Xie T, Belinsky M, Xu Y, Jaiswal A K
Department of Pharmacology, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111.
J Biol Chem. 1995 Mar 24;270(12):6894-900. doi: 10.1074/jbc.270.12.6894.
Antioxidant response elements (AREs) containing 12-O-tetradecanoylphorbol-13-acetate response element (TRE) (perfect AP1) and TRE-like (imperfect AP1) elements mediate high basal transcription of the NAD(P)H:quinone oxidoreductase1 (NQO1) and glutathione S-transferase Ya genes in tumor cells and its induction in response to xenobiotics and antioxidants. Mutations in the human NQO1 gene ARE (hARE) revealed the requirement for two TRE or TRE-like elements arranged in inverse orientation at the interval of three base pairs and a GC box for optimal expression and beta-naphthoflavone induction of the NQO1 gene. A single TRE element from the human collagenase gene failed to respond to beta-naphthoflavone. These results demonstrate that ARE (2 x TRE or TRE-like elements)-containing detoxifying enzyme genes and not genes that contain 1 x TRE are responsive to xenobiotics and antioxidants. Bandshift assays showed shifting of a complex of more or less similar mobility with hARE and TRE that could be competed by each other. Mutations in the 3'-TRE of the NQO1 gene hARE eliminated binding of nuclear proteins to the hARE and resulted in the loss of basal and induced expression, indicating that 3'-TRE is the most important element within the hARE. 5'-TRE-like element within the NQO1 gene hARE is required for xenobiotic response but may not bind to the nuclear proteins by itself. The GC box located immediately following the 3'-TRE is required for optimal expression and induction of the NQO1 gene. The comparison of AREs from several different genes indicated the requirement for specific arrangement and spacing of two TRE and TRE-like elements within the AREs.
含有12 - O - 十四烷酰佛波醇 - 13 - 乙酸酯反应元件（TRE）（完美AP1）和类TRE（不完美AP1）元件的抗氧化反应元件（ARE）介导肿瘤细胞中NAD(P)H:醌氧化还原酶1（NQO1）和谷胱甘肽S - 转移酶Ya基因的高基础转录及其对外源化合物和抗氧化剂的诱导反应。人类NQO1基因ARE（hARE）中的突变表明，需要两个以相反方向排列、间隔三个碱基对的TRE或类TRE元件以及一个GC框，才能实现NQO1基因的最佳表达和β - 萘黄酮诱导。来自人类胶原酶基因的单个TRE元件对β - 萘黄酮无反应。这些结果表明，含有ARE（2个TRE或类TRE元件）的解毒酶基因而非含有1个TRE的基因对外源化合物和抗氧化剂有反应。凝胶迁移试验表明，hARE和TRE形成的迁移率或多或少相似的复合物会发生迁移，且二者可相互竞争。NQO1基因hARE的3'-TRE中的突变消除了核蛋白与hARE的结合，并导致基础表达和诱导表达丧失，表明3'-TRE是hARE中最重要的元件。NQO1基因hARE中的5'-类TRE元件是外源化合物反应所必需的，但它本身可能不与核蛋白结合。紧跟3'-TRE之后的GC框是NQO1基因最佳表达和诱导所必需的。对几个不同基因的ARE进行比较表明，ARE中两个TRE和类TRE元件需要特定的排列和间距。
