Ectopic Bcl-2 expression does not enhance colony formation of c-Myb^f/d p210^BCR/ABL-transduced HSCs. (A) Expression of c-Myb–regulated genes in p210^BCR/ABL-transduced c-Myb^f/f and c-Myb^f/d progenitors. Western blot analysis of c-Myb, c-Myc, cyclin B1, and Bcl-2 expression in nontransduced and p210^BCR/ABL-transduced enriched Lin⁻ cells from c-Myb^f/f and c-Myb^f/d mice. Actin expression served as a control. (B) Colony formation of Bcl-2–transduced p210^BCR/ABL-expressing c-Myb^f/d progenitors. c-Myb^f/d Lin⁻Sca-1⁺Kit⁺ cells were transduced with the MigRI/p210^BCR/ABL retrovirus and 24 hours after retroviral transduction sorted for GFP expression. p210^BCR/ABL-expressing c-Myb^f/d Lin⁻Sca-1⁺Kit⁺ cells were subsequently transduced with a Bcl-2/MSCV/puro retrovirus or the empty MSCV/puro vector as a negative control. After 24 hours, cells (4 × 10⁴/plate) were plated in methylcellulose in the presence of puromycin (1 μg/mL). Colony formation was assessed 9 days later. Representative of 3 different experiments.