Linear interaction between transcription and replication shapes DNA break dynamics
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE254765 | GEO | 2024/03/18
REPOSITORIES: GEO
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Project description:Yeast Sen1Senataxin is a RNA/DNA helicase that preserves replication forks across RNA Polymerase II-transcribed genes by counteracting RNA:DNA hybrids accumulation. We show that in Sen1-depleted cells early forks clashing head-on with transcription halt, and impair progression of sister forks within the same replicon. Unsolved replication-transcription collisions trigger the local firing of dormant origins that rescue arrested forks. In sen1 mutants the MRX and Mrc1/Ctf4-complexes protect those forks clashing with transcription by preventing genotoxic fork-resection events mediated by the Exo1 nuclease. Hence, sister forks within the same replicon remain coupled when one of the two forks halts. This is different when forks encounter double strand breaks. Moreover, the local firing of dormant origins is not prevented by checkpoint activation but depends on delayed adjacent forks. Furthermore, a productive head-on clash between replication and transcription requires the tuning of origin firing and coordination between Sen1, the MRX and Mrc1/Ctf4-complexes and Exo1.
2017-10-11 | GSE97046 | GEO
Project description:Our laboratory identified robust recurrent DNA double-strand break (DSB) cluster (“RDC”) genes in mouse neural stem/progenitor cells (NSPCs) by applying the high-throughput, genome-wide, translocation sequencing (HTGTS) method. Genomic alterations of most of the identified RDC-genes have been associated with psychiatric disorders such as autism and schizophrenia and several are altered in brain cancer. The most robust mouse RDCs are all in genes that tend to be very long, actively transcribed and were enhanced after mild inhibition of replication stress. The common transcription and replication characteristics we observe in RDC-genes suggest that frequent RDC DSBs might be generated by collision between transcription and replication processes. However, the underlying mechanism of RDC formation is still unknown. To elucidate mechanisms that generate and resolve DSBs in these cells, we established an in vitro system of induced neural progenitor cells derived from embryonic stem cells. HTGTS bait-DSBs introduced by CRISPR/Cas9 on three mouse chromosomes identified only 5 RDC-genes in embryonic stem cells and 27 RDC-genes in the neural progenitor cells differentiated from them. All RDC-genes identified in induced neural progenitor cells belonged to the group of genes identified in primary neural and progenitor cells. These results indicate that our in vitro differentiation system is both effective and robust in terms of recapitulating our previous findings and facilitating mechanistic studies.
2020-01-13 | GSE142289 | GEO
Project description:Our laboratory identified robust recurrent DNA double-strand break (DSB) cluster (“RDC”) genes in mouse neural stem/progenitor cells (NSPCs) by applying the high-throughput, genome-wide, translocation sequencing (HTGTS) method. Genomic alterations of most of the identified RDC-genes have been associated with psychiatric disorders such as autism and schizophrenia and several are altered in brain cancer. The most robust mouse RDCs are all in genes that tend to be very long, actively transcribed and were enhanced after mild inhibition of replication stress. The common transcription and replication characteristics we observe in RDC-genes suggest that frequent RDC DSBs might be generated by collision between transcription and replication processes. However, the underlying mechanism of RDC formation is still unknown. To elucidate mechanisms that generate and resolve DSBs in these cells, we established an in vitro system of induced neural progenitor cells derived from embryonic stem cells. HTGTS bait-DSBs introduced by CRISPR/Cas9 on three mouse chromosomes identified only 5 RDC-genes in embryonic stem cells and 27 RDC-genes in the neural progenitor cells differentiated from them. All RDC-genes identified in induced neural progenitor cells belonged to the group of genes identified in primary neural and progenitor cells. These results indicate that our in vitro differentiation system is both effective and robust in terms of recapitulating our previous findings and facilitating mechanistic studies.
