Extracellular dGMP enhances Deinococcus radiodurans tolerance to oxidative stress.
Free extracellular DNA provides nutrition to bacteria and promotes bacterial evolution by inducing excessive mutagenesis of the genome. To understand the influence of extracellular DNA fragments on D. radiodurans, we investigated cell growth and survival after extracellular DNA or dNMPs treatment. The results showed that the extracellular DNA fragments inhibited the growth of D. radiodurans. Interestingly, dGMP, a DNA component, enhanced D. radiodurans tolerance to H(2)O(2) and gamma-radiation significantly. Further experiments indicated that extracellular dGMP stimulated the activity of one catalase (KatA, DR1998), and induced gene transcription including the extracellular nuclease (drb0067). When this only extracellular nuclease gene (drb0067) in D. radiodurans was deleted, the mutant strain showed more sensitive to H(2)O(2) and gamma-radiation than the wild type strain. These results suggest that DRB0067 plays an important role in oxidative stress resistance. Taken together, we proposed a new anti-oxidation mechanism in D. radiodurans. This mechanism acts to increase expression levels of DRB0067 which then secretes active nuclease to degrade extracellular DNA fragments. The extracellular nuclease has a two-fold benefit, creating more free dNTPs for further cell protection and the removal of extracellular DNA fragments.
Key Laboratory for Nuclear-Agricultural Sciences of Chinese Ministry of Agriculture and Zhejiang Province, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou, China.
Mingfeng
M
Li
Hongxing
H
Sun
Qiong
Q
Feng
Huiming
H
Lu
Ye
Y
Zhao
Hui
H
Zhang
Xin
X
Xu
Jiandong
J
Jiao
Liangyan
L
Wang
Yuejin
Y
Hua
D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002374:Catalase / Q000235:genetics / Q000378:metabolism; D004269:DNA, Bacterial; D034301:Deinococcus / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics* / Q000528:radiation effects; D003848:Deoxyguanine Nucleotides / Q000494:pharmacology*; D003851:Deoxyribonucleases / Q000235:genetics* / Q000378:metabolism; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics / Q000378:metabolism / Q000528:radiation effects; D005110:Extracellular Space / Q000378:metabolism; D005720:Gamma Rays; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects / Q000528:radiation effects; D006861:Hydrogen Peroxide / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects / Q000528:radiation effects; D011836:Radiation Tolerance / Q000187:drug effects; D014158:Transcription, Genetic / Q000187:drug effects / Q000528:radiation effects
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D003848:Deoxyguanine Nucleotides; C007257:2'-deoxyguanosine 5'-phosphate; D006861:Hydrogen Peroxide; D002374:Catalase; D003851:Deoxyribonucleases