Base editors are composed of a modified Cas9 enzyme fused to a deaminase enzyme. The Cas9 enzyme is engineered to nick only one strand of the DNA, while the deaminase carries out the specific base conversion. For instance, a cytosine base editor (CBE) can convert cytosine (C) to thymine (T), and an adenine base editor (ABE) can convert adenine (A) to guanine (G). This precise editing allows for the correction of point mutations at the DNA level.
