A new aspect of transcriptional control of the <i>Escherichia coli crp</i> gene: positive autoregulation

Hanamura, Akemi; Aiba, Hirofumi

doi:10.1111/j.1365-2958.1992.tb01425.x

Cited by 48 publications

(19 citation statements)

References 33 publications

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“…Our data demonstrate that Vfr is a positive regulatory factor with respect to its own transcription. In contrast, the E. coli crp promoter is negatively autoregulated by CRP, except at high concentrations of cAMP, where positive autoregulation has been reported (1,8,21). The different modes of autoregulation displayed by the crp and vfr promoters are presumably due to their different promoter architectures and reflect their specific regulatory roles in E. coli and P. aeruginosa (catabolite repression versus virulence factor expression, respectively).…”

Section: Discussionmentioning

confidence: 80%

“…Furthermore, it was demonstrated through electrophoretic mobility shift assays (EMSAs) that Vfr could specifically bind to a vfr promoter probe containing both putative sites (24). Although the role of these sites in vfr promoter activity has not been tested, direct binding of Vfr to this region suggests that vfr expression is autoregulated, as is the case for E. coli crp (1,8,21).…”

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confidence: 99%

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The Pseudomonas aeruginosa Vfr Regulator Controls Global Virulence Factor Expression through Cyclic AMP-Dependent and -Independent Mechanisms

et al. 2010

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Vfr is a global regulator of virulence factor expression in the human pathogen Pseudomonas aeruginosa. Although indirect evidence suggests that Vfr activity is controlled by cyclic AMP (cAMP), it has been hypothesized that the putative cAMP binding pocket of Vfr may accommodate additional cyclic nucleotides. In this study, we used two different approaches to generate apo-Vfr and examined its ability to bind a representative set of virulence gene promoters in the absence and presence of different allosteric effectors. Of the cyclic nucleotides tested, only cAMP was able to restore DNA binding activity to apo-Vfr. In contrast, cGMP was capable of inhibiting cAMP-Vfr DNA binding. Further, we demonstrate that vfr expression is autoregulated and cAMP dependent and involves Vfr binding to a previously unidentified site within the vfr promoter region. Using a combination of in vitro and in vivo approaches, we show that cAMP is required for Vfr-dependent regulation of a specific subset of virulence genes. In contrast, we discovered that Vfr controls expression of the lasR promoter in a cAMP-independent manner. In summary, our data support a model in which Vfr controls virulence gene expression by distinct (cAMP-dependent and -independent) mechanisms, which may allow P. aeruginosa to fine-tune its virulence program in response to specific host cues or environments.

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Section: Discussionmentioning

confidence: 80%

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confidence: 99%

The Pseudomonas aeruginosa Vfr Regulator Controls Global Virulence Factor Expression through Cyclic AMP-Dependent and -Independent Mechanisms

et al. 2010

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“…Expression of cyaA is negatively regulated by Crp/cAMP in both E. coli (10,387,395,576) and S. enterica serovar Typhimurium (221), whereas expression of crp is both positively (310) and negatively (9,140,311) affected by Crp/cAMP. As a result, strong crp expression occurs at low and high Crp/cAMP concentrations (due to reduced inhibition and increased stimulation, respectively), whereas low crp expression is observed at intermediate Crp/ cAMP concentrations (310). The concentration of Crp/cAMP in exponentially growing cells is an order of magnitude higher than that allowing minimal crp transcription (310,365).…”

Section: Glcmentioning

confidence: 99%

“…As a result, strong crp expression occurs at low and high Crp/cAMP concentrations (due to reduced inhibition and increased stimulation, respectively), whereas low crp expression is observed at intermediate Crp/ cAMP concentrations (310). The concentration of Crp/cAMP in exponentially growing cells is an order of magnitude higher than that allowing minimal crp transcription (310,365). Consequently, a decrease in the cAMP concentration caused by the addition of glucose to these cells should lower the transcription of crp and hence the concentration of Crp.…”

Section: Glcmentioning

confidence: 99%

How Phosphotransferase System-Related Protein Phosphorylation Regulates Carbohydrate Metabolism in Bacteria

