FIG. 3.

Autonomous maintenance of the circular chromosome of EBV mutants lacking the DS of oriP. BL30 clones carrying P3HR1 derivatives, 10⁶ cells each, were lysed in the wells of a horizontal agarose gel as previously described (12). During electrophoresis, circular EBV chromosomes migrate more slowly than linear chromosomes, as indicated. The Southern blot shown was probed with radiolabeled EBV sequences from position 109802 (SacI) to 110760 (XbaI). Raji cells, which carry approximately 60 circular copies of the EBV chromosome per diploid human genome, were included for comparison.