Kim Kihoon, Liu Fenyong
Program in Comparative Biochemistry, University of California, Berkeley, CA 94720, USA.
Biochim Biophys Acta. 2007 Nov-Dec;1769(11-12):603-12. doi: 10.1016/j.bbaexp.2007.09.001. Epub 2007 Sep 29.
Ribonuclease P (RNase P) complexed with an external guide sequence (EGS) represents a novel nucleic acid-based gene interference approach to modulate gene expression. This enzyme is a ribonucleoprotein complex for tRNA processing. In Escherichia coli, RNase P contains a catalytic RNA subunit (M1 ribozyme) and a protein subunit (C5 cofactor). EGSs, which are RNAs derived from natural tRNAs, bind to a target mRNA and render the mRNA susceptible to hydrolysis by RNase P and M1 ribozyme. When covalently linked with a guide sequence, M1 can be engineered into a sequence-specific endonuclease, M1GS ribozyme, which cleaves any target RNAs that base pair with the guide sequence. Studies have demonstrated efficient cleavage of mRNAs by M1GS and RNase P complexed with EGSs in vitro. Moreover, highly active M1GS and EGSs were successfully engineered using in vitro selection procedures. EGSs and M1GS ribozymes are effective in blocking gene expression in both bacteria and human cells, and exhibit promising activity for antimicrobial, antiviral, and anticancer applications. In this review, we highlight some recent results using the RNase P-based technology, and offer new insights into the future of using EGS and M1GS RNA as tools for basic research and as gene-targeting agents for clinical applications.
与外部引导序列（EGS）复合的核糖核酸酶P（RNase P）代表了一种基于核酸的新型基因干扰方法，用于调节基因表达。这种酶是一种用于tRNA加工的核糖核蛋白复合体。在大肠杆菌中，RNase P包含一个催化RNA亚基（M1核酶）和一个蛋白质亚基（C5辅因子）。EGS是源自天然tRNA的RNA，它与靶mRNA结合，使mRNA易于被RNase P和M1核酶水解。当与引导序列共价连接时，M1可以被改造成一种序列特异性内切核酸酶，即M1GS核酶，它能切割任何与引导序列碱基配对的靶RNA。研究表明，在体外，M1GS以及与EGS复合的RNase P能有效切割mRNA。此外，通过体外筛选程序成功构建了高活性的M1GS和EGS。EGS和M1GS核酶在细菌和人类细胞中都能有效阻断基因表达，在抗菌、抗病毒和抗癌应用中展现出了良好的活性。在这篇综述中，我们重点介绍了一些使用基于RNase P技术的最新成果，并对将EGS和M1GS RNA用作基础研究工具以及临床应用中的基因靶向剂的未来发展提供了新的见解。
