MRN complex-dependent recruitment of ubiquitylated BLM helicase to DSBs negatively regulates DNA repair pathways

Tripathi, Vivek; Agarwal, Himanshi; Priya, Swati; Batra, Harish; Modi, Priyanka; Pandey, Monica; Saha, Dhurjhoti; Raghavan, Sathees C.; Sengupta, Sagar

doi:10.1038/s41467-018-03393-8

Cited by 59 publications

(54 citation statements)

References 46 publications

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“…Importantly, SCR7-pyrazine also inhibited the joining of different 5 0 -5 0 noncompatible ends, which requires processing of DNA breaks prior to ligation, and is dependent on classical NHEJ proteins [29,31]. This was also consistent with the observed inhibition of NHEJ by SCR7 [17][18][19][46][47][48]. Besides, similar to SCR7-cyclized, SCR7-pyrazine also showed specific inhibition of joining catalyzed by Ligase IV and their effect on Ligase III, Ligase I, and T4 DNA ligase-mediated joining was minimal in vitro.…”

Section: Scr7-cyclized and Scr7-pyrazine Inhibit Nhej In A Ligase Iv-supporting

confidence: 77%

Autocyclized and oxidized forms ofSCR7 induce cancer cell death by inhibiting nonhomologousDNAend joining in a LigaseIVdependent manner

et al. 2018

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Nonhomologous DNA end joining (NHEJ) is the major DNA double-strand break (DSB) repair pathway in mammals. Previously, we have described a small molecule inhibitor, SCR7, which can inhibit NHEJ in a Ligase IV-dependent manner. Administration of SCR7 within the cells resulted in the accumulation of DNA breaks, cell death, and inhibition of tumor growth in mice. In the present study, we report that parental SCR7, which is unstable, can be autocyclized into a stable form. Both parental SCR7 and cyclized SCR7 possess the same molecular weight (334.09) and molecular formula (C H N OS), whereas its oxidized form, SCR7-pyrazine, possesses a different molecular formula (C H N OS), molecular weight (332.07), and structure. While cyclized form of SCR7 showed robust inhibition of NHEJ in vitro, both forms exhibited efficient cytotoxicity. Cyclized and oxidized forms of SCR7 inhibited DNA end joining catalyzed by Ligase IV, whereas their impact was minimal on Ligase III, Ligase I, and T4 DNA Ligase-mediated joining. Importantly, both forms inhibited V(D)J recombination, although the effect was more pronounced for SCR7-cyclized. Both forms blocked NHEJ in a Ligase IV-dependent manner leading to the accumulation of DSBs within the cells. Although cytotoxicity due to SCR7-cyclized was Ligase IV specific, the pyrazine form exhibited nonspecific cytotoxicity at higher concentrations in Ligase IV-null cells. Finally, we demonstrate that both forms can potentiate the effect of radiation. Thus, we report that cyclized and oxidized forms of SCR7 can inhibit NHEJ in a Ligase IV-dependent manner, although SCR7-pyrazine is less specific to Ligase IV inside the cell.

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Section: Scr7-cyclized and Scr7-pyrazine Inhibit Nhej In A Ligase Iv-supporting

confidence: 77%

Autocyclized and oxidized forms ofSCR7 induce cancer cell death by inhibiting nonhomologousDNAend joining in a LigaseIVdependent manner

et al. 2018

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“…Thus, PARP initiates the cascade of dynamic recruitment of factors, some of which compete with each other, to fine-tune repair pathway choice. Interestingly, a recent study showed that BLM is also recruited to damage sites in a biphasic fashion, initially by the ATM signaling, and subsequently by the MRE11 complex (Tripathi, et al, 2018), suggests that this type of two-step mechanism may be commonly used to ensure versatility and specificity of the factor recruitment.…”

Section: Trf2 Facilitates Intra-chromosomal Hr Repairmentioning

confidence: 99%

Biphasic recruitment of TRF2 to DNA damage sites promotes non-sister chromatid homologous recombination repair

