Structural organization of human cytomegalovirus DNA

HCMV DNA preparations in which purity was characterized by sedimentation, buoyant density, and restriction enzyme cleavage contain two molecular weight size classes of HCMV DNA molecules (150--155 x 10(6) and 100 x 10(6) daltons) in addition to some shear products. Partial denaturation mapping reveals that both size classes contain the same sequences and that molecules of 150--155 x 10(6) daltons contain the apparent full complement of sequences which are variously contained in the smaller molecules. The complete genome (150--155 x 10(6) daltons) seems to be divisible into regions of about 78--82% and 18--22%, which undergo complete inversions with respect to one another. Enriched or purified preparations of molecules of 150--155 x 10(6) daltons generate cleavage products identical to those from total HCMV DNA preparations.