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A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues
Published on: February 19, 2019
Bacteriophage-mediated toxin gene regulation in Clostridium difficile
Revathi Govind1, Govindsamy Vediyappan, Rial D Rolfe
1Department of Microbiology and Immunology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA. revathi.govind@ttuhsc.edu
Journal of Virology
|September 25, 2009
Summary
Lysogeny by the PhiCD119 phage reduces toxin production in Clostridium difficile. A phage repressor protein, RepR, was identified to downregulate key toxin genes, impacting C. difficile pathogenesis.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Clostridium difficile is a major cause of antibiotic-associated diarrhea and colitis.
- Virulent strains produce toxins A and B, crucial for pathogenesis.
Purpose of the Study:
- To investigate the impact of PhiCD119 phage lysogeny on Clostridium difficile toxin production.
- To identify the molecular mechanisms underlying toxin gene regulation by the phage.
Main Methods:
- Transcriptional analysis of pathogenicity locus (PaLoc) genes in PhiCD119 lysogens.
- Reporter gene assays in Escherichia coli to assess the function of the putative repressor gene repR.
- Gel shift and DNA footprinting assays to characterize RepR protein binding to target DNA sequences.
Main Results:
- Lysogeny by PhiCD119 decreased the expression of PaLoc genes (tcdA, tcdB, tcdR, tcdE, tcdC).
- The PhiCD119 repressor protein, RepR, was found to downregulate tcdA and tcdR expression.
- RepR binds to specific upstream regions of tcdR in Clostridium difficile and its own upstream region in PhiCD119.
Conclusions:
- PhiCD119 lysogeny influences Clostridium difficile toxin gene regulation.
- The RepR protein acts as a repressor, potentially modulating virulence in this pathogen.
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