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A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues
Published on: February 19, 2019
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Regulation of the Sae Two-Component System by Branched-Chain Fatty Acids in Staphylococcus aureus
Augustus Pendleton1, Won-Sik Yeo1, Shahad Alqahtani1
1Department of Biology, Georgetown Universitygrid.213910.8, Washington, DC, USA.
Mbio
|September 22, 2022
Summary
Staphylococcus aureus virulence is regulated by branched-chain fatty acids (BCFAs) affecting sensor kinase activity. Disrupting BCFA synthesis reduces toxin production and bacterial virulence.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
- Molecular Biology
Background:
- Staphylococcus aureus is a major human pathogen.
- Virulence relies on regulatory networks controlling gene expression.
- The CodY repressor and SaeRS two-component system (TCS) are key regulators.
Purpose of the Study:
- Investigate the mechanism linking CodY to Sae-mediated toxin secretion.
- Determine the role of branched-chain fatty acids (BCFAs) in regulating TCS activity.
- Elucidate a novel posttranscriptional virulence regulation pathway in S. aureus.
Main Methods:
- Genetic disruption of codY and lpdA genes.
- Analysis of SaeR phosphorylation levels.
- Quantification of membrane BCFA content.
- Genetic and chemical complementation experiments.
Main Results:
- codY disruption increased SaeR phosphorylation and membrane BCFA content.
- lpdA disruption reduced SaeR, SaeR~P, and BCFAs, leading to lower toxin production and virulence.
- BCFA levels modulated SaeS sensor kinase activity, with exogenous BCFAs restoring Sae activity.
- lpdA mutation affected other TCSs, indicating a broader role for BCFAs.
Conclusions:
- BCFAs are essential for the activation of multiple TCSs in S. aureus.
- BCFA synthesis represents a novel mechanism for posttranscriptional regulation of virulence.
- CodY's regulation of virulence may involve alterations in membrane BCFA composition.
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