Analysis and minimization of cellular RNA editing by DNA adenine base editors
Key Finding
Discovered that ABEmax generates low but widespread off-target RNA editing (~15,000 A-to-I edits across transcriptome). Developed V106W mutation in TadA* deaminase that reduces RNA editing 7.2-fold while maintaining DNA editing efficiency. ABEmaxAW (TadA E59A + TadA* V106W) provides 2.7-fold improvement in off-target DNA editing and 3.7-fold reduction in indel formation. Both wild-type TadA and evolved TadA* contribute to RNA editing, requiring mutations in both domains for optimal specificity. V106W acts by sterically blocking accommodation of RNA 2'-hydroxyl groups, decoupling DNA and RNA editing activities.