Homologous recombination repair is regulated by domains at the N- and C-terminus of NBS1 and is dissociated with ATM functions

Sakamoto, Shuichi; Iijima, Kenta; Mochizuki, Daisuke; Nakamura, Kae; Teshigawara, Keisuke; Kobayashi, Junya; Matsuura, Shinya; Tauchi, Hiroshi; Komatsu, Kenshi

doi:10.1038/sj.onc.1210428

Cited by 60 publications

(63 citation statements)

References 27 publications

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“…It was previously shown that point mutations in the forkhead-associated domain and deletion of amino acids 682 to 693 on human NBS1, corresponding to the MRE11 binding domain, resulted in a failure to observe MRE11 focus formation following gamma irradiation (31). However, the deletion of amino acids 682 to 693 of human NBS1 resulted in an about threefold decrease in homologous recombination, although NBS1 foci were still formed.…”

Section: Discussionmentioning

confidence: 99%

A Glycine-Arginine Domain in Control of the Human MRE11 DNA Repair Protein

Déry

Coulombe

Rodrigue

et al. 2008

Molecular and Cellular Biology

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Human MRE11 is a key enzyme in DNA double-strand break repair and genome stability. Human MRE11 bears a glycine-arginine-rich (GAR) motif that is conserved among multicellular eukaryotic species. We investigated how this motif influences MRE11 function. Human MRE11 alone or a complex of MRE11, RAD50, and NBS1 (MRN) was methylated in insect cells, suggesting that this modification is conserved during evolution. We demonstrate that PRMT1 interacts with MRE11 but not with the MRN complex, suggesting that MRE11 arginine methylation occurs prior to the binding of NBS1 and RAD50. Moreover, the first six methylated arginines are essential for the regulation of MRE11 DNA binding and nuclease activity. The inhibition of arginine methylation leads to a reduction in MRE11 and RAD51 focus formation on a unique double-strand break in vivo. Furthermore, the MRE11-methylated GAR domain is sufficient for its targeting to DNA damage foci and colocalization with ␥-H2AX. These studies highlight an important role for the GAR domain in regulating MRE11 function at the biochemical and cellular levels during DNA double-strand break repair.Genome stability relies on the accurate repair of doublestrand breaks (DSBs) that arise naturally during DNA replication or from treatment with exogenous DNA-damaging agents. DSBs in human cells may be repaired by nonhomologous end joining or homologous recombination. The MRE11-RAD50-NBS1 (MRN) complex has essential functions in numerous facets of genome stability. During the cell cycle, MRN is associated to chromatin, which is consistent with a role in the surveillance of genome integrity. Chromatin association is not increased following ionizing radiation (41). However, a redistribution of the MRN complex from the chromatin to sites of DNA damage occurs. When cells are challenged with ionizing radiation, ataxia-telangiectasia mutated protein (ATM) phosphorylates histone H2AX (30), a key event in this process. The phosphorylation of H2AX is thought to recruit MRN directly to DSBs, since NBS1 interacts directly with phosphorylated H2AX (17). MDC1 is also a key molecular linker responsible for bridging NBS1 with phosphoepitopes generated in DSBflanking chromatin, as MRN components do not form foci in the absence of MDC1 (22). MRN is a central player during checkpoint signaling of DNA damage. MRN stimulates ATM kinase activity on p53, CHK2, and H2AX (19). ATM phosphorylates NBS1 on serine 343, which is necessary for the proper S-phase checkpoint following ionizing radiation (21). Consistent with key functions in DNA damage signaling and repair, ataxia-telangiectasia-like disorder (34) and Nijmegen breakage syndrome (40), which are caused by mutations in MRE11 and NBS1, respectively, are characterized by an increased sensitivity to ionizing radiation, checkpoint problems, and the accumulation of DSBs and aberrant chromosomes, leading to cancer.DNA repair functions of the MRN complex involve the processing of DNA ends during homologous recombination, nonhomologous end joining, and maintenance of telomere...

