A loxP site was inserted upstream of exon 2 and a floxed neomycin selection cassette was inserted downstream of the exon. Exon 2 was removed by crossing founder mice with transgenic mice that express cre recombinase in the germline removed exon 2, and led to an out-of-frame mutation and the appearance of a stop codon within exon 3. Immunoblot analysis indicated a reduction in protein expression in heterozygote brain, and absence of protein in homozygote brain.