Characterization of the role of the RadS/RadR two-component system in the radiation resistance of Deinococcus radiodurans

Microbiology (Reading). 2011 Oct;157(Pt 10):2974-2982. doi: 10.1099/mic.0.049361-0. Epub 2011 Jul 7.


Deinococcus radiodurans shows extraordinary tolerance to DNA damage, and exhibits differential gene expression and protein recycling. A putative response regulator, the DRB0091 (RadR) ORF, was identified from a pool of DNA-binding proteins induced in response to gamma radiation in this bacterium. radR is located upstream of drB0090, which encodes a putative sensor histidine kinase (RadS) on the megaplasmid. Deletion of these genes both individually and together resulted in hypersensitivity to DNA-damaging agents and a delayed or altered double-strand break repair. A ΔradRradS double mutant and a ΔradR single mutant showed nearly identical responses to gamma radiation and UVC. Wild-type RadR and RadS complemented the corresponding mutant strains, but also exhibited significant cross-complementation, albeit at lower doses of gamma radiation. The radS transcript was not detected in the ΔradR mutant, suggesting the existence of a radRS operon. Recombinant RadS was autophosphorylated and could catalyse the transfer of γ phosphate from ATP to RadR in vitro. These results indicated the functional interaction of RadS and RadR, and suggested a role for the RadS/RadR two-component system in the radiation resistance of this bacterium.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • DNA Damage
  • DNA Repair
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Deinococcus / enzymology
  • Deinococcus / genetics
  • Deinococcus / metabolism
  • Deinococcus / radiation effects*
  • Gamma Rays
  • Gene Expression Regulation, Bacterial
  • Histidine Kinase
  • Operon
  • Oxidative Stress
  • Protein Binding
  • Protein Kinases / genetics
  • Protein Kinases / metabolism*
  • Radiation Tolerance
  • Ultraviolet Rays


  • Bacterial Proteins
  • DNA-Binding Proteins
  • Protein Kinases
  • Histidine Kinase