FIG. 3.
Analysis of MCMV ectopic termini. (A) The HindIII restriction map of the entire MCMV genome is illustrated with the C- and X-terminal sequences represented by hatched boxes. Below are expanded the ectopic insertions of RM4070 and RM4072, showing the SacI sites flanking the insertions, the point at which ectopic cleavage occurs (vertical arrow), and the gpt expression cassette (open box). Arrows above the hatched boxes indicate the relative orientations of terminal and ectopic repeated sequences. Shown below each virus insertion are the predicted SacI fragments containing C-terminal (TC) and X-terminal (TX) sequences resulting from cleavage at each ectopic site. Thin lines indicate the locations of pac1 and pac2, and thick lines indicate the regions used as a hybridization probe. (B) Autoradiographs of DNA blot hybridizations to detect ectopic terminal restriction fragments. Concatemeric DNAs and 230-kb virion DNAs from RM4070 and RM4072 were prepared by FIGE and digested with SacI, then separated by agarose electrophoresis, transferred to a nylon membrane, and hybridized with probe D. The positions and molecular sizes of ectopic terminal fragments TC and TX are indicated.