Cleavage maps for human cytomegalovirus DNA strain AD169 for restriction endonucleases EcoRI, BglII, and HindIII

We have used cloned EcoRI fragments of the human CMV (HCMV) genome, strain AD169, to prepare restriction endonuclease maps of the DNA. Individual 32P-labeled cloned fragments were hybridized to Southern blots of HCMV DNA cleaved to completion with the restriction endonucleases BglII and HindIII and cleaved partially with EcoRI. By determining which EcoRI fragments hybridized to the same band on a Southern blot, we were able to establish linkage groups. This information coupled with the data derived from digestion of the cloned fragments with the enzymes BglII and HindIII (Tamashiro et al., J. Virol. 42:547-557, 1982) provided the basis for the construction of detailed maps for the enzymes EcoRI, BglII, and HindIII. We also identified the EcoRI fragments derived from the termini of this genome and mapped them with respect to the BglII and HindIII terminal fragments. From our mapping data, we conclude that the genome of HCMV is approximately 240 kilobases in length and is divided into long (198 kilobases) and short (42 kilobases) regions. Both regions consist of a unique sequence bounded by inverted repeats (11 to 12 kilobases for the long region and 2 to 3 kilobases for the short region). Furthermore, the long and short regions can invert relative to each other.