Project description:In Bacillus subtilis and its relatives carbon catabolite control, a mechanism enabling to reach maximal efficiency of carbon and energy sources metabolism, is achieved by the global regulator CcpA (carbon catabolite protein A). CcpA in a complex with HPr-Ser-P (seryl-phosphorylated form of histidine-containing protein, HPr) binds to operator sites called catabolite responsive elements, cre. Depending on the cre box position relative to the promoter, the CcpA/HPr-Ser-P complex can either act as a positive or a negative regulator. The cre boxes are highly degenerate semi-palindromes with a lowly conserved consensus sequence. So far, studies aimed at revealing how CcpA can bind such diverse sites were focused on the analysis of single cre boxes. In this study, a genome-wide analysis of cre sites was performed in order to identify differences in cre sequence and position, which determine their binding affinity. The transcriptomes of B. subtilis cultures with three different CcpA expression levels were compared. The higher the amount of CcpA in the cells, the more operons possessing cre sites were differentially regulated. The cre boxes that mediated regulation at low CcpA levels were designated as strong (high affinity) and those which responded only to high amounts of CcpA, as weak (low affinity). Differences in the sequence and position in relation to the transcription start site between strong and weak cre boxes were revealed. Certain residues at specific positions in the cre box as well as, to a certain extent, a more palindromic nature of cre sequences and the location of cre in close vicinity to the transcription start site contribute to the strength of CcpA-dependent regulation. The main factors contributing to cre regulatory efficiencies, enabling subtle differential control of various subregulons of the CcpA regulon, are identified. Bacillus subtilis strain MP902 [strain MP901 (Ptet-ccpA, KmR) carrying pWH119 (Pxyl-tetR, EmR)] was grown in presence of three different concentrations of Ptet inducer, anhydrotetracycline (ATc), leading to three levels of ccpA expression induction. The control culture was grown in absence of ATc. The total RNA for transcriptome analyses was isolated at OD600 = 0.8 from 16 ml culture. Three independent cultures of each strain (target strains and controls) were used, and cells were sampled for microarray experiment.
Project description:In Bacillus subtilis and its relatives carbon catabolite control, a mechanism enabling to reach maximal efficiency of carbon and energy sources metabolism, is achieved by the global regulator CcpA (carbon catabolite protein A). CcpA in a complex with HPr-Ser-P (seryl-phosphorylated form of histidine-containing protein, HPr) binds to operator sites called catabolite responsive elements, cre. Depending on the cre box position relative to the promoter, the CcpA/HPr-Ser-P complex can either act as a positive or a negative regulator. The cre boxes are highly degenerate semi-palindromes with a lowly conserved consensus sequence. So far, studies aimed at revealing how CcpA can bind such diverse sites were focused on the analysis of single cre boxes. In this study, a genome-wide analysis of cre sites was performed in order to identify differences in cre sequence and position, which determine their binding affinity. The transcriptomes of B. subtilis cultures with three different CcpA expression levels were compared. The higher the amount of CcpA in the cells, the more operons possessing cre sites were differentially regulated. The cre boxes that mediated regulation at low CcpA levels were designated as strong (high affinity) and those which responded only to high amounts of CcpA, as weak (low affinity). Differences in the sequence and position in relation to the transcription start site between strong and weak cre boxes were revealed. Certain residues at specific positions in the cre box as well as, to a certain extent, a more palindromic nature of cre sequences and the location of cre in close vicinity to the transcription start site contribute to the strength of CcpA-dependent regulation. The main factors contributing to cre regulatory efficiencies, enabling subtle differential control of various subregulons of the CcpA regulon, are identified.
Project description:Identification of the specific WalR (YycF) binding regions on the B. subtilis chromosome during exponential and phosphate starvation growth phases. The data serves to extend the WalRK regulon in Bacillus subtilis and its role in cell wall metabolism, as well as implying a role in several other cellular processes.
Project description:Study the effect of single amino acid point mutations in CcpA at the transcriptome level. Cells were grown in LB with or without 1% glucose and harvested at an OD600 of 0.3 (early exponential phase). Bacillus subtilis strain ccpA::spec carrying pHT304 (empty plasmid), pWH_ccpA_M17R, pWH_ccpA_T62H, or pWH_ccpA_R304W were grown in LB with or without 1% glucose. The control in the microarray study was the strain Bacillus subtilis ccpA::spec carrying pWH_ccpA-wt. All Bacillus subtilis cultures were harvested in the early exponential growth phase at an OD600 of 0.3 from 100 ml culture. Two independent cultures of each strain per growth condition (+/- glucose) and a technical replicate (dye-swap) were used. Please note that '[A}' and '{B}' channels (in the raw data *slide.txt files) correspond to Cy3 (Ch1) and Cy5 (Ch2) in each sample record.
Project description:Identification of the specific WalR (YycF) binding regions on the B. subtilis chromosome during exponential and phosphate starvation growth phases. The data serves to extend the WalRK regulon in Bacillus subtilis and its role in cell wall metabolism, as well as implying a role in several other cellular processes. For each sample analyzed in this study three biological replicates were performed. Three different samples were taken from a strain expressing the WalR-SPA protein as well as from wild-type (168) without a tagged WalR. Samples were taken from exponentially growing cells in low phosphate medium (LPDM) as well as from phosphate-limited cells (T2). Each sample compares ChIP DNA vs. Total DNA from the same cells.
Project description:In this study the isogenic Bacillus subtilis mutant strains ccpA topA+ and ccpA topA(S478P) were analyzed. The S478P suppressor mutation occurred when the ccpA mutant was grown on minimal medium supplemented with glucose and ammonium as single sources of carbon and nitrogen, respectively. Under these conditions, the ccpA mutant is unable to produce enough glutamate for growth, since gltAB, encoding the glutamate synthase, is not expressed. In order to get an insight how the S478P mutation in the DNA topoisomerase I affects expression on a global level, the two strains were subjected to a microarray analysis. Bacteria were cultivated in minimal medium supplemented with glucose and glutamate. The microarray data show that the topA(S478P) mutation results in a global re-direction of the central carbon metabolism that includes glutamate biosynthesis.
Project description:Investigation of the whole genome expression level changes in phosphate limited Bacillus subtilis wild-type and delta-phoPR cells Investigation of the whole genome expression level changes of wild-type and delta-phoPR Bacills subtilis cells comparing high and low phosphate medium