scholarly journals A Gene Capable of Blocking Apoptosis Can Substitute for the Herpes Simplex Virus Type 1 Latency-Associated Transcript Gene and Restore Wild-Type Reactivation Levels

2002 ◽  
Vol 76 (3) ◽  
pp. 1224-1235 ◽  
Author(s):  
Guey-Chuen Perng ◽  
Barak Maguen ◽  
Ling Jin ◽  
Kevin R. Mott ◽  
Nelson Osorio ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Virus Type ◽  
Gene Function ◽  
Herpes Simplex Virus Type ◽  
Null Mutant ◽  
Wild Type ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT After ocular herpes simplex virus type 1 (HSV-1) infection, the virus travels up axons and establishes a lifelong latent infection in neurons of the trigeminal ganglia. LAT (latency-associated transcript), the only known viral gene abundantly transcribed during HSV-1 neuronal latency, is required for high levels of reactivation. The LAT function responsible for this reactivation phenotype is not known. Recently, we showed that LAT can block programmed cell death (apoptosis) in neurons of the trigeminal ganglion in vivo and in tissue culture cells in vitro (G.-C. Perng et al., Science 287:1500–1503, 2000; M. Inman et al., J. Virol. 75:3636–3646, 2001). Consequently, we proposed that this antiapoptosis function may be a key to the mechanism by which LAT enhances reactivation. To study this further, we constructed a recombinant HSV-1 virus in which the HSV-1 LAT gene was replaced by an alternate antiapoptosis gene. We used the bovine herpes virus 1 (BHV-1) latency-related (LR) gene, which was previously shown to have antiapoptosis activity, for this purpose. The resulting chimeric virus, designated CJLAT, contains two complete copies of the BHV-1 LR gene (one in each viral long repeat) in place of the normal two copies of the HSV-1 LAT, on an otherwise wild-type HSV-1 strain McKrae genomic background. We report here that in both rabbits and mice reactivation of CJLAT was significantly greater than the LAT null mutant dLAT2903 (P < 0.0004 and P = 0.001, respectively) and was at least as efficient as wild-type McKrae. This strongly suggests that a BHV-1 LR gene function was able to efficiently substitute for an HSV-1 LAT gene function involved in reactivation. Although replication of CJLAT in rabbits and mice was similar to that of wild-type McKrae, CJLAT killed more mice during acute infection and caused more corneal scarring in latently infected rabbits. This suggested that the BHV-1 LR gene and the HSV-1 LAT gene are not functionally identical. However, LR and LAT both have antiapoptosis activity. These studies therefore strongly support the hypothesis that replacing LAT with an antiapoptosis gene restores the wild-type reactivation phenotype to a LAT null mutant of HSV-1 McKrae.

scholarly journals The UL12.5 Gene Product of Herpes Simplex Virus Type 1 Exhibits Nuclease and Strand Exchange Activities but Does Not Localize to the Nucleus

2004 ◽  
Vol 78 (9) ◽  
pp. 4599-4608 ◽  
Author(s):  
Nina Bacher Reuven ◽  
Susumu Antoku ◽  
Sandra K. Weller
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Virus Type ◽  
Herpes Simplex Virus Type ◽  
Intracellular Localization ◽  
Strand Exchange ◽  
Null Mutant ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT The herpes simplex virus type 1 (HSV-1) alkaline nuclease, encoded by the UL12 gene, plays an important role in HSV-1 replication, as a null mutant of UL12 displays a severe growth defect. Although the precise in vivo role of UL12 has not yet been determined, several in vitro activities have been identified for the protein, including endo- and exonuclease activities, interaction with the HSV-1 single-stranded DNA binding protein ICP8, and an ability to promote strand exchange in conjunction with ICP8. In this study, we examined a naturally occurring N-terminally truncated version of UL12 called UL12.5. Previous studies showing that UL12.5 exhibits nuclease activity but is unable to complement a UL12 null virus posed a dilemma and suggested that UL12.5 may lack a critical activity possessed by the full-length protein, UL12. We constructed a recombinant baculovirus capable of expressing UL12.5 and purified soluble UL12.5 from infected insect cells. The purified UL12.5 exhibited both endo- and exonuclease activities but was less active than UL12. Like UL12, UL12.5 could mediate strand exchange with ICP8 and could also be coimmunoprecipitated with ICP8. The primary difference between the two proteins was in their intracellular localization, with UL12 localizing to the nucleus and UL12.5 remaining in the cytoplasm. We mapped a nuclear localization signal to the N terminus of UL12, the domain absent from UL12.5. In addition, when UL12.5 was overexpressed so that some of the enzyme leaked into the nucleus, it was able to partially complement the UL12 null mutant.

