A loxP site was inserted into intron 2 and a loxP site flanked neomycin resistance gene cassette into intron 3. HA epitope sequence was added to the the 3' end of the coding region in exon 3. Exon 3 and the neo cassette were removed by cre-mediated recombination. Immunoblots of splenocytes failed to detect any protein. (J:160935)