Mechanism of synergy between TATA and initiator: synergistic binding of TFIID following a putative TFIIA-induced isomerization
Mechanism of synergy between TATA and initiator: synergistic binding of TFIID following a putative TFIIA-induced isomerization
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DOI：
10.1101/gad.11.22.3007
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发表时间：
1997-11-15
影响因子：
10.5
通讯作者：
Smale, ST
中科院分区：
文献类型：
--
作者：
Emami, KH;Jain, A;Smale, ST
TFIID复合物与蛋白质编码基因中至少三种类型的核心启动子元件相互作用，包括TATA、启动子（Inr）和下游启动子元件。我们已经开始探索TPIID-Inr相互作用在基础转录和激活转录过程中导致TATA和Inr元件之间功能协同的机制。在DNase I足迹分析中，GAL4-VP16将TEIID-TFIIA招募到包含TATA盒、Inr或TATA和Inr元件的核心启动子上，在TATA-Inr启动子上存在明显的协同相互作用。两个元素之间的适当间距对于协同结合至关重要。尽管有序列特异性的TFIID-Inr相互作用，凝胶转移实验显示TPIID单独对TATA- inr和TATA启动子具有相似的亲和力。然而，有趣的是，重组TFIIA强烈且选择性地增强了TPIID与TATA- inr启动子的结合，而对TATA启动子的结合几乎没有影响。对天然腺病毒主要晚期启动子的研究证实了这些发现，尽管在该启动子的Inr下游存在特异性但无功能的TFIID相互作用。这些结果表明，tfiia诱导的构象变化是序列特异性tfiia -Inr相互作用发生的必要条件，具有足够的亲和力，以支持TATA和Inr元件之间的功能协同作用。
The TFIID complex interacts with at least three types of core promoter elements within protein-coding genes, including TATA, initiator (Inr), and downstream promoter elements. We have begun to explore the mechanism by which the TPIID-Inr interaction leads to functional synergy between TATA and Inr elements during both basal and activated transcription. In DNase I footprinting assays, GAL4-VP16 recruited TEIID-TFIIA to core promoters containing either a TATA box, an Inr, or both TATA and Inr elements, with synergistic interactions apparent on the TATA-Inr promoter. Appropriate spacing between the two elements was essential for the synergistic binding. Despite the sequence-specific TFIID-Inr interactions, gel shift experiments revealed that TPIID alone possesses similar affinities for the TATA-Inr and TATA promoters. Interestingly, however, recombinant TFIIA strongly and selectively enhanced TPIID binding to the TATA-Inr promoter, with little effect on binding to the TATA promoter. Studies of the natural adenovirus major late promoter confirmed these findings, despite the existence of specific but nonfunctional TFIID interactions downstream of the Inr in that promoter. These results suggest that a TFIIA-induced conformational change is essential for the sequence-specific TFIID-Inr interaction to occur with sufficient affinity to support the functional synergism between TATA and Inr elements.