A loxP site was inserted between exons 1 and 2. An FRT-flanked neomycin resistance cassette with a loxP site was inserted between exons 7 and 8. Flp-mediated recombination remove the selection cassette. Cre-mediated recombination removed exons 2 through 7. Western blot analysis confirmed the absence of protein expression in primary hepatocytes. (J:236223)