scholarly journals Herpes Simplex Virus Type 1 Latently Infected Neurons Differentially Express Latency-Associated and ICP0 Transcripts

2006 ◽  
Vol 80 (18) ◽  
pp. 9310-9321 ◽  
Author(s):  
Séverine Maillet ◽  
Thierry Naas ◽  
Sophie Crepin ◽  
Anne-Marie Roque-Afonso ◽  
Florence Lafay ◽  
...  
Keyword(s):  
Gene Expression ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Virus Type ◽  
Herpes Simplex Virus Type ◽  
Rt Pcr ◽  
Latently Infected ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT During the latent phase of herpes simplex virus type 1 (HSV-1) infection, the latency-associated transcripts (LATs) are the most abundant viral transcripts present in neurons, but some immediate-early viral transcripts, such as those encoding ICP0, have also been reported to be transcribed in latently infected mouse trigeminal ganglia (TG). A murine oro-ocular model of herpetic infection was used to study ICP0 gene expression in the major anatomical sites of HSV-1 latency, including the TG, superior cervical ganglion, spinal cord, and hypothalamus. An HSV-1 recombinant strain, SC16 110LacZ, revealed ICP0 promoter activity in several neurons in latently infected ganglia, and following infection with wild-type HSV-1 strain SC16, in situ hybridization analyses identified ICP0 transcripts in the nuclei of neurons at times consistent with the establishment of latency. Reverse transcription (RT)-PCR assays performed on RNA extracted from latently infected tissues indicated that ICP0 transcripts were detected in all anatomical sites of viral latency. Furthermore, quantitative real-time RT-PCR showed that neurons differentially expressed the LATs and ICP0 transcripts, with splicing of ICP0 transcripts being dependent on the anatomical location of latency. Finally, TG neurons were characterized by high-level expression of LATs and detection of abundant unspliced ICP0 transcripts, a pattern markedly different from those of other anatomical sites of HSV-1 latency. These results suggest that LATs might be involved in the maintenance of HSV-1 latency through the posttranscriptional regulation of ICP0 in order to inhibit expression of this potent activator of gene expression during latency.

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 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 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 The Latency-Associated Transcript Gene Enhances Establishment of Herpes Simplex Virus Type 1 Latency in Rabbits

2000 ◽  
Vol 74 (4) ◽  
pp. 1885-1891 ◽  
Author(s):  
Guey-Chuen Perng ◽  
Susan M. Slanina ◽  
Ada Yukht ◽  
Homayon Ghiasi ◽  
Anthony B. Nesburn ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Virus Type ◽  
Herpes Simplex Virus Type ◽  
Fluorescent Protein ◽  
Ocular Infection ◽  
Latently Infected ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT The latency-associated transcript (LAT) gene the only herpes simplex virus type 1 (HSV-1) gene abundantly transcribed during neuronal latency, is essential for efficient in vivo reactivation. Whether LAT increases reactivation by a direct effect on the reactivation process or whether it does so by increasing the establishment of latency, thereby making more latently infected neurons available for reactivation, is unclear. In mice, LAT-negative mutants appear to establish latency in fewer neurons than does wild-type HSV-1. However, this has not been confirmed in the rabbit, and the role of LAT in the establishment of latency remains controversial. To pursue this question, we inserted the gene for the enhanced green fluorescent protein (EGFP) under control of the LAT promoter in a LAT-negative virus (ΔLAT-EGFP) and in a LAT-positive virus (LAT-EGFP). Sixty days after ocular infection, trigeminal ganglia (TG) were removed from the latently infected rabbits, sectioned, and examined by fluorescence microscopy. EGFP was detected in significantly more LAT-EGFP-infected neurons than ΔLAT-EGFP-infected neurons (4.9% versus 2%, P < 0.0001). The percentages of EGFP-positive neurons per TG ranged from 0 to 4.6 for ΔLAT-EGFP and from 2.5 to 11.1 for LAT-EGFP (P = 0.003). Thus, LAT appeared to increase neuronal latency in rabbit TG by an average of two- to threefold. These results suggest that LAT enhances the establishment of latency in rabbits and that this may be one of the mechanisms by which LAT enhances spontaneous reactivation. These results do not rule out additional LAT functions that may be involved in maintenance of latency and/or reactivation from latency.

