A loxP site and FRT flanked neo cassette were inserted in intron 1 and an arginine to stop (p.Arg102*; c.304 CGG>TGA) mutation was inserted in exon 2 via homologous recombination. Flp-mediated recombination removed the neo cassette. Western blot analysis indicated lack of expression in whole brain lysates from homozygous mice. (J:268565)