 To assess this, the investigators will ChIP the chromatin prepared from virus infected cells with the origin specific primers and epitope specific antibodies as appropriate to detect origin loading of HBO1. the investigators will then re-Chip the ChIP precipitates using anti-H4 tetra-Ac antibodies to detect K5, K8, and K12 acetylation. In cells expressing E1A and HBO1, H4 acetylation will be increased considerably as compared to cells infected with HBO1 virus alone. H4 acetylation may be affected depending on the mutants used. 