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A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues
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Coordinate control of virulence gene expression in Francisella tularensis involves direct interaction between key

Amy E Rohlfing1, Simon L Dove2

  • 1Division of Infectious Diseases, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA.

Journal of Bacteriology
|July 30, 2014
PubMed

Insights

The bacterial virulence regulator PigR requires interaction with the MglA-SspA complex to control essential intramacrophage genes in Francisella tularensis. This study identifies specific mutations, clarifying PigR

Area of Science:

  • Microbiology
  • Bacterial Pathogenesis
  • Molecular Biology

Background:

  • Francisella tularensis requires specific gene expression for survival within host macrophages.
  • The MglA-SspA complex interacts with RNA polymerase (RNAP) to regulate gene expression.
  • The precise mechanism of PigR's interaction with the MglA-SspA complex remains unclear, with conflicting models.

Purpose of the Study:

  • To elucidate the mechanism by which PigR collaborates with the MglA-SspA complex.
  • To determine if PigR directly interacts with the MglA-SspA complex.
  • To identify specific interaction surfaces between PigR and the MglA-SspA complex.

Main Methods:

  • Utilized genetic assays to identify mutants of MglA and SspA.
  • Screened for mutants specifically defective in their interaction with PigR.
  • Analyzed the function of these mutants in Francisella tularensis.

Main Results:

  • Identified MglA and SspA mutants that fail to interact with PigR.
  • Demonstrated that the PigR-MglA-SspA interaction is essential for PigR's positive regulation of virulence genes.
  • Uncovered a specific surface on the MglA-SspA complex critical for PigR binding.

Conclusions:

  • PigR requires direct interaction with the MglA-SspA complex to regulate virulence gene expression.
  • This interaction is crucial for the coordinated action of PigR with MglA and SspA.
  • PigR likely exerts its regulatory function by interacting with the RNAP-associated MglA-SspA complex.

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