The NH2 terminus of the herpes simplex virus type 1 regulatory protein ICP0 contains a promoter-specific transcription activation domain.
The transcriptional program of herpes simplex virus is regulated by the concerted action of three immediate-early (alpha) proteins, ICP4, ICP27, and ICP0. The experiments described in this study examine the role of the acidic amino terminus (amino acids 1 to 103) of ICP0 in gene activation. When tethered to a DNA binding domain, this sequence activates transcription in the yeast Saccharomyces cerevisiae. Deletion of these amino acids affects the ability of ICP0 to activate alpha-gene promoter reporters in transient expression assays, while it has little or no effect on a beta- and a gamma-gene reporter in the same assay. Viruses that express the deleted form of ICP0 (ICP0-NX) have a small-plaque phenotype on both Vero cells and the complementing cell line L7. Transient expression and immunofluorescence analyses demonstrate that ICP0-NX is a dominant negative form of ICP0. Immunoprecipitation of ICP0 from cells coinfected with viruses expressing ICP0-NX and ICP0 revealed that ICP0 oligomerizes in infected cells. These data, in conjunction with the finding that ICP0-N/X is dominant negative, provide both biochemical and genetic evidence that ICP0 functions as a multimer in infected cells.
Lium
E K
EK
Department of Microbiology and College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA.
Panagiotidis
C A
CA
Wen
X
X
Silverstein
S J
SJ
D000818:Animals; D002460:Cell Line; D002522:Chlorocebus aethiops; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000235:genetics; D019281:Dimerization; D017874:Immediate-Early Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics; D017384:Sequence Deletion; D018139:Simplexvirus / Q000737:chemistry*; D015533:Transcriptional Activation; D044767:Ubiquitin-Protein Ligases; D014709:Vero Cells
D017931:DNA Primers; D004268:DNA-Binding Proteins; D017874:Immediate-Early Proteins; D011993:Recombinant Fusion Proteins; D044767:Ubiquitin-Protein Ligases; C051804:Vmw110 protein, Human herpesvirus 1