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

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The extracytoplasmic function sigma factor σVreI is active during infection and contributes to phosphate

Joaquín R Otero-Asman1, José M Quesada1, Kin K Jim2

  • 1Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, Granada, Spain.

Scientific Reports
|February 22, 2020
PubMed

Insights

The sigma factor VreI is active during Pseudomonas aeruginosa infection, contributing to virulence under phosphate starvation. Surprisingly, its inhibitor VreR also impacts virulence, suggesting complex regulatory roles.

Area of Science:

  • Microbiology
  • Bacterial Pathogenesis
  • Molecular Biology

Background:

  • The extracytoplasmic function sigma factor σVreI in Pseudomonas aeruginosa regulates virulence factors.
  • σVreI activity is controlled by the anti-σ factor VreR, particularly under inorganic phosphate (Pi) starvation.
  • The role of σVreI in vivo during infection and its contribution to Pi starvation-induced virulence remain uncharacterized.

Purpose of the Study:

  • To investigate the in vivo activity and role of σVreI during Pseudomonas aeruginosa infection.
  • To determine the contribution of σVreI to Pi starvation-induced virulence.
  • To elucidate the function of the VreR anti-σ factor in P. aeruginosa pathogenicity.

Main Methods:

  • Utilized zebrafish embryos and a human alveolar basal epithelial cell line as infection models.
  • Assessed the virulence of wild-type, ΔvreI, and ΔvreR P. aeruginosa mutants.
  • Performed transcriptomic analyses to understand gene expression changes.

Main Results:

  • σVreI is active during P. aeruginosa infection and is crucial for Pi starvation-induced virulence.
  • Deletion of the VreR anti-σ factor also reduced P. aeruginosa virulence.
  • VreR influences gene expression both dependently and independently of σVreI, affecting virulence determinants and regulators.

Conclusions:

  • σVreI plays a significant role in P. aeruginosa virulence during infection, especially under Pi-limiting conditions.
  • The anti-σ factor VreR has a complex regulatory role, impacting virulence through both σVreI-dependent and -independent pathways.
  • Further investigation into VreR's targets is needed to fully understand its contribution to P. aeruginosa pathogenicity.

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