CRISPR-associated Cas12 proteins are a highly variable collection of nucleic acid-targeting proteins. All Cas12 variants use RNA guides and a single nuclease domain to target complementary DNA or, in rare cases, RNA. The high variability of Cas12 effectors can be explained by a series of independent evolution events from different transposon-associated TnpB-like ancestors. Despite basic structural and functional similarities, this has resulted in unprecedented variation of the Cas12 effector proteins in terms of size, domain composition, guide structure, target identity and interference strategy. In this Review, we compare the unique molecular features of natural and engineered Cas12 and TnpB variants. Furthermore, we provide an overview of established genome editing and diagnostic applications and discuss potential future directions.

CRISPR 相关 Cas12 蛋白是高度可变的核酸靶向蛋白集合。所有 Cas12 变体都使用 RNA 向导和单个核酸酶结构域来靶向互补 DNA，或者在极少数情况下靶向 RNA。Cas12 效应子的高变异性可以用来自不同转座子相关 TnpB 样祖先的一系列独立进化事件来解释。尽管基本的结构和功能相似，但这导致 Cas12 效应蛋白在大小、结构域组成、向导结构、靶标身份和干扰策略方面发生了前所未有的变化。在这篇综述中，我们比较了天然和工程化 Cas12 和 TnpB 变体的独特分子特征。此外，我们概述了已建立的基因组编辑和诊断应用，并讨论了潜在的未来方向。