Lysine codons 49 (AAG) and 50 (AAA) in exon 2 were changed to alanine (GCA) (p.49_50delKKinsAA) and a loxP site flanked neomycin resistance gene was inserted into intron 2. The mutations prevent ATP binding to the kinase and renders it kinase-dead. (J:224353, J:294106)