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Expression data from lack of DNA topoisomerase I, DNA topoisomerase II and complete lack of both topoisomerases

ABSTRACT: To investigate the role of DNA topoisomerases in transcription, we have studied global gene expression in Saccharomyces cerevisiae cells deficient for topoisomerases I and II and performed single-gene analyses to support our findings. The genome-wide studies show a general transcriptional down-regulation upon lack of the enzymes, which correlates with gene activity but not gene length. Furthermore, our data reveal a distinct subclass of genes with a strong requirement for topoisomerases. These genes are characterized by high transcriptional plasticity, chromatin regulation, TATA box presence, and enrichment of a nucleosome at a critical position in the promoter region, in line with a repressible/inducible mode of regulation. Single-gene studies with a range of genes belonging to this group demonstrate that topoisomerases play an important role during activation of these genes. Subsequent in-depth analysis of the inducible PHO5 gene reveals that topoisomerases are essential for binding of the Pho4p transcription factor to the PHO5 promoter, which is required for promoter nucleosome removal during activation. In contrast, topoisomerases are dispensable for constitutive transcription initiation and elongation of PHO5, as well as the nuclear entrance of Pho4p. Finally, we provide evidence that topoisomerases are required to maintain the PHO5 promoter in a superhelical state, which is competent for proper activation. In conclusion, our results reveal a hitherto unknown function of topoisomerases during transcriptional activation of genes with a repressible/inducible mode of regulation

ORGANISM(S): Saccharomyces cerevisiae Schizosaccharomyces pombe

PROVIDER: GSE22809 | GEO | 2012/08/01

SECONDARY ACCESSION(S): PRJNA127897

REPOSITORIES: GEO

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Expression data from lack of DNA topoisomerase I, DNA topoisomerase II and complete lack of both topoisomerases

Project description:Here we dissect the transcriptional response in S. cerevisiae cells lacking DNA topoisomerases. We use microarray technology coupled with a functional genomics approach and demonstrate intimate connections between topoisomerase dependency, promoter chromatin architecture and gene transcription. Our findings suggest that DNA topoisomerases I and II play a role for transcription initiation. We observe a genome wide reduction in mRNA levels and identify a distinct functional subset of the genome with particular requirements for topoisomerases. These genes are characterized by high transcriptional plasticity, they are chromatin regulated and distinguished by having an enrichment of a nucleosome at a critical position in the promoter region, suggesting that topoisomerases influence transcription initiation by affecting promoter chromatin structure. In further support of a role of topoisomerases for initiation, we demonstrate that genome wide topoisomerase dependency reflects transcriptional activity but not transcriptional length. We exemplify the importance of topoisomerases for initiation of chromatin-regulated genes by showing that the enzymes are essential although redundant for PHO5 induction and are necessary for a step required for promoter nucleosome removal. W303 versus top1Î?, top2ts and top1Î?top2ts. 3 biological replicates for each mutant versus wildtype counterpart amounting to 12 microarrays.

2012-07-31 | E-GEOD-22809 | biostudies-arrayexpress

Topoisomerase II binds nucleosome-free DNA and acts redundantly with Topoisomerase I to enhance recruitment of RNA Pol II in budding yeast

Project description:DNA topoisomerases are known to promote transcription in prokaryotes by removing excessive DNA supercoils produced during elongation. However, it is unclear how topoisomerases in eukaryotes are recruited and function in the transcription pathway in the context of nucleosomes. To address this problem we present high-resolution genome wide maps of one of the major eukaryotic topoisomerases, Topoisomerase II (Top2) and nucleosomes in the budding yeast, Saccharomyces cerevisiae. Our data indicate that at promoters Top2 binds primarily to DNA that is nucleosome free. However, while nucleosome loss enables Top2 occupancy the opposite is not the case and the loss of Top2 has little effect on nucleosome density. We also find that Top2 is involved in transcription. Not only is Top2 enriched at highly transcribed genes but Top2 is required redundantly with Top1 for optimal recruitment of RNA polymerase II at their promoters. These findings and the examination of candidate activated genes suggest that nucleosome loss induced by nucleosome remodeling factors during gene activation enable Top2 binding which in turn acts redundantly with Top1 to enhance recruitment of RNA polymerase II.

2011-08-01 | GSE22626 | GEO

Chromatin immunoprecipitation of fission yeast to identify topoisomerase I and II activity

Project description:Eukaryotic topoisomerase I and II relax DNA and are key components in the processes of DNA replication, transcription and genome stability. It is not clear, however, how their activity controls epigenetic states across an entire eukaryotic genome. Using the fission yeast model Schizosaccharomyces pombe, we investigate genome-wide how topoisomerases affect chromatin formation through nucleosome occupancy and regulate transcription. We show that topoisomerase activity is required for nucleosome turnover at promoter regions, affecting epigenetic gene regulatory states, and for effective termination of transcription.

