Holder Isabelle T, Hartig Jörg S
Chem Biol. 2014 Nov 20;21(11):1511-21. doi: 10.1016/j.chembiol.2014.09.014.
We provide important insights into secondary-structure-mediated regulation of gene expression in Escherichia coli. In a comprehensive survey, we show that the strand orientation and the exact position of a G-quadruplex sequence strongly influence its effect on transcription and translation. We generated a series of reporter gene constructs that contained systematically varied positions of quadruplexes and respective control sequences inserted into several positions within the promoter, 50-UTR, and 30-UTR regions. G-rich sequences at specific locations in the promoter and also in proximity to the ribosome-binding site (RBS) showed pronounced inhibitory effects. Additionally, we rationally designed a system where quadruplex formation showed a gene-activating behavior. Moreover, we characterized quadruplexes in proximity to the RBS that occur naturally in E. coli genes, demonstrating that some of these quadruplexes exert significant modulation of gene expression. Taken together, our data show strong position-dependent effects of quadruplex secondary structures on bacterial gene expression.
我们对大肠杆菌中二级结构介导的基因表达调控提供了重要见解。在一项全面的研究中，我们表明G-四链体序列的链方向和确切位置强烈影响其对转录和翻译的作用。我们构建了一系列报告基因构建体，其中包含系统变化的四链体位置以及插入启动子、5′-UTR和3′-UTR区域内多个位置的相应对照序列。启动子中特定位置以及靠近核糖体结合位点（RBS）的富含G的序列显示出明显的抑制作用。此外，我们合理设计了一个系统，其中四链体形成表现出基因激活行为。此外，我们对大肠杆菌基因中自然存在的靠近RBS的四链体进行了表征，证明其中一些四链体对基因表达有显著调节作用。综上所述，我们的数据表明四链体二级结构对细菌基因表达有强烈的位置依赖性影响。
