DNA Double-Strand Breaks Induce H2Ax Phosphorylation Domains in a Contact-Dependent Manner
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE150384 | GEO | 2020/05/13
REPOSITORIES: GEO
Similar Datasets
Project description:DNA Double Strand Breaks (DSBs) are a deleterious product of genotoxic agents or radiotherapy. Despite the inherent chromatin localization of DSBs, the literature has largely ignored the effect of local chromatin or histone post translational modifications (PTMs) on DSB induction or recognition especially in a therapy-relevant setting. Analysis of epigenetic linkages to the DNA Damage Response are challenging owing to the random nature of exogenous DSB induction. Here, we directly measure stochastic DNA damage induced by ionizing radiation (IR) and infer relationships between basal epigenetic states and cellular ability to detect DSBs. Contrary to the expected uniform localization of DSBs and γH2AX, we show that DSB recognition is separate from DSB induction and that both processes are dependent on the local chromatin milieu. In general, actively transcribed regions contain more γH2AX than heterochromatic regions suggesting a link between transcription and the DDR. In contrast to previous studies, we suggest that transcription proximal to DNA damage is necessary for early DSB detection and suggest a requirement for transcription mediated repair in genome maintenance. Finally, we reveal a dual effect of the repressive mark H3K27me3 on the DNA damage response. While basal H3K27me3 attenuates γH2AX deposition, transcribed regions recruit H3K27me3 following DSB induction possibly as an obligate step in DSB recognition. We uncover epigenetic determinants of DSB recognition and suggest new mechanisms by which the epigenome direct DNA repair. Our findings suggest new targets for radio-adjuvant therapy and reframe the current stochastic model of radiotherapy induced damage.
2021-12-31 | GSE181934 | GEO
Project description:Chromatin undergoes major remodeling around DNA double strand breaks (DSB) to promote repair and DNA damage response (DDR) activation. We recently reported a high resolution map of gammaH2AX around multiple breaks on the human genome, using a new cell-based DSB inducible system. In an attempt to further characterize the chromatin landscape induced around DSBs, we now report the profile of SMC3, a subunit from the cohesin complex, previously characterized as required for repair by homologous recombination. We found that the recruitment of cohesin is moderate and restricted to the immediate vicinity of DSBs. In addition, we show that the cohesin complex, which was also recently proposed to be a key player in chromosome organisation and chromatin looping, controls gammaH2AX distribution within domains. Indeed, as we reported for transcription, cohesin binding antagonizes gammaH2AX spreading. Remarkably, depletion of cohesin leads to an increase of gammaH2AX at cohesin-bound genes (revelead by gammaH2AX mapping in upon SCC1 siRNA), associated with a decrease in their expression level after DSB induction. Thus our study identifies a novel role for the cohesin complex in protecting the genes located in gammaH2AX domains from both gammaH2AX spreading and transcriptional shut-down after DSB induction.
2012-01-01 | E-TABM-1164 | biostudies-arrayexpress
Project description:DNA Double Strand Breaks (DSBs) repair is essential to safeguard genome integrity but little is known about the contribution of chromosome folding into these processes. Here we unveiled basic principles of chromosome dynamics occurring post-DSB both locally and at a genome wide scale in mammalian cells. We report that topologically associating domains (TAD) that experience a DSB undergo acute ATM-dependent but DNAPK- independent changes. Within these damaged TADs, DSB-induced loop extrusion ensures local transcriptional regulation in response to DSBs. Damaged TADs further coalesce in an ATM-dependent manner, forming a new “D” compartment, where upregulated genes of the DNA damage response (DDR) physically localize suggesting a function of DSB clustering in activating the DNA damage Response. However, these alterations of chromosome folding induced by DSB also come at the expense of an increased translocations rate. Our work highlights the critical impact of chromosome conformation in the maintenance of genome integrity.
