FIG. 5.
Analysis of virally mediated replication of test plasmids containing the HHV-6B DRR-DRL concatemeric junction. Plasmids were introduced into naive (minus sign) or HHV-6B-infected (plus sign) J-Jahn cells. Ninety-six hours later, cells were collected and extrachromosomal DNA was harvested. This DNA was digested with DpnI plus either XhoI (for pΔ2C and pΔ2C) or XmnI (for pO and pCO) and was subjected to Southern blot analysis with a radiolabeled pKS probe. Shown is a photograph of the resulting autoradiogram. Numbers correspond to the sizes of λ HindIII DNA fragments (in kilobases). Cleavage of replicated (DpnI-resistant) plasmid DNA with XhoI or XmnI should give rise to unit length plasmid monomers (approximately 4.6 to 4.8 kb) (top arrowhead) and to two terminal fragments of roughly 3.0 and 1.8 kbp (pΔ2C) or 3.8 and 1.0 kbp (pCO), reflecting specific, virally mediated cleavage of replicated plasmid concatemers. Of these terminal fragments, only the larger molecules should be detected by the plasmid probe used (middle and bottom arrowheads).