Disease-onset kinetics and clonal patterns of B-ALL derived from wild-type versus p19^ARF-null pro-B cells. Pro-B cells from wild-type and p19^ARF-null bone marrow were flow sorted and transduced with vectors coexpressing p210BCR/ABL and EGFP, followed by transplantation into sublethally irradiated wild-type recipients. (A) Kaplan-Meier analysis of survival for the recipients of p19^ARF-null (solid line) and wild-type (dashed line) proB cells. (B) Peripheral blood from recipients of p19^ARF-null (solid lines, closed symbols) and wild-type (dashed lines, open symbols) proB cells were sampled starting on approximately 10 to 14 days after transplantation and continued approximately every 5 to 10 days until the mice succumbed to B-ALL. The percentage of EGFP⁺ leukocytes was measured by flow cytometric analysis. (C) Spleen DNA of naive control (lane 1), 5 recipients of p19^ARF-null proB (lanes 2-6) and 4 recipients of wild-type pro-B (lanes 7-10) was digested with EcoRI and hybridized with an EGFP probe for Southern blot analysis to reveal the proviral integration pattern.