The rat is the preferred animal model in many areas of biomedical research and 
drug development. Genetic manipulation in rats has lagged behind that in mice 
due to the lack of efficient gene targeting tools. Previously, we generated a 
knockout rat via conventional homologous recombination in rat embryonic stem 
(ES) cells. Here, we show that efficient gene targeting in rat ES cells can be 
achieved quickly through transcription activator-like effector nuclease 
(TALEN)-mediated DNA double-strand breaks. Using the Golden Gate cloning 
technique, we constructed a pair of TALEN targeting vectors for the gene of 
interest in 5 days. After gene transfection, the targeted rat ES cell colonies 
were isolated, screened, and confirmed by PCR without the need of drug 
selection. Our results suggest that TALEN-mediated gene targeting is a superior 
means of establishing genetically modified rat ES cell lines with high 
efficiency and short turnaround time.