Exons 22 and 23 were floxed to create a premature stop at the C-teminus in the presence of cre recombinase. A Neo cassette and a 3rd loxP site were inserted within intron 23. Exons 22, 23 and the neo cassette were removed by cre-mediated recombination. Absence of protein in brain was confirmed by western blot and immunohistochemistry. (J:156578)