2023-11-17 | E-MTAB-10865 | biostudies-arrayexpress
Project description:Damage to genomic DNA, especially as DNA double strand breaks (DSB), elicits prompt activation of DNA damage response (DDR) which arrest cell-cycle either G1/S or G2/M to avoid entering S and M phase with DNA damage. In mammalian organs cells are in both proliferating and quiescent states. Quiescent cells are already arrested in G0, therefore there may be fundamental difference in DDR between proliferating and quiescent cells. To address these differences we studied recruitment of DSB repair factors and resolution of DNA lesions induced at site-specific DSBs occurring at different cell cycle phases, i.e. in asynchronously proliferating, G0, and G1 arrested cells. Strikingly, DSBs occurring in G0 quiescent cells are irreparable with a sustained activation of p53-pathway. Conversely, reentry of G0-damaged cells into cell cycle progression, show a delayed clearance of recruited DNA repair factors bound at DSBs, indicating an inefficient repair when compared to DSBs induced in asynchronously proliferating or G1 cells. Moreover, we found that initial recognition of DSBs and assembly of DSB factors is largely similar at different cell cycle phases. Our study thereby demonstrates the crucial role of cell cycle phases in repair and resolution of DSBs.
2015-12-30 | GSE71447 | GEO
Project description:Various modes of DNA repair counteract genotoxic DNA double-strand breaks (DSBs) to maintain genome stability. Recent findings suggest that the human DNA damage response (DDR) utilises damage-induced small RNA for efficient repair of DSBs. However, production and processing of RNA is poorly understood. Here we show that localised induction of DSBs triggers phosphorylation of RNA polymerase II (RNAPII) on carboxy-terminal domain (CTD) residue tyrosine-1 in an Mre11-Rad50-Nbs1 (MRN) complex-dependent manner. CTD Tyr1-phosphorylated RNAPII synthetises, strand-specific, damage-responsive transcripts (DARTs). DART synthesis occurs via formation of transient RNA-DNA hybrid (R-loop) intermediates. Impaired R-loop formation attenuates DART synthesis, impairs recruitment of repair factors and delays the DDR. Collectively, we provide mechanistic insight in RNA-dependent DSB repair.
2019-02-04 | GSE96825 | GEO
Project description:The DNA damage response (DDR) is an extensive signaling network that is robustly mobilized by DNA double-strand breaks (DSBs). The primary transducer of the DSB response is the protein kinase, ataxia-telangiectasia, mutated (ATM). Here, we establish nuclear poly(A)-binding protein 1 (PABPN1) as a novel target of ATM and a crucial player in the DSB response. PABPN1 usually functions in regulation of RNA processing and stability. We establish that PABPN1 is recruited to the DDR as a critical regulator of DSB repair. A portion of PABPN1 relocalizes to DSB sites and is phosphorylated on Ser95 in an ATM-dependent manner. PABPN1 depletion sensitizes cells to DSBinducing agents and prolongs the DSB-induced G2/M cell-cycle arrest, and DSB repair is hampered by PABPN1 depletion or elimination of its phosphorylation site. PABPN1 is required for optimal DSB repair via both nonhomologous end-joining (NHEJ) and homologous recombination repair (HRR), and specifically is essential for efficient DNAend resection, an initial, key step in HRR. Using mass spectrometry analysis, we capture DNA damage-induced interactions of phospho-PABPN1, including well-established DDR players as well as other RNA metabolizing proteins. Our results uncover a novel ATM-dependent axis in the rapidly growing interface between RNA metabolism and the DDR.
