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Characterization of a two-component system, devR-devS, of Mycobacterium tuberculosis
N Dasgupta1, V Kapur, K K Singh
1Department of Biotechnology, All India Institute of Medical Sciences, New Delhi, India.
Tubercle and Lung Disease : the Official Journal of the International Union Against Tuberculosis and Lung Disease
|September 6, 2000
Summary
Researchers identified the devR-devS two-component system in Mycobacterium tuberculosis, potentially regulating virulence. This system
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Mycobacterium tuberculosis (M. tuberculosis) virulence is a complex phenotype.
- Understanding gene regulation is crucial for identifying virulence factors.
- Two-component systems are common regulators in bacteria.
Purpose of the Study:
- To identify genes differentially expressed in virulent M. tuberculosis strains.
- To characterize a novel two-component system potentially involved in virulence.
Main Methods:
- Subtractive hybridization to identify differentially expressed genes.
- DNA sequencing to identify the devR-devS locus.
- DevR-lacZ transcriptional fusion assays.
- Quantitative analysis of devR and devS transcript levels.
- Western blot analysis for DevR protein levels.
- Electron microscopic immunogold labeling.
Main Results:
- The devR-devS two-component system was identified and found to be differentially expressed.
- devR and devS genes were cotranscribed, with lower transcript levels in avirulent strains.
- DevR protein was localized within M. tuberculosis and infected monocytes.
- The devR-devS locus was conserved in M. tuberculosis and M. bovis BCG.
Conclusions:
- The devR-devS system is differentially regulated between virulent and avirulent M. tuberculosis strains.
- DevR protein is present in bacteria and within the phagosomal lumen of infected monocytes.
- The devR-devS system likely plays a role in regulating M. tuberculosis virulence.