Yanofsky Charles
Department of Biological Sciences, Stanford University, Stanford, CA 94305, USA.
RNA. 2007 Aug;13(8):1141-54. doi: 10.1261/rna.620507. Epub 2007 Jun 29.
We are now aware that RNA-based regulatory mechanisms are commonly used to control gene expression in many organisms. These mechanisms offer the opportunity to exploit relatively short, unique RNA sequences, in altering transcription, translation, and/or mRNA stability, in response to the presence of a small or large signal molecule. The ability of an RNA segment to fold and form alternative hairpin secondary structures -- each dedicated to a different regulatory function -- permits selection of specific sequences that can affect transcription and/or translation. In the present paper I will focus on our current understanding of the RNA-based regulatory mechanisms used by Escherichia coli and Bacillus subtilis in controlling expression of the tryptophan biosynthetic operon. The regulatory mechanisms they use for this purpose differ, suggesting that these organisms, or their ancestors, adopted different strategies during their evolution. I will also describe the RNA-based mechanism used by E. coli in regulating expression of its operon responsible for tryptophan degradation, the tryptophanase operon.
我们现在已经认识到，基于RNA的调控机制在许多生物体中普遍用于控制基因表达。这些机制提供了利用相对较短的独特RNA序列的机会，以响应小或大信号分子的存在来改变转录、翻译和/或mRNA稳定性。RNA片段折叠并形成不同发夹二级结构的能力——每个结构都具有不同的调控功能——允许选择能够影响转录和/或翻译的特定序列。在本文中，我将重点关注我们目前对大肠杆菌和枯草芽孢杆菌用于控制色氨酸生物合成操纵子表达的基于RNA的调控机制的理解。它们用于此目的的调控机制不同，这表明这些生物体或其祖先在进化过程中采用了不同的策略。我还将描述大肠杆菌用于调节其负责色氨酸降解的操纵子（色氨酸酶操纵子）表达的基于RNA的机制。
