A targeting construct was used to introduce a conditional knock-in to an exon 9 modulatory site (loxP-exon 9-FRT-Neo-FRT-loxP). The KK385-386AA (lysine to alanine) mutation represents an AAGAAG to GCCGCC sequence modification. Flp-mediated recombination removed the neomycin resistance cassette. (J:228551)