Etoposide does not significantly alter the ability of E1, E2 or TopBP1 to be recruited to the origin. C33a cells were transfected with 1 µg pOriLacZ, 1 µg E1 and 1 µg E2, in the presence or absence of 5 µM etoposide. Forty eight hours post-transfection, cells were cross-linked, harvested and lysed, and chromatin was sheared via sonication. One hundred micrograms of chromatin were used per antibody. The chromatin, bead and antibody slurry was incubated with rotation at 4 °C overnight. The following day, beads were washed and chromatin prepared. TaqMan qPCR using the pOri primer and probe set was used to quantify the levels of (A) E1(HA), (B) E2 and (C) TopBP1 at the HPV origin of replication. qPCR data are presented as the fold from three replicate experiments.