Pre-B cells up-regulate Arf in response to BCR-ABL expression. (A) expression of Arf relative to β-Actin was assessed by qPCR at 120 hours after transduction with a retrovirus encoding either GFP or BCR-ABL/GFP. The results are pooled from 2 independent experiments, and reactions for each experiment were run 2 to 4 times. (B) Frequency of apoptotic BCR-ABL/GFP–transduced pre-B cells and pro-B cells at 72 hours (gray shaded area) and 96 hours (area under dashed line) after transduction. Apoptosis was measured by annexin V staining. (C) Number of BCR-ABL/GFP–expressing pro-B and pre-B cells harvested from cultures at 40, 48, 72, and (in an independent experiment) 96 hours after culture initiation. Dashed horizontal line indicates the number of cells (105) used to initiate cultures.
