Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1137835 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Collisions of the transcription and replication machineries on the same DNA strand can pose a significant threat to genomic stability. These collisions occur in part due to the formation of RNA-DNA hybrids termed R-loops, in which a newly transcribed RNA molecule hybridizes with the DNA template strand. This study investigated the role of RAD52, a known DNA repair factor, in preventing collisions by directing R-loop formation and resolution. We show that RAD52 deficiency increases R-loop accumulation, exacerbating collisions and resulting in elevated DNA damage. Furthermore, RAD52's ability to interact with the transcription machinery, coupled with its capacity to facilitate R-loop dissolution, highlights its role in preventing collisions. Lastly, we provide evidence of an increased mutational burden from double-strand breaks at conserved R-loop sites in human tumor samples, which is increased in tumors with low RAD52 expression. In summary, this study underscores the importance of RAD52 in orchestrating the balance between replication and transcription processes to prevent collisions and maintain genome stability.
2024-08-25 | PXD054611 | Pride
Project description:ATP-dependent chromatin remodelers are commonly mutated in human cancer. Mammalian SWI/SNF complexes comprise three conserved multi-subunit chromatin remodelers (cBAF, ncBAF and PBAF) that share the BRG1 (also known as SMARCA4) subunit responsible for the main ATPase activity. BRG1 is the most frequently mutated Snf2-like ATPase in cancer. Here we have investigated the role of SWI/SNF in genome instability, a hallmark of cancer cells, given its role in transcription, DNA replication and DNA damage repair. We show that depletion of BRG1 increases R-loops and R-loop-dependent DNA breaks, as well as transcription-replication conflicts. BRG1 colocalizes with R-loops and replication fork blocks, as determined by FANCD2 foci, with BRG1 depletion being epistatic to FANCD2 silencing. Our study, extended to other components of SWI/SNF, uncovers a key role of the SWI/SNF complex, in particular cBAF, in helping resolve R-loop-mediated transcription-replication conflicts; thus, unveiling a novel mechanism by which chromatin remodeling protects genome integrity.
2021-05-10 | GSE154631 | GEO
Project description:Collisions of transcription and replication machinery on the same DNA strand can pose a significant threat to genomic stability. These collision occur in part due to of RNA-DNA hybrids termed R-loops, in which a newly synthesized RNA molecule hybridizes with the DNA template strand. This study investigated the novel role of RAD52, a known DNA repair factor, in preventing collisions by managing R-loop formation and resolution. We show that RAD52 deficiency increases R-loop accumulation, exacerbating collisions and resulting in elevated DNA damage. Further, RAD52's ability to interact with the transcription machinery, coupled with its capacity to facilitate R-loop dissolution, highlights its role in preventing collisions. Lastly, we provide the first evidence of an increased mutational burden at conserved R-loop sites in human tumor samples. In summary, this study underscores the importance of RAD52 in orchestrating the delicate balance between replication and transcription processes to prevent collisions and maintain genome stability.
2024-07-11 | GSE266483 | GEO
Project description:During the S-phase, conflicts of replication forks with RNA Polymerase II (RNAPII) threaten genomic stability. While the PAF complex can resolve such conflicts during elongation, the particularly deleterious conflicts with stalling RNAPII are resolved by an as of yet unknown mechanism. Here we show that the MYCN oncoprotein forms a ternary complex with RNAPII and the nuclear RNA exosome, a 3’‑5’ exoribonuclease complex. Together with TFIIS, this complex restarts promoter‑proximal RNAPII, allows escape from co-directional transcription-replication conflicts and prevents double‑strand break accumulation. In cells lacking RNA exosome function, MYCN globally terminates transcription. MYCN-mediated termination is triggered by ATM‑dependent recruitment of BRCA1, which then stabilizes nuclear mRNA decapping complexes. Disruption of mRNA decapping activates ATR, indicative of head-on transcription-replication conflicts, and inhibits DNA replication. We propose that MYCN resolves transcription-replication conflicts via this two-step mechanism to sustain the rapid proliferation of neuroendocrine tumor cells.
2021-12-10 | GSE164555 | GEO
Project description:During the S-phase, conflicts of replication forks with RNA Polymerase II (RNAPII) threaten genomic stability. While the PAF complex can resolve such conflicts during elongation, the particularly deleterious conflicts with stalling RNAPII are resolved by an as of yet unknown mechanism. Here we show that the MYCN oncoprotein forms a ternary complex with RNAPII and the nuclear RNA exosome, a 3’‑5’ exoribonuclease complex. Together with TFIIS, this complex restarts promoter‑proximal RNAPII, allows escape from co-directional transcription-replication conflicts and prevents double‑strand break accumulation. In cells lacking RNA exosome function, MYCN globally terminates transcription. MYCN-mediated termination is triggered by ATM‑dependent recruitment of BRCA1, which then stabilizes nuclear mRNA decapping complexes. Disruption of mRNA decapping activates ATR, indicative of head-on transcription-replication conflicts, and inhibits DNA replication. We propose that MYCN resolves transcription-replication conflicts via this two-step mechanism to sustain the rapid proliferation of neuroendocrine tumor cells.
