The targeting construct contains from 3'; to 5': a loxP-lox2272-CAG (in reverse orientation)-loxP-FRT-lox272-VIVIT peptide (MAGPHPVIVITGPHEE)-IRES-tdTomato-pA. An FRT-flanked neomycin cassette is a part of the construct. Flp-mediated recombination removed the neomycin cassette. (J:321772)