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Updated: Apr 10, 2026

Substrate Generation for Endonucleases of CRISPR/Cas Systems
Published on: September 8, 2012
Molecular basis of target RNA cleavage by Cas13
Joe K C Lam1, Summerloretta S K Leung1, Jason Ying Ki Li1
1School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China.
Abstract:
RNA-targeting CRISPR-Cas13 enzymes are robust RNA knockdown tools with both on-target and collateral cleavage activities. However, to date, the in vivo RNA cleavage mechanisms remain poorly understood. Here, we combine in vitro and in vivo methods to elucidate the exact cleavage sites of Cas13. We reveal that some subtypes of Cas13, including Cas13b and Cas13bt, cleave the target RNA at predominant positions, and rational engineering of Cas13 further improves precision. Building on these findings, we develop RNA segment editing (RSE), a targeted RNA cleavage and repair method, to restore dysfunctional RNA in cells. We anticipate that RSE will enable precision RNA engineering for therapeutics and basic research.
Insights
CRISPR-Cas13 enzymes precisely cleave RNA targets in vivo. This research elucidates Cas13 cleavage mechanisms and develops RNA Segment Editing (RSE) for precise RNA repair and engineering.
Area of Science:
- Molecular Biology
- Biotechnology
- Genetics
Background:
- RNA-targeting CRISPR-Cas13 enzymes offer potent RNA knockdown capabilities.
- However, their in vivo RNA cleavage mechanisms are not fully understood.
- Understanding these mechanisms is crucial for advancing RNA-based technologies.
Purpose of the Study:
- To elucidate the precise in vivo RNA cleavage sites of CRISPR-Cas13 enzymes.
- To engineer Cas13 subtypes for improved cleavage precision.
- To develop a novel RNA repair method based on precise cleavage.
Main Methods:
- Combined in vitro and in vivo experimental approaches.
- Characterization of cleavage site specificity for Cas13 subtypes (e.g., Cas13b, Cas13bt).
- Rational engineering of Cas13 enzymes to enhance cleavage accuracy.
Main Results:
- Identified predominant cleavage positions for specific Cas13 subtypes.
- Demonstrated that rational engineering significantly improves Cas13 cleavage precision.
- Developed RNA Segment Editing (RSE) for targeted RNA cleavage and repair.
Conclusions:
- Cas13 subtypes exhibit specific in vivo RNA cleavage patterns.
- Engineered Cas13 variants offer enhanced precision for RNA targeting.
- RNA Segment Editing (RSE) presents a promising tool for precision RNA engineering in therapeutics and research.
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