FIG. 2.

Products of the E1 and E2 viral ORFs are required for initial HPV-16 plasmid amplification. Replication of mutant HPV plasmids and complementation of HPV-16 E1 function in SCC13 cell transfections, using equimolar cotransfection of HPV-16 genomes as measured by Southern blotting, where ORI refers to the viral origin of replication. Relative replication was expressed as the increase over the normalized wt activity and quantified by scanning densitometry of detected DpnI-resistant HPV genomic fragments; shown are averages from two to three independent experiments. Fragments “A” and “B” were derived from their respective plasmid sources. Linearized HPV-16 genome (30 pg) was included as a positive blotting control.