PprI: A General switch responsible for extreme radioresistance of

Hua, Y.*; Narumi, Issei; Gao, G.*; Tian, B.*; Sato, Katsuya; Kitayama, Shigeru; Shen, B.*

We have identified a unique deinococcal gene, , as a general switch for downstream DNA repair and protection pathways, from a natural mutant, in which is disrupted by a transposon. Complete functional disruption of the gene in wild-type leads to dramatic sensitivity to ionizing radiation. Radioresistance of the disruptant could be fully restored by complementation with . In response to radiation stress, PprI can significantly and specifically induce the gene expression of and and enhance the enzyme activities of catalases. These results strongly suggest that PprI plays a crucial role in regulating multiple DNA repair and protection pathways in response to radiation stress.