RecO Is Essential for DNA Damage Repair in
            <i>Deinococcus radiodurans</i>

Xu, Guangzhi; Wang, Liangyan; Chen, Huan; Lu, Haijun; Ying, Nanjiao; Teng, Bing; Hua, Yuejin

doi:10.1128/jb.01851-07

Cited by 40 publications

(26 citation statements)

References 34 publications

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“…However, according to the present genomic and genetic analysis, the enzymology of deinococcal DNA repair does not seem to be exceptional. DNA repair systems appear even less complex than those reported for E. coli or Shewanella oneidensis (120,123,381,383), and the most radiation-sensitive DNA repair mutants in D. radiodurans can be fully (polA [224]) or partially (recA and recO [541,665]) complemented with the respective E. coli genes. Moreover, the mechanism of DSB repair in D. radiodurans is remarkably similar to those of yeast cells (124,126,127,572,676).…”

Section: Dna Damage Resistance and Dna Repair Mechanisms Of D Radiodmentioning

confidence: 97%

“…Furthermore, both CPDs and 6-4 PPs are eliminated even in the absence of UvrABC and UVDE (603). Mutations in other recombination genes, recO and recF, also result in UV-sensitive phenotypes (91,665). In E. coli, recombinational repair is essential for replication fork restart in UV-damaged cells (322,333).…”

Section: Resistance Of D Radiodurans To Uv-c Radiationmentioning

confidence: 99%

“…D. radiodurans recA mutants were obtained by MNNG treatment (rec30; G224S) (439), targeted insertion (223), or a replacement of the recA operon with an antibiotic resistance cassette (64,342). The three recA mutants share similar degrees of sensitivity to ionizing radiation but are not phenotypically equivalent with respect to UV and MMC sensitivity, with the rec30 mutant being less sensitive than either the insertional or the replacement mutants (88,223,439,541,665). Surprisingly, the insertional D. radiodurans recA mutant is slightly more radiation resistant than wild-type E. coli (414), which may be explained by the high level of antioxidation protection of the DNA repair enzymes in D. radiodurans that can somewhat compensate for the absence of RecA (see "Antioxidation Protection in D. radiodurans" and "The RecAIndependent pathway of DSB Repair in D. radiodurans").…”

Section: Recombinational Processes In D Radiodurans Dna Repairmentioning

confidence: 99%

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Oxidative Stress Resistance inDeinococcus radiodurans

Slade

Radman

2011

Microbiol Mol Biol Rev

646

639

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SUMMARY Deinococcus radiodurans is a robust bacterium best known for its capacity to repair massive DNA damage efficiently and accurately. It is extremely resistant to many DNA-damaging agents, including ionizing radiation and UV radiation (100 to 295 nm), desiccation, and mitomycin C, which induce oxidative damage not only to DNA but also to all cellular macromolecules via the production of reactive oxygen species. The extreme resilience of D. radiodurans to oxidative stress is imparted synergistically by an efficient protection of proteins against oxidative stress and an efficient DNA repair mechanism, enhanced by functional redundancies in both systems. D. radiodurans assets for the prevention of and recovery from oxidative stress are extensively reviewed here. Radiation- and desiccation-resistant bacteria such as D. radiodurans have substantially lower protein oxidation levels than do sensitive bacteria but have similar yields of DNA double-strand breaks. These findings challenge the concept of DNA as the primary target of radiation toxicity while advancing protein damage, and the protection of proteins against oxidative damage, as a new paradigm of radiation toxicity and survival. The protection of DNA repair and other proteins against oxidative damage is imparted by enzymatic and nonenzymatic antioxidant defense systems dominated by divalent manganese complexes. Given that oxidative stress caused by the accumulation of reactive oxygen species is associated with aging and cancer, a comprehensive outlook on D. radiodurans strategies of combating oxidative stress may open new avenues for antiaging and anticancer treatments. The study of the antioxidation protection in D. radiodurans is therefore of considerable potential interest for medicine and public health.

