A loxP site and rox-flanked PGK-Hygromycin/Zeocin cassette were targeted to intron 1. A 2A peptide, tdTomato cDNA, SV40 polyA cassette, FRT-flanked PGK-Neo cassette, loxP, splice acceptor, EGFP cDNA, and rabbit beta-globin poly adenylation cassette were targeted to exon 12 immediately before the stop codon.Dre- and Flp-mediated recombination excised the rox- and FRT-flanked antibiotic resistance cassettes. (J:341391)