scholarly journals hSSB1 interacts directly with the MRN complex stimulating its recruitment to DNA double-strand breaks and its endo-nuclease activity

2011 ◽  
Vol 39 (9) ◽  
pp. 3643-3651 ◽  
Author(s):  
Derek J. Richard ◽  
Liza Cubeddu ◽  
Aaron J. Urquhart ◽  
Amanda Bain ◽  
Emma Bolderson ◽  
...  
Keyword(s):  
Nuclease Activity ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Mrn Complex

scholarly journals Genetic Separation of Sae2 Nuclease Activity from Mre11 Nuclease Functions in Budding Yeast

2017 ◽  
Vol 37 (24) ◽  
Author(s):  
Sucheta Arora ◽  
Rajashree A. Deshpande ◽  
Martin Budd ◽  
Judy Campbell ◽  
America Revere ◽  
...  
Keyword(s):  
Nuclease Activity ◽  
Double Strand Breaks ◽  
Endonuclease Activity ◽  
Dna Double Strand Breaks ◽  
Dna Breaks ◽  
Content Type ◽  
Strand Breaks ◽  
Dna Ends

ABSTRACT Sae2 promotes the repair of DNA double-strand breaks in Saccharomyces cerevisiae. The role of Sae2 is linked to the Mre11/Rad50/Xrs2 (MRX) complex, which is important for the processing of DNA ends into single-stranded substrates for homologous recombination. Sae2 has intrinsic endonuclease activity, but the role of this activity has not been assessed independently from its functions in promoting Mre11 nuclease activity. Here we identify and characterize separation-of-function mutants that lack intrinsic nuclease activity or the ability to promote Mre11 endonucleolytic activity. We find that the ability of Sae2 to promote MRX nuclease functions is important for DNA damage survival, particularly in the absence of Dna2 nuclease activity. In contrast, Sae2 nuclease activity is essential for DNA repair when the Mre11 nuclease is compromised. Resection of DNA breaks is impaired when either Sae2 activity is blocked, suggesting roles for both Mre11 and Sae2 nuclease activities in promoting the processing of DNA ends in vivo. Finally, both activities of Sae2 are important for sporulation, indicating that the processing of meiotic breaks requires both Mre11 and Sae2 nuclease activities.

scholarly journals hSSB1 rapidly binds at the sites of DNA double-strand breaks and is required for the efficient recruitment of the MRN complex

2010 ◽  
Vol 39 (5) ◽  
pp. 1692-1702 ◽  
Author(s):  
Derek J. Richard ◽  
Kienan Savage ◽  
Emma Bolderson ◽  
Liza Cubeddu ◽  
Sairei So ◽  
...  
Keyword(s):  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Mrn Complex

scholarly journals A Survey of Reported Disease-Related Mutations in the MRE11-RAD50-NBS1 Complex

Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1678 ◽  
Author(s):  
Samiur Rahman ◽  
Marella D. Canny ◽  
Tanner A. Buschmann ◽  
Michael P. Latham
Keyword(s):  
Genomic Stability ◽  
Nijmegen Breakage Syndrome ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Response Factors ◽  
Strand Breaks ◽  
Mrn Complex ◽  
Damage Response ◽  
Biochemical Level

The MRE11-RAD50-NBS1 (MRN) protein complex is one of the primary vehicles for repairing DNA double strand breaks and maintaining the genomic stability within the cell. The role of the MRN complex to recognize and process DNA double-strand breaks as well as signal other damage response factors is critical for maintaining proper cellular function. Mutations in any one of the components of the MRN complex that effect function or expression of the repair machinery could be detrimental to the cell and may initiate and/or propagate disease. Here, we discuss, in a structural and biochemical context, mutations in each of the three MRN components that have been associated with diseases such as ataxia telangiectasia-like disorder (ATLD), Nijmegen breakage syndrome (NBS), NBS-like disorder (NBSLD) and certain types of cancers. Overall, deepening our understanding of disease-causing mutations of the MRN complex at the structural and biochemical level is foundational to the future aim of treating diseases associated with these aberrations.

scholarly journals Role of the Nuclease Activity ofSaccharomyces cerevisiaeMre11 in Repair of DNA Double-Strand Breaks in Mitotic Cells

Genetics ◽  
2004 ◽  
Vol 166 (4) ◽  
pp. 1701-1713 ◽  
Author(s):  
L Kevin Lewis ◽  
Francesca Storici ◽  
Stephen Van Komen ◽  
Shanna Calero ◽  
Patrick Sung ◽  
...  
Keyword(s):  
Nuclease Activity ◽  
Double Strand Breaks ◽  
Nonhomologous End Joining ◽  
Dna Double Strand Breaks ◽  
End Joining ◽  
Strand Breaks ◽  
Complex Functions ◽  
Mitotic Cells

