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Sigma B contributes to PrfA-mediated virulence in Listeria monocytogenes
Celine A Nadon1, Barbara M Bowen, Martin Wiedmann
1Department of Food Science, Cornell University, Ithaca, New York 14853, USA.
Abstract:
Transcription of the Listeria monocytogenes positive regulatory factor A protein (PrfA) is initiated from either of two promoters immediately upstream of prfA (prfAp(1) and prfAp(2)) or from the upstream plcA promoter. We demonstrate that prfAp(2) is a functional sigma(B)-dependent promoter and that a sigB deletion mutation affects the virulence phenotype of L. monocytogenes. Thus, the alternative sigma factor sigma(B) contributes to virulence in L. monocytogenes.
Insights
The alternative sigma factor sigma(B) influences Listeria monocytogenes virulence by regulating the positive regulatory factor A protein (PrfA) transcription. A sigB deletion mutation impacts the bacterium's virulence, highlighting sigma(B)'s role.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
- Molecular Biology
Background:
- Listeria monocytogenes is an important foodborne pathogen.
- The positive regulatory factor A protein (PrfA) is a key virulence regulator.
- PrfA transcription is controlled by multiple promoters.
Purpose of the Study:
- To investigate the role of the alternative sigma factor sigma(B) in regulating PrfA transcription.
- To determine the contribution of sigma(B) to L. monocytogenes virulence.
Main Methods:
- Analysis of prfA promoter activity.
- Construction and characterization of a sigB deletion mutant in L. monocytogenes.
- Assessment of the virulence phenotype of the mutant strain.
Main Results:
- The prfAp(2) promoter was identified as a functional sigma(B)-dependent promoter.
- A sigB deletion mutation significantly altered the virulence phenotype of L. monocytogenes.
Conclusions:
- The alternative sigma factor sigma(B) plays a significant role in L. monocytogenes virulence.
- Sigma(B) contributes to virulence by regulating PrfA expression through the prfAp(2) promoter.