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

Erin L Fuchs; Evan D Brutinel; Adriana K Jones; Nanette B Fulcher; Mark L Urbanowski; Timothy L Yahr; Matthew C Wolfgang

doi:10.1128/JB.00363-10

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

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

Erin L Fuchs, Evan D Brutinel, Adriana K Jones, Nanette B Fulcher, Mark L Urbanowski, Timothy L Yahr and Matthew C Wolfgang

Journal of bacteriology, Vol.192(14), pp.3553-3564

07/2010

DOI: 10.1128/JB.00363-10

PMCID: PMC2897347

PMID: 20494996

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Abstract

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.

Molecular Biology of Pathogens

Details

Title: Subtitle: The Pseudomonas aeruginosa Vfr Regulator Controls Global Virulence Factor Expression through Cyclic AMP-Dependent and -Independent Mechanisms
Creators: Erin L Fuchs - Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
Evan D Brutinel - Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
Adriana K Jones - Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
Nanette B Fulcher - Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
Mark L Urbanowski - Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
Timothy L Yahr - Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
Matthew C Wolfgang - Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
Resource Type: Journal article
Publication Details: Journal of bacteriology, Vol.192(14), pp.3553-3564
DOI: 10.1128/JB.00363-10
PMID: 20494996
PMCID: PMC2897347
NLM abbreviation: J Bacteriol
ISSN: 0021-9193
eISSN: 1098-5530
Publisher: American Society for Microbiology (ASM)
Language: English
Date published: 07/2010
Academic Unit: Microbiology and Immunology
Record Identifier: 9984001210802771

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