title: Intracellular forms of adenovirus DNA. 3. Integration of the DNA of adenovirus type 2 into host DNA in productively infected cells.
abstract: KB cells productively infected with human adenovirus type 2 contain an alkalistable class of viral DNA sedimenting in a broad zone between 50 and 90S as compared to 34S for virion DNA. This type of DNA is characterized as viral by DNA-DNA hybridization. It is extremely sensitive to shear fragmentation. Extensive control experiments demonstrate that the fast-sedimenting viral DNA is not due to artifactual drag of viral DNA mechanically trapped in cellular DNA or to association of viral DNA with protein or RNA. Furthermore, the fast-sedimenting DNA is found after infection with multiplicities between 1 and 1,000 PFU/cell and from 6 to 8 h postinfection until very late in infection (24 h). Analysis in dye-buoyant density gradients eliminates the possibility that the fast-sedimenting viral DNA represents supercoiled circular molecules. Upon equilibrium centrifugation in alkaline CsCl density gradients, the fast-sedimenting viral DNA bands in a density stratum intermediate between that of cellular and viral DNA. In contrast, the 34S virion DNA isolated and treated in the same manner as the fast-sedimenting DNA cobands with viral marker DNA. After ultrasonic treatment of the fast-sedimenting viral DNA, it shifts to the density positions of viral DNA and to a lesser extent to that of cellular DNA. The evidence presented here demonstrates that the 50 to 90S viral DNA represents adenovirus DNA covalently integrated into cell DNA.
mesh_terms: D000256:Adenoviridae; D002250:Carbon Radioisotopes; D002277:Carcinoma; D002460:Cell Line; D002499:Centrifugation, Density Gradient; D002501:Centrifugation, Zonal; D004273:DNA, Neoplasm; D004279:DNA, Viral / Q000096:biosynthesis; D005561:Formates; D009062:Mouth Neoplasms; D009693:Nucleic Acid Hybridization; D013936:Thymidine; D013997:Time Factors; D014316:Tritium
chemical_list: D002250:Carbon Radioisotopes; D004273:DNA, Neoplasm; D004279:DNA, Viral; D005561:Formates; D014316:Tritium; D013936:Thymidine