title: Identification and Functional Analysis of RelA/SpoT Homolog (RSH) Genes inDeinococcus radiodurans.
abstract: To identify the global effects of (p)ppGpp in the gram-positive bacteriumDeinococcus radiodurans, which exhibits remarkable resistance to radiation and other stresses, RelA/SpoT homolog (RSHs) mutants were constructed by direct deletion mutagenesis. The results showed that RelA has both synthesis and hydrolysis domains of (p)ppGpp, whereas RelQ only synthesizes (p)ppGpp inD. radiodurans. The growth assay for mutants and complementation analysis revealed that deletion ofrelAandrelQsensitized the cells to H₂O₂, heat shock, and amino acid limitation. Comparative proteomic analysis revealed that the bifunctional RelA is involved in DNA repair, molecular chaperone functions, transcription, the tricarboxylic acid cycle, and metabolism, suggesting thatrelAmaintains the cellular (p)ppGpp levels and plays a crucial role in oxidative resistance inD. radiodurans. TheD. radiodurans relAandrelQgenes are responsible for (p)ppGpp synthesis/hydrolysis and (p)ppGpp hydrolysis, respectively. (p)ppGpp integrates a general stress response with a targeted re-programming of gene regulation to allow bacteria to respond appropriately towards heat shock, oxidative stress, and starvation. This is the first identification of RelA and RelQ involvement in response to oxidative, heat shock, and starvation stresses inD. radiodurans, which further elucidates the remarkable resistance of this bacterium to stresses.
authors: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China.
authors: Jinhui
authors: J
authors: Wang
authors: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China.
authors: Ye
authors: Y
authors: Tian
authors: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China.
authors: Zhengfu
authors: Z
authors: Zhou
authors: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China.
authors: Liwen
authors: L
authors: Zhang
authors: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China.
authors: Wei
authors: W
authors: Zhang
authors: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China.
authors: Min
authors: M
authors: Lin
authors: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China.
authors: Ming
authors: M
authors: Chen
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D004260:DNA Repair; D034301:Deinococcus / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D001277:GTP Pyrophosphokinase / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D006159:Guanosine Tetraphosphate / Q000378:metabolism; D018384:Oxidative Stress
chemical_list: D001426:Bacterial Proteins; D006159:Guanosine Tetraphosphate; D001277:GTP Pyrophosphokinase
keywords: (p)ppGpp; Deinococcus radiodurans; RelA; RelA/SpoT homolog; RelQ; oxidative stress