TALEN (transcription-activator-like effector nuclease) technology has revolutionized the array of genome modifications in biotechnology and biomedical research. TALEN are restriction enzymes made by fusing a TAL effector DNA-binding domain to a DNA cleavage domain in a nuclease, which can create a site-specific double-stranded DNA break. Subsequently, the dsDNA break is repaired by cellular machinery and then creates a deletion mutation or a knock-in site for introducing site-specific DNA sequences of interest.