Browse
Submit Data
Databases
API
Help

Dataset Information

29 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

NF-κB regulates DNA double-strand break repair in conjunction with BRCA1-CtIP complexes.

ABSTRACT: NF-κB is involved in immune responses, inflammation, oncogenesis, cell proliferation and apoptosis. Even though NF-κB can be activated by DNA damage via Ataxia telangiectasia-mutated (ATM) signalling, little was known about an involvement in DNA repair. In this work, we dissected distinct DNA double-strand break (DSB) repair mechanisms revealing a stimulatory role of NF-κB in homologous recombination (HR). This effect was independent of chromatin context, cell cycle distribution or cross-talk with p53. It was not mediated by the transcriptional NF-κB targets Bcl2, BAX or Ku70, known for their dual roles in apoptosis and DSB repair. A contribution by Bcl-xL was abrogated when caspases were inhibited. Notably, HR induction by NF-κB required the targets ATM and BRCA2. Additionally, we provide evidence that NF-κB interacts with CtIP-BRCA1 complexes and promotes BRCA1 stabilization, and thereby contributes to HR induction. Immunofluorescence analysis revealed accelerated formation of replication protein A (RPA) and Rad51 foci upon NF-κB activation indicating HR stimulation through DSB resection by the interacting CtIP-BRCA1 complex and Rad51 filament formation. Taken together, these results define multiple NF-κB-dependent mechanisms regulating HR induction, and thereby providing a novel intriguing explanation for both NF-κB-mediated resistance to chemo- and radiotherapies as well as for the sensitization by pharmaceutical intervention of NF-κB activation.

SUBMITTER: Volcic M

PROVIDER: S-EPMC3245919 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

CtIP-BRCA1 modulates the choice of DNA double-strand-break repair pathway throughout the cell cycle.

Project description:The repair of DNA double-strand breaks (DSBs) is tightly regulated during the cell cycle. In G1 phase, the absence of a sister chromatid means that repair of DSBs occurs through non-homologous end-joining or microhomology-mediated end-joining (MMEJ). These pathways often involve loss of DNA sequences at the break site and are therefore error-prone. In late S and G2 phases, even though DNA end-joining pathways remain functional, there is an increase in repair of DSBs by homologous recombination, which is mostly error-free. Consequently, the relative contribution of these different pathways to DSB repair in the cell cycle has a large influence on the maintenance of genetic integrity. It has remained unknown how DSBs are directed for repair by different, potentially competing, repair pathways. Here we identify a role for CtIP (also known as RBBP8) in this process in the avian B-cell line DT40. We establish that CtIP is required not only for repair of DSBs by homologous recombination in S/G2 phase but also for MMEJ in G1. The function of CtIP in homologous recombination, but not MMEJ, is dependent on the phosphorylation of serine residue 327 and recruitment of BRCA1. Cells expressing CtIP protein that cannot be phosphorylated at serine 327 are specifically defective in homologous recombination and have a decreased level of single-stranded DNA after DNA damage, whereas MMEJ remains unaffected. Our data support a model in which phosphorylation of serine 327 of CtIP as cells enter S phase and the recruitment of BRCA1 functions as a molecular switch to shift the balance of DSB repair from error-prone DNA end-joining to error-free homologous recombination.

| S-EPMC2857324 | biostudies-literature

Mre11 regulates CtIP-dependent double-strand break repair by interaction with CDK2.

Project description:Homologous recombination facilitates accurate repair of DNA double-strand breaks (DSBs) during the S and G2 phases of the cell cycle by using intact sister chromatids as sequence templates. Homologous recombination capacity is maximized in S and G2 by cyclin-dependent kinase (CDK) phosphorylation of CtIP, which subsequently interacts with BRCA1 and the Mre11-Rad50-NBS1 (MRN) complex. Here we show that, in human and mouse, Mre11 controls these events through a direct interaction with CDK2 that is required for CtIP phosphorylation and BRCA1 interaction in normally dividing cells. CDK2 binds the C terminus of Mre11, which is absent in an inherited allele causing ataxia telangiectasia-like disorder. This newly uncovered role for Mre11 does not require ATM activation or nuclease activities. Therefore, functions of MRN are not restricted to DNA damage responses but include regulating homologous recombination capacity during the normal mammalian cell cycle.

| S-EPMC3272152 | biostudies-literature

Collaborative action of Brca1 and CtIP in elimination of covalent modifications from double-strand breaks to facilitate subsequent break repair.