Kong

Cruz

Trinh

et al. 2018

Preprint

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Summary StatementTRF2 is recruited to damage sites by a two-step mechanism and functions in non-sister chromatid homologous recombination repair Abstract TRF2 is a shelterin component critical for telomere integrity. While TRF2 directly recognizes and binds telomeric repeats, evidence suggests that it also localizes to nontelomeric DNA damage sites. However, this recruitment appears to be precarious and functionally controversial. We find that TRF2 recruitment to damage sites occurs by a two-step mechanism: the initial rapid recruitment (phase I) and stable and prolonged association with damage sites (phase II). Phase I is poly(ADP-ribose) polymerase (PARP)-dependent and requires positively charged amino acid residues in the Nterminal domain. The phase II recruitment is through the C-terminal MYB/SANT domain and requires the iDDR region in the hinge domain of TRF2. Phase II is mediated by the MRE11 complex and is stimulated by hTERT. PARP-dependent recruitment of intrinsically disordered proteins contributes to transient displacement of TRF2 that separates phases I and II. TRF2 depletion specifically affects non-sister chromatid homologous recombination (HR) repair, but not HR between sister chromatids or classic and alternative non-homologous endjoining. Our results demonstrate a unique recruitment mechanism and function of TRF2 at non-telomeric DNA damage sites.All rights reserved. No reuse allowed without permission.(which was not peer-reviewed) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity.

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“…The recognition of DSBs by the MRN complex (MRE11, RAD50, and NBS1) results in activation of ATM kinase and triggers its autophosphorylation (30). The activated ATM subsequently catalyzes the phosphorylation of a subset of downstream substrates to initiate an early DSB repair response (31, 32). To measure the activation of DDR directly, we analyzed key DDR proteins by Western blot and found that the expression levels of MRE11, RAD50, and NBS1 were strongly increased by RMI1 knockdown in CPT‐treated HeLa cells ( Fig .…”

Section: Resultsmentioning

confidence: 99%

“…The data represented are the mean of 3 independent experiments 6 SEM. *P , 0.05, **P , 0.01. subset of downstream substrates to initiate an early DSB repair response (31,32). To measure the activation of DDR directly, we analyzed key DDR proteins by Western blot and found that the expression levels of MRE11, RAD50, and NBS1 were strongly increased by RMI1 knockdown in CPT-treated HeLa cells (Fig.…”

Section: Rmi1 Depletion Activates the Ddr And Causes A Greater G2/m Dmentioning

confidence: 99%

RMI1 contributes to DNA repair and to the tolerance to camptothecin

et al. 2019

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Maintenance of genome integrity is critical for faithful propagation of genetic information and the prevention of the mutagenesis induced by various DNA damage events. RecQ‐mediated genome instability protein 1 (RMI1), together with Bloom syndrome protein and topoisomerase IIIα, form an evolutionarily conserved complex that is critical for the maintenance of genomic stability. Herein, we report that RMI1 depletion increases cell sensitivity to camptothecin treatment, as shown by an elevation of genotoxic stress‐induced DNA double‐strand breaks, a stronger activation of the DNA damage response, and a greater G2/M cell cycle delay. Our findings support that, upon DNA damage, RMI1 forms nuclear foci at the damaged regions, interacts with RAD51, and facilitates the recruitment of RAD51 to initiate homologous recombination. Our data reveal the importance of RMI1 in response to DNA double‐strand breaks and shed light on the molecular mechanisms by which RMI1 contributes to maintain genome stability.—Fang, L., Sun, X., Wang, Y., Du, L., Ji, K., Wang, J., He, N., Liu, Y., Wang, Q., Zhai, H., Hao, J., Xu, C., Liu, Q. RMI1 contributes to DNA repair and to the tolerance to camptothecin. FASEB J. 33, 5561–5570 (2019). http://www.fasebj.org

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MRN complex-dependent recruitment of ubiquitylated BLM helicase to DSBs negatively regulates DNA repair pathways

Cited by 59 publications

References 46 publications

Autocyclized and oxidized forms ofSCR7 induce cancer cell death by inhibiting nonhomologousDNAend joining in a LigaseIVdependent manner

Autocyclized and oxidized forms ofSCR7 induce cancer cell death by inhibiting nonhomologousDNAend joining in a LigaseIVdependent manner

Biphasic recruitment of TRF2 to DNA damage sites promotes non-sister chromatid homologous recombination repair

RMI1 contributes to DNA repair and to the tolerance to camptothecin

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