Characterization and location of myc homologous sequences in human cytomegalovirus DNA

Specific DNA fragments from human cytomegalovirus (HCMV) strains Towne and AD169 exhibited homology to myc DNA sequences under hybridization conditions corresponding to a 22-28% base mismatch. In a specific subset of hybridizing HCMV fragments, the homology was restricted to the 5' half of viral v-myc and the 5' half of human c-myc. No hybridization was observed between HCMV fragments and the 3' v-myc and 3' human c-myc probes. In Towne DNA, myc homologous sequences mapped in four regions within the long unique segment (0.070-0.094, 0.134-0.156, 0.454-0.470, and 0.591-0.605 map unit) and one region in each of the short terminal repeats (0.832-0.847 and 0.984-1.0 map unit). In strain AD169, myc homology mapped in three regions within the long unique segment (0.123-0.147, 0.174-0.198, and 0.583-0.606 map unit) and one region in each of the short terminal repeats (0.833-0.863 and 0.976-1.0 map unit). By utilizing probes specific for the 5' and 3' portions of v-myc and human c-myc, we established that the regions of homology in a specific subset of HCMV restriction fragments corresponded to the 5' half of myc and were not due to MC29 viral helper sequences, flanking cellular sequences, or binding of probe to G-C-rich DNA.