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PROVIDER: PRJNA704995 | ENA |
REPOSITORIES: ENA
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Project description:Initiation of eukaryotic DNA replication requires temporal separation of helicase loading from helicase activation and replisome assembly. Using an in vitro assay for eukaryotic origin-dependent replication initiation, we investigated the control of these events. After helicase loading, we found that the Dbf4-dependent Cdc7 kinase (DDK) initially drives origin recruitment of Sld3 and the Cdc45 helicase-activating protein. Corresponding in vivo studies found that DDK was required for Cdc45 binding at early origins during G1. Upon activation of S-phase cyclin-dependent kinases (S-CDK), a second helicase-activating protein (GINS) and the remainder of the replisome are recruited to the origin. Investigation of DNA polymerase recruitment showed that Mcm10 and DNA unwinding both were critical for recruitment of the lagging but not leading strand DNA polymerases. Our studies identify distinct roles for DDK and S-CDK during helicase activation and support a model in which the leading strand DNA polymerase is recruited prior to DNA unwinding and initial RNA primer synthesis. We performed chromatin immunoprecipitation (ChIP) against Cdc45 in CDC7 and cdc7-4 cells arrested in G1 phase to assess the requirement of the Dbf4-dependent kinase on the recruitment of Cdc45 to origin DNA during G1.
2011-07-21 | E-GEOD-29646 | biostudies-arrayexpress
Project description:Initiation of eukaryotic DNA replication requires temporal separation of helicase loading from helicase activation and replisome assembly. Using an in vitro assay for eukaryotic origin-dependent replication initiation, we investigated the control of these events. After helicase loading, we found that the Dbf4-dependent Cdc7 kinase (DDK) initially drives origin recruitment of Sld3 and the Cdc45 helicase-activating protein. Corresponding in vivo studies found that DDK was required for Cdc45 binding at early origins during G1. Upon activation of S-phase cyclin-dependent kinases (S-CDK), a second helicase-activating protein (GINS) and the remainder of the replisome are recruited to the origin. Investigation of DNA polymerase recruitment showed that Mcm10 and DNA unwinding both were critical for recruitment of the lagging but not leading strand DNA polymerases. Our studies identify distinct roles for DDK and S-CDK during helicase activation and support a model in which the leading strand DNA polymerase is recruited prior to DNA unwinding and initial RNA primer synthesis.
2011-07-22 | GSE29646 | GEO
Project description:During routine genome duplication, many potential replication origins remain inactive, or dormant. Such origin dormancy is achieved, in part, by an interaction with the metabolic sensor SIRT1 deacetylase. We report here that dormant origins are a group of consistent, pre-determined genomic sequences that can be distinguished from baseline (i.e. ordinarily active) origins by their preferential association with MCM2, a component of the replicative helicase, phosphorylated on serine 108 (pS108-MCM2). pS108-MCM2 is a substrate of the ATR kinase, which is recruited to chromatin via an interaction with hyperacetylated TOPBP1 in cells undergoing replication stress or in cells devoid of SIRT1 deacetylase activity. In turn, S108-MCM2 phosphorylation enhances a second, DDK-dependent, S139-MCM2 phosphorylation, which triggers initiation of DNA replication at dormant origins. These observations suggest that replication origin dormancy and activation are regulated by distinct post-translational modifications on the MCM helicase that reflect a balance between SIRT1 activity and ATR signaling.
| MSV000088134 | MassIVE
Project description:Eukaryotic genomes are replicated from many origin sites that are licensed by the loading of inactive double hexamers of the replicative DNA helicase, Mcm2-7. How eukaryotic origin positions are specified remains elusive. Here we show that, contrary to the bacterial paradigm, eukaryotic origins are not irrevocably defined by selection of the loading site for the replicative helicase, but can shift in position after helicase loading. Using purified proteins, we show that DNA translocases, including RNA polymerase, can push budding yeast Mcm2-7 double hexamers along DNA. Displaced Mcm2-7 double hexamers support DNA replication initiation distal to the loading site in vitro. In yeast cells that are defective for transcription termination, collisions with RNA polymerase induce a shift in origin positions that correlates with the direction of transcription. These results reveal a eukaryotic origin specification mechanism that departs from the classical replicon model, helping eukaryotic cells to negotiate transcription-replication conflict. 4 samples: one replicate for WT at 37C, two replicates for rat1-1 at 37C, and one replicate for rat1-1 at 24C. All are single-end sequenced via Ion Torrent PGM methodology. rat1 = Nuclear 5' to 3' single-stranded RNA exonuclease; involved in RNA metabolism (http://www.yeastgenome.org/locus/S000005574/overview). 4 ChIP seq samples and their duplicates are submitted. rat1-1 ORC ChIP at 24C and 37C; rat1-1 MCM ChIP at 24C and 37C.
