Exon 11 was replaced with a floxed neo cassette and a modified exon 11 in which the wild-type sequence is replaced with a TCTG insertion after the coding sequence nucleotide 8657 (c.854_857dupTCTG). This "conventional" mutation mimics the human mutation observed in patients with acute myeloid leukemia (AML;type A, c.860_863dupTCTG) without any "humanized" sequence. (J:194999)