Clustered regularly interspaced short palindromic repeats (CRISPR)-based genome editors are powerful tools in biology and hold great promise for the treatment of human diseases. Advanced DNA base editing tools, such as cytosine base editor and adenine base editor, have been developed to correct permanent mistakes in genetic material. However, undesired off-target edits would also be permanent, which poses a considerable risk for therapeutics. Alternatively, base editing at the RNA level is capable of correcting disease-causing mutations but does not lead to lasting genotoxic effects. RNA base editors offer temporary and reversible therapies and have been catching on in recent years. Here, we summarize some emerging RNA editors based on A-to-inosine, C-to-U and U-to-pseudouridine changes. We review the programmable RNA-targeting systems as well as modification enzyme-based effector proteins and highlight recent technological breakthroughs. Finally, we compare editing tools, discuss limitations and opportunities, and provide insights for the future directions of RNA base editing.

基于成簇规则间隔短回文重复序列 (CRISPR) 的基因组编辑器是生物学中的强大工具，为治疗人类疾病带来了巨大希望。先进的 DNA 碱基编辑工具，例如胞嘧啶碱基编辑器和腺嘌呤碱基编辑器，已被开发用于纠正遗传物质中的永久性错误。然而，不需要的脱靶编辑也将是永久性的，这给治疗带来了相当大的风险。另外，RNA 水平的碱基编辑能够纠正致病突变，但不会导致持久的基因毒性效应。RNA 碱基编辑器提供临时且可逆的疗法，并且近年来一直流行。在这里，我们总结了一些基于 A 至肌苷、C 至 U 和 U 至假尿苷变化的新兴 RNA 编辑器。我们回顾了可编程 RNA 靶向系统以及修饰酶效应蛋白，并重点介绍了最新的技术突破。最后，我们比较编辑工具，讨论局限性和机遇，并为 RNA 碱基编辑的未来方向提供见解。