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The multifaceted RisA regulon of Bordetella pertussis
Loïc Coutte1,2,3,4, Ludovic Huot1,2,3,4, Rudy Antoine1,2,3,4
1Institut Pasteur de Lille, Center for Infection and Immunity of Lille, Lille, France.
Scientific Reports
|September 14, 2016
Summary
The whooping cough bacterium Bordetella pertussis uses RisA to control virulence genes. RisA adds complexity to how B. pertussis regulates virulence factors, impacting gene expression.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
- Gene Regulation
Background:
- Bordetella pertussis, the agent of whooping cough, employs the BvgA/S two-component system to regulate virulence factors.
- BvgA/S controls virulence-activated genes (vags) and virulence-repressed genes (vrgs), with vrgs expressed under modulating conditions (e.g., MgSO4).
Purpose of the Study:
- To investigate the role of the transcriptional regulator RisA in B. pertussis virulence gene expression.
- To identify the kinase responsible for RisA activation and characterize the RisA regulon.
Main Methods:
- Genetic manipulation to create risA knockout and mutant strains (RisAD(60)N, RisAD(60)E).
- Analysis of gene expression (vags, vrgs, chemotaxis, flagellar, iron-regulated genes) in wild-type and mutant backgrounds.
- Identification of RisK as the cognate kinase for RisA.
Main Results:
- RisA is essential for the expression of most virulence-repressed genes (vrgs).
- Loss of RisA affects the modulation of some virulence-activated genes (vags) by MgSO4.
- RisA regulates additional genes, including those involved in chemotaxis, flagellar function, and iron metabolism.
- RisK is identified as the kinase activating RisA, crucial for most RisA-regulated genes.
Conclusions:
- The RisA regulon represents a significant layer of complexity in B. pertussis virulence gene regulation, independent of and interacting with the BvgA/S system.
- RisA and its kinase RisK are important targets for understanding and potentially controlling B. pertussis pathogenesis.
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