The herpes simplex virus type 1 VP5 promoter contains a cis-acting element near the cap site which interacts with a cellular protein.

The promoter controlling the expression of the transcript encoding the major herpes simplex virus type 1 capsid protein (VP5, UL19) extends only 60 bases or so from a functional Sp1 site at --48 to include a cis-acting element 3' of the transcript start site. In the present communication, we report the generation of recombinant viruses bearing mutations between --6 and + 8 relative to the cap site in the VP5 promoter controlling expression of a reporter gene. Analysis of the effects of these mutations upon reporter gene expression along with the results of protein binding assays demonstrates that this cap transcription element functionally interacts with a cellular protein of a normal size of 40 kDa. Thus, like the strict late UL38 promoter characterized earlier, the late VP5 promoter has the essential properties of a cellular promoter.