Using CRISPR/Cas9 technology, a GSG linker, a T2A viral peptide, an iCre recombinase, and a bovine growth hormone polyadenylation signal (bPA) were inserted between the final Prokr2 codon and termination codon. The sgRNA target was cloned into the plasmid pX330. The circular pX330 plasmidand
circular donor plasmid were mixed and injected into the pronuclei of B6SJLF1 fertilized zygotes. Embryos were transferred to pseudopregnant B6D2F1 females to establish the mouse line.