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Section: Dna Damage Resistance and Dna Repair Mechanisms Of D Radiodmentioning

confidence: 97%

Section: Resistance Of D Radiodurans To Uv-c Radiationmentioning

confidence: 99%

Section: Recombinational Processes In D Radiodurans Dna Repairmentioning

confidence: 99%

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Oxidative Stress Resistance inDeinococcus radiodurans

Slade

Radman

2011

Microbiol Mol Biol Rev

646

639

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“…An ATPase assay was performed as previously described (45), which was measured by spectrophotometric detection of inorganic phosphate (P i ) with malachite green reagent 35,40,45,50,55, and 60°C were used.) Malachite green reagent (200 ml in 700 ml water) was added, and P i release was monitored at 630 nm.…”

Section: Methodsmentioning

confidence: 99%

Biochemical and Functional Characterization of the NurA-HerA Complex from Deinococcus radiodurans

Cheng

Chen

et al. 2015

J Bacteriol

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In archaea, the NurA nuclease and HerA ATPase/helicase, together with the Mre11-Rad50 complex, function in 3= singlestranded DNA (ssDNA) end processing during homologous recombination (HR). However, bacterial homologs of NurA and HerA have not been characterized. From Deinococcus radiodurans, we identified the manganese-dependent 5=-to-3= ssDNA/double-stranded DNA (dsDNA) exonuclease/endonuclease NurA (DrNurA) and the ATPase HerA (DrHerA). These two proteins stimulated each other's activity through direct protein-protein interactions. The N-terminal HAS domain of DrHerA was the key domain for this interaction. Several critical residues of DrNurA and DrHerA were verified by site-directed mutational analysis. Temperature-dependent activity assays confirmed that the two proteins had mesophilic features, with optimum activity temperatures 10°C to 15°C higher than their optimum growth temperatures. Knocking out either nurA or herA affected cell proliferation by shortening the growth phase, especially for growth at a high temperature (37°C). In addition, both mutant strains displayed almost 10-fold-reduced intermolecular recombination efficiency, indicating that DrNurA and DrHerA might be involved in homologous recombination in vivo. However, single-and double-gene deletions did not show significantly decreased radioresistance. Our results confirmed that the biochemical activities of bacterial NurA and HerA proteins were conserved with archaea. Our phenotypical results suggested that these proteins might have different functions in bacteria. IMPORTANCEDeinococcus radiodurans NurA (DrNurA) was identified as a manganese-dependent 5=-to-3= ssDNA/dsDNA exonuclease/endonuclease, and Deinococcus radiodurans HerA (DrHerA) was identified as an ATPase. Physical interactions between DrNurA and DrHerA explained mutual stimulation of their activities. The N-terminal HAS domain on DrHerA was identified as the interaction domain. Several essential functional sites on DrNurA and DrHerA were characterized. Both DrHerA and DrNurA showed mesophilic biochemical features, with their optimum activity temperatures 10°C to 15°C higher than their optimum growth temperatures in vitro. Knockout of nurA or herA led to abnormal cell proliferation and reduced intermolecular recombination efficiency but no obvious effect on radioresistence.

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“…The principle players in the RecF pathway are the RecF, RecO, and RecR proteins, which form an epistatic group that is important for SSG repair, for restart of stalled DNA replication, and under specific conditions, can also process DSBs (14 -20). Homologs of RecF, -O, and -R are present in the majority of known bacteria (21), including Deinococcus radiodurans, extremely radiation-resistant bacteria that lacks the RecBCD pathway, yet is capable of repairing thousands of DSBs (22,23). In addition, the sequence or functional homologs of RecF pathway proteins are involved in similar pathways in eukaryotes that include among others WRN, BLM, RAD52, and BRCA2 proteins (4 -8).…”

Section: Homologous Recombination (Hr)mentioning

confidence: 99%