Fig. 1. Diagram of the EBV genome indicating the terminal (TR) and internal (IR) repeat regions, unique (U) regions, and the location of latent genes, several of which (EBNA-2 and LMP) may be essential for growth transformation of B lymphocytes. Arrows indicate length and direction of transcription of latency associated mRNAs. The origin of DNA replication in latent (ori P) or lytically (ori lyt, right and left) infected cells is noted.