C-1027-induced alterations in Epstein-Barr viral DNA replication in latently infected cultured human Raji cells: Relationship to DNA damage

This study is the first detailing drug-induced changes in EBV DNA replicati on intermediates (RIs). Both EBV replication inhibition and damage inductio n were studied in latently infected human Raji cells treated with the enedi yne DNA strand-scission agent C-1027. Analysis of RIs on two-dimensional ag arose gels revealed a rapid loss in the EBV bubble are. When elongation of nascent chains was blocked by aphidicolin, this loss was inhibited, suggest ing that C-1027-induced disappearance of RIs was related to maturation of p reformed replication molecules in the absence of initiation of new RIs. C-1 027 damage to EBV DNA was limited at concentrations where loss of the bubbl e are was nearly complete, and none was detected within the replicating ori gin (ori P)-containing fragment, indicating that replication inhibition occ urred in trans. By contrast, the non-nuclear mitochondrial genome was insen sitive to replication inhibition but highly sensitive to damage induced by C-1027. C-1027-induced trans inhibition of nuclear but not mitochondrial DN A replication is consistent with a cell cycle checkpoint response to a DNA- damaging agent. EBV replication and Raji cell growth were inhibited at equi valent C-1027 doses.