Deutscher

Francke

Postma

2006

Microbiol Mol Biol Rev

1,187

769

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SUMMARY The phosphoenolpyruvate(PEP):carbohydrate phosphotransferase system (PTS) is found only in bacteria, where it catalyzes the transport and phosphorylation of numerous monosaccharides, disaccharides, amino sugars, polyols, and other sugar derivatives. To carry out its catalytic function in sugar transport and phosphorylation, the PTS uses PEP as an energy source and phosphoryl donor. The phosphoryl group of PEP is usually transferred via four distinct proteins (domains) to the transported sugar bound to the respective membrane component(s) (EIIC and EIID) of the PTS. The organization of the PTS as a four-step phosphoryl transfer system, in which all P derivatives exhibit similar energy (phosphorylation occurs at histidyl or cysteyl residues), is surprising, as a single protein (or domain) coupling energy transfer and sugar phosphorylation would be sufficient for PTS function. A possible explanation for the complexity of the PTS was provided by the discovery that the PTS also carries out numerous regulatory functions. Depending on their phosphorylation state, the four proteins (domains) forming the PTS phosphorylation cascade (EI, HPr, EIIA, and EIIB) can phosphorylate or interact with numerous non-PTS proteins and thereby regulate their activity. In addition, in certain bacteria, one of the PTS components (HPr) is phosphorylated by ATP at a seryl residue, which increases the complexity of PTS-mediated regulation. In this review, we try to summarize the known protein phosphorylation-related regulatory functions of the PTS. As we shall see, the PTS regulation network not only controls carbohydrate uptake and metabolism but also interferes with the utilization of nitrogen and phosphorus and the virulence of certain pathogens.

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“…Fuchs and colleagues (2010a) identified a single novel Vfr binding site within the vfr promoter, and in vitro transcription studies demonstrated that both cAMP and Vfr are required for vfr positive autoregulation (Fuchs, 2010a). A similar mechanism of autoregulation has been demonstrated for E. coli crp (Cossart, 1982;Hanamura, 1992).…”

Section: Allosteric Regulation Of Vfr: Camp-dependent/independent Mecmentioning

confidence: 88%

Global Regulatory Pathways and Cross-talk ControlPseudomonas aeruginosaEnvironmental Lifestyle and Virulence Phenotype

Coggan

Wolfgang

2012

Current Issues in Molecular Biology

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Pseudomonas aeruginosa is a metabolically versatile environmental bacterium and an opportunistic human pathogen that relies on numerous signaling pathways to sense, respond, and adapt to fluctuating environmental cues. Although the environmental signals sensed by these pathways are poorly understood, they are largely responsible for determining whether P. aeruginosa adopts a planktonic or sessile lifestyle. These environmental lifestyle extremes parallel the acute and chronic infection phenotypes observed in human disease. In this review, we focus on four major pathways (cAMP/Vfr and c-di-GMP signaling, quorum sensing, and the Gac/Rsm pathway) responsible for sensing and integrating external stimuli into coherent regulatory control at the transcriptional, translational, and post-translational level. A common theme among these pathways is the inverse control of factors involved in promoting motility and acute infection and those associated with biofilm formation and chronic infection. In many instances these regulatory pathways influence one another, forming a complex network allowing P. aeruginosa to assimilate numerous external signals into an integrated regulatory circuit that controls a lifestyle continuum.

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A new aspect of transcriptional control of the Escherichia coli crp gene: positive autoregulation

Cited by 48 publications

References 33 publications

The Pseudomonas aeruginosa Vfr Regulator Controls Global Virulence Factor Expression through Cyclic AMP-Dependent and -Independent Mechanisms

The Pseudomonas aeruginosa Vfr Regulator Controls Global Virulence Factor Expression through Cyclic AMP-Dependent and -Independent Mechanisms

How Phosphotransferase System-Related Protein Phosphorylation Regulates Carbohydrate Metabolism in Bacteria

Global Regulatory Pathways and Cross-talk ControlPseudomonas aeruginosaEnvironmental Lifestyle and Virulence Phenotype

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