Base editing involves a fusion of nuclease-deficient Cas9 (dCas9) or Cas9 nickase with a deaminase enzyme. The dCas9 or nickase guides the complex to a specific DNA sequence, where the deaminase chemically alters a targeted base. For example, cytosine base editors (CBEs) can convert a cytosine (C) to a thymine (T), and adenine base editors (ABEs) can convert an adenine (A) to a guanine (G).
