Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

DNA Topoisomerase I differentially modulates R loop across long genes and at human replication origins

ABSTRACT: Co-transcriptional R-loops are abundant non-B DNA structures in mammalian genomes. DNA Topoisomerase I (Top1) is often thought to regulate R-loop formation owing to its ability to resolve both positive and negative supercoils. How Top1 regulates R-loop structures at a global level is unknown. Here, we performed high-resolution strand-specific R-loop mapping in human cells depleted for Top1 and found that Top1 depletion resulted in both R-loop gains and losses at thousands of transcribed loci, delineating two distinct gene classes. R-loop gains were characteristic for long, highly transcribed, genes located in gene-poor regions anchored to Lamin B1 domains and in proximity to H3K9me3-marked heterochromatic patches. R-loop losses, by contrast, occurred in gene-rich regions overlapping H3K27me3-marked active replication origins. Interestingly, Top1 depletion coincided with a block of the cell cycle in G0/G1 phase and a trend towards global replication delay. Our findings reveal new properties of Top1 in regulating R-loop homeostasis and suggest a potential role for Top1 in controlling replication origin via R-loop formation.

ORGANISM(S): Homo sapiens

PROVIDER: GSE102474 | GEO | 2018/06/26

REPOSITORIES: GEO

ACCESS DATA

Json Xml

Similar Datasets

G-quadruplex on Chromosomal DNA Negatively Regulates Topoisomerase 1 Activity [ChIP-seq]

Project description:Human DNA topoisomerase 1 (Top1) is a crucial enzyme responsible for alleviating torsional stress on DNA during transcription and replication, thereby maintaining genome stability. Previous researches had found that non-working Top1 interacted extensively with chromosomal DNA in human cells. However, the reason for its retention on chromosomal DNA remained unclear. In this study, we discovered a close association between Top1 and chromosomal DNA, specifically linked to the presence of G-quadruplex (G4) structures. G4 structures, formed during transcription, trap Top1 and hinder its ability to relax neighboring DNAs. Disruption of the Top1-G4 interaction using G4 ligand relieved the inhibitory effect of G4 on Top1 activity, resulting in a further reduction of R-loop levels in cells. Additionally, the activation of Top1 through the use of a G4 ligand enhanced the toxicity of Top1 inhibitors towards cancer cells. Our study uncovers a negative regulation mechanism of human Top1 and highlights a novel pathway for activating Top1.

2024-01-01 | GSE239692 | GEO

G-quadruplex on Chromosomal DNA Negatively Regulates Topoisomerase 1 Activity [CUT&Tag]

2024-01-01 | GSE239690 | GEO

The Epigenetic dysregulation of lncRNA on gene expression in Colorectal tumor [RNA-seq]

Project description:Our data analysis unveils that differentially expressed long noncoding RNAs and some wrongly transcribed noncoding transcripts have potential DNA binding sites at promoters of differentially expressed or wrongly transcribed coding transcripts, gains and losses of differentially methylated DNA regions also occur at relevant sites, but less specifically. Moreover, both differentially expressed or wrongly transcribed transcripts and gains and losses of differentially methylated DNA regions show significant case-to-case variation.

2020-12-07 | GSE109203 | GEO

The Epigenetic dysregulation of lncRNA on gene expression in Colorectal tumor [MeDIP-seq]

2020-12-07 | GSE109202 | GEO

Genome-wide R-loop analysis defines unique roles for DDX5, XRN2, and PRMT5 in DNA/RNA hybrid resolution

