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

Here we show that through fusion of cytidine and adenine deaminases with Cas9n, a novel cytidine-adenine base editor (ACBE) was developed. ACBE is able to generate C>T and A>G conversions in the same allele. Moreover, ACBE showed much higher (up to 14-fold) editing activity of cytidine deaminase with similar activity for adenine conversion compared to CBE and ABE respectively.