CHARACTERIZATION OF PHYSICAL INTERACTIONS OF THE PUTATIVE TRANSCRIPTIONAL ADAPTER, ADA2, WITH ACIDIC ACTIVATION DOMAINS AND TATA-BINDING PROTEIN
CHARACTERIZATION OF PHYSICAL INTERACTIONS OF THE PUTATIVE TRANSCRIPTIONAL ADAPTER, ADA2, WITH ACIDIC ACTIVATION DOMAINS AND TATA-BINDING PROTEIN
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DOI：
10.1074/jbc.270.33.19337
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发表时间：
1995-08-18
影响因子：
4.8
通讯作者：
BERGER, SL
中科院分区：
文献类型：
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作者：
BARLEV, NA;CANDAU, R;BERGER, SL
RNA聚合酶II转录需要与上游DNA位点结合的激活蛋白和与核心启动子结合的一般因子之间的功能性相互作用。辅助转录因子，如衔接子和辅激活因子，在激活过程中具有重要但仍不清楚的作用。我们测试了物理相互作用的假定适配器ADA 2与激活结构域来自酸性激活蛋白和某些一般的转录因子。ADA 2与疱疹病毒VP 16和酵母GCN 4激活结构域相关，但不与酵母HAP 4的激活结构域相关，而酵母HAP 4的激活结构域先前被证明在体内和体外不依赖于ADA 2功能。此外，ADA 2的氨基末端直接与VP 16激活结构域相互作用，表明ADA 2为激活结构域和接头复合物之间的相互作用提供了决定因素。TATA结合蛋白（TBP）和TFIIB两者先前已显示在体外与VP 16活化结构域直接相互作用（Stringer，K. F.、英格尔斯角J.，和Greenblatt，J.（1990）Nature 345，783-786; Lin，Y.美国，哈，我，马尔多纳多，E.，Reinberg，D.，和绿色，M. R.（1991）Nature 353，569-571）。有趣的是，当在酵母核提取物中测试VP 16与这些一般因子之间的结合时，两种因子都与VP 16相互作用，但只有TBP/VP 16缔合依赖于ADA 2。此外，ADA 2与TBP物理相关，但不与TFIIB。这些结果表明，ADA 2在转录激活中的作用是促进激活结构域和TBP之间的物理相互作用。
RNA polymerase II transcription requires functional interactions between activator proteins bound to upstream DNA sites and general factors bound to the core promoter. Accessory transcription factors, such as adaptors and coactivators, have important, but still unclear, roles in the activation process. We tested physical interactions of the putative adaptor ADA2 with activation domains derived from acidic activator proteins and with certain general transcription factors. ADA2 associated with the herpesvirus VP16 and yeast GCN4 activation domains but not with the activation domain of yeast HAP4, which previously was shown to be independent of ADA2 function in vivo and in vitro. Furthermore, the amino terminus of ADA2 directly interacted with the VP16 activation domain, suggesting that ADA2 provides determinants for interaction between activation domains and the adaptor complex. Both TATA-binding protein (TBP) and TFIIB have previously been shown to interact directly with the VP16 activation domain in vitro (Stringer, K. F., Ingles, C. J., and Greenblatt, J. (1990) Nature 345, 783-786; Lin, Y. S., Ha, I., Maldonado, E., Reinberg, D., and Green, M. R. (1991) Nature 353, 569-571). Interestingly, when binding was tested between VP16 and these general factors in yeast nuclear extracts, both factors interacted with VP16, but only the TBP/VP16 association was dependent on ADA2. In addition, ADA2 physically associated with TBP, but not with TFIIB. These results suggest that the role of ADA2 in transcriptional activation is to promote physical interaction between activation domains and TBP.