RelA/(p)ppGpp regulates the glucose-starvation induced stringent response in the zoonostic Streptococcus suis
Ontology highlight
ABSTRACT:
ORGANISM(S): Streptococcus suis
PROVIDER: GSE70092 | GEO | 2015/08/08
SECONDARY ACCESSION(S): PRJNA287626
REPOSITORIES: GEO
Similar Datasets
Project description:Growth curves and (p)ppGpp accumulation assays showed that RelA inactivation could influence S. suis growth and led to incapacity of (p)ppGpp synthesis during glucose starvation. To identify the roles of RelA/(p)ppGpp in global gene regulation in S. suis, we compared the transcriptional profiles of SC-19 [a (p)ppGpp+ strain] and ΔrelA [a (p)ppGpp0 strain during glucose starvation] in both glucose-abundant and -deficient CDM in exponential phase by microarray analysis. A less stringent cut-off limit, 2-fold change, was used. qRT-PCR validation displayed the same trends observed in the microarrays relA mutant strain and its parents strain SC-19 were cultured in both glucose-abundant CDM (CDM containing 1% glucose) and glucose-deficient CDM (CDM containing 2% glucose) respectively. The bacteriain in exponential phase were collected for microarray analysis. Three independent experiments were performed.
2015-08-08 | E-GEOD-70092 | biostudies-arrayexpress
Project description:Escherichia coli RelA is a ribosomal factor with strong (p)ppGpp synthesis activity that is dramatically activated in the presence of deacylated tRNA in the ribosomal A-site. RelA is a unique enzyme in that it is directly positively regulated by its product, alarmone nucleotide (p)ppGpp. Using HDX-MS, mulecular docking, biochemsitry, and microbiology approaches, we localise the (p)ppGpp binding site of E. coli RelA and uncover the molecular mechanism of RelA regulation by the alarmone.
2021-08-11 | PXD019953 | Pride
Project description:Guanosine 3 ,5 -bispyrophosphate (ppGpp), also known as ‘‘magic spot,’’ has been shown to bind prokaryotic RNA polymerase to down-regulate ribosome production and increase transcription of amino acid biosynthesis genes during the stringent response to amino acid starvation. Because many environmental growth perturbations cause ppGpp to accumulate, we hypothesize ppGpp to have an overarching role in regulating the genetic program that coordinates transitions between logarithmic growth (feast) and growth arrest (famine). We used the classic glucose-lactose diauxie as an experimental system to investigate the temporal changes in transcription that accompany growth arrest and recovery in wildtype Escherichia coli and in mutants that lack RelA (ppGpp synthetase) and other global regulators, i.e., RpoS and Crp. When cultured on a mixture of glucose and lactose, E. coli grows preferentially on glucose until it is exhausted, resulting in growth arrest while the cells adjust to growth on lactose, i.e., diauxie. Diauxie was delayed in the relA mutant and was accompanied by a 15% decrease in the number of carbon sources used and a 3-fold overall decrease in the induction of RpoS and Crp regulon genes. Thus the data significantly expand the previously known role of ppGpp and support a model wherein the ppGpp-dependent redistribution of RNA polymerase across the genome is the driving force behind control of the stringent response, general stress response, and starvation-induced carbon scavenging. Our conceptual model of diauxie describes these global control circuits as dynamic, interconnected, and dependent upon ppGpp for the efficient temporal coordination of gene expression that programs the cell for transitions between feast and famine.
2007-03-17 | GSE7265 | GEO
Project description:These two projects are about the proteome of wild type E. coli K-12 NCM3722 strain (RE198LQ) and its rpoS-null strain (XA00994LQ). Both projects include replicates of two conditions, the normal conditions and (p)ppGpp overproduction conditions via RelA* OE.
2023-12-20 | PXD042250 | Pride
Project description:RelA/SpoT Homologs (RSHs) are ubiquitous bacterial enzymes that synthesize and hydrolyze (p)ppGpp in response to environmental challenges. Bacteria cannot survive in hosts and produce infection without activating the (p)ppGpp-mediated stringent response, but it is not yet understood how the enzymatic activities of RSHs are controlled. Using UV crosslinking and deep sequencing, we show that Escherichia coli RelA [(p)ppGpp synthetase I] interacts with uncharged tRNA during steady-state cell growth without being activated. Amino acid starvation leads to loading of cognate tRNA·RelA complexes at vacant ribosomal A-sites. In turn, RelA is activated and synthesizes (p)ppGpp. Mutation of a single, conserved residue in RelA simultaneously prevents tRNA binding, ribosome binding, and activation of RelA, showing that all three processes are interdependent. Our results support a model in which (p)ppGpp synthesis occurs by ribosome-bound RelA interacting with the Sarcin-Ricin Loop of 23S rRNA.