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Section: Discussionmentioning

confidence: 99%

A Glycine-Arginine Domain in Control of the Human MRE11 DNA Repair Protein

Déry

Coulombe

Rodrigue

et al. 2008

Molecular and Cellular Biology

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“…Consistent with this, MRE11/RAD50/NBS1 is localized with PCNA at replication forks 58 and is essential for homologous recombination. 42,59 DSBs induced by irradiation occur outside of active replicons, and the speed at which NBS1 moves throughout the entire nucleus is also compatible with damaged regions being recognized on the principle of rapid diffusion and collision. 60 In a second step, the ATM kinase is activated.…”

Section: Model For the Nbs1 Dependent Dna Damage Responsementioning

confidence: 90%

“…40,41 Loss of the NBS1 FHA domain reduced the interaction between mutant NBS1 and MDC1 as well as the stable interaction between NBS1 and g-H2AX modified chromatin. 40 Although the NBS1 N-terminal region has been reported to be essential for functions including cell survival in response to IR, optimal ATM activation, for the intra-S phase checkpoint and efficient homologous recombination, 11,14,17,34,42 the direct phospho-interaction partner of the NBS1 FHA-BRCT domain remains unclear.…”

Section: Functional Domains Of Nbs1mentioning

confidence: 99%

The NBS1-ATM Connection Revisited

Difilippantonio

Nussenzweig²

2007

Cell Cycle

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Nijmegen Breakage syndrome (NBS) is a rare autosomal recessive disorder characterized by microcephaly, immunodeficiency, and increased predisposition to the development of malignancy. 1,2 Due to the overlap of clinical and cellular features of patients with ataxia telangiectasia (AT), NBS was described as an AT variant syndrome until the underlying gene product mutation was identified. 3-5 Cells from both AT and NBS patients show increased sensitivity to ionizing radiation (IR), genomic instability and cell cycle checkpoint defects following DNA damage, 6,7 suggesting that both gene products participate in the same DNA damage response pathway. Here we highlight recent developments and refinements in our understanding of the interplay between NBS1 and ATM in vivo.

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“…Mouse models recapitulate many of the phenotypes seen in patients with ATM mutations, including tumor predisposition, radiosensitivity, and gonadal dysgenesis (30,33,34). Although some studies using transformed cell lines have reported that ATM is not required for HDR (44), others have suggested that ATM plays a critical role (45,46). ATM has been reported to be necessary for DSB resection to generate Replication protein A (RPA)-coated ssDNA (29), an essential early intermediate in HDR.…”

Section: Discussionmentioning

confidence: 99%

Double-strand break repair by homologous recombination in primary mouse somatic cells requires BRCA1 but not the ATM kinase

Kass¹,

Helgadottir

Chen

et al. 2013

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

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Homology-directed repair (HDR) is a critical pathway for the repair of DNA double-strand breaks (DSBs) in mammalian cells. Efficient HDR is thought to be crucial for maintenance of genomic integrity during organismal development and tumor suppression. However, most mammalian HDR studies have focused on transformed and immortalized cell lines. We report here the generation of a Direct Repeat (DR)-GFP reporter-based mouse model to study HDR in primary cell types derived from diverse lineages. Embryonic and adult fibroblasts from these mice as well as cells derived from mammary epithelium, ovary, and neonatal brain were observed to undergo HDR at I-SceI endonuclease-induced DSBs at similar frequencies. When the DR-GFP reporter was crossed into mice carrying a hypomorphic mutation in the breast cancer susceptibility gene Brca1, a significant reduction in HDR was detected, showing that BRCA1 is critical for HDR in somatic cell types. Consistent with an HDR defect, Brca1 mutant mice are highly sensitive to the cross-linking agent mitomycin C. By contrast, loss of the DSB signaling ataxia telangiectasia-mutated (ATM) kinase did not significantly alter HDR levels, indicating that ATM is dispensable for HDR. Notably, chemical inhibition of ATM interfered with HDR. The DR-GFP mouse provides a powerful tool for dissecting the genetic requirements of HDR in a diverse array of somatic cell types in a normal, nontransformed cellular milieu.

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Homologous recombination repair is regulated by domains at the N- and C-terminus of NBS1 and is dissociated with ATM functions

Cited by 60 publications

References 27 publications

A Glycine-Arginine Domain in Control of the Human MRE11 DNA Repair Protein

A Glycine-Arginine Domain in Control of the Human MRE11 DNA Repair Protein

The NBS1-ATM Connection Revisited

Double-strand break repair by homologous recombination in primary mouse somatic cells requires BRCA1 but not the ATM kinase

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