Abstract:Adenovirus DNA replication was studied in a partially reconstituted system consisting of purified viral proteins (DNA-binding protein, precursor terminal protein and Ad DNA polymerase) and a nuclear extract from uninfected HeLa cells. Optimal DNA replication required the presence of a heat-stable, ribonuclease-sensitive fraction from the cytosol of uninfected cells. This fraction stimulated the initiation about 3-fold and the replication of origin fragments 5–10-fold. Sedimentation analysis indicated the presence of a fast-sedimenting and a slow-sedimenting component which complemented each other. At least part of the stimulation was caused by low-molecular-mass RNA.