scholarly journals Reactivation of Expression from Quiescent Herpes Simplex Virus Type 1 Genomes in the Absence of Immediate-Early Protein ICP0

2007 ◽  
Vol 81 (21) ◽  
pp. 11781-11789 ◽  
Author(s):  
Chris M. Preston
Keyword(s):  
Gene Expression ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Virus Replication ◽  
Human Fibroblasts ◽  
Protein Icp0 ◽  
Simplex Virus ◽  
Null Mutants ◽  
Hsv 1

ABSTRACT Model systems have previously been developed in which herpes simplex virus (HSV) is retained in human fibroblasts in a nonreplicating state known as quiescence. The HSV type 1 (HSV-1) immediate-early (IE) protein ICP0, an important activator of gene expression, reactivates the quiescent genome and promotes the resumption of virus replication. Previous studies reported that infection with ICP0-null HSV-1 mutants fails to reactivate quiescent HSV, even when the mutant itself undergoes productive replication, leading to the hypothesis that quiescent genomes exist in a silent configuration in which they are shielded from trans-acting factors. I reinvestigated these findings, using HSV-1 mutants with lesions in the transcription activators VP16, ICP0, and ICP4 to establish quiescent infection at high efficiency. Superinfection with ICP0-null HSV-1 mutants at a low multiplicity of infection (MOI), so that individual plaques were formed, reactivated expression from the quiescent genome, demonstrating that the requirement for ICP0 is not absolute. The previously reported failure to observe reactivation by ICP0-null mutants was shown to be a consequence of either a low initial MOI or a high superinfecting MOI. Competition between viral genomes at the level of gene expression and virus replication, especially when ICP0 was absent, was demonstrated during reactivation and also during normal infection of human fibroblasts. The results show that the multiplicity-dependent phenotype of ICP0-null mutants limits the efficiency of reactivation at low MOIs and that competition between genomes occurs at high MOIs. The conclusion that quiescent HSV genomes are extensively silenced and intrinsically insensitive to trans-acting factors must be reevaluated.

scholarly journals Replication of ICP0-Null Mutant Herpes Simplex Virus Type 1 Is Restricted by both PML and Sp100

2007 ◽  
Vol 82 (6) ◽  
pp. 2661-2672 ◽  
Author(s):  
Roger D. Everett ◽  
Carlos Parada ◽  
Philippe Gripon ◽  
Hüseyin Sirma ◽  
Anne Orr
Keyword(s):  
Gene Expression ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Virus Type ◽  
Herpes Simplex Virus Type ◽  
Human Fibroblasts ◽  
Null Mutant ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT Herpes simplex virus type 1 (HSV-1) mutants that fail to express the viral immediate-early protein ICP0 have a pronounced defect in viral gene expression and plaque formation in limited-passage human fibroblasts. ICP0 is a RING finger E3 ubiquitin ligase that induces the degradation of several cellular proteins. PML, the organizer of cellular nuclear substructures known as PML nuclear bodies or ND10, is one of the most notable proteins that is targeted by ICP0. Depletion of PML from human fibroblasts increases ICP0-null mutant HSV-1 gene expression, but not to wild-type levels. In this study, we report that depletion of Sp100, another major ND10 protein, results in a similar increase in ICP0-null mutant gene expression and that simultaneous depletion of both proteins complements the mutant virus to a greater degree. Although chromatin assembly and modification undoubtedly play major roles in the regulation of HSV-1 infection, we found that inhibition of histone deacetylase activity with trichostatin A was unable to complement the defect of ICP0-null mutant HSV-1 in either normal or PML-depleted human fibroblasts. These data lend further weight to the hypothesis that ND10 play an important role in the regulation of HSV-1 gene expression.

scholarly journals Activation of cellular interferon-responsive genes after infection of human cells with herpes simplex virus type 1

2000 ◽  
Vol 81 (9) ◽  
pp. 2215-2218 ◽  
Author(s):  
Mary Jane Nicholl ◽  
Laurence H. Robinson ◽  
Chris M. Preston
Keyword(s):  
Gene Expression ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Virus Type ◽  
Herpes Simplex Virus Type ◽  
Human Fibroblasts ◽  
Interferon Α ◽  
Simplex Virus ◽  
Hsv 1

