Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Phosphorylated SIRT1 associates with replication origins to prevent excess replication initiation and preserve genomic stability

ABSTRACT: Chromatin structure affects DNA replication patterns, but the role of specific chromatin modifiers in regulating the replication process is yet unclear. We report that phosphorylation of the human SIRT1 deacetylase on Threonine 530 (T530-pSIRT1) modulates DNA synthesis. T530-pSIRT1 associates with replication origins and inhibits replication from a group of ÒdormantÓ potential replication origins, which initiate replication only when cells are subject to replication stress. Although both active and dormant origins bind T530-pSIRT1, active origins are distinguished from dormant origins by their unique association with an open chromatin mark, histone H3 methylated on lysine 4. SIRT1 phosphorylation also facilitates leading and lagging strand coordination. SIRT1 T530 phosphorylation is essential to prevent DNA breakage upon replication stress and cells harboring SIRT1 that cannot be phosphorylated exhibit a high prevalence of extrachromosomal elements, hallmarks of perturbed replication. These observations suggest that SIRT1 phosphorylation modulates the distribution of replication initiation events to insure genomic stability.

ORGANISM(S): Homo sapiens

PROVIDER: GSE94403 | GEO | 2017/06/02

SECONDARY ACCESSION(S): PRJNA369608

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

Convergence of SIRT1 and ATR signaling to modulate replication origin dormancy

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

Convergence of SIRT1 and ATR signaling to modulate replication origin dormancy

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

SIRT1 prevents R-loops during chronological aging by modulating DNA replication at rDNA loci

Project description:In metazoans, the largest sirtuin, SIRT1, is a nuclear protein implicated in epigenetic modifications, circadian signaling, DNA recombination, replication and repair. Our previous studies have demonstrated that SIRT1 binds replication origins and inhibits replication initiation from a group of potential initiation sites (dormant origins). We studied the effects of aging and SIRT1 activity on replication origin usage and the incidence of transcription-replication collisions (creating R-loop structures) in adult human cells obtained at different time points during chronological aging and in cancer cells. In primary, untransformed cells, SIRT1 activity declined, and the prevalence of R-loops rose with chronological aging. Both the reduction of SIRT1 activity and the increased abundance of R-loops were also observed during the passage of primary cells in culture. All cells, regardless of donor age or transformation status, reacted to short-term, acute chemical inhibition of SIRT1 with the activation of excessive replication initiation events coincident with an increased prevalence of R-loops. However, only cancer cells showed genome-wide activation of dormant origins during long-term proliferation with mutated or depleted SIRT1, whereas in primary cells, aging-associated SIRT1-mediated activation of dormant origins was restricted to rDNA loci. These observations suggest that chronological aging and the associated decline in SIRT1 activity relaxes the regulatory networks that protect cells against excess replication and that the mechanisms protecting from replication-transcription collisions at the rDNA loci manifest as a differentially enhanced sensitivity to SIRT1 decline and chronological aging.

2023-11-27 | GSE247469 | GEO

Conservation of replication timing reveals global and local regulation of replication origin activity.

Project description:DNA replication initiates from defined locations called replication origins; some origins are highly active whereas others are dormant and rarely used. Origins also differ in their activation time resulting in particular genomic regions replicating at characteristic times and in a defined temporal order. Here we report the comparison of genome replication in four budding yeast species: Saccharomyces cerevisiae, S. paradoxus, S. arboricolus and S. bayanus. First, we find that the locations of active origins are predominantly conserved between species, whereas dormant origins are poorly conserved. Second, we generated genome-wide replication profiles for each of these species and discovered that the temporal order of genome replication is highly conserved. Therefore, active origins are not only conserved in location, but also activation time. Only a minority of these conserved origins show differences in activation time between these species. To gain insight as to the mechanisms by which origin activation time is regulated we generated replication profiles for a S. cerevisiae / S. bayanus hybrid strain and find that there are both local and global regulators of origin function. Measurement of genome replication time from 4 budding yeast species (Saccharomyces cerevisiae, S. paradoxus, S. arboricolus and S. bayanus) and a hybrid (between Saccharomyces cerevisiae and S. bayanus). For each strain two samples were analysed: a replicating sample (from S phase) and a non-replicating sample (from G2 phase) The reference genome sequences for each yeast species are available as Series supplementary file [sac*.fa]

