A cassette, comprised of a LoxP site, adenovirus splice acceptor, porcine teschovirus-1 2A (P2A) site, EGFP coding sequence, 3 copies of SV40 polyadenylation sequence (Stop), FRT site, and another LoxP site was inserted into intron 17. The sequence of the guide RNA (gRNA) was 5- GTCGTGCCTTACGTAGCTGGG- 3. (J:308040)