Precise adenine base editors that exhibit minimized cytosine catalysis

To alleviate the ABE-mediated cytosine editing activity, we engineered the commonly-used version of adenosine deaminase, TadA7.10. We found that the D108Q mutation also reduces cytosine deamination activity in two recently-developed versions of ABE, ABE8e and ABE8s, and has a synergistic effect with V106W, a key mutation that reduces off-target RNA editing. We conducted RNA-seq experiments for one control (nCas9 only) and five ABE variants (ABE8e, ABE8eW, ABE8eWQ, ABE8s, and ABE8sQ).