Mapping of genome-wide action sites of topoisomerase IIbeta by a functional ChIP-chip technique (eTIP-tiling array)
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ABSTRACT:
ORGANISM(S): Rattus norvegicus
PROVIDER: GSE13145 | GEO | 2008/11/27
SECONDARY ACCESSION(S): PRJNA109581
REPOSITORIES: GEO
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Project description:DNA topoisomerase II (topo II) catalyzes a strand passage reaction in that one duplex is passed through a transient brake in another. Completion of late stages of neuronal development depends on the presence of active isoform (topo IIbeta). We identified topo IIbeta action sites on 7 selected genomic regions (about 79 Mb in total), each containing at least one gene that is controlled by topo IIbeta in neuronal differentiation. We used a novel method, etoposide-mediated topoisomerase immunoprecipitation (eTIP), followed by identification of precipitated DNA fragments on genomic tiling arrays. These DNA fragments were first fractionated by concentrated salt prior to the array analysis. The 0.5 M NaCl-released fraction was analyzed as P2 and the salt-resistant fraction wad analyzed as P1. The genomic DNA fractions from the immunoprecipitate (P1 or P2) were co-hybridized with a reference DNA isolated from the input of immunoprecipitation.
2010-05-15 | E-GEOD-13145 | biostudies-arrayexpress
Project description:Neuronal activity causes the rapid expression of immediate early genes that are crucial for experience driven changes to synapses, learning, and memory. Here, using both molecular and genome-wide next generation sequencing methods, we report that neuronal activity stimulation triggers the formation of DNA double strand breaks (DSBs) in the promoters of a subset of early-response genes, including Fos, Npas4, and Egr1. Generation of targeted DNA DSBs within Fos and Npas4 promoters is sufficient to induce their expression even in the absence of an external stimulus. Activity-dependent DSB formation is likely mediated by the type II topoisomerase, Topoisomerase IIb (Topo IIb), and knockdown of Topo IIb attenuates both DSB formation and early response gene expression following neuronal stimulation. Our results suggest that DSB formation is a physiological event that rapidly resolves topological constraints to early-response gene expression in neurons. Generation of sequencing data from ChIP-seq with antibodies against γH2AX and Topo IIβ after neuronal activity stimulation, and RNA-seq after etoposide treatment
2015-06-04 | E-GEOD-61887 | biostudies-arrayexpress
Project description:Topoisomerase II (topo II) is essential for disentangling newly-replicated chromosomes. DNA unlinking involves the physical passage of one DNA duplex through another and depends on the transient formation of double-strand DNA breaks, a step exploited by frontline chemotherapies to kill cancer cells. Although anti-topo II drugs are efficacious, they also elicit cytotoxic side effects in normal cells; insights into how topo II is regulated in different cellular contexts is essential to improve their targeted use. Using chemical fractionation and mass spectrometry, we have discovered that topo II is subject to metabolic control through the TCA cycle. We show that TCA metabolites stimulate topo II activity in vitro and that levels of TCA flux modulate cellular sensitivity to anti-topo II drugs in vivo. Our works reveals an unanticipated connection between the control of DNA topology and cellular metabolism, a finding with important ramifications for the clinical use of anti-topo II therapies.
2021-01-21 | ST001658 | MetabolomicsWorkbench
Project description:Neuronal activity causes the rapid expression of immediate early genes that are crucial for experience driven changes to synapses, learning, and memory. Here, using both molecular and genome-wide next generation sequencing methods, we report that neuronal activity stimulation triggers the formation of DNA double strand breaks (DSBs) in the promoters of a subset of early-response genes, including Fos, Npas4, and Egr1. Generation of targeted DNA DSBs within Fos and Npas4 promoters is sufficient to induce their expression even in the absence of an external stimulus. Activity-dependent DSB formation is likely mediated by the type II topoisomerase, Topoisomerase IIb (Topo IIb), and knockdown of Topo IIb attenuates both DSB formation and early response gene expression following neuronal stimulation. Our results suggest that DSB formation is a physiological event that rapidly resolves topological constraints to early-response gene expression in neurons.
