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bioRxiv · 10.1101/2021.12.18.473271

High-fidelity Cas13 variants for targeted RNA degradation with minimal collateral effect

Abstract

CRISPR-Cas13 systems have recently been employed for targeted RNA degradation in various organisms. However, collateral degradation of bystander RNAs has imposed a major barrier for their in vivo applications. We designed a dual-fluorescent 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. Importantly, high-fidelity Cas13 variants show comparable RNA knockdown activity with wild-type Cas13 but no detectable collateral damage in transgenic mice and adeno-associated virus-mediated somatic cell targeting. Thus, high-fidelity Cas13 variants with minimal collateral effect are now available for targeted degradation of RNAs in basic research and therapeutic applications.

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BibTeXRIS

Tong, H., Huang, J., Xiao, Q., He, B., Dong, X., Liu, Y., Yang, X., Han, D., Wang, Z., Ying, W., Zhang, R., Wei, Y., Wang, X., Xu, C., Zhou, Y., Li, Y., Cai, M., Wang, Q., Xue, M., Li, G., Fang, K., Zhang, H., Yang, H.. 2021-12-23. High-fidelity Cas13 variants for targeted RNA degradation with minimal collateral effect. https://doi.org/10.1101/2021.12.18.473271

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