scholarly journals Varicella-Zoster Virus ORF4 Latency-Associated Protein Is Important for Establishment of Latency

2005 ◽  
Vol 79 (11) ◽  
pp. 6969-6975 ◽  
Author(s):  
Jeffrey I. Cohen ◽  
Tammy Krogmann ◽  
Jeffrey P. Ross ◽  
Lesley Pesnicak ◽  
Elena A. Prikhod'ko
Keyword(s):  
Varicella Zoster Virus ◽  
Deletion Mutant ◽  
Immediate Early ◽  
Varicella Zoster ◽  
Early Protein ◽  
Orf4 Protein ◽  
Cotton Rats ◽  
In Cells ◽  
Hsv 1

ABSTRACT Varicella-zoster virus (VZV) encodes at least six genes that are expressed during latency. One of the genes, ORF4, encodes an immediate-early protein that is present in the virion tegument. ORF4 RNA and protein have been detected in latently infected human ganglia. We have constructed a VZV mutant deleted for ORF4 and have shown that the gene is essential for replication in vitro. The ORF4 mutant virus could be propagated when grown in cells infected with baculovirus expressing the ORF4 protein under the human cytomegalovirus immediate-early promoter. In contrast, the VZV ORF4 deletion mutant could not be complemented in cells expressing herpes simplex virus type 1 (HSV-1) ICP27, the homolog of ORF4. Cells infected with baculovirus expressing ORF4 did not complement an HSV-1 ICP27 deletion mutant. VZV-infected cotton rats have been used as a model for latency; viral DNA and latency-associated transcripts are expressed in dorsal root ganglia 1 month or more after experimental infection. Cotton rats inoculated with VZV lacking ORF4 showed reduced frequency of latency compared to animals infected with the parental or ORF4-rescued virus. Thus, in addition to VZV ORF63, which was previously shown to be critical for efficient establishment of latency, ORF4 is also important for latent infection.

scholarly journals The Varicella-Zoster Virus Portal Protein Is Essential for Cleavage and Packaging of Viral DNA

2014 ◽  
Vol 88 (14) ◽  
pp. 7973-7986 ◽  
Author(s):  
Melissa A. Visalli ◽  
Brittany L. House ◽  
Anca Selariu ◽  
Hua Zhu ◽  
Robert J. Visalli
Keyword(s):  
Varicella Zoster Virus ◽  
Deletion Mutant ◽  
Human Herpesvirus ◽  
Artificial Chromosome ◽  
Cell Nuclei ◽  
Viral Dna ◽  
Portal Protein ◽  
Varicella Zoster ◽  
Hsv 1

ABSTRACTThe varicella-zoster virus (VZV) open reading frame 54 (ORF54) gene encodes an 87-kDa monomer that oligomerizes to form the VZV portal protein, pORF54. pORF54 was hypothesized to perform a function similar to that of a previously described herpes simplex virus 1 (HSV-1) homolog, pUL6. pUL6 and the associated viral terminase are required for processing of concatemeric viral DNA and packaging of individual viral genomes into preformed capsids. In this report, we describe two VZV bacterial artificial chromosome (BAC) constructs with ORF54 gene deletions, Δ54L (full ORF deletion) and Δ54S (partial internal deletion). The full deletion of ORF54 likely disrupted essential adjacent genes (ORF53 and ORF55) and therefore could not be complemented on an ORF54-expressing cell line (ARPE54). In contrast, Δ54S was successfully propagated in ARPE54 cells but failed to replicate in parental, noncomplementing ARPE19 cells. Transmission electron microscopy confirmed the presence of only empty VZV capsids in Δ54S-infected ARPE19 cell nuclei. Similar to the HSV-1 genome, the VZV genome is composed of a unique long region (UL) and a unique short region (US) flanked by inverted repeats. DNA from cells infected with parental VZV (VZVLUCstrain) contained the predicted ULand UStermini, whereas cells infected with Δ54S contained neither. This result demonstrates that Δ54S is not able to process and package viral DNA, thus making pORF54 an excellent chemotherapeutic target. In addition, the utility of BAC constructs Δ54L and Δ54S as tools for the isolation of site-directed ORF54 mutants was demonstrated by recombineering single-nucleotide changes within ORF54 that conferred resistance to VZV-specific portal protein inhibitors.IMPORTANCEAntivirals with novel mechanisms of action would provide additional therapeutic options to treat human herpesvirus infections. Proteins involved in the herpesviral DNA encapsidation process have become promising antiviral targets. Previously, we described a series ofN-α-methylbenzyl-N′-aryl thiourea analogs that target the VZV portal protein (pORF54) and prevent viral replicationin vitro. To better understand the mechanism of action of these compounds, it is important to define the structural and functional characteristics of the VZV portal protein. In contrast to HSV, no VZV mutants have been described for any of the seven essential DNA encapsidation genes. The VZV ORF54 deletion mutant described in this study represents the first VZV encapsidation mutant reported to date. We demonstrate that the deletion mutant can serve as a platform for the isolation of portal mutants via recombineering and provide a strategy for more in-depth studies of VZV portal structure and function.