2017-11-30 | PXD005913 | Pride
Project description:Chromatin acts as a key regulator of DNA related processes such as DNA damage repair. While ChIP-chip is a powerful technique to provide high-resolution maps of protein-genome interactions, its use to study DNA Double Strand Break (DSB) repair has been hindered by the limitations of the available damage induction methods. We have developed a human cell line that permits induction of multiple DSBs randomly distributed and unambiguously positioned within the genome. Using this system, we have generated the first genome-wide mapping of gammaH2AX around DSBs. We found that all DSBs trigger large gammaH2AX domains, which extend from the DSB in a bidirectional, discontinuous and not necessarily symmetrical manner. Strikingly we uncovered that, within domains, gammaH2AX distribution is highly influenced by gene transcription since parallel mapping of RNA Polymerase II and strand specific expression revealed that ?H2AX does not propagate on active genes. In addition, we demonstrate that transcription is accurately maintained within gammaH2AX domains, indicating that mechanisms may exist to protect genes transcription from gammaH2AX spreading and from the chromatin rearrangements induced by DSBs.
2010-04-20 | E-MEXP-1769 | biostudies-arrayexpress
Project description:Double-strand breaks (DSBs) can lead to the loss of genetic information and cell death. Consequently, cells in all domains of life have evolved mechanisms to repair DSBs, including through homologous recombination. Although recombination has been well characterized, the spatial organization of this process in living cells remains poorly understood. Here, we introduced site-specific DSBs in Caulobacter crescentus, and then used time-lapse microscopy to visualize the homology search, DSB repair, and the resegregation of chromosomal DNA. Even loci tethered to opposite cell poles can efficiently release, pair to enable recombination-based repair, and then resegregate to their original locations. Resegregation occurs independent of DNA replication and without disrupting global chromosome organization. Origin-proximal regions are resegregated by the same machinery, ParABS, used to segregate undamaged chromosomes following DNA replication. In contrast, origin-distal regions efficiently resegregate after a DSB independent of ParABS, and likely without dedicated segregation proteins. Instead, we propose that a physical, spring-like force drives the resegregation of origin-distal loci after DSB repair.
2015-07-03 | GSE66811 | GEO
Project description:DNA Double Strand Breaks (DSBs) are harmful lesions that require rapid detection and repair in order to avoid toxic genomic rearrangements. DSBs elicit the so called DNA Damage Response (DDR), largely relying on ataxia telangiectasia mutated (ATM) and DNA Protein Kinase (DNAPK), two members of the PI3K-like kinase family, whose respective functions during the sequential steps of the DDR remains controversial. Using the DIvA cell line, expressing the AsiSI restriction enzyme, we have investigated the role of ATM and DNAPK in several aspects of the DDR upon induction of multiple clean DSBs throughout the human genome. High resolution mapping revealed that they are activated and spread in cis on a confined region surrounding all DSBs, independently of the pathway used for repair. However, a thorough analysis of repair kinetics, H2AX domain establishment and H2AX foci structure and dynamics revealed non overlapping functions for the two kinases once recruited at DSBs. Our results suggest that ATM is not solely acting on chromatin marks but also on chromatin organisation in order to ensure repair accuracy and survival.
2015-09-30 | E-MTAB-2992 | biostudies-arrayexpress
Project description:The DNA damage response (DDR) is the signaling cascade that recognizes DNA double-strand breaks (DSB) and promotes their resolution via the DNA repair pathways of Non-Homologous End Joining (NHEJ) or Homologous Recombination (HR). We and others have shown that DDR activation requires DROSHA. However, whether DROSHA exerts its functions by associating with damage sites, what controls its recruitment and how DROSHA influences DNA repair, remains poorly understood. Here we show that DROSHA associates to DSBs independently from transcription. Neither H2AX, nor ATM nor DNA-PK kinase activities are required for its recruitment to break site. Rather, DROSHA interacts with RAD50 and inhibition of MRN by Mirin treatment abolishes this interaction. MRN inactivation by RAD50 knockdown or mirin treatment prevents DROSHA recruitment to DSB and, as a consequence, also 53BP1 recruitment. During DNA repair, DROSHA inactivation reduces NHEJ and boosts HR frequency. Indeed, DROSHA knockdown also increase the association of downstream HR factors such as RAD51 to DNA ends. Overall, our results demonstrate that DROSHA is recruited at DSBs by the MRN complex and direct DNA repair toward NHEJ.
2021-03-15 | GSE166631 | GEO