The mechanism of variability in transcription start site selection
The mechanism of variability in transcription start site selection
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DOI：
10.7554/elife.32038
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发表时间：
2017-11-23
期刊：
影响因子：
7.7
通讯作者：
Ebright, Richard H.
中科院分区：
文献类型：
--
作者：
Yu, Libing;Winkelman, Jared T.;Ebright, Richard H.
在转录起始期间，RNA聚合酶（RNAP）结合启动子DNA，解开启动子DNA以形成含有单链“转录泡”的RNAP-启动子开放复合物（RPo），并选择转录起始位点（TSS）。TSS选择发生在启动子区域内的不同位置，这取决于启动子序列和起始底物浓度。TSS选择中的可变性已经被提出涉及DNA“挤压”和“反挤压”，其特征是：（i）RNAP前缘相对于DNA的向前和反向移动，但不是后缘，以及（ii）转录泡的膨胀和收缩。在这里，使用在体外和体内的蛋白质-DNA光交联和单分子纳米操纵，我们显示细菌TSS选择表现出两个特点的挤压和反挤压，我们定义的挤压和反挤压的能量学。这些结果建立了细菌RNAP选择TSS的机制，并提出了细菌、古细菌和真核生物RNAP选择TSS的一般机制。
During transcription initiation, RNA polymerase (RNAP) binds to promoter DNA, unwinds promoter DNA to form an RNAP-promoter open complex (RPo) containing a single stranded 'transcription bubble,' and selects a transcription start site (TSS). TSS selection occurs at different positions within the promoter region, depending on promoter sequence and initiating substrate concentration. Variability in TSS selection has been proposed to involve DNA 'scrunching' and 'anti-scrunching,' the hallmarks of which are: (i) forward and reverse movement of the RNAP leading edge, but not trailing edge, relative to DNA, and (ii) expansion and contraction of the transcription bubble. Here, using in vitro and in vivo protein-DNA photocrosslinking and single molecule nanomanipulation, we show bacterial TSS selection exhibits both hallmarks of scrunching and anti-scrunching, and we define energetics of scrunching and anti-scrunching. The results establish the mechanism of TSS selection by bacterial RNAP and suggest a general mechanism for TSS selection by bacterial, archaeal, and eukaryotic RNAP.