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Topoisomerase II inhibition involves characteristic chromosomal expression patterns: Trovafloxacin study

ABSTRACT: Trovafloxacin is a broad spectrum antibiotic that inhibits the uncoiling of supercoiled DNA in various bacteria by blocking the activity of DNA gyrase and topoisomerase IV. Specific members of this drug family display high activity against eukaryotic type II topoisomerase, as well as cultured mammalian cells and in vivo tumor models. Trovafloxacin seems to have a higher affinity for eukaryotic polymerase II system than the other quinolone agents tested. This effect coupled with other factors, such as an inflammatory response, might result in a hepatotoxic reaction seen with drug. In this study we found genes regulated by trovafloxacin - induced and repressed - to be located much closer to each other than genes distributed randomly all over the genome (< 100 kbp). Keywords: Trovafloxacin-treated human hepatocytes versus non-treated human hepatocytes

ORGANISM(S): Homo sapiens

PROVIDER: GSE11941 | GEO | 2008/10/01

SECONDARY ACCESSION(S): PRJNA109253

REPOSITORIES: GEO

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Transcription profiling by array of human primary hepatocytes treated with trovafloxacin

Project description:Trovafloxacin is a broad spectrum antibiotic that inhibits the uncoiling of supercoiled DNA in various bacteria by blocking the activity of DNA gyrase and topoisomerase IV. Specific members of this drug family display high activity against eukaryotic type II topoisomerase, as well as cultured mammalian cells and in vivo tumor models. Trovafloxacin seems to have a higher affinity for eukaryotic polymerase II system than the other quinolone agents tested. This effect coupled with other factors, such as an inflammatory response, might result in a hepatotoxic reaction seen with drug. In this study we found genes regulated by trovafloxacin - induced and repressed - to be located much closer to each other than genes distributed randomly all over the genome (< 100 kbp). Experiment Overall Design: We calculated specifically the probability by which particular genes which were deregulated by the treatment of human hepatocytes with trovafloxacin will occur within DNA windows of different sizes as compared to the probability of all known mapped genes (RefSeq transcripts) of the human genome (NCBI RefSeq 19,360; build 36.2) to occur within the same DNA windows.<br><br>This experiment was reloaded in November 2010 after additional curation.

2008-10-10 | E-GEOD-11941 | biostudies-arrayexpress

Topoisomerase II inhibition involves characteristic chromosomal expression patterns: Doxorubicin study

2008-10-01 | GSE11940 | GEO

Transcription profiling by array of human hepatocytes treated with doxorubicin

Project description:A variety of important anticancer drugs kill cells by increasing cellular levels of topoisomerase II-DNA cleavage complex. The anthracycline anticancer drug doxorubicin forms a stable ternary complex with DNA and topoisomerase IIa, thereby inhibiting the normal function of the enzyme. In this study we found genes regulated by doxorubicin - induced and repressed - to be located much closer to each other than genes distributed randomly all over the genome (< 100 kbp). Experiment Overall Design: We calculated specifically the probability by which particular genes which were deregulated by the treatment of human hepatocytes with doxorubicin will occur within DNA windows of different sizes as compared to the probability of all known mapped genes (RefSeq transcripts) of the human genome (NCBI RefSeq 19,360; build 36.2) to occur within the same DNA windows.

2008-10-10 | E-GEOD-11940 | biostudies-arrayexpress

Transcriptional consequences of DNA gyrase inhibition

Project description:DNA gyrase is an essential enzyme whose activity is required for DNA replication and chromosome maintenance. Inhibition of gyrase results in multiple physiological effects including changes in DNA superhelicity, replication arrest and DNA damage. Using genetic, genomic, statistical and biochemical techniques, we have untangled the contribution of individual effects, assessed their relative significance and concluded that: i) DNA replication is required for the formation of spatial transcriptional domains; ii) transcriptional response to gyrase inhibition is coordinated between at least two modules involved in DNA maintenance, relaxation and damage response; iii) genes whose transcriptional response to gyrase inhibition does not depend on the activity of topoisomerase I can be classified on the basis of the GC excess in their upstream and coding sequences into, respectively, activated and repressed by gyrase inhibition; iv) relaxation by topoisomerase I dominates the transcriptional response upon gyrase inhibition, followed by the effects of replication and RecA. Keywords: time course

2006-03-10 | GSE4408 | GEO

A bacterial chromosome structuring protein binds overtwisted DNA to stimulate type II topoisomerases and enable DNA replication

Project description:When DNA is unwound during replication, it becomes overtwisted and forms positive supercoils in front of the translocating DNA polymerase. Unless removed or dissipated, this superhelical tension can impede replication elongation. Topoisomerases, including gyrase and topoisomerase IV in bacteria, are required to relax positive supercoils ahead of DNA polymerase, but may not be sufficient for replication. Here, we find that GapR, a chromosome structuring protein in Caulobacter crescentus, is required to complete DNA replication. GapR associates in vivo with positively supercoiled chromosomal DNA, and our biochemical and structural studies demonstrate that GapR forms a dimer-of-dimers that fully encircles overtwisted DNA. Further, we show that GapR stimulates gyrase and topo IV to relax positive supercoils, thereby enabling DNA replication. Analogous chromosome structuring proteins that locate to the overtwisted DNA in front of replication forks may be present in other organisms, similarly helping to recruit and stimulate topoisomerases during DNA replication.

2018-09-13 | GSE100657 | GEO

RNA Polymerase-II-generated DNA supercoils destabilize nucleosomes

Project description:The twin supercoiled domain model posits that, as RNA Polymerase II (Pol II) transcribes a gene, it generates negative and positive supercoils upstream and downstream respectively, but little is known about the functional consequence in vivo of the resulting torsional strain. Here we provide a method for high resolution mapping of DNA supercoils using next-generation sequencing, and show that the level of supercoiling is correlated with gene expression in Drosophila cells. Inhibition of topoisomerases, enzymes that relieve torsional strain, leads to accumulation of supercoils surrounding gene bodies and of Pol II at the transcription start sites. Topoisomerase I inhibition results in increased nascent RNA transcripts with Topoisomerase II inhibition shows little change in nascent RNA levels. Despite these different effects on transcription, inhibition of either enzyme results in increased nucleosome turnover within gene bodies, suggesting that torsional stress contributes to destabilizing nucleosomes ahead of Pol II. 12 paired-end samples and 8 single-end samples were sequenced and analyzed.

2013-10-31 | E-GEOD-47795 | biostudies-arrayexpress

Transcription facilitated genome-wide recruitment of topoisomerase I and DNA gyrase

Project description:Genome-wide distribution of topoisomerase I and DNA gyrase is directed by transcription induced supercoiling

2017-01-31 | GSE85357 | GEO

RNA Polymerase-II-generated DNA supercoils destabilize nucleosomes

2013-10-31 | GSE47795 | 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

Topoisomerase function in E. coli replication fork movement

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

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