Previous studies have shown that infection of human fibroblasts with human cytomegalovirus (HCMV) results in activation of cellular interferon-responsive gene expression. We demonstrate here that infection of human fibroblasts with herpes simplex virus type 1 (HSV-1) in the absence of de novo protein synthesis also induces the expression of interferon-responsive genes. Five genes tested (encoding ISG54, IFI56, ISG15, 9-27 and MxA) were activated by infection with HSV-1, although the degree of response varied between the individual genes. HSV-1 was a less efficient inducer than HCMV. The effect was a consequence of binding of the virus particle to the cell surface or of the presence of virion components within the infected cell. Induction was mediated by a pathway other than the mechanism through which interferon-α mediates its effects on cellular gene expression.

scholarly journals Induction of Cellular Stress Overcomes the Requirement of Herpes Simplex Virus Type 1 for Immediate-Early Protein ICP0 and Reactivates Expression from Quiescent Viral Genomes

2008 ◽  
Vol 82 (23) ◽  
pp. 11775-11783 ◽  
Author(s):  
Chris M. Preston ◽  
Mary Jane Nicholl
Keyword(s):  
Gene Expression ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Herpes Simplex Virus Type ◽  
Physiological State ◽  
Human Fibroblasts ◽  
Gramicidin D ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT Herpes simplex virus type 1 (HSV-1) mutants impaired in the activities of the structural protein VP16 and the immediate-early (IE) proteins ICP0 and ICP4 establish a quiescent infection in human fibroblasts, with most cells retaining an inactive, repressed viral genome for sustained periods in culture. To date, the quiescent state has been considered stable, since it has been reversed only by provision of herpesviral proteins, such as ICP0, not by alteration of the cell physiological state. We report that the interaction of HSV-1 with human fibroblasts can be altered significantly by transient treatment of cultures with sodium arsenite, an inducer of heat shock and oxidative stress, or gramicidin D, a toxin that selectively permeabilizes cell membranes, prior to infection. These regimens stimulated gene expression from IE-deficient HSV-1 mutants in a promoter sequence-independent manner and also overcame the replication defect of ICP0-null mutants. Reactivation of gene expression from quiescent HSV-1 genomes and the resumption of virus replication were observed following addition of arsenite or gramicidin D to cultures. Both agents induced reorganization of nuclear domain 10 structures, the sites of quiescent genomes, but appeared to do so through different mechanisms. The results demonstrate that the physiological state of the cell is important in determining the outcome of infection with IE-deficient HSV-1 and show novel methods for reactivating quiescent HSV-1 in fibroblasts with a high efficiency.

scholarly journals Depletion of CoREST Does Not Improve the Replication of ICP0 Null Mutant Herpes Simplex Virus Type 1

2010 ◽  
Vol 84 (7) ◽  
pp. 3695-3698 ◽  
Author(s):  
Roger D. Everett
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Virus Type ◽  
Herpes Simplex Virus Type ◽  
Regulatory Protein ◽  
Null Mutant ◽  
Protein Icp0 ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT It has been proposed that the cellular corepressor protein CoREST is involved in repressing herpes simplex virus type 1 (HSV-1) infection in the absence of the viral regulatory protein ICP0. This proposal predicts that depletion of CoREST should improve the plaque-forming efficiency and replication of ICP0 null mutant virus. To test this hypothesis, human HepaRG cells that were highly depleted of CoREST were isolated using RNA interference technology. Depletion of CoREST had no effect on the replication of ICP0 null mutant HSV-1, demonstrating that CoREST does not play an influential role in regulating HSV-1 infection in this cell type.

scholarly journals Specific Histone Tail Modification and Not DNA Methylation Is a Determinant of Herpes Simplex Virus Type 1 Latent Gene Expression

2004 ◽  
Vol 78 (3) ◽  
pp. 1139-1149 ◽  
Author(s):  
Nicole J. Kubat ◽  
Robert K. Tran ◽  
Peterjon McAnany ◽  
David C. Bloom
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Virus Type ◽  
Herpes Simplex Virus Type ◽  
Epigenetic Mechanism ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT During herpes simplex virus type 1 (HSV-1) latency, gene expression is tightly repressed except for the latency-associated transcript (LAT). The mechanistic basis for this repression is unknown, but its global nature suggests regulation by an epigenetic mechanism such as DNA methylation. Previous work demonstrated that latent HSV-1 genomes are not extensively methylated, but these studies lacked the resolution to examine methylation of individual CpGs that could repress transcription from individual promoters during latency. To address this point, we employed established models to predict genomic regions with the highest probability of being methylated and, using bisulfite sequencing, analyzed the methylation profiles of these regions. We found no significant methylation of latent DNA isolated from mouse dorsal root ganglia in any of the regions examined, including the ICP4 and LAT promoters. This analysis indicates that methylation is unlikely to play a major role in regulating HSV-1 latent gene expression. Subsequently we focused on differential histone modification as another epigenetic mechanism that could regulate latent transcription. Chromatin immunoprecipitation analysis of the latent HSV-1 DNA repeat regions demonstrated that a portion of the LAT region is associated with histone H3 acetylated at lysines 9 and 14, consistent with a euchromatic and nonrepressed structure. In contrast, the chromatin associated with the HSV-1 DNA polymerase gene located in the unique long segment was not enriched in H3 acetylated at lysines 9 and 14, suggesting a transcriptionally inactive structure. These data suggest that histone composition may be a major regulatory determinant of HSV latency.

