Figure 3.

Transcription activator-like effector nucleases (TALENs) are dimeric transcription factors/nucleases engineered from an array of 34-amino-acid molecules, each of which targets one nucleotide. The target sequence is recognized; a corresponding TALEN sequence is built and inserted into a cellular plasmid. The cellular plasmid is inserted into the host cell, where it is translated to produce the functional TALEN, which penetrates the nucleus and binds to and cleaves the target sequence. The applications of this system include the knockout of a target gene or the addition of a replacement nucleotide into the target gene.