Figure 2
From: Regulation of the retinoblastoma proteins by the human herpesviruses
Genes for DNA replication machinery and nucleotide biosynthesis encoded by the human herpesviruses. Listed are the virally encoded genes involved or implicated in viral DNA replication (top), nucleotide biosynthesis (middle) and activation (by phosphorylation) of the nucleoside analogs (bottom) employed as anti-herpesviral drugs for the alpha- (yellow), beta- (blue) and gamma- (green) herpesviruses. Note the striking lack of nucleotide biosynthetic enzymes encoded by the betaherpesviruses.