2021-12-10 | GSE164568 | GEO
Project description:During the S-phase, conflicts of replication forks with RNA Polymerase II (RNAPII) threaten genomic stability. While the PAF complex can resolve such conflicts during elongation, the particularly deleterious conflicts with stalling RNAPII are resolved by an as of yet unknown mechanism. Here we show that the MYCN oncoprotein forms a ternary complex with RNAPII and the nuclear RNA exosome, a 3’‑5’ exoribonuclease complex. Together with TFIIS, this complex restarts promoter‑proximal RNAPII, allows escape from co-directional transcription-replication conflicts and prevents double‑strand break accumulation. In cells lacking RNA exosome function, MYCN globally terminates transcription. MYCN-mediated termination is triggered by ATM‑dependent recruitment of BRCA1, which then stabilizes nuclear mRNA decapping complexes. Disruption of mRNA decapping activates ATR, indicative of head-on transcription-replication conflicts, and inhibits DNA replication. We propose that MYCN resolves transcription-replication conflicts via this two-step mechanism to sustain the rapid proliferation of neuroendocrine tumor cells.
2021-12-10 | GSE164567 | GEO
Project description:R-loops are formed when replicative forks collide with the transcriptional machinery and can cause genomic instability. However, it is unclear how R-loops are regulated at transcription-replication conflicts (TRC) sites and how replisome proteins are regulated to prevent R-loop formation or mediate R-loop tolerance. Here, we report that ATAD5, a PCNA unloader, plays dual functions to reduce R-loops both under normal and replication stress conditions. ATAD5 interacts with RNA helicases such as DDX1, DDX5, DDX21 and DHX9 and increases the abundance of these helicases at replication forks to facilitate R-loop resolution. Depletion of ATAD5 or RNA helicases consistently increases R-loops during the S phase and reduces the replication rate, both of which are enhanced by replication stress. In addition to R-loop resolution, ATAD5 prevents the generation of new R-loops behind the replication forks by unloading PCNA which, otherwise, accumulates and persists on DNA, causing a collision with the transcription machinery. Depletion of ATAD5 reduces transcription rates due to PCNA accumulation. Consistent with the role of ATAD5 and RNA helicases in maintaining genomic integrity by regulating R-loops, the corresponding genes were mutated or downregulated in several human tumors.
2021-09-09 | PXD018207 | Pride
Project description:Multiple replication abnormalities cause cells lacking BRCA2 to enter mitosis with under-replicated DNA and to activate mitotic DNA synthesis (MiDAS). However, the precise position of these MiDAS sites, as well as their origin, remains unknown. Here we labelled mitotic nascent DNA and performed high-throughput sequencing to identify at high-resolution the sites where MiDAS occurs in the absence of BRCA2. This approach revealed 150 genomic loci affected by MiDAS, which map within regions replicating during early S-phase and are therefore distinct from the aphidicolin-induced common fragile sites. Moreover, these sites largely localise near early firing origins and within genes transcribed in early S, suggesting that they stem from transcription-replication conflicts (TCRs). Inhibiting transcription with 5,6-dichloro-1-β-D-ribofuranosylbenzimidazole (DRB) during early S-phase abrogates MiDAS. Strikingly, MiDAS sites co-localise with genomic loci where R-loops form in unchallenged conditions, suggesting that R-loop accumulation caused by BRCA2 inactivation leads to DNA lesion which are repaired by MiDAS. RAD52 is required in this process, as its abrogation in BRCA2-deficient cells reduces the rate of MiDAS and causes DNA damage accumulation in G1. Furthermore, MiDAS sites triggered by BRCA2 inactivation are hotspots for genomic rearrangement in BRCA2-mutated breast tumours. These results indicate that BRCA2 acts in early S-phase to protect TRC- and R-loop-induced DNA lesions, thereby preventing them from becoming a source of genomic instability and tumorigenesis.
2022-08-01 | GSE196163 | GEO
Project description:Transcription is a major obstacle for replication fork progression and transcription-replication collisions constitute a main cause of genome instability. At a genome-wide scale these obstacles can be detected by the accumulation of the replicative Rrm3 helicase required for RF progression through protein obstacles. Here we show that FACT, a chromatin-reorganizing complex that swaps nucleosomes around the RNA polymerase during transcription elongation and that also has a role in replication, is needed to resolve transcription-replication conflicts in Saccharomyces cerevisiae. Importantly, ChIP-chip analyses of Rrm3 reveal that replication progression impairment in FACT mutants occur genome-wide, but preferentially at highly transcribed regions. ChIP-chip studies were perfomed with antibodies against Rrm3-FLAG in the yeast S. cerevisiae.
2014-03-17 | E-GEOD-51653 | biostudies-arrayexpress