Fig. 1.

Amplification of viral cell junctions. Viral DNA (shaded box) is schematically shown integrated into cell DNA (solid line). Steps are indicated as follows and are described in detail in Materials and Methods: 1, digestion of cellular PvuII sites; 2, ligation of ends to LNK-D (open box) and termination of 3′ ends (data not shown); 3, denaturation and endpoint dilution amplification of one strand with viral and linker-specific primers; 4, removal of LNK-D sequences with PvuII, circularization, and digestion with HindIII; and 5, nested PCR with viral-specific primers.