Immediate-early protein of pseudorabies virus is not continuously required to reinitiate transcription of induced genes.

We examined the role of herpesvirus immediate-early proteins in inducing and maintaining transcription by using tsG, a temperature-sensitive mutant in the immediate-early gene of pseudorabies virus. Cells infected at the permissive temperature were shifted to the nonpermissive temperature. Initially, early gene transcription rates were similar at both temperatures. Early gene transcription subsequently decreased slowly over several hours. Our results suggest that immediate-early protein function is required only for the initial activation of early gene transcription and is not required for multiple reinitiation events from activated early genes.