Swaffield J C, Melcher K, Johnston S A
Department of Medicine, University of Texas Southwestern Medical Center, Dallas 75325-8573.
Nature. 1995 Mar 2;374(6517):88-91. doi: 10.1038/374088a0.
Biochemical and genetic studies suggest the existence of mediators that work between the activation domains (ADs) of regulatory proteins and the basic transcriptional machinery. We have previously shown genetically that Sug1 interacts with the AD of the yeast activator Ga14. Here we provide evidence that the Sug1 protein of yeast binds directly to the ADs of Ga14 and the viral activator, VP16. Sug1 protein is associated with the TATA-binding protein in vivo and binds to it in vitro, consistent with a mediator function. We also demonstrate that Sug1 is not a component of the 26S proteasome, contrary to previous reports. Sug1 is a member of a large, highly conserved family of ATPases, implying a role for ATP hydrolysis in the activation of transcription.
生化和遗传学研究表明，在调节蛋白的激活结构域（ADs）与基本转录机制之间存在起作用的介质。我们之前通过遗传学方法证明，Sug1与酵母激活剂Gal4的AD相互作用。在此，我们提供证据表明，酵母的Sug1蛋白直接与Gal4和病毒激活剂VP16的AD结合。Sug1蛋白在体内与TATA结合蛋白相关联，并在体外与之结合，这与一种介质功能相符。我们还证明，与之前的报道相反，Sug1不是26S蛋白酶体的组成成分。Sug1是一个大型的、高度保守的ATP酶家族的成员，这意味着ATP水解在转录激活中起作用。
