Assessing the effects of four two-component system response regulator knockouts in E. coli
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ABSTRACT:
ORGANISM(S): Escherichia coli str. K-12 substr. MG1655
PROVIDER: GSE225096 | GEO | 2023/02/12
REPOSITORIES: GEO
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Project description:Escherichia coli use two-component systems (TCSs) to respond to environmental signals. TCSs affect gene expression and are parts of E. coli’s global transcriptional regulatory network (TRN). Here, we identified the regulons of five TCSs in E. coli MG1655: BaeSR and CpxAR, which were stimulated by ethanol stress, and KdpDE, PhoRB, and ZraSR, which were stimulated by potassium, phosphate, and zinc, respectively. We analyzed RNA-seq data using independent component analysis (ICA). ChIP-exo data was used to validate condition-specific target gene binding sites. Based on this data we (1) identify the target genes for each TCS; (2) show how the target genes are transcribed in response to stimulus; and (3) reveal novel relationships between TCSs, which indicate non-cognate inducers for various response regulators, such as BaeR to iron starvation, CpxR to phosphate limitation, and PhoB and ZraR to cell envelope stress. Our understanding of the TRN in E. coli is thus notably expanded.
2020-10-21 | GSE143855 | GEO
Project description:Escherichia coli use two-component systems (TCSs) to respond to environmental signals. TCSs affect gene expression and are parts of E. coli’s global transcriptional regulatory network (TRN). Here, we identified the regulons of five TCSs in E. coli MG1655: BaeSR and CpxAR, which were stimulated by ethanol stress, and KdpDE, PhoRB, and ZraSR, which were stimulated by potassium, phosphate, and zinc, respectively. We analyzed RNA-seq data using independent component analysis (ICA). ChIP-exo data was used to validate condition-specific target gene binding sites. Based on this data we (1) identify the target genes for each TCS; (2) show how the target genes are transcribed in response to stimulus; and (3) reveal novel relationships between TCSs, which indicate non-cognate inducers for various response regulators, such as BaeR to iron starvation, CpxR to phosphate limitation, and PhoB and ZraR to cell envelope stress. Our understanding of the TRN in E. coli is thus notably expanded.
2020-10-21 | GSE143851 | GEO
Project description:Two component sensor-response regulator systems (TCSs) are very common in the genomes of the Streptomyces species that have been fully sequenced to date. It has been suggested that this large number is an evolutionary response to the variable environment that Streptomyces encounter in soil. Notwithstanding this, TCSs are also more common in the sequenced genomes of other Actinomycetales when these are compared to the genomes of most other eubacteria. In this study, we have used DNA/DNA genome microarray analysis to compare fourteen Streptomyces species and one closely related genus to Streptomyces coelicolor in order to identify a core group of such systems. This core group is compared to the syntenous and non-syntenous TCSs present in the genome sequences of other Actinomycetales in order to separate the systems into those present in Actinomycetales in general, the Streptomyces specific systems and the species specific systems. Horizontal transfer does not seem to play a very important role in the evolution of the TCS complement analyzed in this study. However, cognate pairs do not necessarily seem to evolve at the same pace, which may indicate the evolutionary responses to environmental variation may be reflected differently in sequence changes within the two components of the TCSs. The overall analysis allowed subclassification of the orphan TCSs and the TCS cognate pairs and identification of possible targets for further study using gene knockouts, gene overexpression, reporter genes and yeast two hybrid analysis. DNA/DNA comparative analysis using the University of Surrey PCR Microarray chip
2010-06-24 | E-GEOD-13621 | biostudies-arrayexpress
Project description:Two component sensor-response regulator systems (TCSs) are very common in the genomes of the Streptomyces species that have been fully sequenced to date. It has been suggested that this large number is an evolutionary response to the variable environment that Streptomyces encounter in soil. Notwithstanding this, TCSs are also more common in the sequenced genomes of other Actinomycetales when these are compared to the genomes of most other eubacteria. In this study, we have used DNA/DNA genome microarray analysis to compare fourteen Streptomyces species and one closely related genus to Streptomyces coelicolor in order to identify a core group of such systems. This core group is compared to the syntenous and non-syntenous TCSs present in the genome sequences of other Actinomycetales in order to separate the systems into those present in Actinomycetales in general, the Streptomyces specific systems and the species specific systems. Horizontal transfer does not seem to play a very important role in the evolution of the TCS complement analyzed in this study. However, cognate pairs do not necessarily seem to evolve at the same pace, which may indicate the evolutionary responses to environmental variation may be reflected differently in sequence changes within the two components of the TCSs. The overall analysis allowed subclassification of the orphan TCSs and the TCS cognate pairs and identification of possible targets for further study using gene knockouts, gene overexpression, reporter genes and yeast two hybrid analysis.
2009-01-31 | GSE13621 | GEO
Project description:Members of the Bacillus cereus group can adapt to a wide range of environmental challenges. In bacteria, these challenges are often translated into a transcriptional response via the cognate response regulators (RRs) of specialized two-component systems (TCSs). We have previously developed a phylogenetic footprinting approach that was successfully implemented to predict specific binding sites (operators) and target genes for the RRs of B. cereus and related species. In this study, this footprinting approach was integrated with transcriptome analyses of two B. cereus TCS deletion mutants, involving the TCSs YvrHG and YufLM. Comparison of mutant versus wild-type transcriptomes revealed that the respective TCSs were significantly active during the exponential growth phase in rich medium and that the footprinting-based predictions were accurate for the two TCSs. Moreover, the predicted specific operators were used in combination with the transcriptome data to guide the identification of more extended TCS regulons. This revealed new roles for the respective TCSs, including the participation in an intricate transcriptional network involved in antibiotic resistance, including the confirmed resistance to oxolinic acid (YvrHG) and the confirmed uptake and metabolism of fumarate and the repression of fermentative pathways (YufLM).
