Replication of adenovirus type 5 DNA in KB cells: Localization and fate of parental DNA during replication

The localization and fate of parental adenovirus type 5 (Ad5) DNA in KB cells at the time viral DNA replication occurs has been investigated by electron-microscope autoradiography and biochemical methods. At 18 hr after infection the majority of the parental Ad5 DNA molecules is present in the nucleus. About 60% of these molecules are involved in viral DNA replication by this time, but about 40% have not yet replicated at all. Electron-microscope autoradiography of cells infected with 3H-labeled Ad5 reveals that replicating parental Ad5 DNA molecules are randomly distributed throughout the nucleus, while nonreplicating viral DNA has a preference to locate in the periphery of the nucleus. Based on the experiments reported in this communication, the intranuclear fate of parental Ad5 DNA is discussed.