Evidence for a herpes simplex virus-specific factor controlling the transcription of deoxypyrimidine kinase.

A cistron-specific, enzyme-forming-capacity method was used to study the control of herpes simplex virus (HSV)-specific deoxypyrimidine kinase (dPyK) mRNA synthesis. A virus-specific factor was formed by a primary infecting virus, and this factor effected the transcription of dPyK mRNA of a superinfecting virus in the presence of cycloheximide, suggesting that the factor acted in "trans" and was a diffusible one. After the addition of actinomycin D to prevent further transcription and upon removal of cycloheximide, the dPyK mRNA was allowed to express into dPyK activity. A factor from HSV-1 could effect the transcription of dPyK mRNA of both HSV-1 and HSV-2. Amino acid analogs, canavanine or ethionine, inhibited the action of this factor, suggesting that a protein was involved. This protein factor was shown to belong to the alpha (or immediate-early) group of HSV-Specific polypeptides in preductively infected cells.