2025-08-18 イェール大学
<関連情報>
- https://news.yale.edu/2025/08/18/risk-management-making-gene-therapy-safer-and-more-effective
- https://www.cell.com/cell/abstract/S0092-8674(25)00854-2
IscBとCas9をRNA誘導型RNAエディターへ変換 Conversion of IscB and Cas9 into RNA-guided RNA editors
Chengtao Xu ∙ Xiaolin Niu ∙ Haifeng Sun ∙ Hao Yan ∙ Weixin Tang ∙ Ailong Ke
Cell published:August 18, 2025
DOI:https://doi.org/10.1016/j.cell.2025.07.032
Graphical abstract
Highlights
- Removal or disruption of the TID domain converts IscB to an RNA editor
- R-IscB has comparable activity to Cas13 but lacks discernible cytotoxicity
- R-IscB is robust in splicing perturbation, A-to-I editing, and trans-splicing
- The same approach converts several Cas9s to efficient RNA editors
Summary
RNA-guided RNA editing represents an attractive alternative to DNA editing. However, the prevailing tool, CRISPR-Cas13, has collateral RNA cleavage activity that causes undesirable cytotoxicity in human cells. Here, we report an ultracompact RNA-editing platform engineered from IscB, which has comparable or higher activity than Cas13 but without cytotoxicity concerns. We show that IscB, the evolutionary ancestor of Cas9, has an intrinsic affinity for complementary single-stranded (ss)DNA and RNA. This activity becomes dominant when its double-stranded DNA binding activity is switched off through the deletion of its target-adjacent motif domain. The resulting R-IscB is comparable to or better than Cas13, can efficiently alter splicing outcomes in human cells, and can further mediate trans-splicing to correct any mutation at the mRNA level. R-IscB also drives efficient A-to-I editing on mRNA when fused to adenosine deaminase acting on RNA 2 (ADAR2) and mediates cleavage-based mRNA knockdown upon HNH engineering. Finally, we show that the same approach converts some Cas9s to RNA-targeting tools.
