Interference with the assembly of a virus-host transcription complex by peptide competition.

Induction of transcription of the immediate-early (IE) genes of herpes simplex virus (HSV) involves the assembly of a DNA-binding complex containing the cellular transcription factor Oct-1 and the virus regulatory protein Vmw65 (VP16). Complex assembly can be observed using deletion variants of Vmw65 which lack the acidic C-terminal activation domain and are therefore defective for IE transactivation. Similar variants of Vmw65 interfere with IE activation by the normal protein, and with HSV replication. It has therefore been suggested that dominant interfering products of viruses such as HSV and HIV could be used in a form of intracellular immunization against virus infection. Here we report that a small peptide overlapping a region of Vmw65 which is critical for complex assembly specifically inhibits assembly of the complex but has no observed effect on the DNA-binding activity of the cellular factor alone. Selective interference with the assembly of transcription complexes by short peptides corresponding to functionally critical regions of virus regulatory proteins may be more feasible than the use of defective polypeptides as an antiviral strategy based on competitive interference.