[Molecular mechanism of lytic phase of Epstein-Barr virus DNA replication]

Epstein-Barr virus(EBV) is a human herpesvirus with a linear double stranded DNA, 172 kbp in length. The EBV has both a latent state and a lytic replicative cycle. Latency replication is dependent on cellular DNA replication machinery except for a single EBV-encoded protein, EBNA1. The EBV genome is maintained as a circular plasmid molecule and ori P, the latent phase replication origin of EBV, mediates this type of replication. The immediate-early BZLF1 protein disrupts viral latency through transactivation of early EBV genes. After induction of the lytic phase of viral replication, the EBV genome is amplified 100- to 1000-fold. The replication product is a head to tail concatemer which is presumed to be synthesized via a rolling circle mechanism initiated from the lytic phase replication origin, ori Lyt. EBV encodes seven viral genes that are essential for ori Lyt-dependent DNA replication. A number of features of EBV DNA replication make it a unique model system for the study of eukaryotic DNA replication. Here, the molecular mechanism of the lytic phase of the EBV DNA replication is discussed.