A loxP site was inserted upstream of exon 5. An FRT-flanked neo cassette with a 5' loxP site was inserted downstream of exon 7. Flp-mediated recombination removed the neo cassette and left exons 5 through 7 floxed. Cre-mediated recombination removed exons 5 through 7. Western blot analysis confirmed the absence of protein expression in the spinal cord, brain and sciatic nerve. (J:177468, J:194977)