Multiple sets of basal factors initiate transcription by RNA polymerase II.
Multiple sets of basal factors initiate transcription by RNA polymerase II.
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发表时间：
1994-07
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影响因子：
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通讯作者：
J. Parvin;B. Shykind;R. Meyers;J. Kim;P. Sharp
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作者：
J. Parvin;B. Shykind;R. Meyers;J. Kim;P. Sharp
细胞提取物中发现的两种主要形式的TATA结合因子，即300 kDa的B-TFIID和1000 kDa的D-TFIID复合体，确定了从超螺旋模板启动转录的最低要求。正如已经观察到的TATA结合蛋白(TBP)亚单位(Parvin和Sharp，1993)一样，从IgH启动子转录最低限度地需要TFIID活性加上TFIIB和RNA聚合酶II。这种最小的反应只在负超螺旋模板DNA上活跃。相反，编码腺病毒主要晚期启动子(MLP)或其他几个启动子的超螺旋模板需要在最小反应的基础上添加TFIIF。进一步添加TFIIE和TFIIH可提高后两个启动子的转录水平，但不是必需的。与线性模板上的完全反应相反，来自超螺旋IgH或MLP模板的转录不需要ATP的β-伽马键的水解。比较了14个不同的核心启动子在TBP、B-TFIID和D-TFIID三种TATA活性之一重组的完整和最小基础转录反应中的作用。在这14个启动子中，只有IgH在没有TFIIF的情况下是活性的，其他启动子表现出不同的转录水平，这取决于反应中存在的基础因子。有研究认为，显著水平的基础转录只需要最少的一组因子，上游激活剂的刺激可能部分是通过在起始反应中加入额外的基础因子来介导的。
The minimal requirements for transcription initiation from supercoiled templates were determined for the two major forms of TATA-binding factors found in cell extracts, the 300-kDa B-TFIID and the 1000-kDa D-TFIID complexes. As had been observed for the TATA-binding protein (TBP) subunit (Parvin and Sharp, 1993), transcription from the IgH promoter minimally requires TFIID activity plus TFIIB and RNA polymerase II. This minimal reaction is only active on negatively supercoiled template DNA. In contrast, the supercoiled templates encoding the adenovirus major late promoter (MLP), or several other promoters, require the addition of TFIIF to the minimal reaction. Further addition of TFIIE and TFIIH boosts the level of transcription from these latter promoters but is not required. In contrast to the complete reaction on linear template, transcription from supercoiled IgH or MLP templates does not require the hydrolysis of the beta-gamma bond of ATP. Fourteen different core promoters were compared in complete and minimal basal transcription reactions reconstituted with one of the three TATA activities: TBP, B-TFIID, and D-TFIID. Of these 14 promoters, only the IgH was active in the absence of TFIIF, and the other promoters demonstrated different levels of transcription depending on which basal factors were present in reaction. It is proposed that a significant level of basal transcription only requires a minimal set of factors, and stimulation by upstream activators may in part be mediated by the inclusion of additional basal factors into the initiation reaction.