Tu Z, Anders M W
Department of Pharmacology and Physiology, School of Medicine and Dentistry, University of Rochester, New York 14642, USA.
Biochem Biophys Res Commun. 1998 Mar 27;244(3):801-5. doi: 10.1006/bbrc.1998.8345.
Several regulatory elements, including AP-1 and NF-kappa B, are present in the 5'flanking region of the human glutamatex-cysteine ligase (EC 6.3.2.2, gamma-glutamyl-cysteine synthetase) catalytic subunit (GLCLC) gene. In this study, we investigated the role of redox-sensitive transcription factors in the regulation of GLCLC gene expression in LLC-PK1 cells that were exposed to the antioxidant butylated hydroxytoluene (BHT). Exposure of LLC-PK1 cells to 100 microM BHT induced expression of transcription factor AP-1, as demonstrated by an electrophoretic mobility shift assay. Peak AP-1 induction occurred after 3 h of incubation with BHT, BHT increased luciferase gene expression in cells that were transfected with a luciferase reporter vector containing an AP-1 element upstream of a SV40 promoter. Northern analysis showed that transcription of GLCLC gene in cells after incubation with BHT was increased 30% compared with control cells. Cellular glutathione concentrations were also significantly increased in cells exposed to BHT. In contrast, exposure of LLC-PK1 cells to 100 microM BHT did not alter expression of the transcription factor NF-kappa B. These results show that induction of transcription factor AP-1 by BHT is involved in transactivation of GLCLC gene expression.
包括AP-1和NF-κB在内的几种调控元件存在于人谷氨酸-半胱氨酸连接酶（EC 6.3.2.2，γ-谷氨酰半胱氨酸合成酶）催化亚基（GLCLC）基因的5'侧翼区域。在本研究中，我们调查了氧化还原敏感转录因子在暴露于抗氧化剂丁基羟基甲苯（BHT）的LLC-PK1细胞中对GLCLC基因表达调控的作用。用凝胶迁移试验证明，将LLC-PK1细胞暴露于100μM BHT可诱导转录因子AP-1的表达。与BHT孵育3小时后，AP-1诱导达到峰值，BHT增加了用含有SV40启动子上游AP-1元件的荧光素酶报告载体转染的细胞中的荧光素酶基因表达。Northern分析显示，与对照细胞相比，用BHT孵育后的细胞中GLCLC基因的转录增加了30%。暴露于BHT的细胞中细胞内谷胱甘肽浓度也显著增加。相反，将LLC-PK1细胞暴露于100μM BHT不会改变转录因子NF-κB的表达。这些结果表明，BHT诱导转录因子AP-1参与了GLCLC基因表达的反式激活。
