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A Protein Microarray Assay for Serological Determination of Antigen-specific Antibody Responses Following Clostridium difficile Infection
Published on: June 15, 2018
Repression of Clostridium difficile toxin gene expression by CodY
Sean S Dineen1, Anuradha C Villapakkam, Jared T Nordman
1Department of Molecular Biology and Microbiology, School of Medicine, Tufts University, Boston, MA, USA.
Molecular Microbiology
|August 30, 2007
Summary
CodY protein represses toxin production in Clostridium difficile by controlling the tcdR gene. Nutrient levels, like GTP and amino acids, influence CodY binding and toxin gene expression.
Area of Science:
- Microbiology
- Bacterial Gene Regulation
- Clostridium difficile Pathogenesis
Background:
- CodY is a global regulator in low G+C Gram-positive bacteria.
- Clostridium difficile produces toxins essential for its pathogenicity.
Purpose of the Study:
- To investigate the role of CodY in regulating toxin gene expression in Clostridium difficile.
- To elucidate the mechanism by which CodY controls toxin production.
Main Methods:
- Gene inactivation experiments to study the effect of codY deletion.
- DNA binding assays to assess CodY's interaction with promoter regions.
- Analysis of gene expression under varying nutrient conditions.
Main Results:
- Inactivation of codY led to derepression of all five genes in the C. difficile pathogenicity locus.
- CodY bound with high affinity to the tcdR promoter, encoding a key sigma factor.
- CodY also showed low-affinity binding to toxin gene promoters, indicating primary regulation via tcdR.
- GTP and branched-chain amino acids enhanced CodY binding to the tcdR promoter.
Conclusions:
- CodY primarily regulates C. difficile toxin gene expression through direct control of tcdR.
- Nutrient availability, specifically GTP and branched-chain amino acids, influences CodY's regulatory activity.
- This suggests a mechanism linking nutrient limitation to C. difficile toxin production.
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