Yoo H Y, Chang M S, Rho H M
Department of Molecular Biology and Research Center for Cell Differentiation, Seoul National University, Seoul 151-742, Korea.
J Biol Chem. 1999 Aug 20;274(34):23887-92. doi: 10.1074/jbc.274.34.23887.
Copper/zinc superoxide dismutase (SOD1) protects cells against oxidative hazards by the dismutation of superoxide radicals. The promoter activity of the SOD1 gene was increased 3-5-fold by hydrogen peroxide, paraquat (PQ) and heat shock. Functional analyses of the regulatory region of the SOD1 gene by deletions, mutations, and heterologous promoter systems confirmed the induction of the SOD1 gene by H(2)O(2) through the hydrogen peroxide-responsive element (HRE) (between nucleotides -533 and -520). Gel mobility shift assays showed that the existence of an H(2)O(2)-inducible protein bound to the oligonucleotide of the HRE. Similar analyses showed that the heat shock activated the SOD1 promoter through the heat shock element (HSE) (between nucleotides -185 and -171). A strong specific far-shifted complex with the oligonucleotide of the HSE was observed by the treatment of heat shock. When cells were treated with PQ, a strong far-shifted complex with the HSE was observed and was competed out by the cold HSE probe, indicating that PQ also activated the SOD1 promoter through the same HSE site. It is very interesting to note that chemical and physical stresses, such as PQ and heat shock, respectively, activated the SOD1 promoter through the same cis-element HSE. These results indicate that the SOD1 was inducible by H(2)O(2) through the HRE and by PQ and heat shock through the same HSE to protect cells from oxidative hazards.
铜/锌超氧化物歧化酶（SOD1）通过歧化超氧阴离子自由基来保护细胞免受氧化损伤。过氧化氢、百草枯（PQ）和热休克可使SOD1基因的启动子活性提高3至5倍。通过缺失、突变和异源启动子系统对SOD1基因调控区进行功能分析，证实过氧化氢通过过氧化氢反应元件（HRE）（核苷酸-533至-520之间）诱导SOD1基因。凝胶迁移率变动分析表明，存在一种与HRE寡核苷酸结合的过氧化氢诱导蛋白。类似分析表明，热休克通过热休克元件（HSE）（核苷酸-185至-171之间）激活SOD1启动子。热休克处理后观察到与HSE寡核苷酸形成强烈的特异性远迁移复合物。当细胞用PQ处理时，观察到与HSE形成强烈的远迁移复合物，且该复合物被冷的HSE探针竞争掉，这表明PQ也通过相同的HSE位点激活SOD1启动子。非常有趣的是，化学和物理应激，如分别为PQ和热休克，通过相同的顺式元件HSE激活SOD1启动子。这些结果表明，SOD1可通过HRE被过氧化氢诱导，通过相同的HSE被PQ和热休克诱导，以保护细胞免受氧化损伤。
