Characterization of the role of DR0171 in transcriptional response to radiation in the extremely radioresistant bacterium Deinococcus radiodurans

The extremely radioresistant bacterium Deinococcus radiodurans encodes a number of function-unknown genes, and some of them involve in the radioresistance. The radiation-inducible gene dr0171 has a recA-like expression pattern in the postirradiation recovery and was also supposed to encode a transcriptional regulator to contribute to the radioresistance. Here, we found that the EGFP-tagged DR0171 proteins gathered in the nucleoid regions after radiation. Further, we constructed a null mutant of dr0171 and found that the incapacitation of the dr0171 led to a significant decline in resistance to γ-rays, UV radiation, and hydrogen peroxide and delayed genomic DNA reconstruction after radiation, indicating that this gene is involved in the postirradiation recovery. The microarray assays showed that the disruption of dr0171 does not lead to a significant change in the transcriptional profile of D. radiodurans under normal conditions, except after the stress of 6 kGy γ radiation was applied. The transcript level of at least 153 genes decreased over twofold in the irradiated dr0171 mutant compared with those in the irradiated wild-type strain, indicating that DR0171 only functions after radiation damage. Taken together, the data presented here indicate that DR0171 serves as a regulator of the transcriptional response to radiation damage in D. radiodurans.