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:Investigating bacterial TFBS evolution by exaptation (CRP, Fis and IHF)
Project description:Fis and H-NS are two well-known NAPs in proteobacteria which play crucial role in both genome organization and gene regulation. However, the global effects of Fis and H-NS on gene expression remain unclear. Here, to decipher transcriptional regulatory roles of Fis and H-NS we have performed RNA-sequencing to compare gene expression between the wild-type E. coli and its knockout mutants for fis and hns. We integrated our RNA-seq results with publically available ChIP-seq data to define direct and indirect regulation by Fis and H-NS. The regulatory networks thus provide a comprehensive view of coordinated regulatory roles for these important nucleoid-associated proteins.
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:To generate and compile data from ChIP-Seq libraries. Looking at CRP, H-NS, and sigma70 binding genome wide under M9 minimal growth conditions in duplicate.
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.