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Phage-Like Streptococcus pyogenes Chromosomal Islands (SpyCI) and Mutator Phenotypes: Control by Growth State and

Julie Scott1, Scott V Nguyen, Catherine J King

  • 1Department of Pharmaceutical Sciences, The University of Oklahoma Health Sciences Center Oklahoma City, OK, USA.

Frontiers in Microbiology
|September 13, 2012
PubMed

Insights

Streptococcus pyogenes chromosomal islands (SpyCI) can induce a mutator phenotype, aiding bacterial adaptation. Even with a decayed gene, a cryptic promoter rescued gene function, showing mobile genetic element evolution.

Area of Science:

  • Microbiology
  • Genetics
  • Molecular Biology

Background:

  • Prophage-like Streptococcus pyogenes chromosomal islands (SpyCI) regulate DNA repair.
  • SpyCI's dynamic excision/reintegration causes phenotype switching in strain SF370.

Purpose of the Study:

  • Investigate mutator phenotypes in S. pyogenes strains with SpyCI.
  • Examine SpyCI's role in DNA mismatch repair and gene regulation.

Main Methods:

  • Comparative genomics of S. pyogenes strains.
  • Phenotypic analysis of mutator activity.
  • Identification of regulatory elements within SpyCI.

Main Results:

  • Most S. pyogenes strains with SpyCI exhibited a mutator phenotype.
  • Strain Manfredo (M5) showed an inactive integrase gene but retained gene function.
  • A cryptic promoter in the integrase gene ensured constitutive mutL expression.

Conclusions:

  • SpyCI confers an inducible mutator phenotype, promoting bacterial adaptation.
  • Cryptic promoters can rescue gene function after mobile genetic element decay.
  • SpyCI's prevalence suggests a role in group A streptococci survival and adaptation.
Keywords:
DNA mismatch repairSpyCIStreptococcus pyogeneschromosomal islandsgroup A streptococcusmutator phenotypeprophages

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