2016-01-07 | E-GEOD-69065 | biostudies-arrayexpress
Project description:During routine genome duplication, many potential replication origins remain inactive, or 'dormant'. Such origin dormancy is achieved, in part, by an interaction with the metabolic sensor SIRT1 deacetylase. We report here that dormant origins are a group of consistent, pre-determined genomic sequences that can be distinguished from baseline (i.e. ordinarily active) origins by their preferential association with MCM2, a component of the replicative helicase, phosphorylated on serine 108 (pS108-MCM2). pS108-MCM2 is a substrate of the ATR kinase, which is recruited to chromatin via an interaction with hyperacetylated TOPBP1 in cells undergoing replication stress or in cells devoid of SIRT1 deacetylase activity. In turn, S108-MCM2 phosphorylation enhances a second, DDK-dependent, S139-MCM2 phosphorylation, which triggers initiation of DNA replication at dormant origins. These observations suggest that replication origin dormancy and activation are regulated by distinct post-translational modifications on the MCM helicase that reflect a balance between SIRT1 activity and ATR signaling.
2022-05-09 | GSE184353 | GEO
Project description:The transmission and maintenance of genetic information in eukaryotic cells rely on the faithful duplication of the entire genome. In each round of division, excessive replication origiNS are licensed, while only a fraction is activated to give rise to bi-directional replication forks travelling in the context of chromatin. However, it remaiNS elusive how eukaryotic replication origiNS are selectively activated. Here we demoNStrate that O-GlcNAc traNSferase (OGT) enhances replication initiation by catalysing H4S47 O-GlcNAcylation. Mutation of H4S47 impairs DBF4-dependent protein kinase (DDK) recruitment on chromatin, causing compromised phosphorylation of replicative helicase mini-chromosome maintenance (MCM) complex. Meanwhile, our short nascent-strand sequencing (SNS-seq) confirms the important role of H4S47 O-GlcNAcylation in origin activation. Together, H4S47 O-GlcNAcylation directs origin activation through facilitating MCM phosphorylation, and this may shed light on the spatial and temporal control of DNA replication by the dynamically changing chromatin environment.
2023-04-08 | GSE205673 | GEO
Project description:The maintenance of genome stability relies on the coordinated control of origin activation and replication fork progression. How the interplay between these processes impacts human genetic disease and cancer remains incompletely characterized. Here we initially show that mouse cells lacking Pole4 and featuring Pole instability exhibit impaired genome-wide activation of DNA replication origins, in a origin location-independent manner. Lack of POLE4 leads to proteasome-dependent Pole degradation prior to CMG (CDC45/MCM2-7/GINS) helicase formation and origin activation. Strikingly, Trp53 ablation in primary Pole4 knock-out cells increased Pole levels and origin activation and reduced DNA damage levels in a transcription-dependent manner. Transcriptome analysis of primary Trp53 knock out cells revealed that the TRP53-CDKN1A/P21 axis maintains appropriate levels of replication initiation factors and CDK activity during unchallenged S-phase. Loss of this control mechanism deregulates origin activation, perturbs genome-wide replication fork progression and induces fork stalling and DNA damage. Thus, while our data support an impaired origin activation model for genetic diseases affecting CMG formation, we propose that loss of the TRP53-CDKN1A/P21 tumour suppressor axis induces inappropriate origin activation and deregulates genome wide fork progression. This phenomenon has broad implications for genetic instability and therapeutic targeting in cancer.
2022-05-16 | GSE200331 | GEO
Project description:DNA replication during S phase involves thousands of replication forks that must be coordinated to ensure that every DNA section is only replicated once. The minichromosome maintenance proteins, MCM2 to MCM7, form a heteromeric DNA helicase required for both initiation of DNA replication and elongation of DNA replication. Although only two DNA helicase activities are required to establish a bidirectional replication fork from each origin of replication, a large excess of MCM complexes is loaded and distributed along the chromatin. The function of the additional MCM complexes is not well understood, as most of them are displaced from the DNA during S-phase, apparently without playing an active role in DNA replication. DNA damage response (DDR) kinases activated by stalled forks prevent the replication machinery from being activated, indicating a tight relationship between DDR and DNA replication. To investigate the role of MCM proteins in the cellular response to DNA damage, we used shRNA targeting MCM2 or MCM3 to determine the impact of the reduction of the MCM complex. The alteration of MCM proteins induced a change in the activation of important factors of the DDR in response to Etoposide treatment. The phosphorylation of γ-H2AX, CHK1 and CHK2 is affected following DNA damage induced by treatment with Etoposide without affecting cell viability. Using assays measuring homologous recombination (HR) and non-homologous end-joining (NHEJ), we have identified a decrease of HR, but not NHEJ, associated with a decrease of the MCM complex demonstrating a role for the MCM complex in homologous recombination.
2019-11-12 | PXD009539 | Pride
Project description:Eukaryotic genomes are replicated from many origin sites that are licensed by the loading of inactive double hexamers of the replicative DNA helicase, Mcm2-7. How eukaryotic origin positions are specified remains elusive. Here we show that, contrary to the bacterial paradigm, eukaryotic origins are not irrevocably defined by selection of the loading site for the replicative helicase, but can shift in position after helicase loading. Using purified proteins, we show that DNA translocases, including RNA polymerase, can push budding yeast Mcm2-7 double hexamers along DNA. Displaced Mcm2-7 double hexamers support DNA replication initiation distal to the loading site in vitro. In yeast cells that are defective for transcription termination, collisions with RNA polymerase induce a shift in origin positions that correlates with the direction of transcription. These results reveal a eukaryotic origin specification mechanism that departs from the classical replicon model, helping eukaryotic cells to negotiate transcription-replication conflict.
2016-01-07 | GSE69065 | 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