ACTIVATION OF THE TFIID-TFIIA COMPLEX WITH HMG-2
ACTIVATION OF THE TFIID-TFIIA COMPLEX WITH HMG-2
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DOI：
10.1101/gad.9.11.1354
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发表时间：
1995-06-01
影响因子：
10.5
通讯作者：
SHARP, PA
中科院分区：
文献类型：
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作者：
SHYKIND, BM;KIM, J;SHARP, PA
非组蛋白染色体蛋白HMG-2被确定为在体外含有RNA聚合酶II和纯化因子的特定转录反应中激活所必需的因子。除免疫球蛋白IgH基因外，所有启动子都被激活。TFIIA是受刺激转录水平所必需的。激活过程依赖于TFIID复合体中TAFs的存在，并产生一个预起始复合体，TFIIB从该复合体中解离得更慢。然而，超过三个数量级的TFIIB滴定并没有消除激活剂和HMG-2的需求，以达到刺激水平的转录。对激活反应的分析表明，TFIID-TFIIA复合物是激活过程中的第一阶段修饰。这些结果表明，激活可以仅在基础因子、激活蛋白和“建筑”HMG因子存在的情况下发生，这可能会稳定激活的tpiid - tfiia -启动子复合物的构象。
The nonhistone chromosomal protein HMG-2 was identified as a factor necessary for activation in a defined transcription reaction in vitro containing RNA polymerase II and purified factors. Activation occurred on all promoters assayed except that of the immunoglobulin IgH gene. TFIIA was required for stimulated levels of transcription. The activation process depended on the presence of TAFs in the TFIID complex and generated a preinitiation complex from which TFIIB dissociated more slowly. However, titration of TFIIB over three orders of magnitude did not obviate the requirement of activator and HMG-2 to achieve stimulated levels of transcription. Analysis of the activated reaction identified the TFIID-TFIIA complex as the first stage of modification during activation. These results suggest that activation can, occur solely in the presence of the basal factors, activator protein, and an ''architectural'' HMG factor, which probably stabilizes an activated conformation of the TPIID-TFIIA-promoter complex.