Understanding the roles of dksA and greA in inorganic polyphosphate accumulation in Escherichia coli
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PROVIDER: PRJNA604995 | ENA |
REPOSITORIES: ENA
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Project description:Inorganic polyphosphate (polyP) is synthesized by bacteria in response to various stresses, but the mechanism of its regulation is unknown. Mutants of Escherichia coli lacking the RNA polymerase-binding transcription factor dksA are defective in polyP synthesis after a nutrient limitation stress, and this defect is reversed in a dksA greA mutant. In this work, we used RNA sequencing to compare transcription in wild-type, dksA, and dksA greA strains of E. coli before and after nutrient limitation, to identify genes whose expression pattern correlates with ability to synthesize polyP.
2020-03-11 | GSE144816 | GEO
Project description:The stringent response, involving the regulatory molecules inorganic polyphosphate (poly P) and (p)ppGpp, is believed to mediate Mycobacterium tuberculosis persistence. In this study, we identified a novel exopolyphosphatase responsible for poly P hydrolysis. Using two different poly P-accumulating M. tuberculosis recombinant strains, we found that increased poly P content drives the organisms into early growth arrest, and contributes to tolerance to the cell wall-active agent isoniazid, increased resistance to stress conditions, and improved survival in macrophages. Transcriptomic and metabolomics analysis revealed metabolic downshift manifested by reduced expression of the transcriptional and translational machinery, and shift from utilization of glucose as a carbon source. In summary, regulation of the poly P balance is critical for persister formation in M. tuberculosis. The transcriptome of poly P accumulation strains, Rv1026 knock-down and ppk1 knock-in were compared to empty vector strains by RNA-seq.
2015-02-20 | E-GEOD-57868 | biostudies-arrayexpress
Project description:Inorganic polyphosphate (Poly P) is a polymer of various phosphate residues linked by phosphoanhydride bonds as in ATP. It is found in all cells in nature with roles in the origin and survival of species, particularly in bacteria. To study the role of the inorganic polyphosphate in bacteria, we obtained knockout mutants of polyP metabolism genes in Escherichia coli K12. We performed DNA microarray experiments of single mutants in polyphosphate kinase 1 (PPK1), exopolyphosphatase (PPX) and also with the double mutant (PPK1 and PPX). The mutant strains growth normally in LB medium but have different colony morphology phenotypes. All mutants have flagellation problems and a detail description of all gain and lost phenotypes o these strains will be published soon because we performed a complete phenotypic microarray study of all three mutant strains.
2011-06-15 | GSE29954 | GEO
Project description:The stringent response, involving the regulatory molecules inorganic polyphosphate (poly P) and (p)ppGpp, is believed to mediate Mycobacterium tuberculosis persistence. In this study, we identified a novel exopolyphosphatase responsible for poly P hydrolysis. Using two different poly P-accumulating M. tuberculosis recombinant strains, we found that increased poly P content drives the organisms into early growth arrest, and contributes to tolerance to the cell wall-active agent isoniazid, increased resistance to stress conditions, and improved survival in macrophages. Transcriptomic and metabolomics analysis revealed metabolic downshift manifested by reduced expression of the transcriptional and translational machinery, and shift from utilization of glucose as a carbon source. In summary, regulation of the poly P balance is critical for persister formation in M. tuberculosis.
2015-02-20 | GSE57868 | GEO
Project description:Strains devoid of ppGpp (ΔrelA ΔspoT; called ppGpp0), and ppGpp0 dksA- exhibit several amino acid requirements for growth on minimal media. We found that overexpression of DksA can complement some of those requirements. Since DksA is a factor that binds to the RNA polymerase secondary channel, we wondered if other secondary channel proteins might also exert a similar role with respect to growth on minimal media. In our study we found that GreA and partially GreB can in fact complement these requirements under certain conditions. Here, we wished to investigate a broader effect of GreA and GreB on ppGpp0 and ppGpp0 dksA- strains. Since the parent strains are unable to grow in minimal media, we had to supplement the M9 glucose medium with a set of amino acids (DFHILQSTV). We found that both, GreA and GreB can affect a much larger set of genes in the absence of dksA, than in its presence. Also, GreA seems to affect more genes than GreB, under both conditions. We used microarrays to detail the effects of overproducing either GreA or GreB in cells devoid of ppGpp, in the dksA+ or dksA- background E. coli cells harbouring plasmids carrying either greA (pA = pHM1873) or greB (pB = pHM1874) genes, or vector control (pGB2), were monitored in an effort to elucidate the effects of their protein products. This was done in two backgrounds- either in E. coli ppGpp0 cells (ΔrelA, ΔspoT) carrying wt dksA gene or a dksA deletion.
