Homo sapiens
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PROVIDER: PRJNA377535 | ENA |
REPOSITORIES: ENA
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Project description:High concentration of NaCl increases DNA breaks both in cell culture and in vivo. The breaks remain elevated as long as NaCl concentration remains high and are rapidly repaired when the concentration is lowered. Repair of the breaks after NaCl is reduced is accompanied by formation of foci containing phosphorylated H2AX (M-NM-3H2AX), which occurs around DNA double-strand breaks and contributes to their repair. By chromatin immunoprecipitation using anti-M-NM-3H2AX antibody, followed by massive parallel sequencing (ChIP-Seq), we find that during repair of doubleM-bM-^@M-^Sstrand breaks induced by high NaCl, M-NM-3H2AX is predominantly localized to regions of the genome devoid of genes (M-bM-^@M-^\gene desertsM-bM-^@M-^]), indicating that the high NaCl-induced double-strand breaks are located there. Localization to gene deserts helps explain why the DNA breaks are less harmful than are the random breaks induced by genotoxic agents such as UV radiation, ionizing radiation and oxidants. We propose that the universal presence of NaCl around animal cells has directly influenced the evolution of the structure of their genomes. ChIP-Seq experiment to find locations of M-NM-3H2AX in mouse genome
2011-11-21 | E-GEOD-32882 | biostudies-arrayexpress
Project description:High concentration of NaCl increases DNA breaks both in cell culture and in vivo. The breaks remain elevated as long as NaCl concentration remains high and are rapidly repaired when the concentration is lowered. Repair of the breaks after NaCl is reduced is accompanied by formation of foci containing phosphorylated H2AX (γH2AX), which occurs around DNA double-strand breaks and contributes to their repair. By chromatin immunoprecipitation using anti-γH2AX antibody, followed by massive parallel sequencing (ChIP-Seq), we find that during repair of double–strand breaks induced by high NaCl, γH2AX is predominantly localized to regions of the genome devoid of genes (“gene deserts”), indicating that the high NaCl-induced double-strand breaks are located there. Localization to gene deserts helps explain why the DNA breaks are less harmful than are the random breaks induced by genotoxic agents such as UV radiation, ionizing radiation and oxidants. We propose that the universal presence of NaCl around animal cells has directly influenced the evolution of the structure of their genomes.
2011-11-21 | GSE32882 | GEO
Project description:Oncogenic mutations in the metabolic enzyme isocitrate dehydrogenase 1 and 2 (IDH1/2) have been found in a number of liquid and solid tumors. Their pathogenic mechanism of action involves production of 2-hydroxyglutarate (2HG), an oncometabolite that acts in part by inhibiting members of a family of dioxygenases that modulate chromatin dynamics. Recent work has suggested that mutant IDH (mIDH) and 2HG also impact sensitivity to inhibitors of poly-ADP ribose polymerases (PARP) but the molecular basis for this sensitivity is unclear. Unlike PARP inhibitor-sensitive BRCA1/2 tumors which exhibit impaired homologous recombination, IDH-mutant tumors have a silent mutational profile and lack mutational signatures associated with impaired homologous recombination. Instead, 2HG-producing IDH mutations lead to heterochromatin-dependent slowing of DNA replication and increased replication stress, resulting in DNA double strand breaks. This replicative stress manifests as replication fork slowing but the breaks are repaired without a significant increase in the cellular mutation burden. Faithful resolution of replicative stress in IDH-mutant cells is dependent on poly-ADP ribosylation. Treatment with PARP inhibitors restores replication fork speed but results in incomplete repair of DNA breaks. These findings provide evidence of a requirement for PARP in the replication of heterochromatin and further validate PARP as a potential therapeutic target in IDH-mutant tumors.
2023-08-28 | GSE211592 | GEO
Project description:The proteins from the Fanconi Anemia (FA) pathway of DNA repair maintain DNA replication fork integrity by preventing the unscheduled degradation of nascent DNA at regions of stalled replication forks. Here, we ask if the bacterial pathogen H. pylori exploits the fork stabilisation machinery to generate double stand breaks (DSBs) and genomic instability. Specifically, we study if the H. pylori virulence factor CagA generates host genomic DSBs through replication fork destabilisation and collapse. An inducible gastric cancer model was used to examine global CagA-dependent transcriptomic and proteomic alterations, using RNA sequencing and SILAC-based mass spectrometry, respectively. The transcriptional alterations were confirmed in gastric cancer cell lines infected with H. pylori. Functional analysis was performed using chromatin fractionation, pulsed-field gel electrophoresis (PFGE), and single molecule DNA replication/repair fiber assays. We found a core set of 31 DNA repair factors including the FA genes FANCI, FANCD2, BRCA1, and BRCA2 that were downregulated following CagA expression. H. pylori infection of gastric cancer cell lines showed downregulation of the aforementioned FA genes in a CagA-dependent manner. Consistent with FA pathway downregulation, chromatin purification studies revealed impaired levels of Rad51 but higher recruitment of the nuclease MRE11 on the chromatin of CagA-expressing cells, suggesting impaired fork protection. In line with the above data, fibre assays revealed higher fork degradation, lower fork speed, daughter strands gap accumulation, and impaired re-start of replication forks in the presence of CagA, indicating compromised genome stability. By downregulating the expression of key DNA repair genes such as FANCI, FANCD2, BRCA1, and BRCA2, H. pylori CagA compromises host replication fork stability and induces DNA DSBs through fork collapse. These data unveil an intriguing example of a bacterial virulence factor that induces genomic instability by interfering with the host replication fork stabilisation machinery.
