Fig 11. Models for the dependence of late gene transcription on continuing DNA replication.

A. Newly replicated linear herpesvirus genomes are shown being bound by DNA binding proteins shortly after production, rendering them inaccessible for the late gene transcription complex. Histones bound to latent genomes prior to lytic transcription are depicted in light blue. Only newly replicated genomes devoid of protein are shown being transcribed. B. Replicated genomes are shown being encapsidated, preventing further transcription which only occurs from newly produced genomes. C. The translocating DNA polymerase complex is shown bringing a component of the vPIC to a late gene promoter. BMRF1 is shown as the protein performing this function by analogy to T4 replication, but the process may be performed by any component of the DNA polymerase machinery, and one or more proteins required for late gene transcription may be involved. D. The replication/transcription factory is shown undergoing dissolution when the process of DNA replication is blocked, with a loss of physical integrity and dispersion of the locally concentrated replication proteins, DNA template and RNA transcription factors. Some of the interacting proteins are shown as maintaining association in the dispersed particles.