What specificity should be expected from a ZFN?
Due to the dimerization requirement of the FokI endonuclease, a pair of ZFNs is required to cause a double strand break. This strategy requires two different ZFNs to bind at the target site. Each ZFN recognizes a different 12-18 base pair target sequence, and these target sequences must be separated by 4-7 base pairs to allow formation of the catalytically active FokI dimer. These positional constraints drive a very high degree of specifi city.
Due to the dimerization requirement of the FokI endonuclease, a pair of ZFNs is required to cause a double strand break. This strategy requires two different ZFNs to bind at the target site. Each ZFN recognizes a different 12-18 base pair target sequence, and these target sequences must be separated by 4-7 base pairs to allow formation of the catalytically active FokI dimer. These positional constraints drive a very high degree of specificity.