2010-07-02 | E-MEXP-1850 | biostudies-arrayexpress

Expression data from lack of DNA topoisomerase I, DNA topoisomerase II and complete lack of both topoisomerases

Project description:Here we dissect the transcriptional response in S. cerevisiae cells lacking DNA topoisomerases. We use microarray technology coupled with a functional genomics approach and demonstrate intimate connections between topoisomerase dependency, promoter chromatin architecture and gene transcription. Our findings suggest that DNA topoisomerases I and II play a role for transcription initiation. We observe a genome wide reduction in mRNA levels and identify a distinct functional subset of the genome with particular requirements for topoisomerases. These genes are characterized by high transcriptional plasticity, they are chromatin regulated and distinguished by having an enrichment of a nucleosome at a critical position in the promoter region, suggesting that topoisomerases influence transcription initiation by affecting promoter chromatin structure. In further support of a role of topoisomerases for initiation, we demonstrate that genome wide topoisomerase dependency reflects transcriptional activity but not transcriptional length. We exemplify the importance of topoisomerases for initiation of chromatin-regulated genes by showing that the enzymes are essential although redundant for PHO5 induction and are necessary for a step required for promoter nucleosome removal. W303 versus top1Δ, top2ts and top1Δtop2ts. 3 biological replicates for each mutant versus wildtype counterpart amounting to 12 microarrays.

2015-09-15 | E-GEOD-22809 | ExpressionAtlas

Gene regulation and priming by Topoisomerase IIÎ± in embryonic stem cells [ChIP-chip]

Project description:Topoisomerases are essential for resolving topological problems in the genome, while their function in gene regulation, especially during cellular differentiation, remains elusive/unknown. We reveal that the expression of two Topo II isoforms, Top2Î± and Top2Î², is characteristic of dividing and postmitotic tissues, respectively. In embryonic stem cells, Top2Î± preferentially binds to promoters embedded in an active chromatin environment. Inhibition of Top2Î± activity results in misregulation of target gene expression that accompanies accumulation of double-strand breaks. Common targets of Top2Î± and Top2Î² are housekeeping genes while their unique targets are involved in proliferation/pluripotency and neurogenesis (Can we say this as this might be because we are driving neurons from ES cells), respectively. Moreover, a small subset of Top2Î± targets exhibit bivalent chromatin state that is resolved upon differentiation concomitant with their activation and occupancy by Top2Î², a feature further observed for large lengthlong genes. These findings suggest that Top2Î± not only contributes to stem cell transcriptome regulation but may also prime developmental genes for subsequent activation by Top2Î². Chromatin IP was performed with Top2Î± antibodies in WT ES cells and hybridized to custom designed tiling array.

2013-10-10 | E-GEOD-45890 | biostudies-arrayexpress

Gene regulation and priming by Topoisomerase IIα in embryonic stem cells [RNA-Seq]

Project description:Topoisomerases are essential for resolving topological problems in the genome, while their function in gene regulation, especially during cellular differentiation, remains unknown. We reveal that the expression of two Topo II isoforms, Top2a and Top2ß, is characteristic of dividing and postmitotic tissues, respectively. In embryonic stem cells, Top2a preferentially binds to promoters embedded in an active chromatin environment. Inhibition of Top2a activity results in misregulation of target gene expression that accompanies accumulation of double-strand breaks. Common targets of Top2a and Top2ß are housekeeping genes while their unique targets are involved in proliferation/pluripotency and neurogenesis, respectively. Moreover, a subset of Top2a targets exhibit bivalent chromatin state that is resolved upon differentiation concomitant with their activation and occupancy by Top2ß, a feature further observed for long genes. These findings suggest that Top2a not only contributes to stem cell transcriptome regulation but may also prime developmental genes for subsequent activation upon differentiation. mRNA profiles of DMSO and ICRF-193 treated mESCs were generated by deep sequencing in triplicates. ICRF-193 is a well established catalytic inhibitor of Topoisomerase II, hence, we used ICRF-193 to the elucidate role of Top2a catalytic activity on transcription by genome wide transcription profiling.

