Establishment of a rapid and scalable gene expression system in livestock by site-specific integration

► We established a gene replacement system in livestock somatic cells. ► The frt site was introduced into goat ColA1 locus by homologous recombination. ► The frt-tagged somatic cells were rejuvenated by embryo cloning. ► The GFP expression cassette was inserted in ColA1 locus by flp/frt recombination. ► The somatic cells undergoing gene replacement exhibited faithful GFP fluorescence.