Bacterial riboswitches are molecular structures that play a crucial role in controlling gene expression to maintain cellular balance. The Escherichia coli lysC riboswitch has been previously shown to regulate gene expression through translation initiation and mRNA decay. Recent research suggests that lysC gene expression is also influenced by Rho-dependent transcription termination. Through a series of in silico, in vitro, and in vivo experiments, we provide experimental evidence that the lysC riboswitch directly and indirectly modulates Rho transcription termination. Our study demonstrates that Rho-dependent transcription termination plays a significant role in the cotranscriptional regulation of lysC expression. Together with previous studies, our work suggests that lysC expression is governed by a lysine-sensing riboswitch that regulates translation initiation, transcription termination, and mRNA degradation. Notably, both Rho and RNase E target the same region of the RNA molecule, implying that RNase E may degrade Rho-terminated transcripts, providing a means to selectively eliminate these incomplete messenger RNAs. Overall, this study sheds light on the complex regulatory mechanisms used by bacterial riboswitches, emphasizing the role of transcription termination in the control of gene expression and mRNA stability.

中文翻译：

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大肠杆菌 lysC 核糖开关直接和间接控制 Rho 依赖性转录终止

细菌核糖开关是在控制基因表达以维持细胞平衡方面发挥关键作用的分子结构。此前已证明大肠杆菌 lysC 核糖开关可通过翻译起始和 mRNA 衰减来调节基因表达。最近的研究表明lysC基因表达也受到 Rho 依赖性转录终止的影响。通过一系列的计算机、体外和体内实验，我们提供了lysC核糖开关直接和间接调节 Rho 转录终止的实验证据。我们的研究表明，Rho 依赖性转录终止在lysC表达的共转录调控中发挥着重要作用。结合之前的研究，我们的工作表明lysC表达是由赖氨酸感应核糖开关控制的，该核糖开关调节翻译起始、转录终止和 mRNA 降解。值得注意的是，Rho 和 RNase E 都靶向 RNA 分子的相同区域，这意味着 RNase E 可能会降解 Rho 终止的转录本，从而提供了一种选择性消除这些不完整信使 RNA 的方法。总的来说，这项研究揭示了细菌核糖开关使用的复杂调节机制，强调了转录终止在控制基因表达和 mRNA 稳定性中的作用。