Cells from Booreana mice are resistant to transformation by AML oncogenes in vitro. (A) Bone marrow cells from WT and Booreana heterozygous but not Booreana homozygous mice form colonies in serial replating assays following transduction with AML oncogene-encoding retroviruses. Error bars represent standard deviation (SD) of four biological replicates; *P < .05 (Mann-Whitney U test). (B) AML oncogenes are unable to block differentiation of Booreana cells; these cells exhibit increased monocytic differentiation compared with transformed WT cells as seen on stained cytospin preparations.