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Growth phase-dependent modulation of Rgg binding specificity in Streptococcus pyogenes
Srivishnupriya Anbalagan1, Alexander Dmitriev, W Michael McShan
1Division of Basic Biomedical Sciences, The Sanford School of Medicine of the University of South Dakota, Vermillion, South Dakota, USA.
Journal of Bacteriology
|May 29, 2012
Summary
Streptococcus pyogenes Rgg, with cofactor LacD.1, directly controls virulence gene expression during exponential growth. Rgg
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Streptococcus pyogenes Rgg is a transcriptional regulator.
- Rgg interacts with cofactor LacD.1 to control gene expression.
- LacD.1's interaction with Rgg is dependent on glycolytic intermediates.
Purpose of the Study:
- To determine if Rgg binds to chromatin during exponential growth.
- To identify Rgg's DNA binding sites during this phase.
Main Methods:
- Chromatin immunoprecipitation coupled with DNA microarrays (ChIP-chip).
- Transcriptional fusion assays.
- In vitro DNA binding assays.
Main Results:
- Rgg bound to 62 chromosomal sites during exponential growth.
- Identified Rgg binding sites upstream of key virulence genes (emm49, sof, sfbX49, SpeH).
- LacD.1 and Rgg are both essential for repressing emm49, sof, sfbX49, and speH expression.
Conclusions:
- Rgg's DNA binding specificity is modulated by environmental cues via LacD.1.
- Rgg and LacD.1 directly regulate Streptococcus pyogenes virulence gene expression in the exponential growth phase.
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