Exon 24, the last coding exon of the gene, encodes the transmembrane region of the protein as well as the cytoplasmic C-terminal. A 2xHA (hemagglutinin) tag followed by a loxP site was inserted in-frame into exon 24. A second loxP site was placed after the stop codon, immediately followed by an FRT-flanked PGK-neomycin resistance cassette. (J:279669)