Fig. 1.

Structure of ZFNs. Schematic representation of ZFNs bound to their target sites. These nucleases are created by fusing an engineered ZF DNA binding domain to the DNA cleavage domain of the FokI type IIS restriction enzyme. An array of 3 ZFs (shaded ovals) for each ZFN protein will recognize a target sequence on DNA (shaded boxes). The binding of two ZFNs on the target DNA with a spacer (5/6 bp) in the middle will trigger the dimerization of the ZFN nuclease domains and the cleavage of the target DNA