Expression of a Yersinia pseudotuberculosis Type VI Secretion System Is Responsive to Envelope Stresses through the OmpR Transcriptional Activator

PLoS One. 2013 Jun 19;8(6):e66615. doi: 10.1371/journal.pone.0066615. Print 2013.

Abstract

The Type VI secretion system (T6SS) is a macromolecular complex widespread in Gram-negative bacteria. Although several T6SS are required for virulence towards host models, most are necessary to eliminate competitor bacteria. Other functions, such as resistance to amoeba predation, biofilm formation or adaptation to environmental conditions have also been reported. This multitude of functions is reflected by the large repertoire of regulatory mechanisms shown to control T6SS expression, production or activation. Here, we demonstrate that one T6SS gene cluster encoded within the Yersinia pseudotuberculosis genome, T6SS-4, is regulated by OmpR, the response regulator of the two-component system EnvZ-OmpR. We first identified OmpR in a transposon mutagenesis screen. OmpR does not control the expression of the four other Y. pseudotuberculosis T6SS gene clusters and of an isolated vgrG gene, and responds to osmotic stresses to bind to and activate the T6SS-4 promoter. Finally, we show that T6SS-4 promotes Y. pseudotuberculosis survival in high osmolarity conditions and resistance to deoxycholate.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Binding Sites
  • DNA Transposable Elements
  • Mutagenesis
  • Promoter Regions, Genetic
  • Trans-Activators / metabolism*
  • Type VI Secretion Systems / metabolism*
  • Yersinia pseudotuberculosis / metabolism*

Substances

  • DNA Transposable Elements
  • Trans-Activators
  • Type VI Secretion Systems

Grant support

This work was supported by the Centre National de la Recherche Scientifique and a grant from the Agence Nationale de la Recherche (ANR-10-JCJC-1303-03) to E.C. E.G. and E.D. were recipients of post-doctoral fellowships from the Fondation pour la Recherche Medicale (SPF-2009-12-17571 and SPF-2010-12-21116 respectively). X.-Y.Z. was supported by the ANR-10-JCJC-1303-03 grant. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.