A floxed neo cassette was inserted into intron 27. Exon 28 was replaced with a modified exon 28 in wich nucleotide substitution results in the amino acid substitution of histidine for tyrosine at position 1229 (Y1229H) in the ankyrin-binding site (FIGQY1229). Cre-mediated recombination removed the neo cassette. (J:131051)