Abstract: Nucleic acid molecules, compositions, recombinant AAV (rAAV) particles, kits, and methods are described herein for delivering a base editor (or “nucleobase editor”) to cells, e.g., via AAV vectors. In particular, the disclosure provides compositions, methods, and uses for delivery of adenine base editors and cytosine base editors in a single AAV vector (or genome). Further described herein are improved AAV vectors containing size-minimized regulatory components that enable, e.g., the packaging of base editors. Provided herein are methods and compositions for delivering base editor proteins to a cell or tissue in a single recombinant AAV (rAAV) vector. Contemplated herein are improved methods and compositions for delivering these base editors in vivo, in a single rAAV particle. Further provided herein are base editors and compositions and cells comprising these base editors.

Abstract: The present disclosure provides Cas9 variants, and base editors comprising these variants, that recognize non-canonical protospacer adjacent motifs (PAMs) and have less restrictive PAM requirements for editing. The present disclosure provides Cas9 protein variants comprising one or more amino acid substitutions relative to wild-type Nme2Cas9. Fusion proteins comprising the Cas protein variants described herein are also provided by the present disclosure. Further provided herein are methods for editing a target nucleic acid using the Cas variants and fusion proteins provided herein. The present disclosure also provides guide RNAs, complexes, polynucleotides, cells, kits, and pharmaceutical compositions. Further described herein are phage-assisted continuous evolution (PACE) systems, vectors, methods, and devices.

Abstract: The present disclosure provides improved adenosine base editors (ABE) that have an expanded range of PAM sequence recognition capability (i.e., recognition of non-canonical ?5-NGG-?3 PAM sequence). In addition, the present disclosure provides improved cytidine base editors (CBE) and adenosine base editors (ABE) comprising circular permutant variants of Cas9 (CP-Cas9) with an increased window of base editing within the protospacer sequence (e.g., from about 4-5 nucleotides to up to about 8-9 nucleotides) and even outside of the protospacer sequence.