2018-04-05 | GSE108758 | GEO
Project description:Guanosine 3 ,5 -bispyrophosphate (ppGpp), also known as ‘‘magic spot,’’ has been shown to bind prokaryotic RNA polymerase to down-regulate ribosome production and increase transcription of amino acid biosynthesis genes during the stringent response to amino acid starvation. Because many environmental growth perturbations cause ppGpp to accumulate, we hypothesize ppGpp to have an overarching role in regulating the genetic program that coordinates transitions between logarithmic growth (feast) and growth arrest (famine). We used the classic glucose-lactose diauxie as an experimental system to investigate the temporal changes in transcription that accompany growth arrest and recovery in wildtype Escherichia coli and in mutants that lack RelA (ppGpp synthetase) and other global regulators, i.e., RpoS and Crp. When cultured on a mixture of glucose and lactose, E. coli grows preferentially on glucose until it is exhausted, resulting in growth arrest while the cells adjust to growth on lactose, i.e., diauxie. Diauxie was delayed in the relA mutant and was accompanied by a 15% decrease in the number of carbon sources used and a 3-fold overall decrease in the induction of RpoS and Crp regulon genes. Thus the data significantly expand the previously known role of ppGpp and support a model wherein the ppGpp-dependent redistribution of RNA polymerase across the genome is the driving force behind control of the stringent response, general stress response, and starvation-induced carbon scavenging. Our conceptual model of diauxie describes these global control circuits as dynamic, interconnected, and dependent upon ppGpp for the efficient temporal coordination of gene expression that programs the cell for transitions between feast and famine. E. coli MG1655 and isogenic mutants were cultured in a 2 l Biostat B fermentor (B. Braun Biotech International) containing 1 liter of Morpholinepropanesulfonic acid (MOPS) minimal medium with 0.5 g/l of glucose and 1.5 g/l of lactose. The temperature was maintained at 37 ºC and pH was kept constant at 7.2 by the addition of 2 M NaOH. The dissolved oxygen level was maintained above 20% of saturation by adjusting the agitation speeds in the range of 270-500 rpm with fixed 1 l/min air flow.
2007-03-17 | E-GEOD-7265 | biostudies-arrayexpress
Project description:ppGpp synthesis was activated in exponentially growing cells of Streptomyces coelicolor in the absence of amino acid starvation by using a strain (M653 [DrelA tipAp::relA(1.46kb)]) that expresses a truncated portion of relA under the control of a thiostrepton-inducible promoter. Samples were harvested at 30 min intervals following induction for comparison to a control set of samples from aliquots of the same cultures that were not induced.
2007-08-01 | E-MEXP-1119 | biostudies-arrayexpress
Project description:There are three projects including AE155LQ, RE161LQ, RE235LQ. AE155LQ is about the proteomes of wild type cells (WT) and E. coli RelA* OE strain during exponential growth in glucose cAA medium. E1 & E2 corresponds to the wild type cells (two biological replicate samples) and E3 & E4 corresponds to RelA* OE data (two biological replicate samples). RE161LQ is about the time-course proteome of wild type (four samples including WT_0, WT_20, WT_40 and WT_80) vs relA-deficient strain (relA_0, relA_1.5 h, relA_3 h and relA_4.5 h) during AA downshift. RE235Q is about the time-course proteome of wild type (three samples including WT_0, WT_60, WT_160) vs relA-deficient strain (three samples including relA_0, relA_60 and relA_160) during carbon downshift.
2023-01-26 | PXD035675 | Pride
Project description:Bacteria synthesize guanosine tetra- and penta phosphate (commonly referred to as (p)ppGpp) in response to environmental stresses. (p)ppGpp reprograms cell physiology and is essential for stress survival, virulence and antibiotic tolerance. Proteins of the RSH superfamily (RelA/SpoT Homologues) are ubiquitously distributed and hydrolyze or synthesize (p)ppGpp. Structural studies have suggested that the shift between hydrolysis and synthesis is governed by conformational antagonism between the two active sites in RSHs. RelA proteins of γ-proteobacteria exclusively synthesize (p)ppGpp and encode an inactive pseudo-hydrolase domain. Escherichia coli RelA synthesizes (p)ppGpp in response to amino acid starvation with cognate uncharged tRNA at the ribosomal A-site, however, mechanistic details to the regulation of the enzymatic activity on the ribosome remain elusive. Here, we show a novel role of the enzymatically inactive hydrolase domain in modulating the activity of the synthetase domain of RelA. Using random mutagenesis screening and functional studies, we identify a loop region (residues 114-130) in the hydrolase domain, which controls the synthetase activity. We show that a synthetase-inactive loop mutant of RelA is not affected for tRNA binding, but binds the ribosome less efficiently than wildtype RelA. Our data provide strong evidence to support the model that the hydrolase domain acts as a molecular switch to regulate the synthetase activity.
2021-03-31 | GSE150416 | GEO
Project description:Transcription profiling of wild type, relA-, and relA-spoT-, crp-, dksA-, rpoS-, lrp- mutant strains of E. coli starved for isoleucine Bacteria comprehensively reorganize their global gene expression when faced with nutrient exhaustion. In Escherichia coli and other free-living bacteria, the alarmone ppGpp facilitates this massive response by directly or indirectly coordinating the down-regulation of genes of the translation apparatus, and the induction of biosynthetic genes and the general stress response. Such a large reorientation likely requires the cooperative activities of many different genetic regulators, yet the structure of the transcription network below the level of ppGpp remains poorly defined. Using isoleucine starvation as an experimental model system for amino acid starvation, we identified genes that required ppGpp, Lrp, and RpoS for their induction. Surprisingly, despite the fact that the overwhelming majority of genes controlled by Lrp and RpoS required ppGpp for their activation, we found that these two regulons were not induced simultaneously. The data reported here suggest that metabolic genes, such as those of the Lrp regulon, require only a low basal level of ppGpp for their efficient induction. In contrast, the RpoS-dependent general stress response is not robustly induced until relatively high levels of ppGpp accumulate. Here we describe a data-driven conceptual model that explains how bacterial cells allocate transcriptional resources between metabolic and stress survival processes by discretely tuning regulatory activities to a central indicator of cellular physiology. The regulatory structure that emerges is consistent with a rheostatic model of the stringent response that allows cells to efficiently adapt to a wide range of nutritional environments. Keywords: genetic modification design; stress response; isoleucine starvation
2008-04-08 | GSE11087 | GEO