Kim Y J, Björklund S, Li Y, Sayre M H, Kornberg R D
Department of Cell Biology, Stanford University School of Medicine, California 94305.
Cell. 1994 May 20;77(4):599-608. doi: 10.1016/0092-8674(94)90221-6.
A mediator was isolated from yeast that enabled a response to the activator proteins GAL4-VP16 and GCN4 in a transcription system reconstituted with essentially homogeneous basal factors and RNA polymerase II. The mediator comprised some 20 polypeptides, including the three subunits of TFIIF and other polypeptides cross-reactive with antisera against GAL11, SUG1, SRB2, SRB4, SRB5, and SRB6 proteins. Mediator not only enabled activated transcription but also conferred 8-fold greater activity in basal transcription and 12-fold greater efficiency of phosphorylation of RNA polymerase II by the TFIIH-associated C-terminal repeat domain (CTD) kinase, indicative of mediator-CTD interaction. A holoenzyme form of RNA polymerase II was independently isolated that supported a response to activator proteins with purified basal factors. The holoenzyme proved to consist of mediator associated with core 12-subunit RNA polymerase II.
从酵母中分离出一种介质，在由基本均一的基础因子和RNA聚合酶II重构的转录系统中，该介质能对激活蛋白GAL4-VP16和GCN4作出反应。该介质由约20种多肽组成，包括TFIIF的三个亚基以及其他与抗GAL11、SUG1、SRB2、SRB4、SRB5和SRB6蛋白的抗血清发生交叉反应的多肽。介质不仅能促进激活转录，还能使基础转录活性提高8倍，并且使TFIIH相关的C末端重复结构域（CTD）激酶对RNA聚合酶II的磷酸化效率提高12倍，这表明介质与CTD存在相互作用。独立分离出了一种RNA聚合酶II的全酶形式，它与纯化的基础因子一起支持对激活蛋白的反应。事实证明，该全酶由与核心12亚基RNA聚合酶II相关的介质组成。
Zotero 插件