Clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein (Cas) systems, especially type II (Cas9) systems, have been widely used in gene/genome targeting. Modifications of Cas9 enable these systems to become platforms for precise DNA manipulations. However, the utilization of CRISPR-Cas systems in RNA targeting remains preliminary. The discovery of type VI CRISPR-Cas systems (Cas13) shed light on RNA-guided RNA targeting. Cas13d, the smallest Cas13 protein, with a length of only ~930 amino acids, is a promising platform for RNA targeting compatible with viral delivery systems. Much effort has also been made to develop Cas9, Cas13a and Cas13b applications for RNA-guided RNA targeting. The discovery of new RNA-targeting CRISPR-Cas systems as well as the development of RNA-targeting platforms with Cas9 and Cas13 will promote RNA-targeting technology substantially. Here, we review new advances in RNA-targeting CRISPR-Cas systems as well as advances in applications of these systems in RNA targeting, tracking and editing. We also compare these Cas protein-based technologies with traditional technologies for RNA targeting, tracking and editing. Finally, we discuss remaining questions and prospects for the future.

簇状规则间隔的短回文重复序列（CRISPR）/ CRISPR相关蛋白（Cas）系统，尤其是II型（Cas9）系统，已广泛用于基因/基因组靶向。Cas9的修改使这些系统成为精确DNA操作的平台。然而，CRISPR-Cas系统在RNA靶向中的应用仍是初步的。VI型CRISPR-Cas系统（Cas13）的发现阐明了RNA引导的RNA靶向。Cas13d是最小的Cas13蛋白，仅约930个氨基酸，是与病毒递送系统兼容的RNA靶向平台。在开发用于RNA引导的RNA靶向的Cas9，Cas13a和Cas13b应用方面也付出了很多努力。新的靶向RNA的CRISPR-Cas系统的发现以及带有Cas9和Cas13的RNA靶向平台的开发将大大促进RNA靶向技术的发展。在这里，我们回顾了RNA靶向CRISPR-Cas系统的新进展以及这些系统在RNA靶向，跟踪和编辑中的应用进展。我们还将这些基于Cas蛋白质的技术与用于RNA靶向，跟踪和编辑的传统技术进行了比较。最后，我们讨论剩下的问题和未来的前景。跟踪和编辑。最后，我们讨论剩下的问题和未来的前景。跟踪和编辑。最后，我们讨论剩余的问题和未来的前景。