FIG. 7.

2D gel analysis of DNA replication at different regions of the EBV chromosome of the strain, P3-ΔDS-33, which lacks the DS of oriP. (A) A 3.5-kb segment between EcoRI and DraI sites, centered at the DS deletion of oriP, showed no evidence of initiation. (B) The EcoRI fragment (∼13 kb) spanning the TR junction, duplicated in this strain, with one copy containing two fewer 0.5-kb TR units due to a cycle of cleavage during packaging in P3HR1 cells and recircularization upon infection of BL30 cells. This fragment, its center near B95-8 coordinate 166000, produced a bubble arc, indicating initiation. (C) A 14-kb XbaI-EcoRI segment, centered near B95-8 position 153000, with its left half within the region that is deleted from B95-8, also produced a bubble arc. (D) A 7.8-kb EcoRI-XbaI centered near position 129000 did not reveal initiation. Probes for hybridization were as follows: A, DraI-MluI (position 7335 to 8314); B, the 5.3-kb BamI′ segment of strain AG876 (36); C, HpaI-XbaI (position 131959 to 133151); D, EcoRI-XbaI (position 125316 to 133151).