Efficient gene targeting by TAL effector nucleases coinjected with exonucleases in zygotes.

TAL Effector Nucleases (TALENs) are versatile tools for targeted gene editing in various species. However, their efficiency is still insufficient, especially in mammalian embryos. Here, we showed that combined expression of Exonuclease 1 (Exo1) with engineered site-specific TALENs provided highly efficient disruption of the endogenous gene in rat fibroblast cells. A similar increased efficiency of up to ~30% with Exo1 was also observed in fertilized rat eggs, and in the production of knockout rats for the albino (Tyr) gene. These findings demonstrate TALENs with Exo1 is an easy and efficient method of generating gene knockouts using zygotes, which increases the range of gene targeting technologies available to various species.