title: DrRRA: a novel response regulator essential for the extreme radioresistance of Deinococcus radiodurans.
abstract: Two-component systems are predominant signal transduction pathways in prokaryotes, and also exist in many archaea as well as some eukaryotes. A typical TCS consists of a histidine kinase and a cognate response regulator. In this study, a novel gene encoding a response regulator (we designate it drRRA) is identified to be essential for the extreme radioresistance of Deinococcus radiodurans. DrRRA null mutant (we designate it MR) is sensitive to gamma-radiation compared with the wild-type strain. Transcriptional assays show that numerous genes are changed in their transcriptional levels in MR at exponential growth phase under normal or gamma-radiation condition. Most of them are related to stress response and DNA repair. Antioxidant activity assays exhibit that both superoxide dismutases and catalases are decreased in the mutant, whereas Western blotting assays show that RecA and PprA are also reduced in MR, verifying the microarray and quantitative real-time PCR data. Furthermore, pulsed-field gel electrophoresis assay demonstrates that deletion of drRRA results in the delay of genome restitution. These data support the hypothesis that DrRRA contributes to the extreme radioresistance of D. radiodurans through its regulatory role in multiple pathways such as antioxidation and DNA repair pathways.
authors.affiliation: Key Laboratory of Chinese Ministry of Agriculture for Nuclear-Agricultural Sciences, Institute of Nuclear-Agricultural Sciences, Zhejiang University, 310029, China.
authors.forename: Liangyan
authors.initials: L
authors.lastname: Wang
authors.forename: Guangzhi
authors.initials: G
authors.lastname: Xu
authors.forename: Huan
authors.initials: H
authors.lastname: Chen
authors.forename: Ye
authors.initials: Y
authors.lastname: Zhao
authors.forename: Nan
authors.initials: N
authors.lastname: Xu
authors.forename: Bing
authors.initials: B
authors.lastname: Tian
authors.forename: Yuejin
authors.initials: Y
authors.lastname: Hua
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D015153:Blotting, Western; D002374:Catalase / Q000235:genetics / Q000378:metabolism; D034301:Deinococcus / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects*; D016521:Electrophoresis, Gel, Pulsed-Field; D004591:Electrophoresis, Polyacrylamide Gel; D005720:Gamma Rays; D015964:Gene Expression Regulation, Bacterial / Q000528:radiation effects*; D016680:Genome, Bacterial; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D017382:Reactive Oxygen Species / Q000378:metabolism; D011938:Rec A Recombinases / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D017382:Reactive Oxygen Species; D002374:Catalase; D013482:Superoxide Dismutase; D011938:Rec A Recombinases