Epidermal growth factor induces, in the EL alpha 4-2 cell line, herpes simplex virus-1 alpha 4 gene transcription in the absence of the viral trans-activator VP16.
We have constructed a fibroblast cell line (EL alpha 4-2) which constitutively expresses the alpha 4 gene of herpes simplex virus type 1. We studied the induction of the alpha 4 gene, in the absence of the viral activator VP16, by stimulating EL alpha 4-2 cells with different growth factors. Here we report that a rapid, transient induction of the alpha 4 gene occurs only when EL alpha 4-2 fibroblasts are stimulated with purified epidermal growth factor (EGF). Such an induction does not require de novo protein synthesis. The role of cellular factors on the EGF-mediated induction of the alpha 4 gene has been analyzed by gel mobility shift assays using nuclear extracts from EL alpha 4-2 cells stimulated or not with EGF. The results obtained show that two factors bind to TAATGARAT (R = purine) regardless of EGF-stimulation. We conclude that a mechanism, different from the one involving VP16, is responsible for alpha 4 gene activation in EL alpha 4-2 cells and that the DNA-protein architecture is maintained at the TAATGARAT regulatory site regardless of changes in the transcriptional state induced by EGF.
Bovolenta
C
C
Institute of Biological Chemistry, School of Medicine, University of Verona, Italy.
Tognon
M
M
Liboi
E
E
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D004279:DNA, Viral / Q000235:genetics / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects; D005814:Genes, Viral / Q000187:drug effects*; D008969:Molecular Sequence Data; D018139:Simplexvirus / Q000187:drug effects* / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects; D015533:Transcriptional Activation; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism
D004279:DNA, Viral; D014764:Viral Proteins; D004815:Epidermal Growth Factor