title: The Site-Directed A184S Mutation in the HTH Domain of the Global Regulator IrrE Enhances Deinococcus radiodurans R1 Tolerance to UV Radiation and MMC Shock.
abstract: IrrE is a highly conserved global regulator in the Deinococcus genus and contributes to survival from high doses of UV radiation, ionizing radiation, and desiccation. Drad-IrrE and Dgob-IrrE from Deinococcus radiodurans and Deinococcus gobiensis I-0 each share 66% sequence identity. However, Dgob-IrrE showed a stronger protection phenotype against UV radiation than Drad- IrrE in the D. radiodurans irrE-deletion mutant (ΔirrE), which may be due to amino acid residues differences around the DNA-binding HTH domain. Site-directed mutagenesis was used to generate a Drad-IrrE A184S single mutant, which has been characterized and compared with the ΔirrE mutant complemented strain with Drad-irrE, designated ΔirrE-E. The effects of the A184S mutation following UV radiation and mitomycin C (MMC) shock were determined. The A184S mutant displayed significantly increased resistance to UV radiation and MMC shock. The corresponding A184 site in Dgob-IrrE was inversely mutated, generating the S131A mutant, which exhibited a loss of resistance against UV radiation, MMC shock, and desiccation. qPCR analysis revealed that critical genes in the DNA repair system, such as recA, pprA, uvrA, and ddrB, were remarkably induced after UV radiation and MMC shock in the ΔirrE-IE and A184S mutants. These data suggested that A184S improves the ability against UV radiation and MMC shock, providing new insights into the modification of IrrE. We speculated that the serine residue may determine the efficiency of DNA binding, leading to the increased expression of IrrE-dependent genes important for protection against DNA damage.
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China.
authors.forename: Chen
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China.
authors.forename: Zhengfu
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhang
authors.affiliation: College of Biological Sciences, China Agricultural University, Beijing 100083, P.R. China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Chen
authors.affiliation: College of Biological Sciences, China Agricultural University, Beijing 100083, P.R. China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Song
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Lu
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China.
authors.forename: Min
authors.initials: M
authors.lastname: Lin
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R. China.
authors.forename: Ming
authors.initials: M
authors.lastname: Chen
mesh_terms: D019943:Amino Acid Substitution; D004252:DNA Mutational Analysis; D045643:DNA Repair Enzymes / Q000235:genetics; D034301:Deinococcus / Q000187:drug effects / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D017353:Gene Deletion; D020869:Gene Expression Profiling; D050296:Microbial Viability / Q000187:drug effects* / Q000528:radiation effects*; D016685:Mitomycin / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D020125:Mutation, Missense; D013312:Stress, Physiological; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014466:Ultraviolet Rays
chemical_list: D014157:Transcription Factors; D016685:Mitomycin; D045643:DNA Repair Enzymes
keywords: D. radiodurans; IrrE; MMC shock; UV radiation; site-directed mutagenesis