Application of Zinc Finger Nucleases in Genome Targeting Modification

The homologous recombination and viral-mediated gene transfer are two commonly used methods in animal genome engineering.The extreme low efficiency and poor specificity hampered their application in generation of transgenic animals and human gene therapy.The newly developed technology,zinc finger nucleases(ZFNs) targeted genome engineering,shows promise in improving the efficiency of gene targeting by introducing DNA double-strand breaks(DSB) in target genes,which then stimulate the cell's endogenous homologous recombination(HR) machinery.Custom-designed zinc finger nucleases(ZFNs) —proteins designed to cut at specific DNA sequences-combine the non-specific cleavage domain(N) of FokI restriction endonuclease with zinc finger proteins(ZFPs).Recent results showed that ZFNs could be used to create targeting frequencies of up to 20% in a human disease-causing gene.Thus ZFN-mediated gene targeting offers molecular biologists with the ability to site-specifically and permanently alter not only plant and mammalian genomes,but also many other organisms by stimulating HR via a targeted genomic DSB.ZFNs technology will exert profound effect on genome engineering,particularly in human gene therapy.