Saccharomyces cerevisiae
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA170079 | ENA |
REPOSITORIES: ENA
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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: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:Transcription hinders replication fork progression and stability, and the Mec1/ATR checkpoint protects fork integrity. Examining checkpoint-dependent mechanisms controlling fork stability, we find that fork reversal or dormant origin firing owing to checkpoint defects are rescued in checkpoint mutants lacking THO, TREX-2 or inner basket nucleoporins. Gene gating tethers transcribed genes to the nuclear periphery and is counteracted by checkpoint kinases through phosphorylation of nucleoporins such as Mlp1. Checkpoint mutants fail to detach transcribed genes from nuclear pores, thus generating topological impediments for incoming forks. Releasing this topological complexity by introducing a double-strand break between a fork and a transcribed unit prevents fork collapse. Mlp1 mutants mimicking constitutive checkpoint-dependent phosphorylation also alleviate checkpoint defects. We propose that the checkpoint assists fork progression and stability at transcribed genes by phosphorylating key nucleoporins and counteracting gene gating, thus neutralizing the topological tension generated at nuclear pore gated genes.
2011-07-22 | GSE30024 | GEO
Project description:The accurate processing of stalled forks by the DNA2 nuclease is pivotal for replication fork restart, as excessive degradation poses a threat to genomic stability. However, the regulation of DNA2 activity at stalled forks remains elusive. Here, we demonstrate that, upon replication stress, RNA polymerase II (RNAPII) is recruited to stalled forks, actively promoting the transient formation of RNA-DNA hybrids. Furthermore, we provide evidence that DDX39A, functioning as an RNA-DNA resolver, unwinds these hybrids, allowing DNA2 access to stalled forks. This orchestrated process facilitates controlled DNA2-dependent stalled fork processing and restart. Nevertheless, premature removal of RNA-DNA hybrids at stalled forks leads to DNA2-dependent excessive degradation of nascent DNA. Finally, we reveal that loss of DDX39A enhances the protection of stalled forks in BRCA1/2-deficient cells, consequently conferring chemoresistance within this specific cellular context. Our results suggest that the dynamic regulation of RNA-DNA hybrid formation at stalled forks by RNAPII and DDX39A precisely governs the timing of DNA2 activation, contributing to stalled fork processing and restart, ultimately promoting genome stability.
2024-12-19 | GSE252172 | GEO
Project description:The accurate processing of stalled forks by the DNA2 nuclease is pivotal for replication fork restart, as excessive degradation poses a threat to genomic stability. However, the regulation of DNA2 activity at stalled forks remains elusive. Here, we demonstrate that, upon replication stress, RNA polymerase II (RNAPII) is recruited to stalled forks, actively promoting the transient formation of RNA-DNA hybrids. Furthermore, we provide evidence that DDX39A, functioning as an RNA-DNA resolver, unwinds these hybrids, allowing DNA2 access to stalled forks. This orchestrated process facilitates controlled DNA2-dependent stalled fork processing and restart. Nevertheless, premature removal of RNA-DNA hybrids at stalled forks leads to DNA2-dependent excessive degradation of nascent DNA. Finally, we reveal that loss of DDX39A enhances the protection of stalled forks in BRCA1/2-deficient cells, consequently conferring chemoresistance within this specific cellular context. Our results suggest that the dynamic regulation of RNA-DNA hybrid formation at stalled forks by RNAPII and DDX39A precisely governs the timing of DNA2 activation, contributing to stalled fork processing and restart, ultimately promoting genome stability.
2024-12-19 | GSE252171 | GEO
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:To ensure efficient genome duplication, cells have evolved a multitude of factors that promote unperturbed DNA replication, and protect, repair and restart damaged forks. Here we identify DONSON as a novel fork protection factor, and report biallelic DONSON mutations in 29 individuals with microcephalic dwarfism. We demonstrate that DONSON is a component of the replisome that stabilises forks during normal genome replication. Loss of DONSON leads to severe replication-associated DNA damage arising from nucleolytic cleavage of stalled replication forks. Furthermore, ATR-dependent signalling in response to replication stress is impaired in DONSON-deficient cells, resulting in decreased checkpoint activity, and potentiating chromosomal instability. Hypomorphic mutations substantially reduce DONSON protein levels and impair fork stability in patient cells, consistent with defective DNA replication underlying the disease phenotype. In summary, we identify mutations in DONSON as a common cause of microcephalic dwarfism, and establish DONSON as a critical replication fork protein required for mammalian DNA replication and genome stability.
| EGAS00001002224 | EGA
Project description:Replication stress activates the Mec1ATR and Rad53 kinases. Rad53 phosphorylates nuclear pores to counteract gene gating, thus preventing aberrant transitions at forks approaching transcribed genes. Here, we show that Rrm3 and Pif1, DNA helicases assisting fork progression across pausing sites, are detrimental in rad53 mutants experiencing replication stress. Rrm3 and Pif1 ablations rescue cell lethality, chromosome fragmentation, replisome-fork dissociation, fork reversal, and processing in rad53 cells. Through phosphorylation, Rad53 regulates Rrm3 and Pif1; phospho-mimicking rrm3 mutants ameliorate rad53 phenotypes following replication stress without affecting replication across pausing elements under normal conditions. Hence, the Mec1-Rad53 axis protects fork stability by regulating nuclear pores and DNA helicases. We propose that following replication stress, forks stall in an asymmetric conformation by inhibiting Rrm3 and Pif1, thus impeding lagging strand extension and preventing fork reversal; conversely, under unperturbed conditions, the peculiar conformation of forks encountering pausing sites would depend on active Rrm3 and Pif1. BrdU incorporation profiles by ssDNA-BrdU IP on chip have been generated as described (Katou et al., 2003). Protein binding profiles by ChIP-chip analysis were generated as described (Bermejo et al., 2009). Labeled probes were hybridized to Affymetrix S.cerevisiae Tiling 1.0 (P/N 900645) arrays and processed with TAS software.
2015-09-24 | E-GEOD-68214 | biostudies-arrayexpress
Project description:Replication forks face multiple obstacles that slow their progression. By two-dimensional gel analysis, yeast forks pause at stable DNA protein complexes, and this pausing is greatly increased in the absence of the Rrm3 helicase. We used a genome wide approach to identify 96 sites of very high DNA polymerase binding in wild type cells. Most of these binding sites were not previously identified pause sites. Rather, the most highly represented genomic category among high DNA polymerase binding sites was the open reading frames (ORFs) of highly transcribed RNA polymerase II genes. Twice as many pause sites were identified in rrm3 compared to wild type cells as pausing in this strain occurred at both highly transcribed RNA polymerase II genes and the previously identified protein DNA complexes. ORFs of highly transcribed RNA polymerase II genes are the first class of natural pause sites that are not exacerbated in rrm3 cells. We alse mapped pause sites using a second replication fork component, Rrm3-13MYC and got similar results.
2009-06-15 | GSE16218 | GEO
Project description:Top1 and Top2-mediated replication fork integrity
| PRJNA101273 | ENA