The targeting vector is designed to replace exon 1 with a membrane-bound form of ovalbumin consisting of a fusion protein made up of the first 118 residues of the human transferrin receptor (which includes the cytoplasmic tail and signal/anchor domain) linked to residues 139-385 of the chicken ovalbumin gene (OVA), followed by a loxP-flanked neo cassette. Cre-mediated recombination removed the floxed neo cassette. (J:252604)