Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia.
ARC Centre of Excellence for Advanced Molecular Imaging, Clayton, VIC 3800, Australia.
Int J Mol Sci. 2019 Jul 4;20(13):3290. doi: 10.3390/ijms20133290.
The general transcription factor TFIID is a core promoter selectivity factor that recognizes DNA sequence elements and nucleates the assembly of a pre-initiation complex (PIC). The mechanism by which TFIID recognizes the promoter is poorly understood. The TATA-box binding protein (TBP) is a subunit of the multi-protein TFIID complex believed to be key in this process. We reconstituted transcription from highly purified components on a ribosomal protein gene () and discovered that TFIIDΔTBP binds and rearranges the promoter DNA topology independent of TBP. TFIIDΔTBP binds ~200 bp of the promoter and changes the DNA topology to a larger extent than the nucleosome core particle. We show that TBP inhibits the DNA binding activities of TFIIDΔTBP and conclude that the complete TFIID complex may represent an auto-inhibited state. Furthermore, we show that the DNA binding activities of TFIIDΔTBP are required for assembly of a PIC poised to select the correct transcription start site (TSS).
一般转录因子 TFIID 是一种核心启动子选择性因子，可识别 DNA 序列元件并引发起始前复合物 (PIC) 的组装。TFIID 识别启动子的机制尚不清楚。TATA 框结合蛋白 (TBP) 是多蛋白 TFIID 复合物的一个亚基，被认为是该过程中的关键。我们在核糖体蛋白基因 () 上用高度纯化的成分重新组装转录，发现 TFIIDΔTBP 可结合并重新排列启动子 DNA 拓扑结构，而无需 TBP。TFIIDΔTBP 结合约 200bp 的启动子，并使 DNA 拓扑结构发生更大程度的变化，超过核小体核心颗粒。我们表明 TBP 抑制 TFIIDΔTBP 的 DNA 结合活性，并得出结论，完整的 TFIID 复合物可能代表一种自动抑制状态。此外，我们表明 TFIIDΔTBP 的 DNA 结合活性对于组装准备选择正确转录起始位点 (TSS) 的 PIC 是必需的。
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