Journal article
The Pseudomonas aeruginosa Magnesium Transporter MgtE Inhibits Transcription of the Type III Secretion System
Infection and immunity, Vol.78(3), pp.1239-1249
03/2010
DOI: 10.1128/IAI.00865-09
PMCID: PMC2825933
PMID: 20028803
Abstract
Pseudomonas aeruginosa
is an opportunistic pathogen that causes life-long pneumonia in individuals with cystic fibrosis (CF). These long-term infections are maintained by bacterial biofilm formation in the CF lung. We have recently developed a model of
P. aeruginosa
biofilm formation on cultured CF airway epithelial cells. Using this model, we discovered that mutation of a putative magnesium transporter gene, called
mgtE
, led to increased cytotoxicity of
P. aeruginosa
toward epithelial cells. This altered toxicity appeared to be dependent upon expression of the type III secretion system (T3SS). In this study, we found that mutation of
mgtE
results in increased T3SS gene transcription. Through epistasis analyses, we discovered that MgtE influences the ExsE-ExsC-ExsD-ExsA gene regulatory system of T3SS by either directly or indirectly inhibiting ExsA activity. While variations in calcium levels modulate T3SS gene expression in
P. aeruginosa
, we found that addition of exogenous magnesium did not inhibit T3SS activity. Furthermore,
mgtE
variants that were defective for magnesium transport could still complement the cytotoxicity effect. Thus, the magnesium transport function of MgtE does not fully explain the regulatory effects of MgtE on cytotoxicity. Overall, our results indicate that MgtE modulates expression of T3SS genes.
Details
- Title: Subtitle
- The Pseudomonas aeruginosa Magnesium Transporter MgtE Inhibits Transcription of the Type III Secretion System
- Creators
- Gregory G Anderson - Department of Microbiology and Immunology, Dartmouth Medical School, Hanover, New Hampshire 03755Timothy L Yahr - Department of Microbiology and Immunology, Dartmouth Medical School, Hanover, New Hampshire 03755Rustin R Lovewell - Department of Microbiology and Immunology, Dartmouth Medical School, Hanover, New Hampshire 03755George A O'Toole - Department of Microbiology and Immunology, Dartmouth Medical School, Hanover, New Hampshire 03755
- Resource Type
- Journal article
- Publication Details
- Infection and immunity, Vol.78(3), pp.1239-1249
- DOI
- 10.1128/IAI.00865-09
- PMID
- 20028803
- PMCID
- PMC2825933
- NLM abbreviation
- Infect Immun
- ISSN
- 0019-9567
- eISSN
- 1098-5522
- Publisher
- American Society for Microbiology (ASM)
- Language
- English
- Date published
- 03/2010
- Academic Unit
- Microbiology and Immunology
- Record Identifier
- 9984001137202771
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