Project description:Topoisomerase inhibitors such as camptothecin and etoposide are used as anti-cancer drugs and induce double-strand breaks (DSBs) in genomic DNA in cycling cells. These DSBs are often covalently bound with polypeptides at the 3' and 5' ends. Such modifications must be eliminated before DSB repair can take place, but it remains elusive which nucleases are involved in this process. Previous studies show that CtIP plays a critical role in the generation of 3' single-strand overhang at "clean" DSBs, thus initiating homologous recombination (HR)-dependent DSB repair. To analyze the function of CtIP in detail, we conditionally disrupted the CtIP gene in the chicken DT40 cell line. We found that CtIP is essential for cellular proliferation as well as for the formation of 3' single-strand overhang, similar to what is observed in DT40 cells deficient in the Mre11/Rad50/Nbs1 complex. We also generated DT40 cell line harboring CtIP with an alanine substitution at residue Ser332, which is required for interaction with BRCA1. Although the resulting CtIP(S332A/-/-) cells exhibited accumulation of RPA and Rad51 upon DNA damage, and were proficient in HR, they showed a marked hypersensitivity to camptothecin and etoposide in comparison with CtIP(+/-/-) cells. Finally, CtIP(S332A/-/-)BRCA1(-/-) and CtIP(+/-/-)BRCA1(-/-) showed similar sensitivities to these reagents. Taken together, our data indicate that, in addition to its function in HR, CtIP plays a role in cellular tolerance to topoisomerase inhibitors. We propose that the BRCA1-CtIP complex plays a role in the nuclease-mediated elimination of oligonucleotides covalently bound to polypeptides from DSBs, thereby facilitating subsequent DSB repair.

| S-EPMC2809774 | biostudies-literature

Chk2 phosphorylation of BRCA1 regulates DNA double-strand break repair.

Project description:The pathway determining malignant cellular transformation, which depends upon mutation of the BRCA1 tumor suppressor gene, is poorly defined. A growing body of evidence suggests that promotion of DNA double-strand break repair by homologous recombination (HR) may be the means by which BRCA1 maintains genomic stability, while a role of BRCA1 in error-prone nonhomologous recombination (NHR) processes has just begun to be elucidated. The BRCA1 protein becomes phosphorylated in response to DNA damage, but the effects of phosphorylation on recombinational repair are unknown. In this study, we tested the hypothesis that the BRCA1-mediated regulation of recombination requires the Chk2- and ATM-dependent phosphorylation sites. We studied Rad51-dependent HR and random chromosomal integration of linearized plasmid DNA, a subtype of NHR, which we demonstrate to be dependent on the Mre11-Rad50-Nbs1 complex. Prevention of Chk2-mediated phosphorylation via mutation of the serine 988 residue of BRCA1 disrupted both the BRCA1-dependent promotion of HR and the suppression of NHR. Similar results were obtained when endogenous Chk2 kinase activity was inhibited by expression of a dominant-negative Chk2 mutant. Surprisingly, the opposing regulation of HR and NHR did not require the ATM phosphorylation sites on serines 1423 and 1524. Together, these data suggest a functional link between recombination control and breast cancer predisposition in carriers of Chk2 and BRCA1 germ line mutations. We propose a dual regulatory role for BRCA1 in maintaining genome integrity, whereby BRCA1 phosphorylation status controls the selectivity of repair events dictated by HR and error-prone NHR.

| S-EPMC343805 | biostudies-other

N terminus of CtIP is critical for homologous recombination-mediated double-strand break repair.

Project description:DNA double-strand breaks (DSBs) represent one of the most lethal types of DNA damage cells encounter. CtIP (also known as RBBP8) acts together with the MRN (MRE11-RAD50-NBS1) complex to promote DNA end resection and the generation of single-stranded DNA, which is critically important for homologous recombination repair. However, it is not yet clear exactly how CtIP participates in this process. Here, we demonstrate that besides the known conserved C terminus, the N terminus of CtIP protein is also required in DSB end resection and DNA damage-induced G(2)/M checkpoint control. We further show that both termini of CtIP can interact with the MRN complex and that the N terminus of CtIP, especially residues 22-45, binds to MRN and plays a critical role in targeting CtIP to sites of DNA breaks. Collectively, our results highlight the importance of the N terminus of CtIP in directing its localization and function in DSB repair.

| S-EPMC2797245 | biostudies-literature

Polo-like kinase 3 regulates CtIP during DNA double-strand break repair in G1.

Project description:DNA double-strand breaks (DSBs) are repaired by nonhomologous end joining (NHEJ) or homologous recombination (HR). The C terminal binding protein-interacting protein (CtIP) is phosphorylated in G2 by cyclin-dependent kinases to initiate resection and promote HR. CtIP also exerts functions during NHEJ, although the mechanism phosphorylating CtIP in G1 is unknown. In this paper, we identify Plk3 (Polo-like kinase 3) as a novel DSB response factor that phosphorylates CtIP in G1 in a damage-inducible manner and impacts on various cellular processes in G1. First, Plk3 and CtIP enhance the formation of ionizing radiation-induced translocations; second, they promote large-scale genomic deletions from restriction enzyme-induced DSBs; third, they are required for resection and repair of complex DSBs; and finally, they regulate alternative NHEJ processes in Ku(-/-) mutants. We show that mutating CtIP at S327 or T847 to nonphosphorylatable alanine phenocopies Plk3 or CtIP loss. Plk3 binds to CtIP phosphorylated at S327 via its Polo box domains, which is necessary for robust damage-induced CtIP phosphorylation at S327 and subsequent CtIP phosphorylation at T847.

| S-EPMC4178966 | biostudies-literature

Neddylation inhibits CtIP-mediated resection and regulates DNA double strand break repair pathway choice.

