Retroviral transduction of 5-FU–selected bone marrow cells. (A) Schematic of experimental plan for analysis of retroviral transduction of 5-FU–selected bone marrow cells. (B) PCR analysis of 5-week LTC-IC–derived colonies plated in semisolid media. Individual colonies arising from 5-FU–selected cells plated in 5-week long-term cultures were picked into separate tubes and the genomic DNA subjected to PCR with primers specific for the retroviral genome. The PCR products were separated by electrophoresis on 2% agarose gels, stained with ethidium bromide, and visualized under ultraviolet light. Lanes 1 through 11, colonies picked from semisolid media, following transduction on 1MI-▵SCF cell line; lane 0, DNA (1 μg) from AM12 cell line; lane C, DNA (1μg) from 1MI parent cell line; lane M,HindIII digest of phage λ DNA and HaeIII digest of phage ▹X174 DNA used as size markers. The arrow denotes the expected size of the PCR product specific to the p47^phox-containing retroviral genome.