The nucleotide messenger (p)ppGpp is an anti-inducer of the purine synthesis transcription regulator PurR in Bacillus
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ABSTRACT:
PROVIDER: PRJNA767850 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR16151838.fastq.gz | Fastqsanger.gz | |||
| SRR16151839.fastq.gz | Fastqsanger.gz | |||
| SRR16151840.fastq.gz | Fastqsanger.gz | |||
| SRR16151841.fastq.gz | Fastqsanger.gz | |||
| SRR16151842.fastq.gz | Fastqsanger.gz |
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Project description:The nucleotide messenger (p)ppGpp allows bacteria to adapt to fluctuating environments by reprogramming the transcriptome. Despite its well-recognized role in gene regulation, (p)ppGpp is only known to directly affect transcription in Proteobacteria by binding to the RNA polymerase. Here we reveal a different mechanism of gene regulation by (p)ppGpp in Firmicutes from soil bacteria to pathogens: (p)ppGpp directly binds to the transcription factor PurR to downregulate purine biosynthesis. We identified PurR as a receptor of (p)ppGpp in Bacillus anthracis and revealed that (p)ppGpp strongly enhances PurR binding to its regulon in the Bacillus subtilis genome. A co-structure reveals that (p)ppGpp binds to a PurR pocket reminiscent of the active site of PRT enzymes that has been repurposed to serve a purely regulatory role, where the effectors (p)ppGpp and PRPP compete to allosterically control transcription. PRPP inhibits PurR DNA binding to induce transcription of purine synthesis genes, whereas (p)ppGpp antagonizes PRPP to enhance PurR DNA binding and repress transcription. A (p)ppGpp-refractory purR mutant fails to downregulate purine synthesis genes upon starvation. Our work establishes the precedent of (p)ppGpp as a classical effector of transcription repressors and reveals the key function of (p)ppGpp in regulating nucleotide synthesis through gene regulation, from the human intestinal tract to host-pathogen interfaces.
2021-12-10 | GSE185164 | GEO
Project description:The nucleotide messenger (p)ppGpp allows bacteria to adapt to fluctuating environments by reprogramming the transcriptome. Despite its well-recognized role in gene regulation, (p)ppGpp is only known to directly affect transcription in Proteobacteria by binding to the RNA polymerase. Here, we reveal a different mechanism of gene regulation by (p)ppGpp in Firmicutes: (p)ppGpp directly binds to the transcription factor PurR to downregulate purine biosynthesis gene expression upon amino acid starvation. We first identified PurR as a receptor of (p)ppGpp in Bacillus anthracis. A co-structure with Bacillus subtilis PurR reveals that (p)ppGpp binds to a PurR pocket reminiscent of the active site of phosphoribosyltransferase enzymes that has been repurposed to serve a purely regulatory role, where the effectors (p)ppGpp and PRPP compete to allosterically control transcription. PRPP inhibits PurR DNA binding to induce transcription of purine synthesis genes, whereas (p)ppGpp antagonizes PRPP to enhance PurR DNA binding and repress transcription. A (p)ppGpp-refractory purR mutant in B. subtilis fails to downregulate purine synthesis genes upon amino acid starvation. Our work establishes the precedent of (p)ppGpp as an effector of a classical transcription repressor and reveals the key function of (p)ppGpp in regulating nucleotide synthesis through gene regulation, from soil bacteria to pathogens.
| S-EPMC8789054 | biostudies-literature
Project description:Staphylococcus aureus is a significant cause of human infection. Here, we demonstrate that mutations in the transcriptional repressor of purine biosynthesis, purR, enhance the pathogenic potential of S. aureus. Indeed, systemic infection with purR mutants causes accelerated mortality in mice, which is due to aberrant up-regulation of fibronectin binding proteins (FnBPs). Remarkably, purR mutations can arise upon exposure of S. aureus to stress, such as an intact immune system. In humans, naturally occurring anti-FnBP antibodies exist that, while not protective against recurrent S. aureus infection, ostensibly protect against hypervirulent S. aureus infections. Vaccination studies support this notion, where anti-Fnb antibodies in mice protect against purR hypervirulence. These findings provide a novel link between purine metabolism and virulence in S. aureus.
2019-02-26 | GSE124869 | GEO
Project description:Short-term adaptation to changing environments relies on regulatory elements translating changing metabolite concentrations into a specifically optimized transcriptome. So far the focus of analyses has been divided between regulatory elements identified in vivo and kinetic studies of small molecules interacting with the regulatory elements in vitro. Here we describe how in vivo Regulatory Kinetics can describe a regulon through the effects of the metabolite controlling it, exemplified by temporal purine exhaustion in Lactococcus lactis. We deduced a causal relation between the pathway precursor 5-phosphoribosyl-1-pyrophosphate (PRPP) and each individual mRNA levels, whereby unambiguous and homogenous relations could be obtained for PurR regulated genes, thus linking a specific regulon to a specific metabolite. As PurR activates gene expression upon binding of PRPP, the pur mRNA curves reflect the in vivo kinetics of PurR PRPP binding and activation. The method singled out the xpt-pbuX operon as kinetically distinct, which was found to be caused by a guanine riboswitch whose regulation was overlaying the PurR regulation. The strategy outlined here can be adapted to analyze the individual effects of members from larger metabolomes in virtually any organism, for elucidating regulatory networks in vivo. Agilent 8x15k custom microarrays Fifteen samples from two cultures were taken in a time-course experiment.
