FIG. 6.

RNase H1 impairs OriLyt-dependent plasmid replication. Wild-type pBluescript OriLyt plasmids were cotransfected with BZLF1 into ZKO-293 cells with an RNase H1 expression plasmid or control vector. Plasmids were recovered from cells, digested with (A and B) or without (C and D) HindIII and DpnI enzymes, and analyzed by Southern blotting. Three identical, independent experiments were conducted in each case. One representative experiment is shown for each (A and C). Relative plasmid amounts were quantified using quantitative Southern blotting (B and D). In the cases where enzymes were used, results were calculated as the DpnI-resistant signal over the DpnI-digested signal and were normalized to the value obtained for vector controls (B). In cases where no enzymes were used, results were calculated as replicating (top band) plasmid over supercoiled (bottom band) signal and normalized to the value obtained for vector controls (D). Data averages from all three identical, independent experiments are shown in each case, with error bars representing the standard deviations. Statistical significance was calculated using a two-tailed, unpaired t test. (E) Western blot assays were used to monitor Zta and BALF2 protein expression levels in all transfected cells.