PprI: a general switch responsible for extreme radioresistance of Deinococcus radiodurans.
Deinococcus radiodurans exhibits an extraordinary ability to withstand the lethal and mutagenic effects of DNA damaging agents, particularly, ionizing radiation. Available evidence indicates that efficient repair of DNA damage and protection of the chromosomal structure are mainly responsible for the radioresistance. Little is known about the biochemical basis for this phenomenon. We have identified a unique gene, pprI, as a general switch for downstream DNA repair and protection pathways, from a natural mutant, in which pprI 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 pprI. In response to radiation stress, PprI can significantly and specifically induce the gene expression of recA and pprA 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.
Hua
Yuejin
Y
Institute of Nuclear-Agricultural Science, Zhejiang University, 310029, Hangzhou, China. yjhua@zju.edu.cn
Narumi
Issay
I
Gao
Guanjun
G
Tian
Bing
B
Satoh
Katsuya
K
Kitayama
Shigeru
S
Shen
Binghui
B
D015153:Blotting, Western; D002374:Catalase / Q000378:metabolism; D003001:Cloning, Molecular; D004247:DNA / Q000528:radiation effects; D004249:DNA Damage; D004260:DNA Repair; D034301:Deinococcus / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D015180:Electrophoresis, Gel, Two-Dimensional; D005609:Free Radicals; D005816:Genetic Complementation Test; D009154:Mutation; D010957:Plasmids / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011836:Radiation Tolerance; D011938:Rec A Recombinases / Q000378:metabolism; D013997:Time Factors; D015534:Trans-Activators / Q000737:chemistry* / Q000235:genetics*
D005609:Free Radicals; D015534:Trans-Activators; D004247:DNA; D002374:Catalase; D011938:Rec A Recombinases