2014-12-31 | GSE18523 | GEO
Project description:We used RNA-seq to profile E. coli K-12 MG1655 strains subjected to adaptive laboratory evolution after chorismate synthase knockouts. Either isochorismate synthase (menF) or isochorismate synthase AND chorismate lyase (ubiC) was deleted from a strain of E. coli K-12 MG1655 that had already been previously adapted for growth on glucose minimal media. RNA-seq profiles of the original glucose-adapted strain, the 2 deletion strains, and 4 laboratory-evolved strains from each deletion are included in duplicate. ubiC catalyzes the first committed step of ubiquinone synthesis, an important molecule for the electron transport chain. Thus, these experiments allowed assessment of cellular adaptations to restore energy metabolism capability.
2023-02-08 | GSE224889 | GEO
Project description:Bacteria regulate gene expression to adapt to changing environments through transcriptional regulatory networks (TRNs). Although extensively studied, TRNs are not fully characterized since the identity of all the transcriptional regulators that comprise a TRN are not known. Here, we experimentally evaluate 40 uncharacterized proteins in the model organism Escherichia coli K-12 MG1655, which were previously predicted to be transcription factors (TFs). First, we used myc-tagging and a multiplexed ChIP-exo assay to characterize genome-wide binding sites for these candidate TFs. We then compared those binding sites with those of RNA polymerase and sigma factors to increase the confidence in the measured DNA-binding events. Finally, we used these data to infer potential functional annotations for 13 candidate TFs. Our results revealed that these candidate TFs have a varied number of regulatory genes and are involved in E. coli’s primary cellular processes. Taken together, thes results: (1) expand the number of confirmed TFs from 249 to 276, close to the estimated total of 280 TFs in E. coli K-12 MG1655; (2) provide a roadmap for the functional characterization of the newly discovered TFs; and (3) enable the elucidation of the first comprehensive TRN in this model organism.
2021-08-17 | GSE159777 | GEO
Project description:In bacterial two-component regulatory systems (TCSs), dephosphorylation of phosphorylated response regulator is essential for resetting the activated systems to the pre-activation state. However, in the SaeRS TCS, a major virulence TCS of Staphylococcus aureus, the mechanism for dephosphorylation of the response regulator SaeR has not been identified. Here we report that two auxiliary proteins from the sae operon, SaeP and SaeQ, form a ternary complex with the sensor kinase SaeS and activate the sensor kinase’s phosphatase activity. Efficient activation of the phosphatase activity of SaeS required the presence of both SaeP and SaeQ. When SaeP and SaeQ were expressed, the expression of coagulase, a sae target with low affinity to phosphorylated SaeR, was greatly reduced, while the expression of alpha-hemolysin, a sae target with high affinity to phosphorylated SaeR, was not, demonstrating a differential effect of SaePQ on sae target gene expression. When expression of SaePQ was abolished, most sae target genes were induced at an elevated level. Since the expression of SaeP and SaeQ is induced by SaeRS TCS, these results suggest that the SaeRS TCS returns to pre-activation state by a negative feedback mechanism. To examine the global effect of SaePQ on sae target gene expression, we treated the wild type strain of USA300-P23 and its P1 promoter mutant with HNP-1 and analyzed the transcription of sae target genes by microarray assays. WT and P1 cells were compared against a each other at the same time point and against a T=0 reference.
2012-03-09 | E-GEOD-36230 | biostudies-arrayexpress
Project description:In bacterial two-component regulatory systems (TCSs), dephosphorylation of phosphorylated response regulator is essential for resetting the activated systems to the pre-activation state. However, in the SaeRS TCS, a major virulence TCS of Staphylococcus aureus, the mechanism for dephosphorylation of the response regulator SaeR has not been identified. Here we report that two auxiliary proteins from the sae operon, SaeP and SaeQ, form a ternary complex with the sensor kinase SaeS and activate the sensor kinase’s phosphatase activity. Efficient activation of the phosphatase activity of SaeS required the presence of both SaeP and SaeQ. When SaeP and SaeQ were expressed, the expression of coagulase, a sae target with low affinity to phosphorylated SaeR, was greatly reduced, while the expression of alpha-hemolysin, a sae target with high affinity to phosphorylated SaeR, was not, demonstrating a differential effect of SaePQ on sae target gene expression. When expression of SaePQ was abolished, most sae target genes were induced at an elevated level. Since the expression of SaeP and SaeQ is induced by SaeRS TCS, these results suggest that the SaeRS TCS returns to pre-activation state by a negative feedback mechanism.
2012-03-09 | GSE36230 | GEO
Project description:We used RNA-seq to investigate the effects of single transcription factor knockouts on growth of E. coli BW25113 in fed-batch cultures at multiple timepoints. Cells were grown in an ambr automated bioreactor and maintained at 30 degrees and pH 6.5 in Medium C.
2022-12-30 | GSE221706 | GEO