The detection of JC viral genome in owl monkey tumors

The JC viral genome is integrated into the cellular DNA of brain tumors from owl monkeys inoculated intracranially with JC virus 16-36 months prior to the development of the tumors. Normal brain tissue of the animals did not contain the viral genome. For at least two tumors, restriction endonuclease analysis of the tumor DNA indicates that there is a complete copy of the viral genome present. Integration of the genome in all but one of the tumors was at only one or only a limited number of sites, indicating a clonal origin for the tumors. In all but one of the tumors, there was tandem, head-to-tail integration of two or more copies of the JC genomes.