Analysis of cytomegalovirus genomes with restriction endonucleases Hin D III and EcoR-1

Cleavage of genomes of eleven human, one simian, and one simian-related cytomegalovirus (CMV) isolate by the restriction endonucleases HinD III and EcoR-1 generated reproducible DNA fragments. The size range of CMV DNA fragments as estimated by contour length measurements in comparison with simian virus 40 form II DNA and by coelectrophoresis with EcoR-1 fragments of herpes simplex virus DNA varied between 15 X 10(6) and 0.5 X 10(6) daltons. Comparison of the cleavage products of each isolate in 1% agarose slab gels showed extensive comigration of fragments among the human CMV isolates. In the HinD III digests, three fragment bands comigrated among all human CMV isolates, and six fragments comigrated among most, but not all, human CMV isolates. In the EcoR-1 digests, nine fragment bands comigrated among all human CMV isolates, and five bands comigrated among most, but not all human isolates. Each isolate had a distinctive electrophoretic profile with either HinD III or EcoR-1 digests. No two isolates had identical HinD III or EcoR-1 patterns although some isolates did share more general pattern similarities than others. No clear-cut subgrouping of isolates based on cleavage pattern characteristics could be discerned. Comparison of HinD III and EcoR-1 patterns showed that human isolates differ greatly from nonhuman CMV isolates. HinD III and EcoR-1 digests of each isolate contained both major and minor molar classes of DNA fragments that ranged from about 1 and multiples of 1 M down to about 0.25 M; however, the summed molecular weights for major molar fragments resulting from HinD III or EcoR-1 digests of several isolates closely approximated the molecular weight of 10(8) of the intact genome.