A loxP site was inserted upstream of exon 2. An FRT-flanked neomycin resistance cassette with a 5' loxP site was inserted downstream of exon 8. Flp-mediated recombination removed the selection cassette. Cre-mediated recombination removed exons 2 through 8. Western blot analysis confirmed the absence of protein expression in the brain. (J:204591)