The σ70 subunit of RNA polymerase induces lacUV5 promoter-proximal pausing of transcription
The σ70 subunit of RNA polymerase induces lacUV5 promoter-proximal pausing of transcription
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DOI：
10.1038/nsmb768
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发表时间：
2004-06-01
影响因子：
16.8
通讯作者：
Heumann, H
中科院分区：
文献类型：
--
作者：
Brodolin, K;Zenkin, N;Heumann, H
大肠杆菌RNA聚合酶（RNAP）的σ（70）亚基是一种转录起始因子，也可以在延伸过程中与RNAP相关。我们提供的生化证据表明，sigma（70）诱导转录暂停后，RNAP已合成了17个核苷酸的转录在紫胶UV 5启动子。sigma（70）依赖性暂停需要sigma（70）和类似于启动子-10共有序列的lac阻遏子操纵子序列的一部分之间的相互作用。多糖肝素触发从暂停的复合物中释放σ（70），支持在从起始到延伸的过渡期间σ（70）和核心RNAP之间的相互作用减弱的观点。我们提出，延伸复合物中sigma（70）的结合和保留通过其与转录泡DNA形成接触的能力而稳定。此外，我们认为延伸复合物中的σ（70）亚基可能为基因表达的调控提供了靶点。
The sigma(70) subunit of Escherichia coli RNA polymerase (RNAP) is a transcription initiation factor that can also be associated with RNAP during elongation. We provide biochemical evidence that sigma(70) induces a transcription pause at the lac UV5 promoter after RNAP has synthesized a 17-nucleotide transcript. The sigma(70)-dependent pausing requires an interaction between sigma(70) and a part of the lac repressor operator sequence resembling a promoter-10 consensus. The polysaccharide heparin triggers the release of sigma(70) from the paused complexes, supporting the view that during the transition from initiation to elongation the interactions between sigma(70) and core RNAP are weakened. We propose that the binding and retention of sigma(70) in elongation complexes are stabilized by its ability to form contacts with DNA of the transcription bubble. In addition, we suggest that the sigma(70) subunit in the elongation complex may provide a target for regulation of gene expression.