Project description:DDX5, XRN2, and PRMT5 have been shown to resolve DNA/RNA hybrids (R-loops) at RNA polymerase II transcription termination sites at few genomic loci. Herein, we perform genome-wide R-loop mapping using classical DNA/RNA immunoprecipitation and high-throughput sequencing (DRIP-seq) of loci regulated by DDX5, XRN2, and PRMT5. We observed hundreds to thousands of R-loop gains and losses at transcribed loci in DDX5-, XRN2-, and PRMT5-deficient U2OS cells. R-loop gains were characteristic of highly transcribed genes located at gene-rich regions, whereas R-loop losses were observed in low-density gene areas. DDX5, XRN2, and PRMT5 shared many R-loop gain loci at transcription termination sites, consistent with their coordinated role in RNA polymerase II transcription termination. DDX5-depleted cells had unique R-loop gain peaks near the transcription start site that did not overlap with those of siXRN2 and siPRMT5 cells, suggesting a role for DDX5 in transcription initiation independent of XRN2 and PRMT5. Moreover, we observed that the accumulated R-loops at certain loci in siDDX5, siXRN2, and siPRMT5 cells near the transcription start site of genes led to antisense intergenic transcription. Our findings define unique and shared roles of DDX5, XRN2, and PRMT5 in DNA/RNA hybrid regulation.

2020-08-08 | GSE155865 | GEO

Topoisomerase 1 dependent R-loop deficiency drives accelerated replication and genomic instability

Project description:DNA replication is a complex process tightly regulated to ensure faithful genome duplication, and its perturbation leads to DNA damage and genomic instability. Replication stress is commonly associated with slow and stalled replication forks. Recently, accelerated replication has emerged as a non-canonical form of replication stress. However, the molecular basis underlying fork acceleration is largely unknown. Here we show that mutated HRAS activation leads to increased topoisomerase 1 (TOP1) expression leading to aberrant replication fork acceleration and DNA damage by decreasing RNA-DNA hybrids or R-loops. In these cells, restoration of TOP1 expression or mild replication inhibition rescues the perturbed replication and reduces DNA damage. Furthermore, TOP1 or RNaseH1 overexpression induces accelerated replication and DNA damage, highlighting the importance of TOP1 equilibrium in regulating R-loop homeostasis to ensure faithful DNA replication and genome integrity. Altogether, our results reveal a novel mechanism of oncogene-induced DNA damage induced by aberrant replication fork acceleration.

2022-09-08 | GSE168738 | GEO

Topoisomerase I cleavage complexes preferentially down-regulate ubiquitin- and RNA degradation-related transcripts in relationship to gene length, exon-intron junctions and p53-dependent up-regulation of miR-142-3p [miRNA]

Project description:DNA topoisomerase I (Top1) is required for transcription as it relaxes positive and negative supercoils by forming transient Top1 cleavage complexes (Top1cc) up- and down-stream of transcription complexes. However, Top1cc can also be trapped by endogenous DNA lesions and by camptothecin (CPT) and its anticancer derivatives, which results in transcription blocks. Here, we undertook a genome-wide analysis of the effects of CPT on gene expression at exon resolution. We tested the impact of Top1 inhibition on miRNA expression at the genome-wide level in human colon carcinoma HCT116. The miRNA of cells treated with camptothecin (CPT) for were measured at several timepoints with Agilent Human miRNA Microarray V3 (8x15K).

2013-04-17 | E-GEOD-37357 | biostudies-arrayexpress

Topoisomerase I suppresses genomic instability by preventing interference between replication and transcription

Project description:Topoisomerase I (Top1) is a key enzyme acting at the interface between DNA replication, transcription and mRNA maturation. Here, we show that Top1 suppresses genomic instability in mammalian cells by preventing conflicts between transcription and DNA replication. Using DNA combing and ChIP-on-chip, we found that Top1-deficient cells accumulate stalled replication forks and chromosome breaks in S phase and that breaks occur preferentially at gene-rich regions of the genome. Strikingly, these phenotypes were suppressed by preventing the formation of RNA-DNA hybrids (R-loops) during transcription. Moreover, these defects could be mimicked by depletion of the splicing factor ASF/SF2, which interacts functionally with Top1. Taken together, these data indicate that Top1 prevents replication fork collapse by suppressing the formation of R-loops in an ASF/SF2-dependent manner. We propose that interference between replication and transcription represents a major source of spontaneous replication stress, which could drive genomic instability during early stages of tumorigenesis. Bed files contain the gamma-H2AX enrichment sites described in the paper

2009-08-08 | GSE17552 | GEO

2013-04-17 | GSE37357 | GEO

Transcription poisoning by topoisomerase I is controlled by gene length, splice sites and miR-142-3p

2013-04-17 | GSE37352 | GEO