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Phosphorylation of the group A Streptococcal CovR response regulator causes dimerization and promoter-specific recruitment by RNA polymerase.

Publication ,  Journal Article
Gusa, AA; Gao, J; Stringer, V; Churchward, G; Scott, JR
Published in: J Bacteriol
July 2006

The group A streptococcus (GAS), Streptococcus pyogenes, is an important human pathogen that causes infections ranging in severity from self-limiting pharyngitis to severe invasive diseases that are associated with significant morbidity and mortality. The pathogenic effects of GAS are mediated by the expression of virulence factors, one of which is the hyaluronic acid capsule (encoded by genes in the has operon). The expression of these virulence factors is controlled by the CovR/S (CsrR/S) two-component regulatory system of GAS which regulates, directly or indirectly, the expression of about 15% of the genome. CovR is a member of the OmpR/PhoB family of transcriptional regulators. Here we show that phosphorylation by acetyl phosphate results in dimerization of CovR. Dimerization was not observed using a D53A mutant of CovR, indicating that D53 is the site of phosphorylation in CovR. Phosphorylation stimulated binding of CovR to a DNA fragment containing the promoter of the has operon (Phas) approximately twofold. Binding of CovR D53A mutant protein to Phas was indistinguishable from the binding of wild-type unphosphorylated CovR. In vitro transcription, using purified GAS RNA polymerase, showed that wild-type CovR repressed transcription, and repression was stimulated more than sixfold by phosphorylation. In the presence of RNA polymerase, binding at Phas of phosphorylated, but not unphosphorylated, CovR was stimulated about fourfold, which accounts for the difference in the effect of phosphorylation on repression versus DNA binding. Thus, regulation of Phas by CovR is direct, and the degree of repression of Phas is controlled by the phosphorylation of CovR.

Duke Scholars

Published In

J Bacteriol

DOI

ISSN

0021-9193

Publication Date

July 2006

Volume

188

Issue

13

Start / End Page

4620 / 4626

Location

United States

Related Subject Headings

  • Transcription, Genetic
  • Streptococcus pyogenes
  • Repressor Proteins
  • Promoter Regions, Genetic
  • Phosphorylation
  • Operon
  • Microbiology
  • Hyaluronic Acid
  • Gene Expression Regulation, Bacterial
  • Dimerization
 

Citation

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MLA
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Gusa, A. A., Gao, J., Stringer, V., Churchward, G., & Scott, J. R. (2006). Phosphorylation of the group A Streptococcal CovR response regulator causes dimerization and promoter-specific recruitment by RNA polymerase. J Bacteriol, 188(13), 4620–4626. https://doi.org/10.1128/JB.00198-06
Gusa, Asiya A., Jinxin Gao, Virginia Stringer, Gordon Churchward, and June R. Scott. “Phosphorylation of the group A Streptococcal CovR response regulator causes dimerization and promoter-specific recruitment by RNA polymerase.J Bacteriol 188, no. 13 (July 2006): 4620–26. https://doi.org/10.1128/JB.00198-06.
Gusa, Asiya A., et al. “Phosphorylation of the group A Streptococcal CovR response regulator causes dimerization and promoter-specific recruitment by RNA polymerase.J Bacteriol, vol. 188, no. 13, July 2006, pp. 4620–26. Pubmed, doi:10.1128/JB.00198-06.
Gusa AA, Gao J, Stringer V, Churchward G, Scott JR. Phosphorylation of the group A Streptococcal CovR response regulator causes dimerization and promoter-specific recruitment by RNA polymerase. J Bacteriol. 2006 Jul;188(13):4620–4626.

Published In

J Bacteriol

DOI

ISSN

0021-9193

Publication Date

July 2006

Volume

188

Issue

13

Start / End Page

4620 / 4626

Location

United States

Related Subject Headings

  • Transcription, Genetic
  • Streptococcus pyogenes
  • Repressor Proteins
  • Promoter Regions, Genetic
  • Phosphorylation
  • Operon
  • Microbiology
  • Hyaluronic Acid
  • Gene Expression Regulation, Bacterial
  • Dimerization