Saccharomyces cerevisiae
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA120567 | ENA |
REPOSITORIES: ENA
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Project description:Top1 and Top2-mediated replication fork integrity
| PRJNA101273 | ENA
Project description:[original title] Chromosome replication initiates at multiple replicons and terminates when forks converge. In Escherichia coli, the Tus-TER complex mediates polar fork converging at the terminator region and aberrant termination events challenge chromosome integrity and segregation. Since in eukaryotes termination is less characterized, we used budding yeast to identify the factors assisting fork fusion at replicating chromosomes. Using genomic and mechanistic studies we have identified and characterized 71 chromosomal termination regions (TERs). TERs contain fork pausing elements that influence fork progression and merging. The Rrm3 DNA helicase assists fork progression across TERs counteracting the accumulation of X-shaped structures. The Top2 DNA topoisomerase associates at TERs in S-phase and G2/M facilitates fork fusion and prevents DNA breaks and genome rearrangements at TERs. We propose that in eukaryotes replication fork barriers, Rrm3 and Top2 coordinate replication fork progression and fusion at termination regions thus counteracting abnormal genomic transitions. Signal tracks in BED format suitable for visualization on the UCSC genome browser can be found at http://bio.ifom-ieo-campus.it/supplementary/Fachinetti_et_al_MOLCELL_2010
2010-08-28 | GSE19061 | GEO
Project description:Quantitative, genome-wide analysis of eukaryotic replication initiation and termination
| PRJNA174633 | ENA
Project description:Despite the critical regulatory function of promoter-proximal pausing, the influence of pausing kinetics on transcriptional control remains an active area of investigation. Here, we present Start-TimeLapse-seq (STL-seq), a method that captures the genome-wide kinetics of short, capped RNA turnover and reveals principles of regulation at the pause site. By measuring the rates of release into elongation and premature termination through inhibition of pause release, we determine that pause-release rates are highly variable and most promoter-proximal paused RNA Polymerase II molecules prematurely terminate (~80%). The preferred regulatory mechanism upon a hormonal stimulus (20-hydroxyecdysone) is to influence pause-release rather than termination rates. Transcriptional shutdown occurs concurrently with induction of promoter-proximal termination under hyperosmotic stress but paused transcripts from TATA box-containing promoters remain stable, demonstrating an important role for cis-acting DNA elements in pausing. STL-seq dissects the kinetics of pause release and termination, providing an opportunity to identify mechanisms of transcriptional regulation.
2021-09-13 | GSE166202 | GEO
Project description:During meiotic prophase, concurrent transcription, recombination, and chromosome synapsis place substantial topological strain on chromosomal DNA, but the role of topoisomerases in this context remains poorly defined. Here, we analyzed the roles topoisomerases I and II (Top1 and Top2) during meiotic prophase in Saccharomyces cerevisiae. We show that both topoisomerases accumulate primarily in promoter-containing intergenic regions of actively transcribing genes, including many meiotic double-strand break (DSB) hotspots. Despite the comparable binding patterns, top1 and top2 mutations have different effects on meiotic recombination. TOP1 disruption delays DSB induction and shortens the window of DSB accumulation by an unknown mechanism. By contrast, temperature-sensitive top2-1 mutants exhibit a marked delay in meiotic chromosome remodeling and elevated DSB signals on synapsed chromosomes. The problems in chromosome remodeling were linked to altered Top2 binding patterns rather than a loss of Top2 catalytic activity and stemmed from a defect in recruiting the chromosome remodeler Pch2/TRIP13 to synapsed chromosomes. No chromosomal defects were observed in the absence of TOP1. Our results imply independent roles for topoisomerases I and II in modulating meiotic chromosome structure and recombination.
2020-03-06 | GSE131994 | GEO
Project description:Topological stress can cause replication forks to stall as they converge upon one another during termination of vertebrate DNA synthesis. However, replication forks ultimately overcome topological stress and complete DNA synthesis, suggesting that alternative mechanisms can overcome topological stress. We performed a proteomic analysis of converging replication forks that were stalled by topological stress induced by loss or inhibition of topoisomerase IIα (TOP2α). Plasmid DNA was replicated in mock- or TOP2α-depleted Xenopus egg extracts as previously described (Heintzman et al. 2019). In parallel, replication was performed in the presence of the TOP2 inhibitor ICRF-193 (‘TOP2-i’) as an alternate means of preventing TOP2 activity (Heintzman et al. 2019). Chromatinized plasmid DNA was recovered 18 minutes after the onset of DNA synthesis, when most forks have normally merged but are stalled when TOP2 activity is prevented (Heintzman et al. 2019). Chromatin-bound proteins were recovered (Larsen et al. 2019) then analyzed by chromatin mass spectrometry and quantified by label free quantification.
2023-02-21 | PXD031170 | Pride
Project description:High-resolution genome replication profiles, modeling and single-cell imaging define the stochastic nature of replication initiation and termination
| PRJNA210660 | ENA
Project description:Genome-wide Replication-independent H3 Exchange Occurs Predominantly at Promoters and Implicates H3K56ac and Asf1
| PRJNA101263 | ENA
Project description:Essential Roles of the Smc5/6 complex in Replication through Pausing Sites and Endogenous DNA Damage Tolerance
| PRJNA293458 | ENA
Project description:Replication forks terminate at TERs and telomeres. Forks that converge or encounter transcription generate topological stress. Combining genetic, genomic and imaging approaches we found that Rrm3hPif1 and Sen1hSenataxin helicases assist termination at TERs, Sen1 at telomeres. rrm3 and sen1 are synthetic lethal, fail to terminate replication exhibiting lagging chromosomes and fragility at TERs and telomeres. sen1 rrm3 build up RNA-DNA hybrids at TERs, sen1 accumulates RNPII at TERs and telomeres. Double mutants exhibit X-shaped gapped or reversed converging forks. Rrm3 and Sen1 restrain Top1 and Top2 activities, preventing toxic accumulation of positive supercoil at TERs and telomeres. We suggest that Rrm3 and Sen1 coordinate the activities of fork-associated Top1 and Top2 with those of gene loop-associated Top1 and Top2 by preventing DNA and RNA polymerases slowing down when forks encounter transcription head-on or codirectionally, respectively. Hence Rrm3 and Sen1 are essential to generate permissive topological conditions for replication termination.
2022-10-11 | GSE214925 | GEO