Improving adenine base editing precision by enlarging recognition domain of CRISPR-Cas9 p2

The natural-evolution-like giant SpCas9 (GS-Cas9) was created and showed a substantial improvement of editing precision. We further find that enlarging the REC domain could enable regulation of the N-terminal adenine deaminase TadA8e tethered to the Cas9 scaffold, which contributes to substantially reducing bystander editing and improving the precision of the adenine base editor ABE8e.