A motif preferred adenine base editor with minimal bystander and off-targets editing

48% of hereditary disease are caused by single C-to-T base conversion, efficient A-to-G base editing tools (ABEs) are very potential tools for the treatment of these diseases. However, the existing efficient ABE, while catalyzing A-to-G conversion, will bring more A and C bystander editing and off-target events, which raises safety concerns especially in clinical disease treatment. Here, we generated ABE8e with A48E (named ABE8e-YA) for efficient and accurate editing As in YA motifs with YAY>YAR (Y=T or C, R=A or G) hierarchy through structure-oriented rational design. Compared with ABE3.1, the only motif (YAC) preference ABE version, ABE8e-YA exhibited A-to-G editing efficiency improvement with average up to 3.1-fold in indicated YA motif while maintaining eliminated bystander Cs editing and minimized DNA or RNA off-target. Also, ABE8e-YA corrected pathogenic mutation with high efficiency and precision in human cells. Moreover, by ABE8e-YA, we efficiently and precisely enabled the generation of hypocholes-terolemia and tail-loss mouse models for mimic human associated disease and mouse PCSK9 base editing in vivo for hypercholesterolemia gene therapy, indicating their great potential in broad applications for and disease modeling and gene therapy.