DNA supercoiling differences in bacteria result from disparate DNA gyrase activation by polyamines
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PROVIDER: PRJNA633508 | ENA |
REPOSITORIES: ENA
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Project description:DNA supercoiling is essential for all living cells because it controls all processes involving DNA. In bacteria, global DNA supercoiling results from the opposing activities of topoisomerase I, which relaxes DNA, and DNA gyrase, which compacts DNA. These enzymes are widely conserved, sharing >91% amino acid identity between the closely related species Escherichia coli and Salmonella enterica serovar Typhimurium. Why, then, do E. coli and Salmonella exhibit different DNA supercoiling when experiencing the same conditions? We now report that this surprising difference reflects disparate activation of their DNA gyrases by the polyamine spermidine and its precursor putrescine. In vitro, Salmonella DNA gyrase activity was sensitive to changes in putrescine concentration within the physiological range, whereas activity of the E. coli enzyme was not. In vivo, putrescine activated the Salmonella DNA gyrase and spermidine the E. coli enzyme. High extracellular Mg2+ decreased DNA supercoiling exclusively in Salmonella by reducing the putrescine concentration. Our results establish the basis for the differences in global DNA supercoiling between E. coli and Salmonella, define a signal transduction pathway regulating DNA supercoiling, and identify potential targets for antibacterial agents.
2020-10-30 | GSE150757 | GEO
Project description:Genome-wide distribution of topoisomerase I and DNA gyrase is directed by transcription induced supercoiling
2017-01-31 | GSE85357 | GEO
Project description: Not available
| S-EPMC7598504 | biostudies-literature
Project description:Various bis-benzimidazole derivatives have been reported to possess activity against Gram-positive pathogens. No mechanism of action has been elucidated to fully account for the antibacterial activity of this class of compounds. A group of symmetric bis-benzimidazoles (BBZ) designed as anticancer agents have previously been shown to possess moderate antiproliferative activity. We sought to assess the antibacterial activity and mechanism of action of BBZ compounds against Staphylococcus aureus. Antibacterial activities were assessed by determination of minimal inhibitory concentrations (MICs), time-kill curves, and scanning electron microscopy. Transcriptional responses to BBZ treatment were determined using whole genome microarrays. Activities against bacterial type II topoisomerases were investigated using in vitro supercoiling, decatenation, DNA binding, and DNA cleavage inhibition assays. MICs for EMRSA-16 were between 0.03 and 0.5 μg/mL. The compounds showed concentration-dependent bactericidal activity and induced cell swelling and lysis. Transcriptional responses to BBZ were consistent with topoisomerase inhibition and DNA damage. A subset of BBZ compounds inhibited S. aureus DNA gyrase supercoiling activity with IC50 values in the range of 5−10 μM. This inhibition was subsequently shown to operate through both inhibition of binding of DNA gyrase to DNA and accumulation of single-stranded DNA breaks. We conclude that BBZ compounds are potent antistaphylococcal agents and operate at least in part through DNA gyrase inhibition, leading to the accumulation of single-stranded DNA breaks, and by preventing the binding of gyrase to DNA. [Data is also available from http://bugs.sgul.ac.uk/E-BUGS-106]
2012-10-14 | E-BUGS-106 | biostudies-arrayexpress
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
Project description:Cold shock adaptability is a key survival skill of gut bacteria of warm-blooded animals. Escherichia coli cold shock responses are controlled by a complex multi-gene, timely-ordered transcriptional program. We investigated its underlying mechanisms. Having identified short-term, cold shock repressed genes, we show that their responsiveness is unrelated to their transcription factors or global regulators, while their single-cell protein numbers’ variability increases after cold shock. We hypothesized that some cold shock repressed genes could be triggered by high propensity for transcription locking due to changes in DNA supercoiling (likely due to DNA relaxation caused by an overall reduction in negative supercoiling). Concomitantly, we found that nearly half of cold shock repressed genes are also highly responsive to gyrase inhibition (albeit most genes responsive to gyrase inhibition are not cold shock responsive). Further, their response strengths to cold shock and gyrase inhibition correlate. Meanwhile, under cold shock, nucleoid density increases, and gyrases and nucleoid become more colocalized. Moreover, the cellular energy decreases, which may hinder positive supercoils resolution. Overall, we conclude that sensitivity to diminished negative supercoiling is a core feature of E. coli’s short-term, cold shock transcriptional program, and could be used to regulate the temperature sensitivity of synthetic circuits.
