Positive transcriptional control of mry regulates virulence in the group A streptococcus

Mol Microbiol. 1993 Mar;7(6):893-903. doi: 10.1111/j.1365-2958.1993.tb01180.x.


Transcription of the antiphagocytic M protein in the group A streptococcus (Streptococcus pyogenes) is environmentally regulated in response to CO2 and requires Mry, a trans-acting positive regulatory protein. We have examined the role of Mry in environmental regulation by analysing the factors that regulate expression of the gene that encodes Mry (mry). By employing a strategy that utilizes integrational plasmids, it was found that expression of mry requires the participation of DNA sequences that extend 473 base pairs upstream of the Mry coding region. Transcription of mry, as analysed in S1 nuclease protection assays, is initiated from two separate promoters located within this extended regulatory region. Construction and analysis of transcriptional fusions between the mry promoters and a promoterless chloramphenicol acetyltransferase gene demonstrated that mry is autoregulated and environmentally regulated in response to the level of CO2. These data suggest a model for the regulation of virulence in S. pyogenes where positive transcriptional control of mry in response to environmental stimuli regulates the expression of the M protein.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Antigens, Bacterial*
  • Bacterial Outer Membrane Proteins*
  • Bacterial Proteins / biosynthesis*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Base Sequence
  • Carbon Dioxide / pharmacology
  • Carrier Proteins*
  • DNA, Bacterial / genetics
  • Gene Expression Regulation, Bacterial* / drug effects
  • Promoter Regions, Genetic
  • Recombinant Fusion Proteins / biosynthesis
  • Regulatory Sequences, Nucleic Acid
  • Streptococcus pyogenes / genetics*
  • Streptococcus pyogenes / metabolism
  • Transcription, Genetic
  • Virulence / genetics


  • Antigens, Bacterial
  • Bacterial Outer Membrane Proteins
  • Bacterial Proteins
  • Carrier Proteins
  • DNA, Bacterial
  • Recombinant Fusion Proteins
  • streptococcal M protein
  • mry protein, Streptococcus pyogenes
  • Carbon Dioxide