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Updated: Jun 10, 2026
07:10
A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues
Published on: February 19, 2019
The sensor kinase MprB is required for Rhodococcus equi virulence.
Iain MacArthur1, Valeria R Parreira, Dion Lepp
1Department of Pathobiology, Ontario Veterinary College, University of Guelph, Gordon Street, Guelph, Ontario, N1G 2W1, Canada.
Veterinary Microbiology
|July 20, 2010
Summary
Researchers identified MprB as a crucial sensor kinase (SK) required for Rhodococcus equi virulence. This finding is vital for understanding how this soil bacterium infects foals and survives within macrophages.
Area of Science:
- Microbiology
- Bacterial Pathogenesis
- Molecular Biology
Background:
- Rhodococcus equi causes pyogranulomatous bronchopneumonia in foals by infecting alveolar macrophages.
- Virulence is mediated by a plasmid-encoded gene, orf8, which is part of an orphan two-component system (TCS).
- The cognate sensor kinase (SK) for orf8, essential for virulence, remained unidentified.
Purpose of the Study:
- To identify the sensor kinase (SK) cognate to the orf8 virulence gene in Rhodococcus equi.
- To investigate the role of identified SKs in R. equi's intracellular survival within macrophages.
- To confirm the role of the identified SK in R. equi virulence and pathogenesis.
Main Methods:
- Genome-wide annotation identified 23 chromosomal TCSs in R. equi.
- DNA microarrays compared TCS gene transcription in macrophages versus in vitro growth.
- Mutagenesis and virulence assays (macrophage persistence, mouse model) were used to assess SK function.
Main Results:
- Six SKs were significantly upregulated in macrophages compared to in vitro growth.
- MprB was identified as essential for R. equi's intracellular survival in macrophages.
- MprB is required for R. equi virulence in a mouse model, with mprB mutants showing significant attenuation.
Conclusions:
- MprB is the first identified sensor kinase (SK) critical for Rhodococcus equi virulence and intracellular survival.
- Rhodococcus equi exhibits distinct responses to the macrophage environment compared to Mycobacterium tuberculosis.
- Understanding MprB's role provides a target for controlling R. equi infections.
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