2022-07-20 | GSE194037 | GEO
Project description:For Staphylococcus aureus it was shown previously that aminocoumarinecoumarin antibiotics such as novobiocin lead to immediate down-regulation of recA expression and thereby inhibition of the SOS response, the mutation frequency and the recombination capacity. Aminocoumarinecoumarin function by inhibition of the ATPase activity of the gyrase subunit B. Here we analysed the global impact of the DNA relaxing agent novobiocin on gene expression in S. aureus. By use of a novobiocin resistant mutant, it became evident that the change in recA expression is due to gyrase inhibition. Microarray analysis and Northern blot hybridization revealed that the expression of a distinct set of genes is increased (e.g. recF-gyrB-gyrA, rib operon and ure operon M-bM-^@M-&)), or decreased (e.g. arlRS, recA, lukA, hlgC, fnbA) by novobiocin. The two-component ArlRS system was previously found to decrease the supercoiling level in S. aureus. Thus, down-regulation of arlRS might in part compensate for the relaxing effect of novobiocin. Novobiocin resulted in down-regulation of several of arlRS repressed target genes in an arl mutant. Global analysis and gene mapping of supercoiling sensitive genes did not give indications that they are clustered in the genome. Promoter fusion assays confirmed that responsiveness of a given gene is intrinsic to the promoter region but independent of the chromosomal location. The results indicate that molecular property of the spacers of a given promoter dictatesa given promoter rather than chromosomal topology dictates the responsiveness towards changes in supercoiling rather than chromosomal topology. We analyzed S. aureus global gene expression changes to the treatment of novobiocin
2014-09-08 | E-GEOD-50157 | biostudies-arrayexpress
Project description:For Staphylococcus aureus it was shown previously that aminocoumarinecoumarin antibiotics such as novobiocin lead to immediate down-regulation of recA expression and thereby inhibition of the SOS response, the mutation frequency and the recombination capacity. Aminocoumarinecoumarin function by inhibition of the ATPase activity of the gyrase subunit B. Here we analysed the global impact of the DNA relaxing agent novobiocin on gene expression in S. aureus. By use of a novobiocin resistant mutant, it became evident that the change in recA expression is due to gyrase inhibition. Microarray analysis and Northern blot hybridization revealed that the expression of a distinct set of genes is increased (e.g. recF-gyrB-gyrA, rib operon and ure operon …)), or decreased (e.g. arlRS, recA, lukA, hlgC, fnbA) by novobiocin. The two-component ArlRS system was previously found to decrease the supercoiling level in S. aureus. Thus, down-regulation of arlRS might in part compensate for the relaxing effect of novobiocin. Novobiocin resulted in down-regulation of several of arlRS repressed target genes in an arl mutant. Global analysis and gene mapping of supercoiling sensitive genes did not give indications that they are clustered in the genome. Promoter fusion assays confirmed that responsiveness of a given gene is intrinsic to the promoter region but independent of the chromosomal location. The results indicate that molecular property of the spacers of a given promoter dictatesa given promoter rather than chromosomal topology dictates the responsiveness towards changes in supercoiling rather than chromosomal topology.
2014-09-08 | GSE50157 | GEO
Project description:DNA supercoiling is essential for life because it controls critical processes, including transcription, replication and recombination. Current methods to measure DNA supercoiling in vivo are laborious and unable to examine single cells. Here we report a method for high-throughput measurement of bacterial DNA supercoiling in vivo. Fluorescent Evaluation of DNA Supercoiling (FEDS) utilizes a plasmid harboring the gene for a green fluorescent protein transcribed by a discovered promoter that responds exclusively to DNA supercoiling, and the gene for a red fluorescent protein transcribed by a constitutive promoter as internal standard. Using FEDS, we uncovered single cell heterogeneity in DNA supercoiling and established that, surprisingly, population-level decreases in DNA supercoiling result from a low mean/high variance DNA supercoiling subpopulation, rather than a homogeneous shift in supercoiling of the whole population. In addition, we identified a regulatory loop in which a gene that decreases DNA supercoiling is transcriptionally repressed when DNA supercoiling increases.
2020-07-02 | GSE137586 | GEO
Project description:Mycobacterium tuberculosis: DNA gyrase depleted Vs control
| PRJNA491719 | ENA