Proviral integration in leukemic mice. Southern hybridization analysis of genomic DNA from leukemic mice. All blots were hybridized with the IRES probe. (A) DNA was digested with XbaI, which has one recognition site within the LTRs of the MSCV AML1-ETO IRES GFP provirus. (B) The genomic DNA of BM cells from the mice that received a transplant of the AML1-ETO-transduced wild-type BM cells and wild-type C57BL/6 Ly5.1 recipient mice was digested with BamHI, which has one recognition site within the AML1-ETO gene of the MSCV AML1-ETO IRES GFP provirus. (C) The genomic DNA of BM and spleen cells from the primary leukemic mice and secondary recipients was digested with BamHI. BM indicates bone marrow cells; Sp, spleen cells.