scholarly journals Downregulation of Varicella-Zoster Virus (VZV) Immediate-Early ORF62 Transcription by VZV ORF63 Correlates with Virus Replication In Vitro and with Latency

2006 ◽  
Vol 80 (7) ◽  
pp. 3459-3468 ◽  
Author(s):  
Susan E. Hoover ◽  
Randall J. Cohrs ◽  
Zoila G. Rangel ◽  
Donald H. Gilden ◽  
Peter Munson ◽  
...  
Keyword(s):  
Varicella Zoster Virus ◽  
Virus Replication ◽  
Deletion Mutant ◽  
Recombinant Adenovirus ◽  
Parental Virus ◽  
Reading Frame ◽  
Fourfold Increase ◽  
Varicella Zoster ◽  
In Cells

ABSTRACT Varicella-zoster virus (VZV) open reading frame 63 (ORF63) protein is expressed during latency in human sensory ganglia. Deletion of ORF63 impairs virus replication in cell culture and establishment of latency in cotton rats. We found that cells infected with a VZV ORF63 deletion mutant yielded low titers of cell-free virus and produced very few enveloped virions detectable by electron microscopy compared with those infected with parental virus. Microarray analysis of cells infected with a recombinant adenovirus expressing ORF63 showed that transcription of few human genes was affected by ORF63; a heat shock 70-kDa protein gene was downregulated, and several histone genes were upregulated. In experiments using VZV transcription arrays, deletion of ORF63 from VZV resulted in a fourfold increase in expression of ORF62, the major viral transcriptional activator. A threefold increase in ORF62 protein was observed in cells infected with the ORF63 deletion mutant compared with those infected with parental virus. Cells infected with ORF63 mutants impaired for replication and latency (J. I. Cohen, T. Krogmann, S. Bontems, C. Sadzot-Delvaux, and L. Pesnicak, J. Virol. 79:5069-5077, 2005) showed an increase in ORF62 transcription compared with those infected with parental virus. In contrast, cells infected with an ORF63 mutant that is not impaired for replication or latency showed ORF62 RNA levels equivalent to those in cells infected with parental virus. The ability of ORF63 to downregulate ORF62 transcription may play an important role in virus replication and latency.

The cellular transcription factor USF cooperates with varicella-zoster virus immediate-early protein 62 to symmetrically activate a bidirectional viral promoter

1994 ◽  
Vol 14 (10) ◽  
pp. 6896-6906 ◽  
Author(s):  
J L Meier ◽  
X Luo ◽  
M Sawadogo ◽  
S E Straus
Keyword(s):  
Dna Binding ◽  
Varicella Zoster Virus ◽  
Dominant Negative ◽  
Immediate Early ◽  
Activation Process ◽  
Viral Promoter ◽  
Varicella Zoster ◽  
Cellular Transcription Factor ◽  
Early Protein ◽  
Target Promoters

The mechanisms governing the function of cellular USF and herpesvirus immediate-early transcription factors are subjects of considerable interest. In this regard, we identified a novel form of coordinate gene regulation involving a cooperative interplay between cellular USF and the varicella-zoster virus immediate-early protein 62 (IE 62). A single USF-binding site defines the potential level of IE 62-dependent activation of a bidirectional viral early promoter of the DNA polymerase and major DNA-binding protein genes. We also report a dominant negative USF-2 mutant lacking the DNA-binding domain that permits the delineation of the biological role of both USF-1 and USF-2 in this activation process. The symmetrical stimulation of the bidirectional viral promoter by IE 62 is achieved at concentrations of USF-1 (43 kDa) or USF-2 (44 kDa) already existing in cells. Our observations support the notion that cellular USF can intervene in and possibly target promoters for activation by a herpesvirus immediate-early protein.

scholarly journals Varicella-Zoster Virus IE63, a Major Viral Latency Protein, Is Required To Inhibit the Alpha Interferon-Induced Antiviral Response

