Southern blot analysis of populations derived from single BCR-ABL–transduced +/+ and IL-3^−/− cells.

Genomic DNA was digested with EcoR1 and probed for GFP.EcoR1 cleaves once within the retroviral sequence (Figure1). Therefore, each fragment represents a unique site of retroviral integration. Lanes 1-5: 5 BCR-ABL–transduced IL-3^−/−clones; lanes 6-10: 5 BCR-ABL–transduced +/+ clones. Molecular size markers are also indicated. The same filter was stripped and reprobed with a BCR-ABL cDNA probe showing the full-length BCR-ABL cDNA in each line isolated (at bottom).