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 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 Suppression of Proinflammatory Cytokine Expression by Herpes Simplex Virus Type 1

2004 ◽  
Vol 78 (11) ◽  
pp. 5883-5890 ◽  
Author(s):  
Trine H. Mogensen ◽  
Jesper Melchjorsen ◽  
Lene Malmgaard ◽  
Antonella Casola ◽  
Søren R. Paludan
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Virus Type ◽  
Proinflammatory Cytokines ◽  
Herpes Simplex Virus Type ◽  
Cytokine Expression ◽  
Wild Type ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT Viral immune evasion strategies are important for establishment and maintenance of infections. Many viruses are in possession of mechanisms to counteract the antiviral response raised by the infected host. Here we show that a herpes simplex virus type 1 (HSV-1) mutant lacking functional viral protein 16 (VP16)—a tegument protein promoting viral gene expression—induced significantly higher levels of proinflammatory cytokines than wild-type HSV-1. This was observed in several cell lines and primary murine macrophages, as well as in peritoneal cells harvested from mice infected in vivo. The enhanced ability to stimulate cytokine expression in the absence of VP16 was not mediated directly by VP16 but was dependent on the viral immediate-early genes for infected cell protein 4 (ICP4) and ICP27, which are expressed in a VP16-dependent manner during primary HSV infection. The virus appeared to target cellular factors other than interferon-induced double-stranded RNA-activated protein kinase R (PKR), since the virus mutants remained stronger inducers of cytokines in cells stably expressing a dominant-negative mutant form of PKR. Finally, mRNA stability assay revealed a significantly longer half-life for interleukin-6 mRNA after infection with the VP16 mutant than after infection with the wild-type virus. Thus, HSV is able to suppress expression of proinflammatory cytokines by decreasing the stability of mRNAs, thereby potentially impeding the antiviral host response to infection.

scholarly journals A Herpes Simplex Virus Type 1 Latency-Associated Transcript Mutant with Increased Virulence and Reduced Spontaneous Reactivation

1999 ◽  
Vol 73 (2) ◽  
pp. 920-929 ◽  
Author(s):  
Guey-Chuen Perng ◽  
Susan M. Slanina ◽  
Ada Yukht ◽  
Barbara S. Drolet ◽  
William Keleher ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Virus Type ◽  
Herpes Simplex Virus Type ◽  
Ocular Infection ◽  
Wild Type ◽  
Simplex Virus ◽  
Spontaneous Reactivation ◽  
Hsv 1

