Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Single-cell mapping of chromosome breaks identifies multiple fragile site classes with distinct DNA replication timing landscapes [scRepli-seq]

ABSTRACT: Common fragile sites (CFSs) are genomic regions susceptible to chromosome breaks. However, because they were identified using cell populations, low-frequency fragile sites (non-CFSs) could have been overlooked. Here we perform single-cell genome-wide mapping and classification of aphidicolin-induced chromosome breaks. In human osteosarcoma cells, 42% of breaks exhibit features of CFSs. The remaining 58% are non-CFSs that are ‘rare’ and replicate throughout the S-phase. Among non-CFSs, we identify early-S replicating breaks associated with transcription-replication conflicts, as well as two additional break classes. One is dependent on transcription and coincides with early-to-late-S replication timing (RT) transition regions, while another class exhibits late-S RT with its frequency increasing upon transcription inhibition. Intriguingly, we find that distinct RT landscapes are associated with aphidicolin-induced RT behavior and break classes. Our data reveal the frequencies, RT landscapes, and mechanistic differences among distinct break classes, providing a comprehensive view of genomic regions prone to breakage under replication stress.

ORGANISM(S): Mus musculus Homo sapiens

PROVIDER: GSE281920 | GEO | 2026/07/13

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Dataset's files

Source:

			Action	DRS
		Other

Items per page:

1 - 1 of 1

Similar Datasets

Single-cell mapping of chromosome breaks identifies multiple fragile site classes with distinct DNA replication timing landscapes [BrdU-IP Repli-seq]

Project description:Common fragile sites (CFSs) are genomic regions susceptible to chromosome breaks. However, because they were identified using cell populations, low-frequency fragile sites (non-CFSs) could have been overlooked. Here we perform single-cell genome-wide mapping and classification of aphidicolin-induced chromosome breaks. In human osteosarcoma cells, 42% of breaks exhibit features of CFSs. The remaining 58% are non-CFSs that are ‘rare’ and replicate throughout the S-phase. Among non-CFSs, we identify early-S replicating breaks associated with transcription-replication conflicts, as well as two additional break classes. One is dependent on transcription and coincides with early-to-late-S replication timing (RT) transition regions, while another class exhibits late-S RT with its frequency increasing upon transcription inhibition. Intriguingly, we find that distinct RT landscapes are associated with aphidicolin-induced RT behavior and break classes. Our data reveal the frequencies, RT landscapes, and mechanistic differences among distinct break classes, providing a comprehensive view of genomic regions prone to breakage under replication stress.

2026-07-13 | GSE281921 | GEO

3D genome organization, transcription and aberrant DNA replication contribute to genome instability at fragile sites

Project description:Common fragile sites (CFSs) are regions susceptible to replication stress and are hotspots for chromosomal instability in cancer. Several features characterizing CFSs have been associated with their instability, however, these features are prevalent across the genome and do not account for all known CFSs. Here we explored the DNA replication timing (RT) and transcriptional profile under mild replication stress in the context of the 3D genome organization. We report the analysis of DNA replication timing profiling of human fibroblasts (BJ-hTERT), grown with or without aphidicolin, a DNA polymerase inhibitor used to induce CFS expression. We find that aphidicolin treatment affects the RT of a small portion of the genome. However, CFSs are enriched for delayed RT regions under stress. We further study the mechanism leading to recurrent chromosomal instability at CFSs and find that the 3D genome organization underlies fragility at RT delayed large expressed genes. We report a fragility signature at the core of CFSs comprised of delayed replication of large expressed gene spanning over a TAD-boundary. The fragility signature allows for mapping of the core fragile site and the identification of novel fragile sites in BJ cells.

2020-06-09 | GSE150543 | GEO

3D genome organization, transcription and aberrant DNA replication contribute to genome instability at fragile sites

Project description:Common fragile sites (CFSs) are regions susceptible to replication stress and are hotspots for chromosomal instability in cancer. Several features characterizing CFSs have been associated with their instability, however, these features are prevalent across the genome and do not account for all known CFSs. Here we explored the transcriptional profile and DNA replication timing under mild replication stress in the context of the 3D genome organization. We report the analysis of nascent RNA-seq for high-throughput profiling of gene expression in human fibroblasts (BJ-hTERT), grown with or without aphidicolin, a DNA polymerase inhibitor used to induce CFS expression. We find that aphidicolin treatment does not affect the transcriptional program. However, large expressed genes are susceptible to replication timing delay under stress. We further study the mechanism leading to recurrent chromosomal instability at CFSs and find that the 3D genome organization underlies fragility at large expressed genes. We report a fragility signature at the core of CFSs comprised of a large expressed gene spanning over a TAD-boundary with delayed DNA replication. The fragility signature allows for mapping of the core fragile site and the identification of novel fragile sites in BJ cells.

