Figure 3.

Induction of hygromycin resistance in MEF p53^−/− cells. (A) MEF or MEF p53^−/− cells were cultured with apoptotic bodies from REF or EGFP-Hyg^r expressing REFrm cells. Coomassie staining of hygromycin-resistant MEF p53^−/− colonies cultured with REFrm apoptotic bodies is shown. (B) PCR detection of the hyg^r gene in donor REFrm (rm), REF, recipient MEF p53^−/− (p53-), and the hygromycin-resistant REFrm × MEF p53^−/− colonies (1–5). (C) Detection of the Hyg^r-GFP fusion protein in MEF p53^−/− recipient cells, REFrm donor cells, and hygromycin-selected REFrm × MEF p53^−/− clones C8 and C12. (Bar = 10 μm.) (D) Detection of the hyg^r gene in foci induced by cultivation of REFrm apoptotic bodies with MEF p53^−/− cells. Approximately 60% of the foci were Hyg^r -positive without hygromycin selection. The Hyg^r gene could be maintained for over 4 weeks in the presence of hygromycin selection. Positive and negative controls were the same as in B.