Human lactoferrin efficiently targeted into caprine beta-lactoglobulin locus with transcription activator-like effector nucleases

Asian-Australas J Anim Sci. 2017 Aug;30(8):1175-1182. doi: 10.5713/ajas.16.0697. Epub 2016 Dec 17.

Abstract

Objective: To create genetically modified goat as a biopharming source of recombinant human lacotoferrin (hLF) with transcription activator-like effector nucleases.

Methods: TALENs and targeting vector were transferred into cultured fibroblasts to insert hLF cDNA in the goat beta-lactoglobulin (BLG) locus with homology-directed repair. The gene targeted efficiency was checked using sequencing and TE7I assay. The bi-allelic gene targeted colonies were isolated and confirmed with polymerase chain reaction, and used as donor cells for somatic cell nuclear transfer (SCNT).

Results: The targeted efficiency for BLG gene was approximately 10%. Among 12 Bi-allelic gene targeted colonies, five were used in first round SCNT and 4 recipients (23%) were confirmed pregnant at 30 d. In second round SCNT, 7 (53%), 4 (31%), and 3 (23%) recipients were confirmed to be pregnant by ultrasound on 30 d, 60 d, and 90 d.

Conclusion: This finding signifies the combined use of TALENs and SCNT can generate bi-allelic knock-in fibroblasts that can be cloned in a fetus. Therefore, it might lay the foundation for transgenic hLF goat generation and possible use of their mammary gland as a bioreactor for large-scale production of recombinant hLF.

Keywords: Beta-lactoglobulin; Gene Targeted; Goat; Human Lacotoferrin; Nuclear Transfer; Transcription Activator-Like Effector Nucleases.