Gene knockout of Tiki1 gene in rabbit by TALEN system

Objective  To obtain a rabbit model of Tiki1 gene knockout by the transcription activator-like effector nuclease (TALEN) system, and provide a rabbit model for investigating the mechanism of Tiki1 gene on early development of animals.

Method  Using TALEN system, the target vector of rabbit Tiki1 gene was constructed and then 10 or 50 ng/μL Tiki1-TALEN mRNA was injected into the cytoplasm of fertilized eggs at pronuclear stage. Embryos developed to blastocyst stage were collected. The blastocyst rate and gene modification efficiency were investigated. To further obtain Tiki1 knockout rabbits, 50 ng/μL Tiki1-TALEN mRNA was subsequently injected into the cytoplasm of 17 prokaryotic fertilized eggs of rabbit, and then the fertilized eggs were transplanted into two recipient rabbits.

Result  The blastocyst rate of the treatment group injected with 50 ng/μL Tiki1-TALEN mRNA（64%) was almost the same as that of the group injected with 10 ng/μL Tiki1-TALEN mRNA(57%), while the blastocyst gene modification efficiency of the group injected with 50 ng/μL Tiki1-TALEN mRNA(100%) was significantly higher than that of the group injected with 10 ng/μL Tiki1-TALEN mRNA (14.3%). The sequencing results showed that mutations of Tiki1 gene ranged from the deletion of 1 bp to 28 bp. A total of three rabbits were born after embryo transfer, and two of them were detected with genetic mutations.

Conclusion  The TALEN technology system established in this study could effectively knock out Tiki1 gene in rabbit.