AbstractThe Rad50:Mre11:Xrs2 (RMX) complex functions in repair of DNA double-strand breaks (DSBs) by recombination and nonhomologous end-joining (NHEJ) and is also required for telomere stability. The Mre11 subunit exhibits nuclease activities in vitro, but the role of these activities in repair in mitotic cells has not been established. In this study we have performed a comparative study of three mutants (mre11-D16A, -D56N, and -H125N) previously shown to have reduced nuclease activities in vitro. In ends-in and ends-out chromosome recombination assays using defined plasmid and oligonucleotide DNA substrates, mre11-D16A cells were as deficient as mre11 null strains, but defects were small in mre11-D56N and -H125N mutants. mre11-D16A cells, but not the other mutants, also displayed strong sensitivity to ionizing radiation, with residual resistance largely dependent on the presence of the partially redundant nuclease Exo1. mre11-D16A mutants were also most sensitive to the S-phase-dependent clastogens hydroxyurea and methyl methanesulfonate but, as previously observed for D56N and H125N mutants, were not defective in NHEJ. Importantly, the affinity of purified Mre11-D16A protein for Rad50 and Xrs2 was indistinguishable from wild type and the mutant protein formed complexes with equivalent stoichiometry. Although the role of the nuclease activity has been questioned in previous studies, the comparative data presented here suggest that the nuclease function of Mre11 is required for RMX-mediated recombinational repair and telomere stabilization in mitotic cells.

scholarly journals MRN complex function in the repair of chromosomal Rag-mediated DNA double-strand breaks

2009 ◽  
Vol 184 (4) ◽  
pp. i10-i10
Author(s):  
Beth A. Helmink ◽  
Andrea L. Bredemeyer ◽  
Baeck-Seung Lee ◽  
Ching-Yu Huang ◽  
Girdhar G. Sharma ◽  
...  
Keyword(s):  
Complex Function ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Mrn Complex

scholarly journals MRN complex function in the repair of chromosomal Rag-mediated DNA double-strand breaks

2009 ◽  
Vol 206 (3) ◽  
pp. 669-679 ◽  
Author(s):  
Beth A. Helmink ◽  
Andrea L. Bredemeyer ◽  
Baeck-Seung Lee ◽  
Ching-Yu Huang ◽  
Girdhar G. Sharma ◽  
...  
Keyword(s):  
Receptor Gene ◽  
Complex Function ◽  
Antigen Receptor ◽  
Double Strand Breaks ◽  
G1 Phase ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Mrn Complex ◽  
Dna Dsbs ◽  
Complex Functions

The Mre11–Rad50–Nbs1 (MRN) complex functions in the repair of DNA double-strand breaks (DSBs) by homologous recombination (HR) at postreplicative stages of the cell cycle. During HR, the MRN complex functions directly in the repair of DNA DSBs and in the initiation of DSB responses through activation of the ataxia telangiectasia-mutated (ATM) serine-threonine kinase. Whether MRN functions in DNA damage responses before DNA replication in G0/G1 phase cells has been less clear. In developing G1-phase lymphocytes, DNA DSBs are generated by the Rag endonuclease and repaired during the assembly of antigen receptor genes by the process of V(D)J recombination. Mice and humans deficient in MRN function exhibit lymphoid phenotypes that are suggestive of defects in V(D)J recombination. We show that during V(D)J recombination, MRN deficiency leads to the aberrant joining of Rag DSBs and to the accumulation of unrepaired coding ends, thus establishing a functional role for MRN in the repair of Rag-mediated DNA DSBs. Moreover, these defects in V(D)J recombination are remarkably similar to those observed in ATM-deficient lymphocytes, suggesting that ATM and MRN function in the same DNA DSB response pathways during lymphocyte antigen receptor gene assembly.

scholarly journals DNA damage signaling in response to double-strand breaks during mitosis

2010 ◽  
Vol 190 (2) ◽  
pp. 197-207 ◽  
Author(s):  
Simona Giunta ◽  
Rimma Belotserkovskaya ◽  
Stephen P. Jackson
Keyword(s):  
Dna Damage ◽  
Mitotic Cell ◽  
Double Strand Breaks ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Histone H2ax ◽  
Mrn Complex ◽  
Dna Damage Signaling ◽  
Dependent Protein ◽  
Mitotic Cells

The signaling cascade initiated in response to DNA double-strand breaks (DSBs) has been extensively investigated in interphase cells. Here, we show that mitotic cells treated with DSB-inducing agents activate a “primary” DNA damage response (DDR) comprised of early signaling events, including activation of the protein kinases ataxia telangiectasia mutated (ATM) and DNA-dependent protein kinase (DNA-PK), histone H2AX phosphorylation together with recruitment of mediator of DNA damage checkpoint 1 (MDC1), and the Mre11–Rad50–Nbs1 (MRN) complex to damage sites. However, mitotic cells display no detectable recruitment of the E3 ubiquitin ligases RNF8 and RNF168, or accumulation of 53BP1 and BRCA1, at DSB sites. Accordingly, we found that DNA-damage signaling is attenuated in mitotic cells, with full DDR activation only ensuing when a DSB-containing mitotic cell enters G1. Finally, we present data suggesting that induction of a primary DDR in mitosis is important because transient inactivation of ATM and DNA-PK renders mitotic cells hypersensitive to DSB-inducing agents.

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