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

• Published in: Microbiology (Society for General Microbiology) 2011-10, Vol.157 (Pt 10), p.2974-2982
• Main Authors: DESAI, Shruti S, RAJPUROHIT, Yogendra S, MISRA, Hari S, DEOBAGKAR, Dileep N
• Format: Article
• Language: English
• Subjects: Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacteriology; Biological and medical sciences; Deinococcus - enzymology; Deinococcus - genetics; Deinococcus - metabolism; Deinococcus - radiation effects; Deinococcus radiodurans; DNA Damage; DNA Repair; DNA-Binding Proteins - genetics; DNA-Binding Proteins - metabolism; Fundamental and applied biological sciences. Psychology; Gamma Rays; Gene Expression Regulation, Bacterial; Histidine Kinase; Microbiology; Miscellaneous; Operon; Oxidative Stress; Protein Binding; Protein Kinases - genetics; Protein Kinases - metabolism; Radiation Tolerance; Ultraviolet Rays
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.049361-0

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.