In: The EMBO Journal, 2019, vol. 38, no. 7, p. e101005
DNA end resection initiates DNA break repair by homologous recombination. MRE11-RAD50-NBS1 and phosphorylated CtIP perform the first resection step by MRE11-catalyzed endonucleolytic DNA cleavage. Human NBS1, more than its Xrs2 homologue from Saccharomyces cerevisiae, is crucial for this process, highlighting complex mechanisms that regulate the MRE11 nuclease in high eukaryotes. Using a...
|
In: Nature communications, 2018, vol. 9, p. 4016
DNA end resection plays a critical function in DNA double-strand break repair pathway choice. Resected DNA ends are refractory to end-joining mechanisms and are instead channeled to homology-directed repair. Using biochemical, genetic, and imaging methods, we show that phosphorylation of Saccharomyces cerevisiae Sae2 controls its capacity to promote the Mre11-Rad50-Xrs2 (MRX) nuclease to...
|
In: Proceedings of the national academy of sciences of the United States of America, 2019, vol. 116, no. 12 (March 19), p. 5505-5513
To repair DNA double-strand breaks by homologous recombination, the 5′-terminated DNA strands must first be resected to produce 3′ overhangs. Mre11 from Saccharomyces cerevisiae is a 3′ → 5′ exonuclease that is responsible for 5′ end degradation in vivo. Using plasmid-length DNA substrates and purified recombinant proteins, we show that the combined exonuclease and endonuclease...
|
In: Cell reports, 2017, vol. 20, no. 8, p. 1921-1935
DNA double-strand break (DSB) repair by homologous recombination (HR) is initiated by CtIP/MRN-mediated DNA end resection to maintain genome integrity. SAMHD1 is a dNTP triphosphohydrolase, which restricts HIV- 1 infection, and mutations are associated with Aicardi-Goutières syndrome and cancer. We show that SAMHD1 has a dNTPase-independent function in promoting DNA end resection to facilitate...
|
In: Cell reports, 2017, vol. 18, no. 2, p. 496-507
The Mre11 complex (Mre11, Rad50, and Nbs1) is integral to both DNA repair and ataxia telangiectasia mutated (ATM)-dependent DNA damage signaling. All three Mre11 complex components are essential for viability at the cellular and organismal levels. To delineate essential and non-essential Mre11 complex functions that are mediated by Nbs1, we used TALEN-based genome editing to derive Nbs1...
|
In: Genes and Development, 2017, vol. 31, no. 5, p. 493-502
DNA2 nuclease–helicase functions in DNA replication and recombination. This requires the nuclease of DNA2, while, in contrast, the role of the helicase activity has been unclear. We now show that the motor activity of both recombinant yeast and human DNA2 promotes efficient degradation of long stretches of ssDNA, particularly in the presence of the replication protein A. This degradation is...
|
In: Genes and development, 2018, vol. 32, no. 3-4, p. 283-296
Meiotic crossover formation requires the stabilization of early recombination intermediates by a set of proteins and occurs within the environment of the chromosome axis, a structure important for the regulation of meiotic recombination events. The molecular mechanisms underlying and connecting crossover recombination and axis localization are elusive. Here, we identified the ZZS...
|
In: Communications Biology, 2019, vol. 2, p. 174
Dna2 is an essential nuclease-helicase that acts in several distinct DNA metabolic pathways including DNA replication and recombination. To balance these functions and prevent unscheduled DNA degradation, Dna2 activities must be regulated. Here we show that Saccharomyces cerevisiae Dna2 function is controlled by sumoylation. We map the sumoylation sites to the N-terminal regulatory domain of...
|
In: Chromosoma, 2018, vol. 127, no. 2 (June), p. 187–214
DNA double-strand breaks arise accidentally upon exposure of DNA to radiation, chemicals or result from faulty DNA metabolic processes. DNA breaks can also be introduced in a programmed manner, such as during the maturation of the immune system, meiosis or cancer chemo- or radiotherapy. Cells have developed a variety of repair pathways, which are fine-tuned to the specific needs of a cell....
|
In: Genes and Development, 2017, vol. 31, no. 23-24, p. 2325-2330
DNA double-strand break repair by homologous recombination is initiated by DNA end resection, which is commenced by the Mre11–Rad50–Xrs2 complex and Sae2 in yeast. Here we report that the nonhomologous end joining factor Ku limits the exonuclease activity of Mre11 and promotes its endonuclease to cleave 5'-terminated DNA strands at break sites. Following initial endonucleolytic cleavage...
|
