Plasmid design and construction
Standard cloning techniques were used to construct a recombinant plasmid. LP was designed where Lox5171/LoxP sites flanked mCherry followed by CMV promotor-driven thymidine kinase (TK ) gene (Fig. 1A). The LP also contained the 5′ homologous arm (HA) (0.2 kb region of exon 1 in Fer1L4 present before the transcription start site) and 3′ HA (0.2kb region of exon 1 in Fer1L4 present after the transcription start site) (Fig. 1A). TV was designed where Lox5171/LoxP sites flanked GFP followed by SV40 promoter-driven neomycin resistance gene (Fig. 1B). Cre recombinase expressing plasmid is composed of SV40 promoter-driven Cre gene.