2007 ◽  
Vol 81 (15) ◽  
pp. 7844-7851 ◽  
Author(s):  
Aruna P. N. Ambagala ◽  
Jeffrey I. Cohen
Keyword(s):  
Varicella Zoster Virus ◽  
Melanoma Cells ◽  
Alpha Interferon ◽  
Parental Virus ◽  
Initiation Factor ◽  
Viral Gene ◽  
Α Subunit ◽  
Varicella Zoster ◽  
In Cells ◽  
Hsv 1

ABSTRACT Varicella-zoster virus (VZV) open reading frame 63 (ORF63) is the most abundant transcript expressed during latency in human sensory ganglia. VZV with ORF63 deleted is impaired for replication in melanoma cells and fibroblasts and for latency in rodents. We found that replication of the ORF63 deletion mutant is fully complemented in U2OS cells, which have been shown to complement the growth of herpes simplex virus type 1 (HSV-1) ICP0 mutants. Since HSV-1 ICP0 mutants are hypersensitive to alpha interferon (IFN-α), we examined the effect of IFN-α on VZV replication. Replication of the ORF63 mutant in melanoma cells was severely inhibited in the presence of IFN-α, in contrast to other VZV mutants that were similarly impaired for replication or to parental virus. The VZV ORF63 mutant was not hypersensitive to IFN-γ. IFN-α inhibited viral-gene expression in cells infected with the ORF63 mutant at a posttranscriptional level. Since IFN-α stimulates gene products that can phosphorylate the α subunit of eukaryotic initiation factor 2 (eIF-2α) and inhibit translation, we determined whether cells infected with the ORF63 mutant had increased phosphorylation of eIF-2α compared with cells infected with parental virus. While phosphorylated eIF-2α was undetectable in uninfected cells or cells infected with parental virus, it was present in cells infected with the ORF63 mutant. Conversely, expression of IE63 (encoded by ORF63) in the absence of other viral proteins inhibited phosphorylation of eIF-2α. Since IFN-α has been shown to limit VZV replication in human skin xenografts, the ability of VZV IE63 to block the effects of the cytokine may play a critical role in VZV pathogenesis.

scholarly journals Persistent High Frequencies of Varicella-Zoster Virus ORF4 Protein-Specific CD4+ T Cells after Primary Infection

2006 ◽  
Vol 80 (19) ◽  
pp. 9772-9778 ◽  
Author(s):  
Louise Jones ◽  
Antony P. Black ◽  
Gathsaurie N. Malavige ◽  
Graham S. Ogg
Keyword(s):  
T Cells ◽  
Varicella Zoster Virus ◽  
Peripheral Blood ◽  
Primary Infection ◽  
Ex Vivo ◽  
High Frequencies ◽  
Varicella Zoster ◽  
Early Protein ◽  
Orf4 Protein ◽  
Ifn Γ

ABSTRACT Open reading frame 4 (ORF4) of varicella-zoster virus (VZV) encodes an immediate-early protein that is believed to be important for viral infectivity and establishing latency. Evidence suggests that VZV-specific T cells are crucial in the control of viral replication, but there are no data addressing the existence of potential ORF4 protein-specific CD4+ T cells. We tested the hypothesis that VZV ORF4 protein-specific CD4+ T cells could be identified and characterized within the peripheral blood of healthy immune donors following primary infection. Gamma interferon (IFN-γ) immunosorbent assays were used to screen peripheral blood mononuclear cells obtained from healthy seropositive donors for responses to overlapping ORF4 peptides, viral lysate, and live vaccine. High frequencies of ORF4 protein-specific T cells were detected ex vivo in individuals up to 52 years after primary infection. Several immunogenic regions of the ORF4 protein were identified, including a commonly recognized epitope which was restricted through HLA-DRB1*07. Total ORF4 protein-specific responses comprised 19.7% and 20.7% of the total lysate and vaccine responses, respectively, and were dominated by CD4+ T cells. Indeed, CD4+ T cells were found to dominate the overall virus-specific IFN-γ cellular immune response both ex vivo and after expansion in vitro. In summary, we have identified an ORF4 protein as a novel target antigen for persistent VZV-specific CD4+ T cells, with implications for disease pathogenesis and future vaccine development.

scholarly journals Varicella-Zoster Virus (VZV) ORF17 Protein Induces RNA Cleavage and Is Critical for Replication of VZV at 37oC but Not 33oC

2002 ◽  
Vol 76 (21) ◽  
pp. 11012-11023 ◽  
Author(s):  
Hitoshi Sato ◽  
Lawrence D. Callanan ◽  
Lesley Pesnicak ◽  
Tammy Krogmann ◽  
Jeffrey I. Cohen
Keyword(s):  
Varicella Zoster Virus ◽  
Deletion Mutant ◽  
Host Protein ◽  
Parental Virus ◽  
Rna Cleavage ◽  
Reading Frame ◽  
Varicella Zoster ◽  
Cotton Rats ◽  
Simplex Virus

