Project description:This SuperSeries is composed of the following subset Series: GSE21820: Genome-wide characterization of PhoB binding profile in Escherichia coli (gene expression data) GSE21856: Genome-wide characterization of PhoB binding profile in Escherichia coli (ChIP-chip data) Refer to individual Series
Project description:Chromatin immunoprecipitation was combined with high-density tiling array (ChIP-chip) and gene expression microarray to reveal the adaptive responses of Escherichia coli to phosphate starvation. The first sketch of the genome-wide distribution of PhoB binding profile was unveiled and 43 regions were identified as the PhoB binding regions. The presence of a significant common motif in these binding regions allowed us to reconstruct the PhoB binding pattern. By comparing the ChIP-chip and microarray datasets, we were also able to identify genes directly or indirectly affected through PhoB regulation. Nineteen out of the 287 differentially expressed genes in the presence and absence of PhoB activity were considered as the genes directly regulated by PhoB. The adaptive responses affected through PhoB regulation are discussed and these responses involve in several important biological functions including transcriptional regulation, transportation, membrane component arrangement, sigma factor modulation and DNA replication inhibition.
Project description:Chromatin immunoprecipitation was combined with high-density tiling array (ChIP-chip) and gene expression microarray to reveal the adaptive responses of Escherichia coli to phosphate starvation. The first sketch of the genome-wide distribution of PhoB binding profile was unveiled and 43 regions were identified as the PhoB binding regions. The presence of a significant common motif in these binding regions allowed us to reconstruct the PhoB binding pattern. By comparing the ChIP-chip and microarray datasets, we were also able to identify genes directly or indirectly affected through PhoB regulation. Nineteen out of the 287 differentially expressed genes in the presence and absence of PhoB activity were considered as the genes directly regulated by PhoB. The adaptive responses affected through PhoB regulation are discussed and these responses involve in several important biological functions including transcriptional regulation, transportation, membrane component arrangement, sigma factor modulation and DNA replication inhibition.
Project description:Chromatin immunoprecipitation was combined with high-density tiling array (ChIP-chip) and gene expression microarray to reveal the adaptive responses of Escherichia coli to phosphate starvation. The first sketch of the genome-wide distribution of PhoB binding profile was unveiled and 43 regions were identified as the PhoB binding regions. The presence of a significant common motif in these binding regions allowed us to reconstruct the PhoB binding pattern. By comparing the ChIP-chip and microarray datasets, we were also able to identify genes directly or indirectly affected through PhoB regulation. Nineteen out of the 287 differentially expressed genes in the presence and absence of PhoB activity were considered as the genes directly regulated by PhoB. The adaptive responses affected through PhoB regulation are discussed and these responses involve in several important biological functions including transcriptional regulation, transportation, membrane component arrangement, sigma factor modulation and DNA replication inhibition. Under phosphate starvation condition, the gene expression profiles from MG1655 and its PhoB knock-out isogenetic strain are compared to identify the PhoB affected genes.
Project description:Chromatin immunoprecipitation was combined with high-density tiling array (ChIP-chip) and gene expression microarray to reveal the adaptive responses of Escherichia coli to phosphate starvation. The first sketch of the genome-wide distribution of PhoB binding profile was unveiled and 43 regions were identified as the PhoB binding regions. The presence of a significant common motif in these binding regions allowed us to reconstruct the PhoB binding pattern. By comparing the ChIP-chip and microarray datasets, we were also able to identify genes directly or indirectly affected through PhoB regulation. Nineteen out of the 287 differentially expressed genes in the presence and absence of PhoB activity were considered as the genes directly regulated by PhoB. The adaptive responses affected through PhoB regulation are discussed and these responses involve in several important biological functions including transcriptional regulation, transportation, membrane component arrangement, sigma factor modulation and DNA replication inhibition. Comparison of the E. coli K12 MG1655 wild type and a PhoB-FLAG fusion expressing strain (MG1655_PhoB_FLAG). The anti-FLAG antibody was used to recognize PhoB-FLAG fusion protein. Therefore, ChIPed DNA from the wild type strain was used as the control group. Three biological replicates were performed.
Project description:We used ChIP-seq to map the binding of of C-terminally FLAG3-tagged PhoB to the Escherichia coli K-12 genome during growth in MOPS minimal media with low phosphate or high phosphate (0.2 mM or 1.32 mM, respectively). As a control, we performed ChIP-seq in an untagged strain. We also used ChIP-seq to map Sigma 70 (associates with initiating RNA polymerase) binding across the E. coli K-12 genome in wild-type, ΔphoB, Δhns, and Δhns ΔphoB strains grown in low phosphate medium to determine whether PhoB modulates recruitment of RNA polymerase to promoters and whether this is modulated by H-NS.
Project description:An ability to sense and respond to changes in extracellular phosphate is critical to the survival of most bacteria. For Caulobacter crescentus, which typically lives in phosphate-limited environments, this process is especially crucial. Like many bacteria, Caulobacter responds to phosphate limitation through a conserved two-component signaling pathway called PhoR-PhoB, but the direct regulon of PhoB in this organism is unknown. Here, we use ChIP-Seq to map the global binding patterns of the phosphate-responsive transcriptional regulator PhoB in both phosphate-limited and -replete conditions. Combined with genome-wide expression profiling, our work demonstrates that PhoB is induced to regulate nearly 50 genes in phosphate-starved conditions. The PhoB regulon is comprised primarily of genes known or predicted to help Caulobacter scavenge for and import inorganic phosphate, including 15 different membrane transporters. We also investigated the regulatory role of PhoU, a widely conserved protein proposed to coordinate phosphate import with expression of the PhoB regulon by directly modulating the histidine kinase PhoR. However, our studies show that it likely does not play such a role in Caulobacter as depleting PhoU has no significant effect on PhoB-dependent gene expression. Instead, cells lacking PhoU exhibit a striking accumulation of large polyphosphate granules suggesting that PhoU participates in controlling intracellular phosphate metabolism.