This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplemental material
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Ollinger, J.
Right arrow Articles by Bergholz, T. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ollinger, J.
Right arrow Articles by Bergholz, T. M.

 Previous Article  |  Next Article 

Infection and Immunity, May 2009, p. 2113-2124, Vol. 77, No. 5
0019-9567/09/$08.00+0     doi:10.1128/IAI.01205-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Listeria monocytogenes {sigma}B Modulates PrfA-Mediated Virulence Factor Expression{triangledown} ,{dagger}

Juliane Ollinger, Barbara Bowen, Martin Wiedmann, Kathryn J. Boor, and Teresa M. Bergholz*

Department of Food Science, Cornell University, Ithaca, New York 14853

Received 29 September 2008/ Returned for modification 2 November 2008/ Accepted 19 February 2009

Listeria monocytogenes {sigma}B and positive regulatory factor A (PrfA) are pleiotropic transcriptional regulators that coregulate a subset of virulence genes. A positive regulatory role for {sigma}B in prfA transcription has been well established; therefore, observations of increased virulence gene expression and hemolytic activity in a {Delta}sigB strain initially appeared paradoxical. To test the hypothesis that L. monocytogenes {sigma}B contributes to a regulatory network critical for appropriate repression as well as induction of virulence gene expression, genome-wide transcript profiling and follow-up quantitative reverse transcriptase PCR (qRT-PCR), reporter fusion, and phenotypic experiments were conducted using L. monocytogenes prfA*, prfA* {Delta}sigB, {Delta}prfA, and {Delta}prfA {Delta}sigB strains. Genome-wide transcript profiling and qRT-PCR showed that in the presence of active PrfA (PrfA*), {sigma}B is responsible for reduced expression of the PrfA regulon. {sigma}B-dependent modulation of PrfA regulon expression reduced the cytotoxic effects of a PrfA* strain in HepG2 cells, highlighting the functional importance of regulatory interactions between PrfA and {sigma}B. The emerging model of the role of {sigma}B in regulating overall PrfA activity includes a switch from transcriptional activation at the P2prfA promoter (e.g., in extracellular bacteria when PrfA activity is low) to posttranscriptional downregulation of PrfA regulon expression (e.g., in intracellular bacteria when PrfA activity is high).

* Corresponding author. Mailing address: Department of Food Science, Cornell University, 405 Stocking Hall, Ithaca, NY 14853. Phone: (607) 255-1266. Fax: (607) 254-4868. E-mail: tmb224{at}cornell.edu

{triangledown} Published ahead of print on 2 March 2009.

{dagger} Supplemental material for this article may be found at http://iai.asm.org/.

Editor: A. Camilli

Infection and Immunity, May 2009, p. 2113-2124, Vol. 77, No. 5
0019-9567/09/$08.00+0     doi:10.1128/IAI.01205-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Sleator, R. D., Watson, D., Hill, C., Gahan, C. G. M. (2009). The interaction between Listeria monocytogenes and the host gastrointestinal tract. Microbiology 155: 2463-2475 [Abstract] [Full Text]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»