ABSTRACT Varicella-zoster virus (VZV) open reading frame 17 (ORF17) is homologous to herpes simplex virus (HSV) UL41, which encodes the viral host shutoff protein (vhs). HSV vhs induces degradation of mRNA and rapid shutoff of host protein synthesis. An antibody to ORF17 protein detected a 46-kDa protein in VZV-infected cells. While HSV vhs is located in virions, VZV ORF17 protein was not detectable in virions. ORF17 protein induced RNA cleavage, but to a substantially lesser extent than HSV-1 vhs. Expression of ORF17 protein did not inhibit expression from a β-galactosidase reporter plasmid, while HSV type 1 vhs abolished reporter expression. Two VZV ORF17 deletion mutants were constructed to examine the role of ORF17 in virus replication. While the ORF17 VZV mutants grew to peak titers that were similar to those of the parental virus at 33°C, the ORF17 mutants grew to 20- to 35-fold-lower titers than parental virus at 37°C. ORF62 protein was distributed in a different pattern in the nuclei and cytoplasm of cells infected with an ORF17 deletion mutant at 37°C compared to 33°C. Inoculation of cotton rats with the ORF17 deletion mutant resulted in a level of latent infection similar to that produced by inoculation with the parental virus. The importance of ORF17 protein for viral replication at 37°C but not at 33°C suggests that this protein may facilitate the growth of virus in certain tissues in vivo.

scholarly journals Identification of phosphorylated residues on varicella-zoster virus immediate-early protein ORF63

2010 ◽  
Vol 91 (5) ◽  
pp. 1133-1137 ◽  
Author(s):  
N. H. Mueller ◽  
M. S. Walters ◽  
R. A. Marcus ◽  
L. L. Graf ◽  
J. Prenni ◽  
...  
Keyword(s):  
Varicella Zoster Virus ◽  
Immediate Early ◽  
Varicella Zoster ◽  
Early Protein

scholarly journals Mutational analysis of varicella-zoster virus (VZV) immediate early protein (IE62) subdomains and their importance in viral replication

Virology ◽  
2016 ◽  
Vol 492 ◽  
pp. 82-91 ◽  
Author(s):  
Mohamed I. Khalil ◽  
Xibing Che ◽  
Phillip Sung ◽  
Marvin H. Sommer ◽  
John Hay ◽  
...  
Keyword(s):  
Viral Replication ◽  
Varicella Zoster Virus ◽  
Mutational Analysis ◽  
Immediate Early ◽  
Varicella Zoster ◽  
Early Protein

scholarly journals Absence or Overexpression of the Varicella-Zoster Virus (VZV) ORF29 Latency-Associated Protein Impairs Late Gene Expression and Reduces VZV Latency in a Rodent Model

2006 ◽  
Vol 81 (4) ◽  
pp. 1586-1591 ◽  
Author(s):  
Jeffrey I. Cohen ◽  
Tammy Krogmann ◽  
Lesley Pesnicak ◽  
Mir A. Ali
Keyword(s):  
Varicella Zoster Virus ◽  
Deletion Mutant ◽  
Latent Infection ◽  
Rodent Model ◽  
Parental Virus ◽  
Late Gene Expression ◽  
Varicella Zoster ◽  
Reduced Frequency ◽  
Immediate Early Proteins ◽  
In Cells

ABSTRACT Varicella-zoster virus (VZV) ORF29 encodes the viral single-stranded DNA binding protein and is expressed during latency in human ganglia. We constructed an ORF29 deletion mutant virus and showed that the virus could replicate only in cells expressing ORF29. An ORF29-repaired virus, in which ORF29 was driven by a cytomegalovirus promoter, grew to peak titers similar to those seen with the parental virus. The level of ORF29 protein in cells infected with the repaired virus was greater than that seen with parental virus. Infection of cells with either the ORF29 deletion or repaired virus resulted in similar levels of VZV immediate-early proteins but reduced levels of glycoprotein E compared to those observed with parental virus. Cotton rats infected with the ORF29 deletion mutant had a markedly reduced frequency of latent infection in dorsal root ganglia compared with those infected with parental virus (P < 0.00001). In contrast, infection of animals with the ORF29 deletion mutant resulted in a frequency of ganglionic infection at 3 days similar to that seen with the parental virus. Animals infected with the ORF29-repaired virus, which overexpresses ORF29, also had a reduced frequency of latent infection compared with those infected with parental virus (P = 0.0044). These studies indicate that regulation of ORF29 at appropriate levels is critical for VZV latency in a rodent model.

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