6S RNA-dependent inhibition of RNA polymerase is released by RNA-dependent synthesis of small de novo products
6S RNA-dependent inhibition of RNA polymerase is released by RNA-dependent synthesis of small de novo products
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DOI：
10.1515/bc.2010.018
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发表时间：
2010-02-01
影响因子：
3.7
通讯作者：
Wagner, Rolf
中科院分区：
文献类型：
--
作者：
Wurm, Reinhild;Neusser, Thomas;Wagner, Rolf
已知来自大肠杆菌的6S RNA与RNA聚合酶结合，在固定生长期间阻止与许多启动子的相互作用。在营养上升的条件下，当生长情况改善时，产生的抑制被释放。与RNA聚合酶活性位点结合的6S RNA具有一个特别有趣的特征，即作为模板，导致与6S RNA特定序列区域互补的定义的新生RNA （dnRNA）的转录。我们分析了dnRNA的合成条件，并在体外和体内测定了它们对6S RNA介导的RNA聚合酶抑制的影响。当营养增加时，RNA聚合酶/6S RNA复合物诱导dnrna快速合成，dnrna与6S RNA模板形成稳定的杂交体。由此产生的结构变化使失活的RNA聚合酶复合物不稳定，导致sigma亚基释放。dnRNA和6S RNA都是经过复杂分解后迅速降解的。使用转录抑制剂利福平的实验表明，RNA聚合酶/6S RNA复合物的分解需要主动转录。我们的研究结果支持了6S RNA不仅在静止生长期间抑制转录，而且使细胞在饥饿后恢复快速生长，帮助细胞脱离静止期的结论。
6S RNA from Escherichia coli is known to bind to RNA polymerase, preventing interaction with many promoters during stationary growth. The resulting repression is released under conditions of nutritional upshift, when the growth situation improves. 6S RNA, which binds to the active site of RNA polymerase, has the particularly interesting feature to act as a template, causing the transcription of defined de novo RNAs (dnRNA) that are complementary to a specific sequence region of the 6S RNA. We analyzed the conditions of dnRNA synthesis and determined their effect on the 6S RNA-mediated inhibition of RNA polymerase in vitro and in vivo. Upon nutritional upshift the RNA polymerase/6S RNA complex induces the rapid synthesis of dnRNAs, which form stable hybrids with the 6S RNA template. The resulting structural change destabilizes the inactivated RNA polymerase complex, causing sigma subunit release. Both dnRNA and 6S RNA are rapidly degraded after complex disintegration. Experiments using the transcriptional inhibitor rifampicin demonstrate that active transcription is required for the disintegration of the RNA polymerase/6S RNA complex. Our results support the conclusion that 6S RNA not only inhibits transcription during stationary growth but also enables cells to resume rapid growth after starvation and help to escape from stationary phase.