The DNA-binding domain in ZFNs is made up of zinc finger motifs, which can be engineered to recognize specific DNA sequences. The DNA-cleaving domain is typically derived from the FokI restriction enzyme, which cuts the DNA when dimerized. When a pair of ZFNs binds to adjacent DNA sequences, the FokI domains dimerize and create a double-strand break. This break is then repaired by the cell's natural DNA repair mechanisms, either through non-homologous end joining (NHEJ) or homologous recombination (HR).
