The equine herpesvirus 1 (EHV-1) UL3 gene, an ICP27 homolog, is necessary for full activation of gene expression directed by an EHV-1 late promoter.
We have previously reported that the equine herpesvirus 1 (EHV-1) XbaI G restriction fragment (nucleotides 1436 to 7943 relative to the left terminus of the EHV-1 genome [Kentucky A strain]) is required in combination with the EHV-1 immediate-early (IE) gene to achieve significant activation of two representative EHV-1 late promoter-chloramphenicol acetyltransferase (CAT) recombinants in transient expression assays. In this report, we demonstrate that the XbaI G-encoded UL3 gene (an ICP27 homolog) provides a trans-acting factor which acts (in combination with the EHV-1 IE gene product) to increase reporter gene expression directed by an EHV-1 late promoter-CAT recombinant plasmid. We show that cloned copies of UL3 can successfully substitute for the XbaI G fragment in CAT assays and that stop codon insertion within the UL3 open reading frame inhibits the ability of UL3 to activate reporter gene expression in trans.
Smith
R H
RH
Department of Microbiology and Immunology, Louisiana State University Medical Center, Shreveport 71130-3932.
Zhao
Y
Y
O'Callaghan
D J
DJ
D003062:Codon / Q000235:genetics; D015967:Gene Expression Regulation, Viral; D005814:Genes, Viral / Q000235:genetics*; D004861:Herpesvirus 1, Equid / Q000235:genetics*; D017874:Immediate-Early Proteins; D011401:Promoter Regions, Genetic / Q000235:genetics*; D016364:Reading Frames / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics*; D015533:Transcriptional Activation / Q000235:genetics; D014764:Viral Proteins / Q000235:genetics*
D003062:Codon; C057120:ICP27 protein, human herpesvirus 1; D017874:Immediate-Early Proteins; D011994:Recombinant Proteins; D015534:Trans-Activators; D014764:Viral Proteins