Abstract

The therapeutic application of base editors is limited by their large sizes, which are beyond the packaging capabilities of adeno-associated viral (AAV) vectors. Despite recent progress that has identified many compact CRISPR proteins, the resulting miniature base editors often exhibit reduced activities and limited targeting scope. Here, we introduce a zinc finger protein (ZFP)-enhanced miniature base editor (zmBE), which integrates programmable ZFPs to improve efficiencies and targeting scopes of miniature base editors, including those based on Un1Cas12f1 and OgeuIscB. Utilizing protein language models to optimize ZFPs designed by modular assembly further simplifies the development of zmBEs. Leveraging these methodologies, we engineer a zmBE that effectively induces the SMN2 exon 7 T:A(6) > C:G conversion, restores the exon 7 inclusion, and improves spinal muscular atrophy in a murine model after being delivered via a single AAV vector. Our study provides a versatile platform for developing miniature base editors for in vivo therapeutic applications.