needed to cleave MMEJ intermediates before DNA synthesis. Moreover, Pol δ recruitment was diminished in cells lacking Pol λ. These data suggest cooperative involvement of both polymerases in MMEJ.DNA repair | genome stability | translocation D NA double-strand breaks (DSBs) are toxic lesions that can be repaired by two major pathways in eukaryotes: nonhomologous end-joining (NHEJ) and homologous recombination (HR) (1). Although HR repairs DSBs in a template-dependent, high-fidelity manner, NHEJ functions to ligate DSB ends together using no or very short (1-4 bp) homology. Recently, a new pathway was identified in eukaryotes, which uses microhomologies (MHs) to repair a DSB and does not require the central proteins used in HR (Rad51, Rad52) or NHEJ (Ku70-Ku80) (2-5). In mammalian cells, this pathway of repair is known as alternative end-joining (Alt-EJ) and is often but not always associated with MHs, whereas in budding yeast, the commensurate pathway, MH-mediated end-joining (MMEJ), will typically use 5-25 bp of MH (6, 7). These pathways are associated with genomic rearrangements, and cancer genomes show evidence of MH-mediated rearrangements (8-12). In addition, eukaryotic genomes contain many dispersed repetitive elements that can lead to genome rearrangements when recombination occurs between them (13-16). Therefore, controlling DSB repair in the human genome, which features a variety of repeats, is especially important given the fact that recombination between repetitive elements has been implicated in genomic instability associated with disease (17-20).The original characterization of Alt-EJ in mammalian cells suggested it did not rep...

show abstract

“…Indeed, the frequency of MMEJ is enhanced in yeast after removal of Rad51, suggesting a competition between the two repair pathways (Villarreal et al 2012;Deng et al 2014). Unlike SSA, Rad52 is not required for MMEJ.…”

Section: Alternative End-joining (Alt-ej)/mmejmentioning

confidence: 97%

“…Subsequent studies in S. cerevisiae identified the molecular machinery that drives MMEJ: (1) initiation of end resection by the MRX-Sae2; (2) if the microhomologous sequences are >2 kb away from the DSB ends, extensive bidirectional resection is performed by Sgs1-Dna2 and/or Exo1; (3) annealing of microhomologous sequences and removal of 3 ′ single-stranded flaps by Rad1-Rad10; (4) and filling of gaps by polymerases Pol λ (Pol 4) and Pol δ in conjunction with its nonessential subunit, Pol 32 (Ma et al 2003;Decottignies 2007;Garcia et al 2011;Symington and Gautier 2011;Villarreal et al 2012;Cannavo and Cejka 2014;Deng et al 2014;Meyer et al 2015). Rad51 filament formation is considered to be a critical feature in dictating GC versus MMEJ events.…”

Section: Alternative End-joining (Alt-ej)/mmejmentioning

confidence: 99%

Noncanonical views of homology-directed DNA repair

2016

View full text Add to dashboard Cite

DNA repair is essential to maintain genomic integrity and initiate genetic diversity. While gene conversion and classical nonhomologous end-joining are the most physiologically predominant forms of DNA repair mechanisms, emerging lines of evidence suggest the usage of several noncanonical homology-directed repair (HDR) pathways in both prokaryotes and eukaryotes in different contexts. Here we review how these alternative HDR pathways are executed, specifically focusing on the determinants that dictate competition between them and their relevance to cancers that display complex genomic rearrangements or maintain their telomeres by homology-directed DNA synthesis.

show abstract

RPA antagonizes microhomology-mediated repair of DNA double-strand breaks

Cited by 179 publications

References 64 publications

Nuclear position dictates DNA repair pathway choice

Nuclear position dictates DNA repair pathway choice

DNA polymerases δ and λ cooperate in repairing double-strand breaks by microhomology-mediated end-joining in Saccharomyces cerevisiae

Noncanonical views of homology-directed DNA repair

Contact Info

Product

Resources

About