Homology between mammalian cell DNA sequences and human herpesvirus genomes detected by a hybridization procedure with high-complexity probe.

Mouse and human DNA used as in vitro-labeled "high-complexity" probes revealed hybridization between specific herpesvirus DNA fragments on Southern transfers and repetitive sequences present at 10(3) to 10(5) copies per mammalian cell genome. Several different sites of major cell-virus sequence homology have been detected in both the herpes simplex virus type 1 and type 2 genomes, and these are located predominantly within the L and S inverted repeat regions and near the center of the L unique region. The hybrids persisted even in relatively stringent conditions, and appear to correlate closely with some of the previously recognized regions of size heterogeneity in the viral genome. Cloned viral DNA fragments from each site hybridized to different sets of discrete bands and dispersed elements within restriction-endonuclease-digested genomic DNA from a variety of vertebrate species. Localized cell-virus homology was also detected in both the human Epstein-Barr virus and cytomegalovirus genomes.