2013-12-01 | E-GEOD-52135 | biostudies-arrayexpress
Project description:The small nucleotide ppGpp is a conserved regulatory molecule in prokaryotes that tunes growth rate in response to nutrient availability. How ppGpp regulates growth remains poorly defined. In Escherichia coli, ppGpp directly binds RNA polymerase to modulate transcription, but it likely has other targets. Here, we develop a capture-compound mass spectrometry approach to identify more than 50 putative ppGpp targets that control many key cellular processes, including translation, polyamine synthesis, and nucleotide metabolism. We validate several proteins as bona fide ppGpp targets in vivo. In particular, we demonstrate that ppGpp inhibits the enzymes Gsk and PurF to block purine salvage and de novo synthesis, respectively. Our results indicate that downregulating ATP and GTP synthesis is a critical facet of growth control by ppGpp. Collectively, our results provide new insight into ppGpp-based growth control in E. coli and candidates for future exploration. The capture compounds developed will also enable identification of ppGpp targets in other species, including many pathogens.
2018-10-04 | PXD010402 | Pride
Project description:Short-term adaptation to changing environments relies on regulatory elements translating changing metabolite concentrations into a specifically optimized transcriptome. So far the focus of analyses has been divided between regulatory elements identified in vivo and kinetic studies of small molecules interacting with the regulatory elements in vitro. Here we describe how in vivo Regulatory Kinetics can describe a regulon through the effects of the metabolite controlling it, exemplified by temporal purine exhaustion in Lactococcus lactis. We deduced a causal relation between the pathway precursor 5-phosphoribosyl-1-pyrophosphate (PRPP) and each individual mRNA levels, whereby unambiguous and homogenous relations could be obtained for PurR regulated genes, thus linking a specific regulon to a specific metabolite. As PurR activates gene expression upon binding of PRPP, the pur mRNA curves reflect the in vivo kinetics of PurR PRPP binding and activation. The method singled out the xpt-pbuX operon as kinetically distinct, which was found to be caused by a guanine riboswitch whose regulation was overlaying the PurR regulation. The strategy outlined here can be adapted to analyze the individual effects of members from larger metabolomes in virtually any organism, for elucidating regulatory networks in vivo. Agilent 8x15k custom microarrays
2013-12-01 | GSE52135 | GEO
Project description:Ionophores are antibacterial compounds that affect bacterial growth by changing intracellular concentrations of the essential cations, sodium and potassium. They are extensively used in animal husbandry to increase productivity and reduce infectious diseases. Given their widespread usage, it is important to determine the potential negative consequences of ionophore use on human and animal health. In this study, we demonstrate that exposure to the ionophore monensin can select for resistant mutants in the human and animal pathogen Staphylococcus aureus, with a majority of the resistant mutants showing increased growth rates in vitro and/or in mice. Whole-genome sequencing and proteomics analysis of the resistant mutants show that the resistance phenotype is associated with de-repression of de novo purine synthesis, which could be achieved through mutations in different transcriptional regulators including mutations in the gene purR, the repressor of the purine de novo synthesis pathway. This study shows that mutants with reduced susceptibility to the ionophore monensin can be readily selected and highlights an unexplored link between ionophore resistance, purine metabolism and fitness in pathogenic bacteria.
2024-01-09 | PXD047199 | Pride
Project description:Here, B. subtilis was used as a model organism to investigate how cells respond and adapt to proteotoxic stress conditions. Our experiments suggested that the stringent response, caused by raised levels of the (p)ppGpp alarmone, plays a role during thermotolerance development and the heat shock response. Accordingly, our experiments revealed a rapid increase of cellular (p)ppGpp levels upon heat shock as well as salt- and oxidative stress. Strains lacking (p)ppGpp exhibited increased stress sensitivity, while raised (p)ppGpp levels conferred increased stress tolerance to heat- and oxidative stress. During thermotolerance development, stress response genes were highly up-regulated together with a concurrent transcriptional down-regulation of the rRNA, which was influenced by the second messenger (p)ppGpp and the transcription factor Spx. Remarkably, we observed that (p)ppGpp appeared to control the cellular translational capacity and that during heat stress the raised cellular levels of the alarmone were able to curb the rate of protein synthesis. Furthermore, (p)ppGpp controls the heat-induced expression of Hpf and thus the formation of translationally inactive 100S disomes. These results indicate that B. subtilis cells respond to heat-mediated protein unfolding and aggregation, not only by raising the cellular repair capacity, but also by decreasing translation involving (p)ppGpp mediated stringent response to concurrently reduce the protein load for the cellular protein quality control system.
2020-03-09 | PXD015416 | Pride
Project description:FAMIN is a multifunctional purine enzyme enabling the purine nucleotide cycle (Macrophage RNA Seq dataset)
| PRJNA522787 | ENA
Project description:Acinetobacter baumannii is a major cause of nosocomial infections which can survive in different hospital environments and its multidrug-resistant capacity is major concern now-a-days. ppGpp dependent stringent response mediates reprogramming of gene expression with diverse function in many bacteria. A baumannii A1S_0579 gene is responsible for ppGpp production. Transcriptome analysis of early stationary phase cultures represents several differentially expressed genes in ppGpp deficient strain (∆A1S_0579). We found that the expression of csu operon, which is important in pili biosynthesis for early biofilm formation, was significantly reduced in the ppGpp-deficient strain. Our findings showed that ppGpp signaling plays critical role in biofilm formation, surface motility, adherence and virulence of A baumannii. This study is the first demonstration of the association between ppGpp and pathogenicity of A. baumannii.
2021-05-01 | GSE173627 | GEO