Project description:We have performed ChIP-Seq experiment for the global regulators, CRP and Fis in early and mid exponential growth phases respectively in Escherichia coli K12 MG1655. The dataset contains the genome wide binding patterns of Fis and CRP in the wildtype and the mutant strains
Project description:To understand the influence of global transcription regulators Fis and CRP on global gene expression in different growth phases of E. coli.
2017-10-03 | GSE104504 | GEO
Project description:Sort-seq data from CRP, Fis and IHF
Project description:Among the most important regulators of gene expression in bacteria are 'nucleoid-associated proteins'. These proteins alter the topology of the bound DNA by bending, wrapping or bridging it, thus having multiple effects, including transcriptional regulation, on the bacterial cell. Among the best-studied nucleoid proteins are H-NS and Fis, which bind to specific sequences on the DNA. H-NS is a global repressor of gene expression. Fis alters the global conformation of the DNA by introducing branched structures in it; but its effect on gene expression on a genomic scale remains largely unclear.<br><br>Several bacterial transcriptional regulators including H-NS and Fis have been studied using ChIP-chip. However, the higher resolution and dynamic range offered by ChIP-Seq have not been exploited for any bacterial species. By performing ChIP-Seq of these two proteins, we present the first such study in a bacterium. In addition to providing a proof-of-principle for the use of this technology for bacteria, we perform our study at multiple time-points during growth in rich medium, thus generating new insights into how these proteins function under different cellular conditions. Further, by analysing our data in conjunction with newly-generated gene expression and RNA polymerase-chromosome interaction data we provide new interpretation of the genome-scale patterns of the interactions of these proteins to the DNA.
Project description:Among the most important regulators of gene expression in bacteria are 'nucleoid-associated proteins'. These proteins alter the topology of the bound DNA by bending, wrapping or bridging it, thus having multiple effects, including transcriptional regulation, on the bacterial cell. Among the best-studied nucleoid proteins are H-NS and Fis, which bind to specific sequences on the DNA. H-NS is a global repressor of gene expression. Fis alters the global conformation of the DNA by introducing branched structures in it; but its effect on gene expression on a genomic scale remains largely unclear. Several bacterial transcriptional regulators including H-NS and Fis have been studied using ChIP-chip. However, the higher resolution and dynamic range offered by ChIP-Seq have not been exploited for any bacterial species. By performing ChIP-Seq of these two proteins, we present the first such study in a bacterium. In addition to providing a proof-of-principle for the use of this technology for bacteria, we perform our study at multiple time-points during growth in rich medium, thus generating new insights into how these proteins function under different cellular conditions. Further, by analysing our data in conjunction with newly-generated gene expression and RNA polymerase-chromosome interaction data we provide new interpretation of the genome-scale patterns of the interactions of these proteins to the DNA. ArrayExpress Release Date: 2010-07-29 Person Roles: submitter Person Last Name: Sai Narain Seshasayee Person First Name: Aswin Person Mid Initials: Person Email: aswin@ebi.ac.uk Person Phone: Person Address: Person Affiliation: EBI
Project description:The Fis nucleoid-associated protein controls the expression of a large and diverse regulon of genes in Gram-negative bacteria. Fis production is normally maximal in bacteria during the early exponential phase of batch culture growth, becoming almost undetectable by the onset of stationary phase. We tested the effect of rewiring the Fis regulatory network in Salmonella by moving the complete fis gene from its usual location near the origin of chromosomal replication to the position normally occupied by the dps gene in the Right macrodomain of the chromosome, creating the strain GX. In a parallel experiment, we tested the effect of placing the fis open reading frame under the control of the stationary-phase-activated dps promoter at the dps genetic location within Ter, creating the strain OX. ChIP-seq was used to measure global Fis protein binding and gene expression patterns. Strain GX showed few changes when compared with the wild type, although we did detect increased Fis binding at Ter, accompanied by reduced binding at Ori. Strain OX displayed a more pronounced version of this distorted Fis protein-binding pattern together with numerous alterations in the expression of genes in the Fis regulon. OX, but not GX, had a reduced ability to infect cultured mammalian cells, had undergone a reduction in competitive fitness and had reduced motility compared to the wild type. These findings illustrate the inherent robustness of the Fis regulatory network to rewiring based on gene repositioning alone and emphasise the importance of fis expression signals in phenotypic determination.
Project description:Pyruvate is a central metabolite that connects many metabolic pathways in living organisms. To meet the cellular pyruvate requirements, Escherichia coli most likely has three pyruvate uptake systems, BtsT, YhjX and CstA. Transport studies in intact cells proved that CstA is a high specific pyruvate transporter with moderate affinity, which is energized by a proton gradient. When the cells of a reporter strain were cultured in complex medium, cstA expression was bimodal, with the maximum being reached in the stationary phase. A DNA affinity capture assay combined with mass spectrometry and an in vivo reporter assay identified Fis as repressor in addition to the known cAMP-CRP as activator for cstA expression.
Project description:The regulatory role of the Fis protein in fis and in the transcription of several gene regions during mid-exponential and late-stationary phase, and during different growth aeration regimes, has been investigated. Studies were done during those two growth phases and in aerated and non-aerated (microaerobic) conditions, to measure Fis enrichment and binding peaks in strategic gene regions by genome-wide microarray analysis ChIP-chip. This research investigation points to central roles for SPI-1, SPI-2, DNA gyrase and topoisomerase I, the elements of the stringent response, and the regulatory function of Fis-binding patterns, in setting and re-setting the activity of the fis gene and other involved promoters as a function of the growth conditions and aeration regimes experienced by Salmonella.