Equal Sister Chromatid Exchange Is a Major Mechanism of Double-Strand Break Repair in Yeast

González-Barrera, Sergio; Cortés‐Ledesma, Felipe; Wellinger, Ralf Erik; Aguilera, Andrés

doi:10.1016/s1097-2765(03)00183-7

Cited by 97 publications

(173 citation statements)

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“…With respect its role in HDR, genetic and physical evidence suggests that the primary function of the Mre11 complex is to promote HDR between sister chromatids via the hook and coiled-coil domains of Rad50 (Bressan et al 1999;Hartsuiker et al 2001;Gonzalez-Barrera et al 2003;Wiltzius et al 2005;Hohl et al 2011). Mre11 complex-mediated NHEJ appears to be primarily dependent on DNA-binding sites in the globular domain (Williams et al 2008(Williams et al , 2009), although we showed that the hook and coiled-coil domains also influence this process, presumably via long-range effects on the disposition of globular domain components (Hohl et al 2011).…”

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confidence: 99%

The Rad50 hook domain regulates DNA damage signaling and tumorigenesis

et al. 2014

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The Mre11 complex (Mre11, Rad50, and Nbs1) is a central component of the DNA damage response (DDR), governing both double-strand break repair and DDR signaling. Rad50 contains a highly conserved Zn 2+ -dependent homodimerization interface, the Rad50 hook domain. Mutations that inactivate the hook domain produce a null phenotype. In this study, we analyzed mutants with reduced hook domain function in an effort to stratify hookdependent Mre11 complex functions. One of these alleles, Rad50 46 , conferred reduced Zn 2+ affinity and dimerization efficiency. Homozygous Rad50 46/46 mutations were lethal in mice. However, in the presence of wildtype Rad50, Rad50 46 exerted a dominant gain-of-function phenotype associated with chronic DDR signaling. At the organismal level, Rad50 +/46 exhibited hydrocephalus, liver tumorigenesis, and defects in primitive hematopoietic and gametogenic cells. These outcomes were dependent on ATM, as all phenotypes were mitigated in Rad50 +/46 Atm +/-mice. These data reveal that the murine Rad50 hook domain strongly influences Mre11 complex-dependent DDR signaling, tissue homeostasis, and tumorigenesis.

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confidence: 99%

The Rad50 hook domain regulates DNA damage signaling and tumorigenesis

et al. 2014

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“…for chromosomal exchanges, it is thought that BLM helicase functions in regulating HR (7)(8)(9). Also, BLM helicase is required for faithful chromosome segregation (10) and repair of stalled replication forks (11,12), the processes that are linked to HR (13)(14)(15).…”

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confidence: 99%

Bloom Syndrome Helicase Stimulates RAD51 DNA Strand Exchange Activity through a Novel Mechanism

Bugreev

Mazina

Mazin

2009

Journal of Biological Chemistry

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Loss or inactivation of BLM, a helicase of the RecQ family, causes Bloom syndrome, a genetic disorder with a strong predisposition to cancer. Although the precise function of BLM remains unknown, genetic data has implicated BLM in the process of genetic recombination and DNA repair. Previously, we demonstrated that BLM can disrupt the RAD51-singlestranded DNA filament that promotes the initial steps of homologous recombination. However, this disruption occurs only if RAD51 is present in an inactive ADP-bound form. Here, we investigate interactions of BLM with the active ATP-bound form of the RAD51-single-stranded DNA filament. Surprisingly, we found that BLM stimulates DNA strand exchange activity of RAD51. In contrast to the helicase activity of BLM, this stimulation does not require ATP hydrolysis. These data suggest a novel BLM function that is stimulation of the RAD51 DNA pairing. Our results demonstrate the important role of the RAD51 nucleoprotein filament conformation in stimulation of DNA pairing by BLM.Mutations of BLM helicase cause Bloom syndrome (BS), 2 a rare autosomal disorder, which is associated with stunted growth, facial sun sensitivity, immunodeficiency, fertility defects, and a greatly elevated incidence of many types of cancer occurring at an early age (1). BLM belongs to the highly conserved family of RecQ helicases that are required for the maintenance of genome integrity in all organisms (2, 3). There are five RecQ helicases in humans; mutations in three of them, WRN, RECQ4, and BLM, have been associated with the genetic abnormalities known as Werner, Rothmund-Thomson, and Bloom syndrome, respectively (4, 5). The cells from BS patients display genomic instability; the hallmark of BS is an increase in the frequency of sister chromatid and interhomolog exchanges (1, 6). Because homologous recombination (HR) is responsible for chromosomal exchanges, it is thought that BLM helicase functions in regulating HR (7-9). Also, BLM helicase is required for faithful chromosome segregation (10) and repair of stalled replication forks (11, 12), the processes that are linked to HR (13-15). BLM was found to interact physically with RAD51, a key protein of HR (16) that catalyzes the central steps in HR including the search for homology and the exchange of strands between homologous ssDNA and dsDNA sequences (17). In cells, BLM forms nuclear foci, a subset of which co-localize with RAD51. Interestingly, the extent of RAD51 and BLM co-localization increases in response to ionizing radiation, indicating a possible role of BLM in the repair of DNA double-strand breaks (16).Biochemical studies suggest that BLM may perform several different functions in HR. BLM was shown to promote the dissociation of HR intermediates (D-loops) (18 -20), branch migration of Holliday junctions (21), and dissolution of double Holliday junctions acting in a complex with . BLM may also facilitate DNA synthesis during the repair process by unwinding the DNA template in front of the replication fork (25). In addition, BLM and its yea...