2020-01-13 | GSE142312 | GEO
Project description:The progression of replication forks (RFs) can be challenged by obstacles of endogenous or exogenous origin. Stalled forks need to be readily stabilized and restarted in order to prevent genomic instability. Replication fork restart requires the recruitment of multiple enzymes and involves different DNA transactions. The MRX (Mre11-Rad50-Xrs2) complex plays a central role in this process. It has been implicated in the nucleolytic degradation of nascent DNA and in the loading of cohesin at stalled forks. However, little is known on how these functions are regulated. Here we show that MRX structural features are predominant on the nuclease activity of Mre11 for DNA resection at stalled replication forks. This results raise the question of the mechanisms by which MRX promotes nascent strand resection. At DNA double strand breaks (DSB) MRX promotes the binding of the chromatin remodeler RSC, from which the activity is required for 5’ end resection. Interestingly, MRX mutants exhibit increased nucleosome occupancy at stalled replication forks. This result suggest that a dynamic chromatin structure promoted by MRX could be required for the processing of stalled replication forks. Strinkingly the absence of two histones modifiers Gcn5 and Set1 recapitulates the phenotype of MRX mutants both on chromatin structure and nascent strand resection at stalled forks even though they are dispensable for its recruitment. Since nucleosomes also represent obstacles for the loading of SMC complexes on DNA, it is coherent that we observed that cohesin is no longer recruited at stalled forks in gcn5 and set1, as in MRX mutants. Together our data suggest that the regulation of chromatin structure at stalled replication forks is essential for their processing and to promote genome stability.
2019-10-04 | GSE107420 | GEO
Project description:Transcription and replication conflict (TRC) are one of the main driving forces for genome instability. Yet, TRC rarely been discussed without the context of DNA:RNA entanglement, rending the role of transcription in other TRC unclear . In neural stem and progenitor cells, genes encode protein regulating neuron adhesion are hotspots for recurrent DNA break clusters (RDC). While RDC-containing genes are all actively transcribed, most RDC lack DNA:RNA entanglement. We demonstrated that, through controlled gain and loss of function genetic approaches, transcription activity is essential while not sufficient to induce RDC formation. In combination of a deep neural network and single-nucleotide resolution DNA break mapping approaches, we found RDC break densities mirror the replication fork dynamics. We demonstrated that, for the first time that, head-on TRC results in higher DNA break density than its co-direction counterparts. In summary, our results revealed that transcription has a higher-level regulatory role that has to be coordinated with DNA replication.
2024-03-18 | GSE233842 | GEO
Project description:RIF1 is a multifunctional protein that plays key roles in the regulation of DNA processing. During repair of DNA double-strand breaks (DSBs), RIF1 functions in the 53BP1-Shieldin pathway that inhibits resection of DNA ends to modulate the cellular decision on which repair pathway to engage. Under conditions of replication stress, RIF1 protects nascent DNA at stalled replication forks from degradation by the DNA2 nuclease. How these RIF1 activities are regulated at the post-translational level has not yet been elucidated. Here, we identified a cluster of conserved ATM/ATR consensus SQ motifs within the intrinsically disordered region (IDR) of mouse RIF1 that are phosphorylated in proliferating B lymphocytes. We found that phosphorylation of the conserved IDR SQ cluster is dispensable for the inhibition of DSB resection by RIF1, but is essential to counteract DNA2-dependent degradation of nascent DNA at stalled replication forks. Therefore, our study identifies a key molecular feature that enables the genome-protective function of RIF1 during DNA replication stress.
2022-04-14 | PXD031972 | Pride
Project description:Meiotic recombination is initiated by the Spo11-dependent programmed DNA double-strand breaks (DSBs) that are preferentially concentrated within genomic regions known as hotspots, but the factor(s) which specify the positions for meiotic DSB hotspots remain unclear. Here, we show that the frequency and distribution of R-loops, a type of functional chromatin structure comprising single-stranded DNA and a DNA:RNA hybrid, change dramatically throughout meiosis. We detected the formation of multiple de novo R-loops in the pachytene stage, and found they co-localize with meiotic DSB hotspots. We further show that transcription-replication head-on collisions could promote R-loop formation during meiosis, and apparently direct the initiation of meiotic DSB formation. Furthermore, the hotspots can be eliminated by reverse the direction of either transcription or replication, and reconstituted by reverse both of their direction. Our study reveals that R-loops may play dual roles in meiotic recombination. In addition to participation in meiotic DSB processing, some meiotic DSB hotspots may be originated from the transcription-replication head-on collisions during meiotic DNA replication.