2020-06-08 | GSE150354 | GEO

Proteomics characterization of Chromosomal Common Fragile Site (CFS) - associated proteins uncovers ATRX as a regulator of CFS stability

Project description:Chromosomal Common Fragile Sites (CFSs) are conserved regions of our genome prone to break in conditions of replication stress (RS. Here, we have performed Chromatin Immunoprecipitation (ChIP) with FACND2 antibodies coupled to Mass Spectrometry to isolate CFSs from HeLa cells and identify the proteins enriched at these loci.

2019-06-11 | PXD011937 | Pride

Genome-wide replication dynamics quantification reveals stress-induced delayed/under-replication as a hallmark of CFSs

Project description:We report Repli-Seq analysis of the replication program in human lymphoblasts grown in the absence or in the presence of aphidicolin, an inhibitor of replicative DNA polymerases used in vitro to destabilize CFSs. We identified regions displaying specific replication delay upon aphidicolin treatment, resulting in under-replication. We then further study the mechanisms leading to such specific delayed/under-replication within CFSs and show that transcription-dependent segregation of initiation events out of the gene body generates long-traveling forks in large transcribed domains, which elicits the replication timing delay responsible for CFS instability upon replication stress.

2019-12-29 | GSE134709 | GEO

TDP1 phosphorylation at S61 promotes Top1cc repair via the MUS81-dependent pathway during mitosis

Project description:Topoisomerase 1 (Top1) removes supercoils from DNA during replication and transcription, is critical for mitotic progression to the G1 phase, and ensures DNA topology. Tyrosyl-DNA phosphodiesterase 1 (TDP1) mediates the removal of trapped Top1-DNA covalent complexes (Top1ccs). Here, we identify CDK1-dependent phosphorylation of TDP1 at S61 residue during mitosis. TDP1 defective for S61 phosphorylation (TDP1S61A) is trapped on the mitotic chromosomes, triggering DNA damage and mitotic defects. Moreover, we show that Top1cc repair in mitosis occurs via MUS81-dependent mitotic DNA repair mechanism. Replication stress (RS) induced by Camptothecin (CPT) or Aphidicolin (APH) leads to TDP1S61A enrichment at common fragile sites (CFSs), which over-stimulates MUS81-dependent chromatid breaks, anaphase bridges, and micronuclei, ultimately culminating in 53BP1 nuclear bodies in the G1-phase. Our findings provide a new insight into the cell cycle-dependent regulation of TDP1 dynamics forthe repair of trapped Top1ccs during mitosis that prevents genomic instability following RS.

2024-06-26 | PXD053309 | Pride

Tight CDK1 inhibition elicits domain-specific pre-RC setting in S-phase, suppressing CFS instability

Project description:Genome integrity requires replication to be completed before chromosome segregation. This coordination essentially relies on replication-dependent activation of a dedicated checkpoint that inhibits CDK1, delaying mitotic onset. Under-replication of Common Fragile Sites (CFSs), however, escapes surveillance, which generates mitotic chromosome breaks. Using human cells, we asked whether this leakage results from insufficient CDK1 inhibition under modest stresses used to destabilize CFSs. We found that tight CDK1 inhibition does suppress CFS instability in so-stressed cells. Molecular combing and Repli-Seq analyses consistently showed a burst of replication initiations in mid S-phase across large origin-poor domains shaped by transcription, including CFSs. CFS rescue and extra-initiations strikingly require availability of essential pre-Replication Complex (pre-RC) proteins during the S-phase, showing that CDK1 inhibition promotes targeted and mistimed pre-RC reloading. In addition to delay mitotic onset, tight checkpoint activation therefore advances replication completion of origin-poor domains at risk of under-replication, two complementary roles preserving genome stability.

2022-12-31 | GSE185282 | GEO

Genome-wide High Resolution Mapping of Mitotic DNA Synthesis Sites and Common Fragile Sites by Direct Sequencing [WGS]

Project description:Common fragile sites (CFSs) are genomic loci prone to the formation of breaks or gaps on metaphase chromosomes. Here, we seek to map human CFSs with high resolution on a genome-wide scale by sequencing the sites of mitotic DNA synthesis (MiDASeq) that are specific for CFSs. We generated a nucleotide-resolution atlas of MiDAS sites (MDSs) that covered most of know CFSs, and comprehensively analyzed their sequence characteristics and genomic features.

2020-05-01 | GSE149375 | GEO