FIG. 3.

Southern blot analysis of coreplication of oriP and HPV-11 origin plasmids in human osteosarcoma 143 cells. p53 blocks replication of the papillomavirus origin but not EBV oriP. Episomal DNA was extracted at 48, 72, and 96 h posttransfection, digested with BamHI and DpnI, and probed with radiolabeled origin plasmid p7072-99. One microgram of oriP plasmid p994 and 250 ng of HPV-11 origin plasmid p7072-99 together with HPV-11 E1 and E2 expression plasmids pMT-E1 and pMT-E2 (1 μg of each) were transfected into the cells; 250 ng of wt or mutant p53 expression plasmid was added as indicated (lanes 2 to 6). Other lanes: oriP and HPV-11 ori, 200 pg of the marker plasmids linearized with BamHI; carrier, negative control with carrier DNA only; 1, positive control with no added p53.