2023-05-14 | GSE167915 | GEO
Project description:Here we analysed the role of yeast Senataxin (Sen1) in coordinating replication with transcription and in protecting genome integrity. Senataxin is mutated in the two severe neurodegenerative diseases AOA2 and ALS4. We show that a fraction of Sen1/Senataxin DNA/RNA helicase associates with replication forks and protects the integrity of those fork encountering highly expressed RNAPII genes. sen1 mutants accumulate aberrant DNA structures and RNA-DNA hybrids while forks clash head-on with RNAPII transcription units and counteract recombinogenic events and accumulation of checkpoint signals. Nrd1, which acts togheter with Sen1 in trascription temination, is not recruited at replication forks. nrd1 mutants does not display replication defects, high genome instability and checkpoint activation observed in sen1 mutants The Sen1 function in replication can be therefore separable from its role in RNA processing. We propose a role for Sen1/Senataxin during chromosome replication in facilitating replisome progression across RNAPII transcribed genes thus preventing DNA-RNA hybrids accumulation when forks encounter nascent transcripts on the lagging strand template.
2012-11-09 | GSE39139 | GEO
Project description:Here we analysed the role of yeast Senataxin (Sen1) in coordinating replication with transcription and in protecting genome integrity. Senataxin is mutated in the two severe neurodegenerative diseases AOA2 and ALS4. We show that a fraction of Sen1/Senataxin DNA/RNA helicase associates with replication forks and protects the integrity of those fork encountering highly expressed RNAPII genes. sen1 mutants accumulate aberrant DNA structures and RNA-DNA hybrids while forks clash head-on with RNAPII transcription units and counteract recombinogenic events and accumulation of checkpoint signals. Nrd1, which acts togheter with Sen1 in trascription temination, is not recruited at replication forks. nrd1 mutants does not display replication defects, high genome instability and checkpoint activation observed in sen1 mutants The Sen1 function in replication can be therefore separable from its role in RNA processing. We propose a role for Sen1/Senataxin during chromosome replication in facilitating replisome progression across RNAPII transcribed genes thus preventing DNA-RNA hybrids accumulation when forks encounter nascent transcripts on the lagging strand template. Chip on chip analysis was carried out as described (Bermejo et al., 2011), employing anti-Flag monoclonal antibody M2 (Sigma-Aldrich) Labelled probes were hybridized to Affymetrix S.cerevisiae Tiling 1.0 (P/N 900645) arrays and processed with TAS software.
2012-11-09 | E-GEOD-39139 | biostudies-arrayexpress
Project description:We previously demonstrated that inactivation of the replication checkpoint via a mec1 mutation led to chromosome breakage at replication forks initiated from virtually all origins of replication, after transient exposure to hydroxyurea (HU), an inhibitor of ribonucleotide reductase. Furthermore, we have shown that chromosomes break at replication forks that have suffered single-stranded DNA (ssDNA) formation. Here we sought to determine whether all replication forks containing ssDNA gaps have equal probability of producing double strand breaks (DSBs) when cells attempt to recover from HU exposure. We devised a new methodology, Break-Seq, that combines our previously described DSB labeling with NextGen sequencing to map chromosome breaks with improved sensitivity and resolution. We show that DSBs preferentially occur at genes transcriptionally induced by HU. Notably, different subsets of the HU-induced genes produced DSBs in MEC1 and mec1 cells as replication forks traversed greater distance in MEC1 cells than in mec1 cells during the recovery from HU. Specifically, while MEC1 cells exhibited chromosome breakage at stress-response transcription factors, mec1 cells predominantly suffered chromosome breakage at transporter genes, many of which are the substrates of the said transcription factors. We propose that HU-induced chromosome fragility arises at higher frequency near HU-induced genes as a result of destabilized replication forks encountering transcription factor binding and/or the act of transcription. Our model provides an explanation for a long-standing problem in chromosome biology: why different replication inhibitors produce different spectra of chromosome breakage? We propose that different inhibitors elicit different transcription responses as well as destabilize replication forks, and, when the two processes collide, ssDNA at the replication fork suffers further strand breakage, causing DSBs. We queried the yeast genome for gene expression after cells were treated with 200 mM hydroxyurea during S phase. Samples were collected from 1) cells synchronized in G1 phase by alpha factor; 2) cells released from G1 into medium containing 200 mM hydroxyurea for 1 h; 3) cells recovering in fresh medium without hydroxyurea for 30 and 60 min after the 1 h exposure to HU. These samples are referred to as G1, HU 1h, R30, and R60, respectively. The strains from which the samples were collected are indicated before the time point, e.g. mec1_G1 or MEC1_R30. Stranded mRNA libraries were prepared according to manufacturer's suggestion and sequenced on Illumina MiSeq with paired-end reads of 75 bp.
2015-01-12 | E-GEOD-63516 | biostudies-arrayexpress