2012-06-19 | E-GEOD-36045 | biostudies-arrayexpress

Genome wide identification of MCM7 binding sites as replication origins

Project description:Here, we precisely determined MCM7 binding sites inHeLa cells by ChIP-Seq, classified them into firing and dormant replication origins using SNS data deposited, and analyzed their association with various chromatin signatures.

2017-11-23 | GSE107248 | GEO

Conservation of replication timing reveals global and local regulation of replication origin activity.

2012-06-19 | GSE36045 | GEO

Convergence of SIRT1 and ATR signaling to modulate replication origin dormancy

Project description:SIRT1 chromatin interactome analysis was performed to identify SIRT1 molecular targets involved in replication initiation from cells containing either WT or H363Y SIRT1. Co-IP-MS of pT530 SIRT1 from chromatin extracts was performed. Files are: 1422 WT SIRT1 untreated U2OS; 1423 WT SIRT1 H2O2 treated, U2OS; 1424 H363Y SIRT1 untreated U2OS; 1425 H363Y SIRT1 H2O2 U2OS; 1426 KO SIRT1 untreated U2OS; 1427 KO SIRT1 H2O2 U2OS; 1428 WT SIRT1 untreated HEK; 1429 WT SIRT1 H2O2 HEK; 1430 WT SIRT1 untreated HCT116; 1431 WT SIRT1 H2O2 HCT116; 1432 WT SIRT1 untreated K562; 1433 WT SIRT1 H2O2 K562. Each sample has 9 fractions.

| MSV000088103 | MassIVE

DYNAMICS OF REPLICATION ORIGIN OVER-ACTIVATION

Project description:Safeguards against excess DNA replication are often dysregulated in cancer, and driving cancer cells towards over-replication is a promising therapeutic strategy. We determined DNA synthesis patterns in cancer cells undergoing partial genome re-replication due to perturbed regulatory interactions ("re-replicating cells"). These cells exhibited slow replication, increased frequency of replication initiation events and a skewed initiation pattern that preferentially reactivated early-replicating origins. Unlike in cells exposed to replication stress, which activated a novel group of hitherto unutilized (”dormant”) replication origins, the preferred re-replicating origins arose from the same pool of potential origins as those activated during normal growth. Mechanistically, the skewed initiation pattern reflected a disproportionate distribution of pre-replication complexes on distinct regions of licensed chromatin prior to replication. This distinct pattern suggests that circumventing the strong inhibitory interactions that normally prevent excess DNA synthesis can occur via at least two pathways, each activating a distinct set of replication origins.

2021-06-01 | GSE172417 | GEO

Cohesin modulates DNA replication to preserve genome integrity [ChIP_seq]

Project description:Cohesin participates in loop formation by extruding DNA fibers from its ring-shaped structure. Cohesin dysfunction eliminates chromatin loops but only causes modest transcription perturbation, which cannot fully explain the frequently observed mutations of cohesin in various cancers. Here, we found that DNA replication initiates at more than one thousand extra dormant origins after acute depletion of RAD21, a core subunit of cohesin, resulting in earlier replicating timing at approximately 30% of the human genomic regions. In contrast, CTCF is dispensable for suppressing the early firing of dormant origins that are distributed away from the loop boundaries. Furthermore, greatly elevated levels of gross DNA breaks and genome-wide chromosomal translocations arise in RAD21-depleted cells, accompanied by dysregulated replication timing at dozens of hotspot genes. Thus, we conclude that cohesin coordinates DNA replication initiation to ensure proper replication timing and safeguards genome integrity.

2022-07-31 | GSE189759 | GEO