The functional analysis of dr1127,a novel gene in Deinococcus radiodurans was performed in this pa-per. The dr1127 gene was found occasionally in our microarray and 2-DE gel experiments. Mutation of the dr1127 gene decreased the γ-radiation and H2O2 resistance of D. radiodurans,and weakened the scavenging abilities of cell extracts for free radicals (superoxide anion,hydrogen peroxide,and hy-droxyl radical). Further oxidative damage assays demonstrated that the purified DR1127 protein of D. radiodurans could bind to double stranded DNA in vitro and protect DNA from oxidative damage in this way. These results suggest that the dr1127 gene is an important gene that can maintain γ-radiation and oxidative resistance in D. radiodurans and may take part in the oxidative stress process.
Deinococcus radiodurans possesses extreme resistance to ionizing radiation,and has been engineered for the remediation of toxic components in radioactive environments.We have previously shown that PprI(also named IrrE)and DrRRA are essential for the DNA protection and repair pathways that respond to ionizing radiation stress in this species.Here,we investigated the combined roles of PprI and DrRRA in resistance to gamma radiation(800 Gy).The double mutant,△drRRA△pprI,was more sensitive to gamma rays than either△drRRA or△pprI single mutants,and exhibited an elevated level of intracellular protein carbonylation,an extended delay in genome reconstitution and reduced transcriptional levels of certain DNA protection and repair proteins,such as kat,sod,recA and pprA.Interestingly,the induction of DrRRA by ionizing radiation was partially inhibited by the deletion of pprI. Taken together,these results suggest that DrRRA and PprI might have collaborative roles in the response of D.radiodurans to extreme ionizing radiation.
WANG LiangYanYIN LongFeiXU GuangZhiLI MingFengZHANG HuiTIAN BinHUA YueJin