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“…This observation suggests that, in contrast to the presumed predominant intrachromatid repair in Arabidopsis (Orel et al, 2003) and in tobacco (Siebert and Puchta, 2002), barley uses the sister chromatid in the majority of cases for repair of staggered DSBs, apparently independent of whether immediate ligation, SDSA, NHEJ, or MMHJ is followed to seal the break. A few hints that SCE could be a major pathway of DSB repair came from the observation of increased SCE frequency after treatment of mammalian cells with restriction endonucleases (Natarajan et al, 1985) and from Rad51 (recombinase)-dependent equal SCE in broken centric monoplasmids of yeast (González-Barrera et al, 2003). In contrast, in cultivated Chinese hamster cells, "the sister chromatid acts as a repair template in a substantial proportion of DSB repair events," but "the outcome.is primarily gene conversion unassociated with reciprocal exchange" (Johnson and Jasin, 2000).…”

Section: Discussionmentioning

confidence: 99%

Repair of Site-Specific DNA Double-Strand Breaks in Barley Occurs via Diverse Pathways Primarily Involving the Sister Chromatid

Cao

Watanabe

et al. 2014

Plant Cell

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ORCID IDs: 0000-0001-7080-7983 (J.K.); 0000-0002-6300-2068 (I.S.)DNA double-strand break (DSB) repair mechanisms differ in their requirements for a homologous repair template and in the accuracy of the result. We aimed to quantify the outcome of repair of a single targeted DSB in somatic cells of young barley (Hordeum vulgare) plants. Amplicon sequencing of three reporter constructs revealed 47 to 58% of reads as repaired via nonhomologous end-joining (NHEJ) with deletions and/or small (1 to 3 bp) insertions. Alternative NHEJ revealed 2 to 5 bp microhomology (15.7% of cases) or new replication-mediated short duplications at sealed breaks. Although deletions outweigh insertions in barley, this bias was less pronounced and deleted sequences were shorter than in Arabidopsis thaliana. Between 17 and 33% of reads likely represent restoration of the original sequence. Depending on the construct, 20 to 33% of reads arose via gene conversion (homologous recombination). Remarkably, <1 to >8% of reads apparently display synthesis-dependent strand annealing linked with NHEJ, inserting 4 to 61 bp, mostly originating from the surrounding of breakpoints. Positional coincidence of >81% of sister chromatid exchanges with target loci is unprecedented for higher eukaryotes and indicates that most repair events for staggered DSBs, at least in barley, involve the sister chromatid and occur during S or G2 phase of the cell cycle.

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Equal Sister Chromatid Exchange Is a Major Mechanism of Double-Strand Break Repair in Yeast

Cited by 97 publications

References 49 publications

The Rad50 hook domain regulates DNA damage signaling and tumorigenesis

The Rad50 hook domain regulates DNA damage signaling and tumorigenesis

Bloom Syndrome Helicase Stimulates RAD51 DNA Strand Exchange Activity through a Novel Mechanism

Repair of Site-Specific DNA Double-Strand Breaks in Barley Occurs via Diverse Pathways Primarily Involving the Sister Chromatid

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