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首页> 外文期刊>Proceedings of the National Academy of Sciences of the United States of America >An inactive open complex mediated by an UP element at Escherichia coli promoters
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An inactive open complex mediated by an UP element at Escherichia coli promoters

机译：在大肠杆菌启动子上由UP元件介导的无活性开放复合物

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摘要

A specific interaction between the #gamma# subunit of RNA polymerase and an A+T-rich upstream sequence (UP element) stimulates transcription at some promoters in Esch- erichia coli. We found that RNA polymerase formed a heparin- resistant nonproductive initiation complex at the malT pro- moter which has an A+T-rich upstream sequence that begins 9 bp upstream of the -35 region. Substitution of other sequences for the A+T-rich sequence eliminated both the formation of heparin-resistant complexes and a binding to the malT promoter. A 5-bp deletion between the A+T-rich se- quence and the -35 region increased promoter activity. The UP element derived from the rrnB P1 promoter stimulated transcription of the malT core promoter when placed 4 bp upstream from the malT -35 region, but insertion of an additional 4 bp between the rrnB P1 UP element and the -35 element eliminated transcription activity without eliminating heparin-resistant complex formation. Similar UP element effects were observed in hybrids with the lac core promoter, even though the region around the transcription start site was melted in both productive and nonproductive complexes. We concludc that UP elements can mediate the formation of both productive and nonproductive open complexes, depending on their location with respect to the core promoter.
机译：RNA聚合酶的＃gamma＃亚基与富含A + T的上游序列（UP元件）之间的特异性相互作用刺激了大肠杆菌中某些启动子的转录。我们发现RNA聚合酶在malT启动子上形成了抗肝素的非生产性起始复合物，该复合物具有富A + T的上游序列，该序列起始于-35区上游9 bp。将其他序列替换为富含A + T的序列消除了肝素抗性复合物的形成以及与malT启动子的结合。富A + T序列和-35区域之间的5 bp缺失增加了启动子活性。当在malT -35区上游4 bp处放置时，源自rrnB P1启动子的UP元件刺激malT核心启动子的转录，但是在rrnB P1 UP元件和-35元件之间插入另外的4 bp消除了转录活性，而没有消除了抗肝素复合物的形成。即使在转录起始位点周围的区域在生产性复合体和非生产性复合体中都融化了，在与lac核心启动子的杂交体中也观察到了类似的UP元件效应。我们认为，UP元件可以介导生产性开放性复合物和非生产性开放性复合物的形成，这取决于它们相对于核心启动子的位置。

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