2015-06-04 | GSE61887 | GEO
Project description:Investigate Topo II levels in dosage compensated and non-dosage compensated genes Dosage compensation refers to the equalization of most X-linked gene products between males and females. In Drosophila, it is mediated by the MSL complex that preferentially associates with numerous sites on the X chromosome in somatic cells of males, and is responsible for an enhancement of the transcriptional rate of a substantial number of X-linked genes. Here we show that topoisomerase II (Topo II) is an integral part of the mechanistic basis of dosage compensation and we highlight a novel function for this enzyme. A widely accepted model of transcription postulates that the moving bubble generated by an RNA polymerase elongating complex induces positive DNA supercoiling in the region ahead of the complex and negative supercoiling in its wake. These transitory changes in supercoiling are resolved by the action of topoisomerases. We have investigated the role of Topo II in dosage compensation by RNAi-mediated depletion, and we have used chromatin immunoprecipitation to determine its genomic distribution and relative abundance on X-linked genes. Topo II is enriched on dosage compensated genes and this enrichment is independent from the approximate two-fold enhancement in transcription of these genes. We have demonstrated an RNA-dependent association of Topo II with MLE, the ATPase-helicase subunit of the MSL complex. Our results indicate a role for Topo II that is additional to and different from its function in restoring normal DNA superhelicity during the transcription process. We suggest that the enhanced level of Topo II alters the DNA supercoiling of compensated gene units to facilitate transcription and could provide a basis for the recent report that the MSL complex enhances transcription by increasing the rate of elongation of RNA polymerase II.
2012-03-30 | GSE36927 | GEO
Project description:Dosage compensation refers to the equalization of most X-linked gene products between males and females. In Drosophila, it is mediated by the MSL complex that preferentially associates with numerous sites on the X chromosome in somatic cells of males, and is responsible for an enhancement of the transcriptional rate of a substantial number of X-linked genes. Here we show that topoisomerase II (Topo II) is an integral part of the mechanistic basis of dosage compensation and we highlight a novel function for this enzyme. A widely accepted model of transcription postulates that the moving bubble generated by an RNA polymerase elongating complex induces positive DNA supercoiling in the region ahead of the complex and negative supercoiling in its wake. These transitory changes in supercoiling are resolved by the action of topoisomerases. We have investigated the role of Topo II in dosage compensation by RNAi-mediated depletion, and we have used chromatin immunoprecipitation to determine its genomic distribution and relative abundance on X-linked genes. Topo II is enriched on dosage compensated genes and this enrichment is independent from the approximate two-fold enhancement in transcription of these genes. We have demonstrated an RNA-dependent association of Topo II with MLE, the ATPase-helicase subunit of the MSL complex. Our results indicate a role for Topo II that is additional to and different from its function in restoring normal DNA superhelicity during the transcription process. We suggest that the enhanced level of Topo II alters the DNA supercoiling of compensated gene units to facilitate transcription and could provide a basis for the recent report that the MSL complex enhances transcription by increasing the rate of elongation of RNA polymerase II. Investigation of dosage compensated gene expression levels in S2 and S2 Topo II RNAi knockdown cells. mRNA was isolated from S2 cells and S2 cells with RNAi knockdown of Topo II. The mRNA was then converted to cDNA and hybridized to a NimbleGen D. melanogaster gene expression array. 2 replicates each.
