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A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues
07:10

A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues

Published on: February 19, 2019

Virulence gene regulation by the agr system in Clostridium perfringens

Kaori Ohtani1, Yonghui Yuan, Sufi Hassan

  • 1Department of Bacteriology, Graduate School of Medical Science, Kanazawa University, Takara-machi Kanazawa, Ishikawa, Japan.

Journal of Bacteriology
|April 14, 2009
PubMed

Insights

The agrBD(Cp) system is crucial for regulating Clostridium perfringens virulence factors, including toxins essential for gas gangrene. This system likely senses extracellular signals, with VirR/VirS being necessary for activating toxin gene transcription.

Area of Science:

  • Microbiology
  • Bacterial Pathogenesis
  • Molecular Biology

Background:

  • Clostridium perfringens causes gas gangrene through potent toxins.
  • The Staphylococcus aureus agr system regulates virulence via quorum sensing.
  • A homologue, agrBD(Cp), was identified in C. perfringens.

Purpose of the Study:

  • To investigate the role of the C. perfringens agrBD(Cp) system in virulence gene regulation.
  • To determine the relationship between agrBD(Cp) and the VirR/VirS regulatory system.

Main Methods:

  • Construction and analysis of agrBD(Cp) knockout mutants.
  • Assessing toxin gene expression (theta-, alpha-, kappa-toxins).
  • Investigating the effect of wild-type supernatant on mutant toxin production.
  • Creating and analyzing an agr-virR double-knockout mutant.

Main Results:

  • agrBD(Cp) knockout mutants showed significantly reduced theta-, alpha-, and kappa-toxin gene expression.
  • Mutant toxin production was restored by adding wild-type supernatant, indicating a missing signal molecule.
  • The VirR/VirS system is essential for sensing extracellular signals and activating toxin gene transcription mediated by agrBD(Cp).

Conclusions:

  • The C. perfringens agrBD(Cp) system is vital for regulating toxin production and virulence.
  • The VirR/VirS two-component system is required for the agrBD(Cp)-mediated sensing and transcriptional activation of virulence genes.

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