scholarly journals Herpes Simplex Virus Type 1 Genomes Are Associated with ND10 Nuclear Substructures in Quiescently Infected Human Fibroblasts

2007 ◽  
Vol 81 (20) ◽  
pp. 10991-11004 ◽  
Author(s):  
Roger D. Everett ◽  
Jill Murray ◽  
Anne Orr ◽  
Chris M. Preston
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Virus Type ◽  
Herpes Simplex Virus Type ◽  
Human Fibroblasts ◽  
Lytic Infection ◽  
Viral Genomes ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT Herpes simplex virus type 1 (HSV-1) genomes become associated with structures related to cellular nuclear substructures known as ND10 or promyelocytic leukemia nuclear bodies during the early stages of lytic infection. This paper describes the relationship between HSV-1 genomes and ND10 in human fibroblasts that maintain the viral genomes in a quiescent state. We report that quiescent HSV-1 genomes detected by fluorescence in situ hybridization (FISH) are associated with enlarged ND10-like structures, frequently such that the FISH-defined viral foci are apparently enveloped within a sphere of PML and other ND10 proteins. The number of FISH viral foci in each quiescently infected cell is concordant with the input multiplicity of infection, with each structure containing no more than a small number of viral genomes. A proportion of the enlarged ND10-like foci in quiescently infected cells contain accumulations of the heterochromatin protein HP1 but not other common markers of heterochromatin such as histone H3 di- or trimethylated on lysine residue 9. Many of the virally induced enlarged ND10-like structures also contain concentrations of conjugated ubiquitin. Quiescent infections can be established in cells that are highly depleted for PML. However, during the initial stages of establishment of a quiescent infection in such cells, other ND10 proteins (Sp100, hDaxx, and ATRX) are recruited into virally induced foci that are likely to be associated with HSV-1 genomes. These observations illustrate that the intimate connections between HSV-1 genomes and ND10 that occur during lytic infection also extend to quiescent infections.

scholarly journals Analysis of the Functions of Herpes Simplex Virus Type 1 Regulatory Protein ICP0 That Are Critical for Lytic Infection and Derepression of Quiescent Viral Genomes

2009 ◽  
Vol 83 (10) ◽  
pp. 4963-4977 ◽  
Author(s):  
Roger D. Everett ◽  
Marie-Laure Parsy ◽  
Anne Orr
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Regulatory Protein ◽  
Lytic Infection ◽  
Viral Genomes ◽  
Protein Icp0 ◽  
Simplex Virus ◽  
Mutant Forms ◽  
Hsv 1

ABSTRACT Herpes simplex virus type 1 (HSV-1) immediate-early regulatory protein ICP0 is important for stimulating the initiation of the lytic cycle and efficient reactivation of latent or quiescent infection. Extensive investigation has suggested several potential functions for ICP0, including interference in the interferon response, disruption of functions connected with PML nuclear bodies (ND10), and inhibition of cellular histone deacetylase (HDAC) activity through an interaction with the HDAC-1 binding partner CoREST. Analysis of the significance of these potential functions and whether they are direct or indirect effects of ICP0 is complicated because HSV-1 mutants expressing mutant forms of ICP0 infect cells with widely differing efficiencies. On the other hand, transfection approaches for ICP0 expression do not allow studies of whole cell populations because of their limited efficiency. To overcome these problems, we have established a cell line in which ICP0 expression can be induced at levels pertaining during the early stages of HSV-1 infection in virtually all cells in the culture. Such cells enable 100% complementation of ICP0-null mutant HSV-1. Using cells expressing the wild type and a variety of mutant forms of ICP0, we have used this system to analyze the role of defined domains of the protein in stimulating lytic infection and derepression from quiescence. Activity in these core functions correlated well the ability of ICP0 to disrupt ND10 and inhibit the recruitment of ND10 proteins to sites closely associated with viral genomes at the onset of infection, whereas the CoREST binding region was neither sufficient nor necessary for ICP0 function in lytic and reactivating infections.

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