Eriksson P, Wrange O
Department of Cell and Molecular Biology, Medical Nobel Institute, Karolinska Institutet, Stockholm, Sweden.
Eur J Biochem. 1993 Jul 15;215(2):505-11. doi: 10.1111/j.1432-1033.1993.tb18060.x.
Glucocorticoid-receptor-dependent and glucocorticoid-response-element-dependent in vitro transcription was established using a crude nuclear extract and purified glucocorticoid receptor from rat liver. The capacity of glucocorticoid receptor to stimulate in vitro transcription was only detectable when basal transcription, i.e. transcription in the absence of glucocorticoid receptor, had been repressed. Transcriptional repression was achieved either by adding purified histone H1, or by lowering the amount of DNA template relative to the amount of crude nuclear extract. Glucocorticoid receptor caused a 1.1 +/- 0.7-fold stimulation of transcription from the mouse-mammary-tumor-virus promoter when basal transcription was not repressed, and a 7.0 +/- 1.5-fold stimulation when basal transcription had been repressed by addition of histone H1. Similar results were obtained when using a minimal promoter consisting of two glucocorticoid-response elements and a TATA box. Our data suggest that glucocorticoid receptor stimulates in vitro transcription by an antirepression mechanism.
利用大鼠肝脏的粗核提取物和纯化的糖皮质激素受体，建立了糖皮质激素受体依赖性和糖皮质激素反应元件依赖性的体外转录体系。只有在基础转录（即不存在糖皮质激素受体时的转录）受到抑制时，才能检测到糖皮质激素受体刺激体外转录的能力。通过添加纯化的组蛋白H1，或相对于粗核提取物的量降低DNA模板的量，均可实现转录抑制。当基础转录未受抑制时，糖皮质激素受体对小鼠乳腺肿瘤病毒启动子的转录刺激为1.1±0.7倍；当通过添加组蛋白H1抑制基础转录时，刺激倍数为7.0±1.5倍。使用由两个糖皮质激素反应元件和一个TATA框组成的最小启动子时，也得到了类似的结果。我们的数据表明，糖皮质激素受体通过抗抑制机制刺激体外转录。