Project description:DNA double strand breaks are the most cytotoxic lesions that can occur on the DNA. They can be repaired by different mechanisms and optimal survival requires a tight control between them. Here we uncover protein deneddylation as a major controller of repair pathway choice. Neddylation inhibition changes the normal repair profile toward an increase on homologous recombination. Indeed, RNF111/UBE2M-mediated neddylation acts as an inhibitor of BRCA1 and CtIP-mediated DNA end resection, a key process in repair pathway choice. By controlling the length of ssDNA produced during DNA resection, protein neddylation not only affects the choice between NHEJ and homologous recombination but also controls the balance between different recombination subpathways. Thus, protein neddylation status has a great impact in the way cells respond to DNA breaks.

| S-EPMC4333419 | biostudies-other

Age-associated deficient recruitment of 53BP1 in G1 cells directs DNA double-strand break repair to BRCA1/CtIP-mediated DNA-end resection.

Project description:DNA repair mechanisms play a crucial role in maintaining genome integrity. However, the increased frequency of DNA double-strand breaks (DSBs) and genome rearrangements in aged individuals suggests an age-associated DNA repair deficiency. Previous work from our group revealed a delayed firing of the DNA damage response in human mammary epithelial cells (HMECs) from aged donors. We now report a decreased activity of the main DSB repair pathways, the canonical non-homologous end-joining (c-NHEJ) and the homologous recombination (HR) in these HMECs from older individuals. We describe here a deficient recruitment of 53BP1 to DSB sites in G1 cells, probably influenced by an altered epigenetic regulation. 53BP1 absence at some DSBs is responsible for the age-associated DNA repair defect, as it permits the ectopic formation of BRCA1 foci while still in the G1 phase. CtIP and RPA foci are also formed in G1 cells from aged donors, but RAD51 is not recruited, thus indicating that extensive DNA-end resection occurs in these breaks although HR is not triggered. These results suggest an age-associated switch of DSB repair from canonical to highly mutagenic alternative mechanisms that promote the formation of genome rearrangements, a source of genome instability that might contribute to the aging process.

| S-EPMC7803562 | biostudies-literature

CtIP links DNA double-strand break sensing to resection.

Project description:In response to DNA double-strand breaks (DSBs), cells sense the DNA lesions and then activate the protein kinase ATM. Subsequent DSB resection produces RPA-coated ssDNA that is essential for activation of the DNA damage checkpoint and DNA repair by homologous recombination (HR). However, the biochemical mechanism underlying the transition from DSB sensing to resection remains unclear. Using Xenopus egg extracts and human cells, we show that the tumor suppressor protein CtIP plays a critical role in this transition. We find that CtIP translocates to DSBs, a process dependent on the DSB sensor complex Mre11-Rad50-NBS1, the kinase activity of ATM, and a direct DNA-binding motif in CtIP, and then promotes DSB resection. Thus, CtIP facilitates the transition from DSB sensing to processing: it does so by binding to the DNA at DSBs after DSB sensing and ATM activation and then promoting DNA resection, leading to checkpoint activation and HR.

| S-EPMC2807415 | biostudies-other

RB Regulates DNA Double Strand Break Repair Pathway Choice by Mediating CtIP Dependent End Resection.

Project description:Inactivation of the retinoblastoma tumor suppressor gene (RB1) leads to genome instability, and can be detected in retinoblastoma and other cancers. One damaging effect is causing DNA double strand breaks (DSB), which, however, can be repaired by homologous recombination (HR), classical non-homologous end joining (C-NHEJ), and micro-homology mediated end joining (MMEJ). We aimed to study the mechanistic roles of RB in regulating multiple DSB repair pathways. Here we show that HR and C-NHEJ are decreased, but MMEJ is elevated in RB-depleted cells. After inducing DSB by camptothecin, RB co-localizes with CtIP, which regulates DSB end resection. RB depletion leads to less RPA and native BrdU foci, which implies less end resection. In RB-depleted cells, less CtIP foci, and a lack of phosphorylation on CtIP Thr847, are observed. According to the synthetic lethality principle, based on the altered DSB repair pathway choice, after inducing DSBs by camptothecin, RB depleted cells are more sensitive to co-treatment with camptothecin and MMEJ blocker poly-ADP ribose polymerase 1 (PARP1) inhibitor. We propose a model whereby RB can regulate DSB repair pathway choice by mediating the CtIP dependent DNA end resection. The use of PARP1 inhibitor could potentially improve treatment outcomes for RB-deficient cancers.

| S-EPMC7730402 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data