2013-10-10 | E-GEOD-46066 | biostudies-arrayexpress

Gene regulation and priming by Topoisomerase II? in embryonic stem cells [FAIRE-Seq]

Project description:Topoisomerases are essential for resolving topological problems in the genome, while their function in gene regulation, especially during cellular differentiation, remains unknown. We reveal that the expression of two Topo II isoforms, Top2a and Top2ß, is characteristic of dividing and postmitotic tissues, respectively. In embryonic stem cells, Top2a preferentially binds to promoters embedded in an active chromatin environment. Inhibition of Top2a activity results in misregulation of target gene expression that accompanies accumulation of double-strand breaks. Common targets of Top2a and Top2ß are housekeeping genes while their unique targets are involved in proliferation/pluripotency and neurogenesis, respectively. Moreover, a subset of Top2a targets exhibit bivalent chromatin state that is resolved upon differentiation concomitant with their activation and occupancy by Top2ß, a feature further observed for long genes. These findings suggest that Top2a not only contributes to stem cell transcriptome regulation but may also prime developmental genes for subsequent activation upon differentiation. mRNA profiles of DMSO and ICRF-193 treated mESCs were generated by deep sequencing in triplicates. ICRF-193 is a well established catalytic inhibitor of Topoisomerase II, hence, we used ICRF-193 to the elucidate role of Top2a catalytic activity on transcription by genome wide transcription profiling.

2013-10-10 | E-GEOD-49141 | biostudies-arrayexpress

Gene regulation and priming by Topoisomerase IIα in embryonic stem cells [FAIRE-Seq]

Project description:Topoisomerases are essential for resolving topological problems in the genome, while their function in gene regulation, especially during cellular differentiation, remains unknown. We reveal that the expression of two Topo II isoforms, Top2a and Top2ß, is characteristic of dividing and postmitotic tissues, respectively. In embryonic stem cells, Top2a preferentially binds to promoters embedded in an active chromatin environment. Inhibition of Top2a activity results in misregulation of target gene expression that accompanies accumulation of double-strand breaks. Common targets of Top2a and Top2ß are housekeeping genes while their unique targets are involved in proliferation/pluripotency and neurogenesis, respectively. Moreover, a subset of Top2a targets exhibit bivalent chromatin state that is resolved upon differentiation concomitant with their activation and occupancy by Top2ß, a feature further observed for long genes. These findings suggest that Top2a not only contributes to stem cell transcriptome regulation but may also prime developmental genes for subsequent activation upon differentiation.

2013-10-10 | GSE49141 | GEO

Gene regulation and priming by Topoisomerase IIα in embryonic stem cells [RNA-Seq]

Project description:Topoisomerases are essential for resolving topological problems in the genome, while their function in gene regulation, especially during cellular differentiation, remains unknown. We reveal that the expression of two Topo II isoforms, Top2a and Top2ß, is characteristic of dividing and postmitotic tissues, respectively. In embryonic stem cells, Top2a preferentially binds to promoters embedded in an active chromatin environment. Inhibition of Top2a activity results in misregulation of target gene expression that accompanies accumulation of double-strand breaks. Common targets of Top2a and Top2ß are housekeeping genes while their unique targets are involved in proliferation/pluripotency and neurogenesis, respectively. Moreover, a subset of Top2a targets exhibit bivalent chromatin state that is resolved upon differentiation concomitant with their activation and occupancy by Top2ß, a feature further observed for long genes. These findings suggest that Top2a not only contributes to stem cell transcriptome regulation but may also prime developmental genes for subsequent activation upon differentiation.

2013-10-10 | GSE46066 | GEO

Gene regulation and priming by Topoisomerase IIα in embryonic stem cells [ChIP-chip]

Project description:Topoisomerases are essential for resolving topological problems in the genome, while their function in gene regulation, especially during cellular differentiation, remains elusive/unknown. We reveal that the expression of two Topo II isoforms, Top2α and Top2β, is characteristic of dividing and postmitotic tissues, respectively. In embryonic stem cells, Top2α preferentially binds to promoters embedded in an active chromatin environment. Inhibition of Top2α activity results in misregulation of target gene expression that accompanies accumulation of double-strand breaks. Common targets of Top2α and Top2β are housekeeping genes while their unique targets are involved in proliferation/pluripotency and neurogenesis (Can we say this as this might be because we are driving neurons from ES cells), respectively. Moreover, a small subset of Top2α targets exhibit bivalent chromatin state that is resolved upon differentiation concomitant with their activation and occupancy by Top2β, a feature further observed for large lengthlong genes. These findings suggest that Top2α not only contributes to stem cell transcriptome regulation but may also prime developmental genes for subsequent activation by Top2β.

2013-10-10 | GSE45890 | GEO

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