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Differential regulation of the two-component regulatory system senX3-regX3 in Mycobacterium tuberculosis.
- Source :
-
Microbiology (Reading, England) [Microbiology (Reading)] 2014 Jun; Vol. 160 (Pt 6), pp. 1125-1133. Date of Electronic Publication: 2014 Apr 10. - Publication Year :
- 2014
-
Abstract
- The highly successful pathogen Mycobacterium tuberculosis (Mtb) has evolved strategies to adapt to various stress conditions, thus promoting survival within the infected host. The two-component regulatory system (2CRS) senX3-regX3, which has been implicated in the Mtb response to inorganic phosphate depletion, is believed to behave as an auto-regulatory bicistronic operon. Unlike other 2CRS, Mtb senX3-regX3 features an intergenic region (IR) containing several mycobacterium interspersed repetitive units (MIRU) of unknown function. In this study, we used a lacZ reporter system to study the promoter activity of the 5' untranslated region of senX3, and that of various numbers of MIRUs in the senX3-regX3 IR, during axenic Mtb growth in nutrient-rich broth, and upon exposure to growth-restricting conditions. Activity of the senX3 promoter was induced during phosphate depletion and nutrient starvation, and IR promoter activity under these conditions was directly proportional to the number of MIRUs present. Quantitative reverse transcriptase (qRT)-PCR analysis of exponentially growing Mtb revealed monocistronic transcription of senX3 and regX3, and, to a lesser degree, bicistronic transcription of the operon. In addition, we observed primarily monocistronic upregulation of regX3 during phosphate depletion of Mtb, which was confirmed by Northern analysis in wild-type Mtb and by RT-PCR in a senX3-disrupted mutant, while upregulation of regX3 in nutrient-starved Mtb was chiefly bicistronic. Our findings of differential regulation of senX3-regX3 highlight the potential regulatory role of MIRUs in the Mtb genome and provide insight into the regulatory mechanisms underlying Mtb adaptation to physiologically relevant conditions.<br /> (© 2014 The Authors.)
- Subjects :
- Artificial Gene Fusion
Blotting, Northern
Gene Expression Profiling
Promoter Regions, Genetic
Real-Time Polymerase Chain Reaction
Reverse Transcriptase Polymerase Chain Reaction
Transcription, Genetic
beta-Galactosidase analysis
beta-Galactosidase genetics
Bacterial Proteins genetics
Gene Expression Regulation, Bacterial
Mycobacterium tuberculosis genetics
Phosphotransferases genetics
Subjects
Details
- Language :
- English
- ISSN :
- 1465-2080
- Volume :
- 160
- Issue :
- Pt 6
- Database :
- MEDLINE
- Journal :
- Microbiology (Reading, England)
- Publication Type :
- Academic Journal
- Accession number :
- 24722908
- Full Text :
- https://doi.org/10.1099/mic.0.077180-0