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A Purification and In Vitro Activity Assay for a pppGpp Synthetase from Clostridium difficile
Published on: November 3, 2018
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Activation of the extracytoplasmic function σ factor σV by lysozyme in Clostridioides difficile
Theresa D Ho1, Craig D Ellermeier2
1Department of Microbiology and Immunology, Carver College of Medicine, University of Iowa, 431 Newton Rd., Iowa City, IA 52242, USA.
Current Opinion in Microbiology
|December 11, 2021
Summary
Clostridioides difficile bacteria resist lysozyme, a key immune protein, using inducible genes. An anti-sigma factor, RsiV, controls the sigma V (σV) factor, activating resistance when lysozyme is present.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
- Innate Immunity
Background:
- Clostridioides difficile possesses natural resistance to lysozyme, a crucial component of the innate immune system.
- The bacterium employs both constitutive and inducible gene expression for lysozyme resistance.
- Inducible resistance is regulated by an alternative sigma factor, σV, part of the Extracytoplasmic function family.
Purpose of the Study:
- To review the regulatory mechanisms controlling the activity of the σV factor in Clostridioides difficile.
- To elucidate the role of the anti-σ factor RsiV in managing lysozyme resistance.
- To highlight the cascade leading to σV activation upon exposure to lysozyme.
Main Methods:
- Review of existing literature on Clostridioides difficile lysozyme resistance.
- Analysis of the σV regulon and its regulation by RsiV.
- Examination of the proteolytic cascade involved in RsiV degradation.
Main Results:
- σV activity is tightly regulated by the anti-σ factor RsiV in the absence of lysozyme.
- Lysozyme triggers a proteolytic cascade that degrades RsiV.
- Degradation of RsiV leads to the activation of σV and enhanced bacterial resistance to lysozyme.
Conclusions:
- The RsiV-σV system represents a critical mechanism for Clostridioides difficile to adapt and survive in the presence of lysozyme.
- Understanding this regulatory pathway offers insights into bacterial immune evasion strategies.
- Targeting this system could be a potential therapeutic approach against C. difficile infections.
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