中国科学院脑科学与智能技术卓越中心杨辉课题组开发出用于靶向 RNA 降解、附带影响最小的高保真 Cas13 变体。2022年8月11日，国际知名学术期刊《自然—生物技术》发表了这一成果。

他们设计了一个双荧光报告系统，用于检测哺乳动物细胞中的附带效应和筛选 Cas13 变体。 在 200 多种工程变体中，包括 Cas13d 和 Cas13X 在内的几种 Cas13 变体表现出有效的靶向活性，但附带活性显著降低。

此外，这些变体不存在由 Cas13 诱导的转录组范围的脱靶和细胞生长停滞。高保真 Cas13 变体显示出与野生型 Cas13 相似的 RNA 敲低活性，但在转基因小鼠或腺相关病毒介导的体细胞靶向中没有可检测到的附带损伤。因此，具有最小附带效应的高保真 Cas13 变体现在可用于基础研究和治疗应用中的 RNA 靶向降解。

据悉，CRISPR–Cas13 系统最近已被用于各种生物体中的靶向 RNA 降解。然而，旁观者 RNA 的附带降解限制了它们在体内的应用。

附：英文原文

Title: High-fidelity Cas13 variants for targeted RNA degradation with minimal collateral effects

Author: Tong, Huawei, Huang, Jia, Xiao, Qingquan, He, Bingbing, Dong, Xue, Liu, Yuanhua, Yang, Xiali, Han, Dingyi, Wang, Zikang, Wang, Xuchen, Ying, Wenqin, Zhang, Runze, Wei, Yu, Xu, Chunlong, Zhou, Yingsi, Li, Yanfei, Cai, Minqing, Wang, Qifang, Xue, Mingxing, Li, Guoling, Fang, Kailun, Zhang, Hainan, Yang, Hui

Issue&Volume: 2022-08-11

Abstract: CRISPR–Cas13 systems have recently been used for targeted RNA degradation in various organisms. However, collateral degradation of bystander RNAs has limited their in vivo applications. Here, we design a dual-fluorescence reporter system for detecting collateral effects and screening Cas13 variants in mammalian cells. Among over 200 engineered variants, several Cas13 variants including Cas13d and Cas13X exhibit efficient on-target activity but markedly reduced collateral activity. Furthermore, transcriptome-wide off-targets and cell growth arrest induced by Cas13 are absent for these variants. High-fidelity Cas13 variants show similar RNA knockdown activity to wild-type Cas13 but no detectable collateral damage in transgenic mice or adeno-associated-virus-mediated somatic cell targeting. Thus, high-fidelity Cas13 variants with minimal collateral effects are now available for targeted degradation of RNAs in basic research and therapeutic applications.

DOI: 10.1038/s41587-022-01419-7

Source: https://www.nature.com/articles/s41587-022-01419-7