2011-10-26 | E-GEOD-28795 | biostudies-arrayexpress
Project description:Strains devoid of ppGpp (ΔrelA ΔspoT; called ppGpp0), and ppGpp0 dksA- exhibit several amino acid requirements for growth on minimal media. We found that overexpression of DksA can complement some of those requirements. Since DksA is a factor that binds to the RNA polymerase secondary channel, we wondered if other secondary channel proteins might also exert a similar role with respect to growth on minimal media. In our study we found that GreA and partially GreB can in fact complement these requirements under certain conditions. Here, we wished to investigate a broader effect of GreA and GreB on ppGpp0 and ppGpp0 dksA- strains. Since the parent strains are unable to grow in minimal media, we had to supplement the M9 glucose medium with a set of amino acids (DFHILQSTV). We found that both, GreA and GreB can affect a much larger set of genes in the absence of dksA, than in its presence. Also, GreA seems to affect more genes than GreB, under both conditions. We used microarrays to detail the effects of overproducing either GreA or GreB in cells devoid of ppGpp, in the dksA+ or dksA- background
2011-10-27 | GSE28795 | GEO
Project description:Transcriptional profiles of wt and dksA minus Salmonella enterica sv Typhimurium 14028S in E salts minimal medium in response to 5 mM DETANONOate for 30 min Total RNA was harvested from three biological replicates of wt and dksA mutant cultures exposed or unexposed to 5mM DETANONOate for 30min in E salts minimal medium.
2014-03-31 | E-GEOD-33529 | biostudies-arrayexpress
Project description:DksA is well-known for its regulatory role in the transcription of ribosomal RNA and genes involved in amino acid synthesis in many bacteria. DksA is also reported to control expression of virulence genes in pathogenic bacteria. Here, we elucidated the roles of the DksA-like protein (CJJ81176_0160, Cj0125c) in the pathogenesis of Campylobacter jejuni. Like in other bacteria, transcription of stable RNA was repressed by DksA under stressful conditions in C. jejuni. Transcriptomic and proteomic analyses of C. jejuni 81-176 and its isogenic dksA mutant showed differential expression of many genes involved in iron-related metabolism, flagellar synthesis and amino acid metabolism. Also the dksA mutant of C. jejuni demonstrated a decreased ability to invade into intestinal cells and to induce release of interleukin-8 from intestinal cells. These results suggest the DksA-like protein plays an important regulatory role in the physiology and virulence of C. jejuni. Keywords: dksA mutation of Campylobacter jejuni The design utilized a commercially available two color microarray slide for the enture transcriptome of Campylobacter jejuni. Six hybridizations were performed each with independently extracted samples of either C. jejuni wildtype of C. jejuni dksA mutant cDNA samples. A dye swap was utilized to help minimize dye dependent bias. Thus there were six biological replicates of each sample.
2008-05-05 | E-GEOD-9866 | biostudies-arrayexpress
Project description:DksA is well-known for its regulatory role in the transcription of ribosomal RNA and genes involved in amino acid synthesis in many bacteria. DksA is also reported to control expression of virulence genes in pathogenic bacteria. Here, we elucidated the roles of the DksA-like protein (CJJ81176_0160, Cj0125c) in the pathogenesis of Campylobacter jejuni. Like in other bacteria, transcription of stable RNA was repressed by DksA under stressful conditions in C. jejuni. Transcriptomic and proteomic analyses of C. jejuni 81-176 and its isogenic dksA mutant showed differential expression of many genes involved in iron-related metabolism, flagellar synthesis and amino acid metabolism. Also the dksA mutant of C. jejuni demonstrated a decreased ability to invade into intestinal cells and to induce release of interleukin-8 from intestinal cells. These results suggest the DksA-like protein plays an important regulatory role in the physiology and virulence of C. jejuni. Keywords: dksA mutation of Campylobacter jejuni
2008-05-06 | GSE9866 | GEO
Project description:In bacteria, translation-transcription coupling inhibits RNA polymerase (RNAP) stalling. We present evidence suggesting that, upon amino acid starvation, inactive ribosomes promote rather than inhibit RNAP stalling. We developed an algorithm to evaluate genome-wide polymerase progression independently of local noise, and used it to reveal that the transcription factor DksA inhibits promoter-proximal pausing and increases RNAP elongation when uncoupled from translation by depletion of charged tRNAs. DksA has minimal effect on RNAP elongation in vitro and on untranslated RNAs in vivo. In these cases, transcripts can form RNA structures that prevent backtracking. Thus, the effect of DksA on transcript elongation may occur primarily upon ribosome slowing/stalling or at promoter-proximal locations that limit the potential for RNA structure. We propose that inactive ribosomes prevent formation of backtrackblocking mRNA structures and that, in this circumstance, DksA acts as a transcription elongation factor in vivo. Chromatin immunoprecipitation (ChIP) experiments were performed by using antibodies against RNA polymerase b subunit in wild-type and DdksA cells treated with 0.5mg/ml serine hydroxamate (SHX) or untreated. DksA and s70 enrichments were compared to RNAP enrichment by ChIP experiments using antibodies against s70 and DksA in wild-type cells (also in DdksA cells as a negative control for DksA ChIP-chip). Differentially labeled ChIP DNA and genomic DNA were competitively hybridized to an E. coli K-12 MG1655 tiling array with overlapping probes at ~12bp spacing across the entire genome. The series contains 19 datasets.
2014-04-21 | E-GEOD-54669 | biostudies-arrayexpress