Department of Biotechnology and Bioinformatics, Korea University, 2511 Sejong-ro, Sejong, 30019, South Korea.
Department of Korean Medicine, Semyung University, 65 Semyeong-ro, Jecheon, Chungbuk, 27136, South Korea.
J Ind Microbiol Biotechnol. 2019 Feb;46(2):241-248. doi: 10.1007/s10295-018-02126-6. Epub 2019 Jan 2.
Among the Corynebacterium glutamicum ORFs that have been implicated in stress responses, we chose ORF cg3230, designated osnR, and analyzed it further. Unlike the osnR-deleted strain (ΔosnR), the osnR-overexpressing strain (P-osnR) developed growth defects and increased sensitivity to various oxidants including HO. Transcription in the P-osnR strain of genes such as sodA (superoxide dismutase), ftn (ferritin biosynthesis), and ahpD (alkyl hydroperoxide reductase; cg2674), which are involved in the detoxification of reactive oxygen species, was only 40% that of the wild type. However, transcription of katA, encoding HO-detoxifying catalase, was unchanged in this strain. Genes such as trxB (thioredoxin reductase) and mtr (mycothiol disulfide reductase), which play roles in redox homeostasis, also showed decreased transcription in the strain. 2D-PAGE analysis indicated that genes involved in redox reactions were considerably affected by osnR overexpression. The NADPH/NADP ratio of the P-osnR strain (1.35) was higher than that of the wild-type stain (0.78). Collectively, the phenotypes of the ΔosnR and P-osnR strains suggest a global regulatory role as well as a negative role for the gene in stress responses, particularly in katA-independent oxidative stress responses.
在与谷氨酸棒杆菌应激反应相关的 ORF 中，我们选择了 ORF cg3230，命名为 osnR，并对其进行了进一步分析。与 osnR 缺失菌株（ΔosnR）不同，osnR 过表达菌株（P-osnR）表现出生长缺陷，并对各种氧化剂（包括 HO）的敏感性增加。在 P-osnR 菌株中，sodA（超氧化物歧化酶）、ftn（铁蛋白生物合成）和 ahpD（烷基氢过氧化物还原酶；cg2674）等基因的转录仅为野生型的 40%。然而，编码 HO 解毒过氧化氢酶的 katA 基因在该菌株中的转录没有变化。trxB（硫氧还蛋白还原酶）和 mtr（mycothiol 二硫键还原酶）等在氧化还原稳态中发挥作用的基因在该菌株中的转录也减少。2D-PAGE 分析表明，参与氧化还原反应的基因受到 osnR 过表达的显著影响。P-osnR 菌株的 NADPH/NADP 比值（1.35）高于野生型菌株（0.78）。总之，ΔosnR 和 P-osnR 菌株的表型表明该基因在应激反应中具有全局调控作用和负调控作用，特别是在 katA 不依赖的氧化应激反应中。
