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A Novel C-Terminal Domain of RecJ is Critical for Interaction with HerA in Deinococcus radiodurans.

Cheng K, Zhao Y, Chen X, Li T, Wang L, Xu H, Tian B, Hua Y - Front Microbiol (2015)

Bottom Line: DrRecJΔC displayed reduced DNA nuclease activity and DNA binding ability.Opposing growth and MMC-resistance phenotypes between the recJ and nurA mutants were observed.A novel modulation mechanism among DrRecJ, DrHerA, and DrNurA was also suggested.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University Hangzhou, China.

ABSTRACT
Homologous recombination (HR) generates error-free repair products, which plays an important role in double strand break repair and replication fork rescue processes. DNA end resection, the critical step in HR, is usually performed by a series of nuclease/helicase. RecJ was identified as a 5'-3' exonuclease involved in bacterial DNA end resection. Typical RecJ possesses a conserved DHH domain, a DHHA1 domain, and an oligonucleotide/oligosaccharide-binding (OB) fold. However, RecJs from Deinococcus-Thermus phylum, such as Deinococcus radiodurans RecJ (DrRecJ), possess an extra C-terminal domain (CTD), of which the function has not been characterized. Here, we showed that a CTD-deletion of DrRecJ (DrRecJΔC) could not restore drrecJ mutant growth and mitomycin C (MMC)-sensitive phenotypes, indicating that this domain is essential for DrRecJ in vivo. DrRecJΔC displayed reduced DNA nuclease activity and DNA binding ability. Direct interaction was identified between DrRecJ-CTD and DrHerA, which stimulates DrRecJ nuclease activity by enhancing its DNA binding affinity. Moreover, DrNurA nuclease, another partner of DrHerA, inhibited the stimulation of DrHerA on DrRecJ nuclease activity by interaction with DrHerA. Opposing growth and MMC-resistance phenotypes between the recJ and nurA mutants were observed. A novel modulation mechanism among DrRecJ, DrHerA, and DrNurA was also suggested.

No MeSH data available.


Related in: MedlinePlus

Comparisons of phenotypes between recJ mutant and nurA mutant. The survival fraction curves (treated with 10, 20, 30, and 40 ug ml-1 MMC) of different strains were plotted using GraphPad Prism 5 software. Data shown mean values from three independent experiments and bars depict the standard deviation (SD).
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Figure 6: Comparisons of phenotypes between recJ mutant and nurA mutant. The survival fraction curves (treated with 10, 20, 30, and 40 ug ml-1 MMC) of different strains were plotted using GraphPad Prism 5 software. Data shown mean values from three independent experiments and bars depict the standard deviation (SD).

Mentions: Because DrNurA could block DrRecJ nuclease activity, we were particularly interested in the functional relationships among these proteins. The phenotypes of drrecJ and drnurA mutants were compared. In contrast to drrecJ mutant, which showed growth defects and sensitivities to high temperature, and MMC treatment, drnurA mutants grew faster and were more resistant to MMC treatment (Figure 6; Supplemental Figure S6). The drrecJ/drnurA double mutant, on the other hand, displayed modest phenotype to high temperature and MMC treatment compared with the drrecJ mutant (Figure 6).


A Novel C-Terminal Domain of RecJ is Critical for Interaction with HerA in Deinococcus radiodurans.

Cheng K, Zhao Y, Chen X, Li T, Wang L, Xu H, Tian B, Hua Y - Front Microbiol (2015)

Comparisons of phenotypes between recJ mutant and nurA mutant. The survival fraction curves (treated with 10, 20, 30, and 40 ug ml-1 MMC) of different strains were plotted using GraphPad Prism 5 software. Data shown mean values from three independent experiments and bars depict the standard deviation (SD).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4663267&req=5

Figure 6: Comparisons of phenotypes between recJ mutant and nurA mutant. The survival fraction curves (treated with 10, 20, 30, and 40 ug ml-1 MMC) of different strains were plotted using GraphPad Prism 5 software. Data shown mean values from three independent experiments and bars depict the standard deviation (SD).
Mentions: Because DrNurA could block DrRecJ nuclease activity, we were particularly interested in the functional relationships among these proteins. The phenotypes of drrecJ and drnurA mutants were compared. In contrast to drrecJ mutant, which showed growth defects and sensitivities to high temperature, and MMC treatment, drnurA mutants grew faster and were more resistant to MMC treatment (Figure 6; Supplemental Figure S6). The drrecJ/drnurA double mutant, on the other hand, displayed modest phenotype to high temperature and MMC treatment compared with the drrecJ mutant (Figure 6).

Bottom Line: DrRecJΔC displayed reduced DNA nuclease activity and DNA binding ability.Opposing growth and MMC-resistance phenotypes between the recJ and nurA mutants were observed.A novel modulation mechanism among DrRecJ, DrHerA, and DrNurA was also suggested.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University Hangzhou, China.

ABSTRACT
Homologous recombination (HR) generates error-free repair products, which plays an important role in double strand break repair and replication fork rescue processes. DNA end resection, the critical step in HR, is usually performed by a series of nuclease/helicase. RecJ was identified as a 5'-3' exonuclease involved in bacterial DNA end resection. Typical RecJ possesses a conserved DHH domain, a DHHA1 domain, and an oligonucleotide/oligosaccharide-binding (OB) fold. However, RecJs from Deinococcus-Thermus phylum, such as Deinococcus radiodurans RecJ (DrRecJ), possess an extra C-terminal domain (CTD), of which the function has not been characterized. Here, we showed that a CTD-deletion of DrRecJ (DrRecJΔC) could not restore drrecJ mutant growth and mitomycin C (MMC)-sensitive phenotypes, indicating that this domain is essential for DrRecJ in vivo. DrRecJΔC displayed reduced DNA nuclease activity and DNA binding ability. Direct interaction was identified between DrRecJ-CTD and DrHerA, which stimulates DrRecJ nuclease activity by enhancing its DNA binding affinity. Moreover, DrNurA nuclease, another partner of DrHerA, inhibited the stimulation of DrHerA on DrRecJ nuclease activity by interaction with DrHerA. Opposing growth and MMC-resistance phenotypes between the recJ and nurA mutants were observed. A novel modulation mechanism among DrRecJ, DrHerA, and DrNurA was also suggested.

No MeSH data available.


Related in: MedlinePlus