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Topoisomerase II-induced Chromosome Breakage and Translocation Is Determined by Chromosome Architecture and Transcriptional Activity [Nascent RNA]

ABSTRACT: Topoisomerase II (TOP2) relieves torsional stress during transcription, DNA replication and chromosome segregation, by forming transient cleavage complex intermediates (TOP2ccs) that contain TOP2-linked DNA breaks. While TOP2ccs are normally reversible they can be ‘trapped’ by chemotherapeutic drugs such as etoposide, and subsequently converted into irreversible TOP2-linked DSBs that threaten genome stability. Here, using genomics approaches, we have quantified the etoposide-induced trapping of TOP2ccs, their conversion into irreversible TOP2-linked DSBs, and their processing during DNA repair genome-wide, as a function of time. We find that while TOP2 trapping is independent of transcription it requires pre-existing binding of cohesin to DNA. In contrast, the conversion of trapped TOP2ccs to irreversible DSBs during DNA repair is accelerated two-fold at transcribed loci, relative to non-transcribed loci. This conversion is dependent on proteasomal degradation and TDP2 phosphodiesterase activity. Quantitative modeling shows that only two critical features of pre-existing chromatin structure- namely, cohesin binding and transcriptional activity- can be used to accurately predict the kinetics of TOP2-induced DSBs. Thus, our study permits a mechanistic understanding of TOP2 induced genome instability.

ORGANISM(S): Mus musculus

PROVIDER: GSE129527 | GEO | 2019/04/26

REPOSITORIES: GEO

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Topoisomerase II-induced Chromosome Breakage and Translocation Is Determined by Chromosome Architecture and Transcriptional Activity [HTGTS]

Project description:Topoisomerase II (TOP2) relieves torsional stress during transcription, DNA replication and chromosome segregation, by forming transient cleavage complex intermediates (TOP2ccs) that contain TOP2-linked DNA breaks. While TOP2ccs are normally reversible they can be ‘trapped’ by chemotherapeutic drugs such as etoposide, and subsequently converted into irreversible TOP2-linked DSBs that threaten genome stability. Here, using genomics approaches, we have quantified the etoposide-induced trapping of TOP2ccs, their conversion into irreversible TOP2-linked DSBs, and their processing during DNA repair genome-wide, as a function of time. We find that while TOP2 trapping is independent of transcription it requires pre-existing binding of cohesin to DNA. In contrast, the conversion of trapped TOP2ccs to irreversible DSBs during DNA repair is accelerated two-fold at transcribed loci, relative to non-transcribed loci. This conversion is dependent on proteasomal degradation and TDP2 phosphodiesterase activity. Quantitative modeling shows that only two critical features of pre-existing chromatin structure- namely, cohesin binding and transcriptional activity- can be used to accurately predict the kinetics of TOP2-induced DSBs. Thus, our study permits a mechanistic understanding of TOP2 induced genome instability.

2019-04-26 | GSE129528 | GEO

Topoisomerase II-induced Chromosome Breakage and Translocation Is Determined by Chromosome Architecture and Transcriptional Activity [END-seq]

2019-04-26 | GSE129524 | GEO

Topoisomerase II-induced Chromosome Breakage and Translocation Is Determined by Chromosome Architecture and Transcriptional Activity [ChIP-seq]

2019-04-26 | GSE129526 | GEO

Suppressing Proteasome Mediated Processing of Topoisomerase II DNA-Protein Adducts Preserves Genome Integrity

Project description:Here, we utilize high-resolution mapping of ETO-induced TOP2 lesions genome-wide (END-seq) (Canela et al., 2016), to examine the impact of proteasome inhibition on the fate of TOP2ccs. We found that once ETO-stabilized TOP2ccs had been proteolytically processed throughout the genome, and a robust DDR had been initiated, the large number of newly generated protein-free DSBs were repaired in a highly error-prone manner, resulting in toxic chromosomal translocations and rearrangements that lead to cell death. Notably, mis-repair of ETO-induced lesions occurred independently of the classical NHEJ or HR pathways. By inhibiting proteasome-mediated degradation of TOP2ccs either through chemical inhibition or by ablation of the ubiquitination of TOP2ccs by RNF4, an intact and enzymatically competent TOP2 was able to re-seal the protein-linked DSBs without invoking a significantly DDR. As a result, cells were protected from genomic instability, which ultimately led to enhanced cell survival after treatment with topoisomerase poisons.

2020-02-20 | GSE140372 | GEO

RAD54L2 mediates a novel mechanism to counter TOP2-DNA adducts

Project description:The catalytic cycle of topoisomerase 2 (TOP2) enzymes proceeds via a transient DNA double-strand break (DSB) intermediate termed the TOP2 cleavage complex (TOP2cc), in which the TOP2 protein is covalently bound to DNA. Anti-cancer agents such as etoposide operate by stabilising TOP2ccs, ultimately generating genotoxic TOP2-DNA protein crosslinks that require processing and repair. Here, we identify RAD54L2 as a factor promoting TOP2cc resolution. We demonstrate that RAD54L2 acts through a novel mechanism together with ZNF451 and independent of TDP2. Our work suggests a model wherein RAD54L2 recognises sumoylated-TOP2 and, using its ATPase activity, promotes TOP2cc resolution and prevents DSB exposure. These findings suggest RAD54L2-mediated TOP2cc resolution as a potential mechanism for cancer-therapy resistance and highlight RAD54L2 as an attractive candidate for drug discovery.