2022-02-22 | PXD031168 | Pride
Project description:Fanconi Anemia (FA) pathway is essential for the repair of inter-strand crosslink (ICLs). ICL induces stalled replication forks and triggers activation of FA pathway for efficient ICL repair. Given that stalled replication fork is proximal to ICLs sites, fork-associated proteins may likely coordinate with FA factors to rapidly sense ICLs for activation of FA signaling. We will use LC-MS/MS to identify such proteins that participated in the ICL repairs.
2023-05-10 | PXD028246 | Pride
Project description:Recent observations show that the single-cell response of p53 to ionizing radiation (IR) is “digital” in that it is the number of oscillations rather than the amplitude of p53 that shows dependence on the radiation dose. We present a model of this phenomenon. In our model, double-strand break (DSB) sites induced by IR interact with a limiting pool of DNA repair proteins, forming DSB–protein complexes at DNA damage foci. The persisting complexes are sensed by ataxia telangiectasia mutated (ATM), a protein kinase that activates p53 once it is phosphorylated by DNA damage. The ATM-sensing module switches on or off the downstream p53 oscillator, consisting of a feedback loop formed by p53 and its negative regulator, Mdm2. In agreement with experiments, our simulations show that by assuming stochasticity in the initial number of DSBs and the DNA repair process, p53 and Mdm2 exhibit a coordinated oscillatory dynamics upon IR stimulation in single cells, with a stochastic number of oscillations whose mean increases with IR dose. The damped oscillations previously observed in cell populations can be explained as the aggregate behavior of single cell
2020-05-13 | MODEL2005130001 | BioModels
Project description:BRD4 belongs to the bromodomain and extraterminal (BET) family of epigenetic reader proteins that bind acetylated histones and regulate gene expression. Pharmacological inhibition of BRD4 by BET inhibitors (BETi) has indicated antitumor activity against multiple cancer types. We define a new function for BRD4 that is distinct from its established role in transcriptional gene regulation. We show that BRD4 is essential for the repair of DNA double-strand breaks (DSBs), and mediates the formation of oncogenic gene rearrangements by engaging the non-homologous end joining (NHEJ) pathway. Mechanistically, genome-wide DNA breaks are associated with enhanced acetylation of histone H4, leading to BRD4 recruitment, and stable establishment of the DNA repair complex. Loss of BRD4 function blocks the recruitment of multiple DNA repair proteins to the chromatin upon DNA damage, and thereby results in defective DNA repair. In support of this, we also show that in clinical tumor samples, BRD4 protein levels are negatively associated with outcome after prostate cancer (PCa) radiation therapy. Thus, in addition to regulating gene-expression, BRD4 is also a central player in the repair of DNA breaks, with significant implications for cancer therapy.
2018-01-04 | GSE103907 | GEO
Project description:Transient obstruction of DNA polymerase progression activates the ATR checkpoint kinase, which suppresses fork breakage, strand resection, and RPA accumulation. Herein, we use a developed DNA break-detection assay, BrITL, to identify replication-problematic loci (RPLs) that become processed into persistent double-strand breaks across the mammalian genome from ATR inhibition.
2018-10-04 | GSE115624 | GEO
Project description:Transient obstruction of DNA polymerase progression activates the ATR checkpoint kinase, which suppresses fork breakage, strand resection, and RPA accumulation. Herein, we use a developed DNA break-detection assay, BrITL, to identify replication-problematic loci that become processed into persistent double-strand breaks across the human genome from ATR inhibition.
2018-10-04 | GSE115623 | GEO
Project description:We have designed a methodology for capture of DNA 3’ ends that allows mapping of resected DNA breaks, stalled replication forks and also normal replication fork progression. This Transferase-activated end ligation or TrAEL-seq method involves ligation of a functionalised linker to DNA 3’ ends followed by fragmentation, purification of adaptor ligated fragments, second adaptor ligation and library amplification. The major advantages of TrAEL-seq compared to other available methods are: i) an ability to map double strand breaks after resection, ii) excellent sensitivity and signal-to-noise in detecting replication fork stalling and iii) ability to map replication fork progression in unsynchronised, unlabelled populations of both yeast and mammalian cells. The samples provided here were selected to demonstrate different aspects of TrAEL-seq activity: the SfiI and dmc1 datasets shows capture of 3’ extended single strand DNA. The other yeast datasets show replication and replication fork stalling information. The RAF and RAF-GAL grown yeast samples show the effect transcriptional induction on replication fork progression. The hESC samples show the capacity to derive replication profiles from mammalian cells.
2020-07-27 | GSE154811 | GEO