Hill C S, Marais R, John S, Wynne J, Dalton S, Treisman R
Transcription Laboratory, Imperial Cancer Research Fund, London, England.
Cell. 1993 Apr 23;73(2):395-406. doi: 10.1016/0092-8674(93)90238-l.
Serum response factor (SRF) forms a ternary complex at the c-fos serum response element (SRE) with an accessory factor, Elk-1. We constructed altered-binding specificity derivatives of SRF and Elk-1 that form a ternary complex at a mutated, inactive SRE; like Elk-1, the Elk-1 variant only binds its target as part of a ternary complex with SRF. Simultaneous expression of these SRF and Elk-1 derivatives restores serum-regulated activity to the mutated SRE in transfected cells. Efficient transcriptional activation is dependent on the regulated phosphorylation of Elk-1 C-terminal MAP kinase sites and requires the C-terminal sequences of SRF as well as SRF sequences that mediate ternary complex formation. These experiments provide direct evidence that SRF and Elk-1 functionally cooperate in the ternary complex at the SRE to regulate transcription.
血清反应因子（SRF）与辅助因子Elk-1在c-fos血清反应元件（SRE）处形成三元复合物。我们构建了SRF和Elk-1的结合特异性改变的衍生物，它们在突变的无活性SRE处形成三元复合物；与Elk-1一样，Elk-1变体仅作为与SRF的三元复合物的一部分与其靶标结合。这些SRF和Elk-1衍生物的同时表达可恢复转染细胞中突变SRE的血清调节活性。有效的转录激活依赖于Elk-1 C末端丝裂原活化蛋白激酶位点的调节性磷酸化，并且需要SRF的C末端序列以及介导三元复合物形成的SRF序列。这些实验提供了直接证据，表明SRF和Elk-1在SRE处的三元复合物中在功能上协同调节转录。