2012-03-29 | E-GEOD-36927 | biostudies-arrayexpress
Project description:Analysis of topoisomerase function in bacterial replication fork movement: use of DNA microarrays. We used DNA microarrays of the Escherichia coli genome to trace the progression of chromosomal replication forks in synchronized cells. We found that both DNA gyrase and topoisomerase IV (topo IV) promote replication fork progression. When both enzymes were inhibited, the replication fork stopped rapidly. The elongation rate with topo IV alone was 1/3 of normal. Genetic data confirmed and extended these results. Inactivation of gyrase alone caused a slow stop of replication. Topo IV activity was sufficient to prevent accumulation of (+) supercoils in plasmid DNA in vivo, suggesting that topo IV can promote replication by removing (+) supercoils in front of the chromosomal fork. This study is detailed in Khodursky AB et al.(2000) Proc Natl Acad Sci U S A 97:9419-24 Keywords: other
2001-07-30 | E-GEOD-8 | biostudies-arrayexpress
Project description:Analysis of topoisomerase function in bacterial replication fork movement: use of DNA microarrays. We used DNA microarrays of the Escherichia coli genome to trace the progression of chromosomal replication forks in synchronized cells. We found that both DNA gyrase and topoisomerase IV (topo IV) promote replication fork progression. When both enzymes were inhibited, the replication fork stopped rapidly. The elongation rate with topo IV alone was 1/3 of normal. Genetic data confirmed and extended these results. Inactivation of gyrase alone caused a slow stop of replication. Topo IV activity was sufficient to prevent accumulation of (+) supercoils in plasmid DNA in vivo, suggesting that topo IV can promote replication by removing (+) supercoils in front of the chromosomal fork. This study is detailed in Khodursky AB et al.(2000) Proc Natl Acad Sci U S A 97:9419-24 Keywords: other
2001-07-30 | GSE8 | GEO
Project description:The chromosomal condensin complex gives metaphase chromosomes structural stability. In addition, condensin is required for sister chromatid resolution during their segregation in anaphase. How condensin promotes chromosome resolution is poorly understood. Chromosome segregation during anaphase also fails after inactivation of topoisomerase II (topo II), the enzyme that removes catenation between sister chromatids left behind after completion of DNA replication. This has led to the proposal that condensin promotes DNA decatenation, but direct evidence for this is missing and alternative roles for condensin in chromosome resolution have been suggested. Using the budding yeast rDNA as a model, we now show that anaphase bridges in a condensin mutant are resolved by ectopic expression of a foreign (Chlorella virus) but not endogenous topo II. This suggests that catenation prevents sister rDNA segregation, and that yeast topo II is ineffective in decatenating the locus without condensin. Condensin and topo II colocalize along both rDNA and euchromatin, consistent with coordination of their activities. We investigate the physiological consequences of condensin-dependent rDNA decatenation and find that late decatenation determines the late segregation timing of this locus during anaphase. Regulation of decatenation therefore provides a means to finetune segregation timing of chromosomes in mitosis. Keywords: ChIP-chip, Cell Cycle
2008-07-18 | GSE11988 | GEO
Project description:We have previously shown that RNA polymerase II (Pol II) pause release and transcriptional elongation involve phosphorylation of the factor TRIM28 by the DNA damage response (DDR) kinases ATM and DNA-PK. Here, we report a significant role for DNA breaks and DDR signaling in the mechanisms of transcriptional elongation in stimulus-inducible genes in humans. Our data show the enrichment of TRIM28 and γH2AX on serum-induced genes and the important function of DNA-PK for Pol II pause release and transcriptional activation-coupled DDR signaling on these genes. γH2AX accumulation decreases when P-TEFb is inhibited, confirming that DDR signaling results from transcriptional elongation. In addition, transcriptional elongation-coupled DDR signaling involves topoisomerase II because inhibiting this enzyme interferes with Pol II pause release and γH2AX accumulation. Our findings propose that DDR signaling is required for effective Pol II pause release and transcriptional elongation through a novel mechanism involving TRIM28, DNA-PK, and topoisomerase II 42 samples in total. IP targets were gammaH2ax, s2-pol-II, pol-II, pTRIM28, DNA-pk, topo-IIB. Experimental conditions included DMSO treatment (control), pTEFb, topoII-i, dnapk-i. Matched non-specific IP samples used for control in peak calling.
2015-11-20 | E-GEOD-75170 | biostudies-arrayexpress