ABSTRACT The herpes simplex virus type 1 (HSV-1) latency-associated transcript (LAT) gene is essential for efficient spontaneous reactivation of HSV-1 from latency. We previously reported that insertion of the LAT promoter and just the first 1.5 kb of the 8.3-kb LAT gene into an ectopic location in the virus restored wild-type spontaneous reactivation to a LAT null mutant. This mutant, LAT3.3A (previously designated LAT1.5a), thus showed that the expression of just the first 1.5 kb of LAT is sufficient for wild-type spontaneous reactivation. We also showed that in the context of the entire LAT gene, deletion of LAT nucleotides 76 to 447 (LAT mutantdLAT371) had no effect on spontaneous reactivation or virulence. We report here on a LAT mutant designated LAT2.9A. This mutant is similar to LAT3.3A, except that the ectopic LAT insert contains the same 371-nucleotide deletion found in dLAT371. We found that LAT2.9A had a significantly reduced rate of spontaneous reactivation compared to marker-rescued and wild-type viruses. This was unexpected, since the combined results of dLAT371 and LAT3.3A predicted that spontaneous reactivation of LAT2.9A would be wild type. We also found that LAT2.9A was more virulent than wild-type or marker-rescued viruses after ocular infection of rabbits. This was unexpected, since LAT null mutants and LAT3.3A have wild-type virulence. These results suggest for the first time (i) that regions past the first 1.5 kb of LAT can compensate for deletions in the first 1.5kb of LAT and may therefore play a role in LAT dependent spontaneous reactivation and (ii) that regions of LAT affect viral virulence.

scholarly journals Negative regulation of herpes simplex virus type 1 ICP4 promoter by IE180 protein of pseudorabies virus

2004 ◽  
Vol 85 (8) ◽  
pp. 2125-2130 ◽  
Author(s):  
S. Gómez-Sebastián ◽  
E. Tabarés
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Virus Type ◽  
Herpes Simplex Virus Type ◽  
Negative Regulation ◽  
Wild Type ◽  
Recombinant Viruses ◽  
Simplex Virus ◽  
Hsv 1

Recombinant pseudorabies viruses (PRVs) gIS8 and N1aHTK were constructed by the insertion of a chimeric gene (α4–TK) from herpes simplex virus type 1 (HSV-1) into wild-type PRV. HSV-1 TK expression by these recombinant viruses resulted in enhanced sensitivity to ganciclovir, compared to that of the wild-type PRV, and was similar to the sensitivity shown by HSV-1. Infection with gIS8 or N1aHTK recombinant viruses led to expression of HSV-1 TK mRNA as an immediate–early (IE) gene, observed by downregulation of the HSV-1 α4 promoter. This negative regulation was due to a PRV IE protein, IE180. IE180, however, does not have all the regulatory functions of the infected-cell protein ICP4, as it does not restore the growth of ICP4-deficient HSV-1 mutants.

scholarly journals The Dominant-Negative Herpes Simplex Virus Type 1 (HSV-1) Recombinant CJ83193 Can Serve as an Effective Vaccine against Wild-Type HSV-1 Infection in Mice

2004 ◽  
Vol 78 (11) ◽  
pp. 5756-5765 ◽  
Author(s):  
Hanka Augustinova ◽  
Daniela Hoeller ◽  
Feng Yao
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Virus Type ◽  
Herpes Simplex Virus Type ◽  
Dominant Negative ◽  
Trigeminal Ganglia ◽  
Wild Type ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT By selectively regulating the expression of the trans-dominant-negative mutant polypeptide UL9-C535C, of herpes simplex virus type 1 (HSV-1) origin binding protein UL9 with the tetracycline repressor (tetR)-mediated gene switch, we recently generated a novel replication-defective and anti-HSV-specific HSV-1 recombinant, CJ83193. The UL9-C535C peptides expressed by CJ83193 can function as a potent intracellular therapy against its own replication, as well as the replication of wild-type HSV-1 and HSV-2 in coinfected cells. In this report, we demonstrate that CJ83193 cannot initiate acute productive infection in corneas of infected mice nor can it reactivate from trigeminal ganglia of mice latently infected by CJ83193 in a mouse ocular model. Given that CJ83193 is capable of expressing the viral α, β, and γ1 genes but little or no γ2 genes, we tested the vaccine potential of CJ83193 against HSV-1 infection in a mouse ocular model. Our studies showed that immunization with CJ83193 significantly reduced the yields of challenge HSV in the eyes and trigeminal ganglia on days 3, 5, and 7 postchallenge. Like in mice immunized with the wild-type HSV-1 strain KOS, immunization of mice with CJ83193 prevents the development of keratitis and encephalitis induced by corneal challenge with wild-type HSV-1 strain mP. Delayed-type hypersensitivity (DTH) assays demonstrate that CJ83193 can elicit durable cell-mediated immunity at the same level as that of wild-type HSV-1 and is more effective than that induced by d27, an HSV-1 ICP27 deletion mutant. Moreover, mice immunized with CJ83193 developed strong, durable HSV-1-neutralizing antibodies at levels at least twofold higher than those induced by d27. The results presented in this report have shed new light on the development of effective HSV viral vaccines that encode a unique safety mechanism capable of inhibiting the mutant's own replication and that of wild-type virus.

