ZFN, TALEN, and CRISPR/Cas-based methods for genome engineering

• ZFNs, TALENs, and CRISPR/Cas-based RNA-guided DNA endonucleases are programmable site-specific nucleases.
• Site-specific nucleases induce DNA DSBs that stimulate NHEJ and HDR at targeted genomic loci.
• We discuss the therapeutic potential of site-specific nuclease technologies and discuss future prospects for the field.

Zinc-finger nucleases (ZFNs) and transcription activator-like effector nucleases (TALENs) comprise a powerful class of tools that are redefining the boundaries of biological research. These chimeric nucleases are composed of programmable, sequence-specific DNA-binding modules linked to a nonspecific DNA cleavage domain. ZFNs and TALENs enable a broad range of genetic modifications by inducing DNA double-strand breaks that stimulate error-prone nonhomologous end joining or homology-directed repair at specific genomic locations. Here, we review achievements made possible by site-specific nuclease technologies and discuss applications of these reagents for genetic analysis and manipulation. In addition, we highlight the therapeutic potential of ZFNs and TALENs and discuss future prospects for the field, including the emergence of clustered regulatory interspaced short palindromic repeat (CRISPR)/Cas-based RNA-guided DNA endonucleases.