scholarly journals Lack of Interleukin-6 (IL-6) Enhances Susceptibility to Infection but Does Not Alter Latency or Reactivation of Herpes Simplex Virus Type 1 in IL-6 Knockout Mice

1999 ◽  
Vol 73 (10) ◽  
pp. 8145-8151 ◽  
Author(s):  
Rona A. LeBlanc ◽  
Lesley Pesnicak ◽  
Erik S. Cabral ◽  
Matthew Godleski ◽  
Stephen E. Straus
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Virus Type ◽  
Herpes Simplex Virus Type ◽  
Interleukin 6 ◽  
Lethal Dose ◽  
Latently Infected ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT The ability of the pleotropic, proinflammatory cytokine interleukin-6 (IL-6) to affect the replication, latency, and reactivation of herpes simplex virus type 1 (HSV-1) in cell culture and in IL-6 knockout (KO) mice was studied. In initial studies, we found no effect of exogenous IL-6, monoclonal antibodies to IL-6, or monoclonal antibody to the IL-6 coreceptor, gp130, on HSV-1 replication in vitro by plaque assay or reactivation ex vivo by explant cocultivation of latently infected murine trigeminal ganglia (TG). Compared with the wild-type (WT) mice, the IL-6 KO mice were less able to survive an ocular challenge with 105 PFU of HSV-1 (McKrae) (40% survival of WT and 7% survival KO mice; P = 0.01). There was a sixfold higher 50% lethal dose of HSV-1 in WT than IL-6 KO mice (1.7 × 104 and 2.7 × 103 PFU, respectively). No differences were observed in titers of virus recovered from the eyes, TG, or brains or in the rates of virus reactivation by explant cocultivation of TG from latently infected WT or KO mice. Exposure of latently infected mice to UV light resulted in comparable rates of reactivation and in the proportions of WT and KO animals experiencing reactivation. Moreover, quantitative PCR assays showed nearly identical numbers of HSV-1 genomes in latently infected WT and IL-6 KO mice. These studies indicate that while IL-6 plays a role in the protection of mice from lethal HSV infection, it does not substantively influence HSV replication, spread to the nervous system, establishment of latency, or reactivation.

scholarly journals Transactivation of Herpes Simplex Virus Type 1 Immediate-Early Gene Expression by Virion-Associated Factors Is Blocked by an Inhibitor of Cyclin-Dependent Protein Kinases

1999 ◽  
Vol 73 (10) ◽  
pp. 8843-8847 ◽  
Author(s):  
Robert Jordan ◽  
Luis Schang ◽  
Priscilla A. Schaffer
Keyword(s):  
Gene Expression ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Virus Type ◽  
Herpes Simplex Virus Type ◽  
Immediate Early ◽  
Dependent Protein ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT Initiation of productive infection by human herpes simplex virus type 1 (HSV-1) requires cell cycle-dependent protein kinase (cdk) activity. Treatment of cells with inhibitors of cdks blocks HSV-1 replication and prevents accumulation of viral transcripts, including immediate-early (IE) transcripts (26). Inhibition of IE transcript accumulation suggests that virion proteins, such as VP16, require functional cdks to activate viral transcription. In this report, we show that a cdk inhibitor, Roscovitine, blocks VP16-dependent IE gene expression. In the presence of Roscovitine, the level of virion-induced activation of a transfected reporter gene (the gene encoding chloramphenicol acetyltransferase) linked to the promoter-regulatory region of the ICP0 gene was reduced 40-fold relative to that of untreated samples. Roscovitine had little effect on the interaction of VP16 with VP16-responsive DNA sequences as measured by electrophoretic mobility shift assays. These data indicate that VP16-dependent activation of IE gene expression requires functional cdks and that this requirement is independent of the ability of VP16 to bind to DNA.

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