Transcription from the early and late classes of the herpes simplex virus type 1 (HSV-1) promoters requires prior immediate early (IE) gene expression. Although the product of IE gene 1, Vmw110, is not absolutely essential for virus growth in tissue culture, transfection experiments have demonstrated that Vmw110 can activate gene expression both by itself and in a synergistic manner with the product of IE gene 3, Vmw175. This paper describes the construction of 10 mutant HSV-1 viruses with deletion and insertion mutations in Vmw110. The mutant viruses were then studied in single-step growth curve experiments, by assaying for plaques in a variety of cell types and by analysis of viral polypeptide synthesis during productive infection at high and low multiplicities. The results show that mutations in Vmw110 reduce the efficiency of plaque formation by HSV-1; the extent of this reduction depends on cell type and the position of the mutation in the polypeptide. In particular, a potential zinc finger domain is crucial for Vmw110 function. The patterns and amounts of viral polypeptide synthesis during high multiplicity infections with mutant and wild-type viruses were similar in all cell types. At low multiplicity, mutations in Vmw110 reduced viral gene expression in the least permissive cell type. The data suggest that the role of Vmw110 during virus infection in tissue culture is at a very early stage of low multiplicity infections; its inactivity leads to the failure to express viral genes so that the virus does not enter the lytic cycle.


Article metrics loading...

Loading full text...

Full text loading...


Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error