Physical interaction and functional synergy between glucocorticoid receptor and Ets2 proteins for transcription activation of the rat cytochrome P-450c27 promoter
Physical interaction and functional synergy between glucocorticoid receptor and Ets2 proteins for transcription activation of the rat cytochrome P-450c27 promoter
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DOI：
10.1074/jbc.m100671200
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发表时间：
2001-05-25
影响因子：
4.8
通讯作者：
Avadhani, NG
中科院分区：
文献类型：
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作者：
Mullick, J;Anandatheerthavarada, HK;Avadhani, NG
我们证明，地塞米松介导的细胞色素P-450c27启动子的转录激活涉及糖皮质激素受体(GR)和Ets2因子之间的物理相互作用和功能协同。Ets2蛋白与启动子的“弱”Ets样位点的结合依赖于与相邻隐蔽的糖皮质激素反应元件结合的OH。免疫共沉淀和化学交联实验表明GR和Ets2蛋白之间存在物理相互作用。突变分析表明，Ets2和GR在地塞米松介导的细胞色素P-450c27启动子激活中具有协同作用。GR的DNA结合区缺乏转录激活和配体结合区，在与完整的Ets2启动子的协同激活中充分发挥作用。Ets2的DNA结合区缺乏转录激活区，对转录活性有明显的负面影响。最后，由GR DNA结合域和Ets2转录激活域组成的融合蛋白完全支持转录活性，这表明这两种蛋白之间存在一种新的协同作用，而不需要GR的反式激活域。我们的结果也为推测弱共识Ets位点在转录激活中的作用提供了新的见解，可能是通过与其他基因特异性转录激活因子的协同作用。
We demonstrate that dexamethasone-mediated transcription activation of the cytochrome P-450c27 promoter involves a physical interaction and functional synergy between glucocorticoid receptor (GR) and Ets2 factor. Ets2 protein binding to a "weak" Ets-like site of the promoter is dependent on Oh bound to the adjacent cryptic glucocorticoid response element. Coimmunoprecipitation and chemical cross-linking experiments show physical interaction between GR and Ets2 proteins. Mutational analyses show synergistic effects of Ets2 and GR in dexamethasone-mediated activation of the cytochrome P-450c27 promoter. The DNA-binding domain of GR, lacking the transcription activation and ligand-binding domains, was fully active in synergistic activation of the promoter with intact Ets2. The DNA-binding domain of Ets2 lacking the transcription activation domain showed a dominant negative effect on the transcription activity. Finally, a fusion protein consisting of the GR DNA-binding domain and the transcription activation domain of Ets2 fully supported the transcription activity, suggesting a novel synergy between the two proteins, which does not require the transactivation domain of GR. Our results also provide new insights on the role of putative weak consensus Ets sites in transcription activation, possibly through synergistic interaction with other gene-specific transcription activators.