title: DR2539 is a novel DtxR-like regulator of Mn/Fe ion homeostasis and antioxidant enzyme in Deinococcus radiodurans.
abstract: Transcriptional regulators of the diphtheria toxin repressor (DtxR) family control the expression of genes involved in the uptake of iron and manganese, which is not only necessitous nutrients but also was suggested to be essential for intracellular redox cycling of microorganisms. We identified a unique DtxR homologue (DR2539) with special characteristics from Deinococcus radiodurans, which is known for its extreme resistance to radiation and oxidants. The dr2539 mutant showed higher resistance to hydrogen peroxide than the wild-type strain R1. Intracellular catalase activity assay and semiquantitative PCR analysis demonstrated that this DtxR is a negative regulator of catalase (katE). Furthermore, quantitative real-time PCR, global transcription profile and inductively coupled plasma-mass spectrometry analysis showed that the DtxR is involved in the regulation of antioxidant system by maintaining the intracellular Mn/Fe ion homeostasis of D. radiodurans. However, unlike the other DtxR homologues, the DtxR of D. radiodurans acts as a negative regulator of a Mn transporter gene (dr2283) and as a positive regulator of Fe-dependent transporter genes (dr1219, drb0125) in D. radiodurans.
authors.affiliation: Key Laboratory for Nuclear-Agricultural Sciences of Chinese Ministry of Agriculture and Zhejiang Province, Institute of Nuclear-Agricultural Sciences, Zhejiang University, Hangzhou 310029, China.
authors.forename: Huan
authors.initials: H
authors.lastname: Chen
authors.forename: Rongrong
authors.initials: R
authors.lastname: Wu
authors.forename: Guangzhi
authors.initials: G
authors.lastname: Xu
authors.forename: Xu
authors.initials: X
authors.lastname: Fang
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Qiu
authors.forename: Hongyin
authors.initials: H
authors.lastname: Guo
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*; D002374:Catalase / Q000235:genetics; D034301:Deinococcus / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D006706:Homeostasis / Q000235:genetics; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007501:Iron / Q000378:metabolism*; D008345:Manganese / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D014157:Transcription Factors; D008345:Manganese; D006861:Hydrogen Peroxide; D007501:Iron; D002374:Catalase