2024-01-26 | PXD046611 | Pride

Nucleotide resolution mapping of Top2-linked DNA breaks in the yeast genome

Project description:DNA topoisomerases are required to resolve DNA topological stress. Despite this essential role, abortive topoisomerase activity generates aberrant protein-linked DNA breaks, jeopardising genome stability. Here, to understand the genomic distribution and mechanisms underpinning topoisomerase-induced DNA breaks, we map Top2 DNA cleavage with strand-specific nucleotide resolution across the S. cerevisiae and human genomes—and use the meiotic Spo11 protein to validate the broad applicability of this method to explore the role of diverse topoisomerase family members. Our data characterises Mre11-dependent repair in yeast and defines two strikingly different fractions of Top2 activity in humans: tightly localised CTCF-proximal, and broadly distributed transcription-proximal, the latter correlated with gene length and expression. Moreover, single nucleotide accuracy reveals the influence primary DNA sequence has upon Top2 cleavage—distinguishing sites likely to form canonical DNA double-strand breaks (DSBs) from those predisposed to form strand-biased DNA single-strand breaks (SSBs) induced by etoposide (VP16) in vivo. This data set contains maps of Top2 CCs in the S. cerevisiae genome, generated by CC-seq of BY4741 cells -/+ etoposide (VP16).

2019-09-28 | GSE136675 | GEO

Nucleotide resolution mapping of Spo11-linked DNA breaks in the yeast genome

Project description:DNA topoisomerases are required to resolve DNA topological stress. Despite this essential role, abortive topoisomerase activity generates aberrant protein-linked DNA breaks, jeopardising genome stability. Here, to understand the genomic distribution and mechanisms underpinning topoisomerase-induced DNA breaks, we map Top2 DNA cleavage with strand-specific nucleotide resolution across the S. cerevisiae and human genomes - and use the meiotic Spo11 protein to validate the broad applicability of this method to explore the role of diverse topoisomerase family members. Our data characterises Mre11-dependent repair in yeast, and defines two strikingly different fractions of Top2 activity in humans: tightly localised CTCF-proximal, and broadly distributed transcription-proximal, the latter correlated with gene length and expression. Moreover, single nucleotide accuracy enables us to reveal the influence primary DNA sequence has upon Top2 cleavage - distinguishing canonical DNA double-strand breaks (DSBs) from a major population of DNA single-strand breaks (SSBs) induced by etoposide (VP16) in vivo.

2019-09-28 | GSE137685 | GEO

Nucleotide resolution mapping of Top2-linked DNA breaks in the human genome

2019-09-28 | GSE136943 | GEO

Genome-wide prediction of topoisomerase IIB binding by architectural factors and chromatin accessibility

Project description:Aberrant activity of type II topoisomerases (TOP2) often causes blocked double-strand breaks (DSBs), whose inefficient repair can seriously compromise genomic stability. One of the two TOP2 paralogs encoded in vertebrates is TOP2B, which has been linked to essential processes such as transcription or genome organization. Few TOP2B genome-wide maps have been profiled, and a comprehensive study of the mechanisms involved in TOP2B-DNA binding is still lacking. Here, we conduct an in silico approach for the prediction of TOP2B binding sites using publicly available sequencing data. We achieve highly accurate predictions and find that open chromatin and architectural factors are the most informative features. We also validate our predictions on experimental data and generate predicted TOP2B tracks that mirror experimental ones with high precision.

2020-12-30 | GSE141528 | GEO

Spatial chromosome folding and active transcription drive DNA fragility and formation of oncogenic MLL translocations [BLISS-Seq]

Project description:How spatial chromosome organization influences genome integrity is still poorly understood. Here we show that DNA double-strand breaks (DSBs) mediated by topoisomerase 2 (TOP2) activities, are enriched at chromatin loop anchors with high transcriptional activity. Recurrent DSBs occur at CTCF/cohesin bound sites at the bases of chromatin loops and their frequency positively correlates with transcriptional output and directionality. The physiological relevance of this preferential positioning is indicated by the finding that genes recurrently translocating to drive leukemias, are highly transcribed and are enriched at loop anchors. These genes accumulate DSBs at recurrent hot spots that give rise to chromosomal fusions relying on the activity of both TOP2 isoforms and on transcriptional elongation. We propose that transcription and 3D chromosome folding jointly pose a threat to genomic stability, and are key contributors to the occurrence of genome rearrangements that drive cancer.

2019-06-12 | GSE121740 | GEO

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