Enhanced expansion of human HPCs by AML1-ETO is polyclonal.

(A) Expansion of transduced, GFP-sorted cells over a 5-week culture period in cytokines. Cell numbers were counted weekly by trypan blue dye exclusion. (B) Immunofluorescent staining of MIGR1-AE–transduced cells for the presence of the fusion protein determined on the basis of detection of the HA epitope. Cells were counterstained with DAPI to identify the nucleus. Magnification is 600×. (C) Southern blot analysis of DNA obtained from MIGR1-AE cells growing in the week-4 culture depicted in panel A. Ten micrograms of genomic DNA was digested with BamHI, which cuts at a single site in the MIGR1-AML1-ETO virus. The full-length GFP cDNA was used as a probe. The membrane was then stripped and rehybridized for the presence of intact DNA with the use of a β-actin probe (data not shown).