Increase base editing efficiency and product variety through fusion of Cas9 nickase to cytosine and adenosine deaminases

Though fusion of Cas9 nickase to either cytidine or adenine deaminase, base editors efficiently catalyze site-specific nucleotide conversions with minimal indel rates. However, both CBE and ABE can only generate base conversion on single nucleotide type. Through fusion of cytidine and adenine deaminases with Cas9n, we developed a novel cytidine-adenine base editor (ACBE) which efficiently edits cytidine and adenine nucleotides in the same allele with increased editing efficiency and products variability.