Oxidative stress and metal ions regulate a ferritin-like gene, dpr, in Streptococcus pyogenes

Int J Med Microbiol. 2010 Apr;300(4):259-64. doi: 10.1016/j.ijmm.2009.09.002. Epub 2009 Oct 29.


Bacteria encounter oxidative stress by exposure to reactive oxygen species (ROS) present in the aerobic environment and during immune responses. In Streptococcus pyogenes, Dpr has been identified as a stress protein conferring resistance to hydrogen peroxide and multiple other stresses. The expression of Dpr is under perR (peroxide stress response regulator) control. However, the exact molecular mechanism of PerR regulation of Dpr is not clear. In this study, a perR deletion mutant was constructed by double cross-over mutagenesis. The profile of Dpr expression, performed by Western blot assay, revealed growth-phase dependency under normal culture conditions. Dpr expression decreased under iron-restricted conditions, whereas iron, zinc, nickel, and hydrogen peroxide induced its expression. The perR mutant does not induce Dpr as well when exposed to environmental signals. PerR binds the promoter region of dpr. Increased iron and hydrogen peroxide concentrations decreased PerR binding to the promoter region of dpr, suggesting that regulation of Dpr by environmental signals is mediated by PerR directly.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / biosynthesis*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / physiology*
  • Blotting, Western
  • DNA, Bacterial / metabolism
  • DNA-Binding Proteins / biosynthesis*
  • Gene Deletion
  • Gene Expression Profiling
  • Gene Expression Regulation, Bacterial*
  • Humans
  • Hydrogen Peroxide / metabolism
  • Ions / metabolism
  • Metals / metabolism*
  • Nickel / metabolism
  • Oxidative Stress*
  • Promoter Regions, Genetic
  • Protein Binding
  • Repressor Proteins / genetics
  • Repressor Proteins / physiology*
  • Streptococcus pyogenes / physiology*
  • Zinc / metabolism


  • Bacterial Proteins
  • DNA, Bacterial
  • DNA-Binding Proteins
  • Dpr protein, Streptococcus
  • Ions
  • Metals
  • Repressor Proteins
  • peroxide repressor proteins
  • Nickel
  • Hydrogen Peroxide
  • Zinc