Herpes simplex virus-1 induces expression of a novel MxA isoform that enhances viral replication (original) (raw)
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Mechanisms of Host IFI16, PML, and Daxx Protein Restriction of Herpes Simplex Virus 1 Replication
Journal of Virology
The initial events after DNA virus infection involve a race between epigenetic silencing of the incoming viral DNA by host cell factors and expression of viral genes. Several host gene products, including the nuclear domain 10 (ND10) components PML (promyelocytic leukemia) and Daxx (death domain-associated protein 6), as well as IFI16 (interferon-inducible protein 16), have been shown to restrict herpes simplex virus 1 (HSV-1) replication. Whether IFI16 and ND10 components work together or separately to restrict HSV-1 replication is not known. To determine the combinatorial effects of IFI16 and ND10 proteins on viral infection, we depleted Daxx or PML in primary human foreskin fibroblasts (HFFs) in the presence or absence of IFI16. Daxx or IFI16 depletion resulted in higher ICP0 mutant viral yields, and the effects were additive. Surprisingly, small interfering RNA (siRNA) depletion of PML in the HFF cells led to decreased ICP0-null virus replication, while short hairpin RNA (shRNA)...
Synthesis of Herpes Simplex Virus Proteins in Interferon-treated Human Cells
Journal of General Virology, 1984
Pretreatment of HeLa cells with human interferon (IFN) resulted in the inhibition of herpes simplex virus (HSV) replication. We examined the stages in the replication of HSV type 1 and type 2 that were affected by IFN. The rate of synthesis of the HSV immediate-early (ct) proteins was inhibited in IFN-pretreated HeLa cells. The subsequent inductions of HSV early (/3) genes, determined by measuring the levels of cytoplasmic mRNA specific for the thymidine kinase, as well as the DNA polymerase enzyme activity, were also suppressed in the IFN-pretreated cells. These results indicate that IFN inhibits HSV replication primarily at a very early step, either prior to, or during the synthesis of ~-proteins.
Journal of Virology, 1998
Herpes simplex virus genes are predominantly intronless. We identified cis -acting elements in the intronless herpes simplex virus type 1 thymidine kinase (TK) gene that facilitate intron-independent gene expression. TK sequences functionally replaced the hepatitis B virus (HBV) posttranscriptional regulatory element (PRE) by inducing the expression of the intronless HBV surface message. TK also activated the pDM138 assay by inducing the cytoplasmic accumulation of intron-containing RNA. Multiple cis -acting RNA sequences, or subelements, that induce cytoplasmic localization of unspliced RNA were mapped within the TK gene. The presence of multiple RNA subelements within the TK gene is reminiscent of the multiple subelements in the HBV PRE required for the cytoplasmic accumulation of intronless HBV RNAs. Similar to HBV PRE subelements, duplication of a single TK subelement resulted in greater-than-additive increases in activity. A reporter chimera containing a single TK subelement ju...
Journal of Virology, 2004
The ␥ 1 34.5 gene product is important for the resistance of herpes simplex virus type 1 (HSV-1) to interferon. However, since the inhibition of protein synthesis observed in cells infected with a ␥ 1 34.5 mutant virus results from the combined loss of the ␥ 1 34.5 gene product and the failure to translate the late Us11 mRNA, we sought to characterize the relative interferon sensitivity of mutants unable to produce either the Us11 or the ␥ 1 34.5 polypeptide. We now demonstrate that primary human cells infected with a Us11 mutant virus are hypersensitive to alpha interferon, arresting translation upon entry into the late phase of the viral life cycle. Furthermore, immediate-early expression of Us11 by a ␥ 1 34.5 deletion mutant is sufficient to render translation resistant to alpha interferon. Finally, we establish that the Us11 gene product is required for wild-type levels of replication in alpha interferontreated cells and, along with the ␥ 1 34.5 gene, is an HSV-1-encoded interferon resistance determinant.
2013
Herpes simplex virus type 1 (HSV-1) is a neurotropic virus causing vesicular oral or genital skin lesions, meningitis and other diseases particularly harmful in immunocompromised individuals. To comprehensively investigate the complex interaction between HSV-1 and its host we combined two genome-scale screens for host factors (HFs) involved in virus replication. A yeast two-hybrid screen for protein interactions and a RNA interference (RNAi) screen with a druggable genome small interfering RNA (siRNA) library confirmed existing and identified novel HFs which functionally influence HSV-1 infection. Bioinformatic analyses found the 358 HFs were enriched for several pathways and multi-protein complexes. Of particular interest was the identification of Med23 as a strongly anti-viral component of the largely pro-viral Mediator complex, which links specific transcription factors to RNA polymerase II. The anti-viral effect of Med23 on HSV-1 replication was confirmed in gain-of-function gene overexpression experiments, and this inhibitory effect was specific to HSV-1, as a range of other viruses including Vaccinia virus and Semliki Forest virus were unaffected by Med23 depletion. We found Med23 significantly upregulated expression of the type III interferon family (IFN-l) at the mRNA and protein level by directly interacting with the transcription factor IRF7. The synergistic effect of Med23 and IRF7 on IFN-l induction suggests this is the major transcription factor for IFN-l expression. Genotypic analysis of patients suffering recurrent orofacial HSV-1 outbreaks, previously shown to be deficient in IFN-l secretion, found a significant correlation with a single nucleotide polymorphism in the IFN-l3 (IL28b) promoter strongly linked to Hepatitis C disease and treatment outcome. This paper describes a link between Med23 and IFN-l, provides evidence for the crucial role of IFN-l in HSV-1 immune control, and highlights the power of integrative genome-scale approaches to identify HFs critical for disease progression and outcome.
