Truncation of the C-Terminal Acidic Transcriptional Activation Domain of Herpes Simplex Virus VP16 Renders Expression of the Immediate-Early Genes Almost Entirely Dependent on ICP0

The herpes simplex virus (HSV) proteins VP16 and ICP0 play key roles in stimulating the onset of the viral lytic cycle. We sought to explore the regulatory links between these proteins by studying the phenotypes of viral mutants in which the activation functions of both were simultaneously inactivated. This analysis unexpectedly revealed that truncation of the C-terminal transcriptional activation domain of VP16 (allele V422) in an …