The targeting construct introduced the mutations W155A in exon 5 and W250A in exon 7 and a P2A_zsGreen immediately prior to the STOP codon. Both W to A mutations were made by mutating a Trp codon TGG to the Ala codon GCC. Exons 5, 6 and 7 and the P2A-zsGreen gene are also all flanked by a pair of loxP sites, thus allowing for the generation of a global or cell type specific knockout of the mutant protein following appropriate Cre expression. (J:342817)