Journal of Virology, 2002
Alpha/beta interferons (IFN-␣/) are potent, endogenous antiviral cytokines that suppress the replication of RNA and DNA viruses, including herpes simplex virus type 1 (HSV-1). The present study compared the efficacies of IFN-␣/ transgenes, including IFN-␣1, -␣4, -␣5, -␣6, -␣9, and -, against HSV-1 infection. L929 cells transfected with the IFN-␣/ transgenes produced similar levels of IFN, as measured by bioassay and enzyme-linked immunosorbent assay. In addition, transfected cells were less susceptible to HSV-1 infection than were cells transfected with a plasmid vector control. The murine IFN- plasmid construct exhibited the greatest reduction, while the murine IFN-␣5 transgene showed a modest inhibitory effect in viral titers recovered from the supernatants of transfected, infected L929 cultures. Consistent with this observation, the IFN- transgene antagonized viral transcript levels, including infected cell protein 27, thymidine kinase, and glycoprotein B, to a greater extent than did the IFN-␣ transgenes at 6 to 10 h postinfection as determined by real-time PCR. Cells transfected with the IFN-␣4, IFN-␣9, or IFN- transgenes showed the greatest reduction in viral protein expression relative to the other transfected cells, which was associated with increased STAT1 expression. The absence of the IFN-responsive protein kinase R (PKR) gene completely abrogated the antiviral induction by all IFN-␣/ against HSV-1. In the absence of RNase L, viral yields were increased 10-fold, but the antiviral effect of IFN was either unaffected or enhanced. These results suggest that the predominant IFNmediated, antiviral pathway during HSV-1 infection taken by IFN-␣/ in L929 cells utilizes PKR.
Journal of General Virology, 1998
The herpes simplex virus type 1 (HSV-1) latencyassociated transcripts (LATs) are the only viral gene products expressed within latently infected neurones. The most abundant (major) LATs consist of two collinear nuclear polyA N RNAs of 2 kb and 1n5 kb which it has been suggested represent stable introns derived from a less abundant primary transcript (minor LAT). Consistent with this proposition is the identification of consensus splice donor and acceptor sites flanking major LATs which are conserved between HSV types 1 and 2. Here we test the functionality of the predicted splice sites within the context of the virus genome during productive infection in vitro and latent infection in vivo. To this end viruses in which the LAT splicing signals were disrupted by site-directed mutagenesis were con-0001-4938 # 1998 SGM BAH Downloaded from www.microbiologyresearch.org by
Journal of Virology, 2004
The γ134.5 gene product is important for the resistance of herpes simplex virus type 1 (HSV-1) to interferon. However, since the inhibition of protein synthesis observed in cells infected with a γ134.5 mutant virus results from the combined loss of the γ134.5 gene product and the failure to translate the late Us11 mRNA, we sought to characterize the relative interferon sensitivity of mutants unable to produce either the Us11 or the γ134.5 polypeptide. We now demonstrate that primary human cells infected with a Us11 mutant virus are hypersensitive to alpha interferon, arresting translation upon entry into the late phase of the viral life cycle. Furthermore, immediate-early expression of Us11 by a γ134.5 deletion mutant is sufficient to render translation resistant to alpha interferon. Finally, we establish that the Us11 gene product is required for wild-type levels of replication in alpha interferon-treated cells and, along with the γ134.5 gene, is an HSV-1-encoded interferon resista...
Journal of General Virology, 1992
Dominant negative or trans-dominant mutants of viral proteins represent a new and exciting potential approach to antiviral therapy. Unfortunately, the extreme specificity of a given dominant negative mutant limits its general utility in treating a broad spectrum of viral diseases, since it can typically interfere with the activity of only a single viral polypeptide encoded by a single virus. However, it seems likely that dominant negative mutants of promiscuous viral trans-activator proteins, which by definition would repress rather than activate gene expression, should be able to inhibit infectious virus production for a number of different viruses. One such dominant negative mutant, derived from the herpes simplex virus type 1 (HSV-1) regulatory protein ICP0, was found previously to behave as a powerful repressor of gene expression from an assortment of HSV-1 and non-HSV-1 promoters in transient expression assays. In the present study, this ICP0 mutant was found to be capable of inhibiting the replication of both HSV-1 and a completely unrelated virus, human immunodeficiency virus, in cell culture. The properties of this dominant negative mutant indicate that it may have potential as a means of treating diseases caused by a number of DNA and RNA viruses. Moreover, a truncated form of ICP0 which can hypothetically be created by alternative splicing was found to possess similar inhibitory capabilities, suggesting that a virusencoded version of this dominant negative mutant may play a role in down-regulating HSV-1 gene expression during infection in vivo.