scholarly journals Differing Roles of Inner Tegument Proteins pUL36 and pUL37 during Entry of Herpes Simplex Virus Type 1

2008 ◽  
Vol 83 (1) ◽  
pp. 105-116 ◽  
Author(s):  
Ashley P. E. Roberts ◽  
Fernando Abaitua ◽  
Peter O'Hare ◽  
David McNab ◽  
Frazer J. Rixon ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Virus Type ◽  
Herpes Simplex Virus Type ◽  
Wild Type ◽  
Tegument Proteins ◽  
Infected Cells ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT Studies with herpes simplex virus type 1 (HSV-1) have shown that secondary envelopment and virus release are blocked in mutants deleted for the tegument protein gene UL36 or UL37, leading to the accumulation of DNA-containing capsids in the cytoplasm of infected cells. The failure to assemble infectious virions has meant that the roles of these genes in the initial stages of infection could not be investigated. To circumvent this, cells infected at a low multiplicity were fused to form syncytia, thereby allowing capsids released from infected nuclei access to uninfected nuclei without having to cross a plasma membrane. Visualization of virus DNA replication showed that a UL37-minus mutant was capable of transmitting infection to all the nuclei within a syncytium as efficiently as the wild-type HSV-1 strain 17+ did, whereas infection by UL36-minus mutants failed to spread. Thus, these inner tegument proteins have differing functions, with pUL36 being essential during both the assembly and uptake stages of infection, while pUL37 is needed for the formation of virions but is not required during the initial stages of infection. Analysis of noninfectious enveloped particles (L-particles) further showed that pUL36 and pUL37 are dependent on each other for incorporation into tegument.

scholarly journals The Herpes Simplex Virus Type 1 Regulatory Protein ICP27 Is Required for the Prevention of Apoptosis in Infected Human Cells

1999 ◽  
Vol 73 (4) ◽  
pp. 2803-2813 ◽  
Author(s):  
Martine Aubert ◽  
John A. Blaho
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Virus Type ◽  
Herpes Simplex Virus Type ◽  
Vero Cells ◽  
Human Cells ◽  
Wild Type ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT The herpes simplex virus type 1 (HSV-1) ICP27 protein is an immediate-early or α protein which is essential for the optimal expression of late genes as well as the synthesis of viral DNA in cultures of Vero cells. Our specific goal was to characterize the replication of a virus incapable of synthesizing ICP27 in cultured human cells. We found that infection with an HSV-1 ICP27 deletion virus of at least three separate strains of human cells did not produce immediate-early or late proteins at the levels observed following wild-type virus infections. Cell morphology, chromatin condensation, and genomic DNA fragmentation measurements demonstrated that the human cells died by apoptosis after infection with the ICP27 deletion virus. These features of the apoptosis were identical to those which occur during wild-type infections of human cells when total protein synthesis has been inhibited. Vero cells infected with the ICP27 deletion virus did not exhibit any of the features of apoptosis. Based on these results, we conclude that while HSV-1 infection likely induced apoptosis in all cells, viral evasion of the response differed among the cells tested in this study.

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