Exon 41 was replaced with one containing GGG to TCA nucleotide substitutions which results in a glycine to serine change at amino acid 2019 (G2019S). A loxP and frt-flanked PGK-neomycin cassette were inserted into intron 41 and another loxP site was inserted in intron 42. Flp-mediated recombination removed the neomycin cassette. This is a gain-of-kinase function mutation. (J:234639)