MX1 and leukemia: To this end, we designed two transplant models: (1) transduction of MLL-AF9 cDNA into control (Brd9fl/fl) or BRD9 null (Mx1-Cre;Brd9fl/fl) lineage (B220/CD3/Ter119/CD11b/Gr1)− cells followed by transplant into sublethally irradiated wildtype recipients and (2) transplant of MLL-AF9 leukemia cells in the background of Mx1-Cre;Brd9fl/fl followed by PBS or pIpC injection to deplete BRD9 after the disease development (Fig. 7a).