151
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Miller CS, Danaher RJ, Jacob RJ. ICP0 is not required for efficient stress-induced reactivation of herpes simplex virus type 1 from cultured quiescently infected neuronal cells. J Virol 2006; 80:3360-8. [PMID: 16537603 PMCID: PMC1440419 DOI: 10.1128/jvi.80.7.3360-3368.2006] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Viral genes sufficient and required for herpes simplex virus type 1 (HSV-1) reactivation were identified using neuronally differentiated PC12 cells (ND-PC12 cells) in which quiescent infections with wild-type and recombinant strains were established. In this model, the expression of ICP0, VP16, and ICP4 from adenovirus vectors was sufficient to reactivate strains 17+ and KOS. The transactivators induced similar levels of reactivation with KOS; however, 17+ responded more efficiently to ICP0. To identify viral transactivators required for reactivation, we examined quiescently infected PC12 cell cultures (QIF-PC12 cell cultures) established with HSV-1 deletion mutants R7910 (deltaICP0), KD6 (deltaICP4), and in1814, a virus containing an insertion mutation in VP16. Although growth of these mutant viruses was impaired in ND-PC12 cells, R7910 and in1814 reactivated at levels equivalent to or better than their respective parental controls following stress (i.e., heat or forskolin) treatment. After treatment with trichostatin A, in1814 and 17+ reactivated efficiently, whereas the F strain and R7910 reactivated inefficiently. In contrast, KD6 failed to reactivate. In experiments with the recombinant KM100, which contains the in1814 mutation in VP16 and the n212 mutation in ICP0, spontaneous and stress-induced reactivation was observed. However, two strains, V422 and KM110, which lack the acidic activation domain of VP16, did not reactivate above low spontaneous levels after stress. These results demonstrate that in QIF-PC12 cells ICP0 is not required for efficient reactivation of HSV-1, the acidic activation domain of VP16 is essential for stress-induced HSV-1 reactivation, and HSV-1 reactivation is modulated uniquely by different treatment constraints and phenotypes.
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Affiliation(s)
- Craig S Miller
- Center for Oral Health Research, University of Kentucky College of Dentistry, Lexington, KY 40536-0297, USA.
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152
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Blanchard Y, Dory D, Briand FX, Félix H, Jestin A. Degradation of cyclins D in pseudorabies virus (PRV) infected proliferating cells. Vet Microbiol 2006; 113:179-84. [PMID: 16330165 DOI: 10.1016/j.vetmic.2005.11.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The pseudorabies virus code for an ICP0 protein which is half the size of the HSV1 ICP0 protein. In this work, we made the assumption that some function might have been lost in the ICP0 from PRV. One function attributed to the ICP0 from HSV1 was the stabilization of cyclins D. We then looked at the stability of these cyclins during the lytic infection with the PRV. Our results show that cyclins D are not stabilized during infection with the PRV. These results are in accord with recent data from the literature.
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Affiliation(s)
- Yannick Blanchard
- Laboratoire de Génétique Virale et Biosécurité, Afssa. BP53, Fr-22440 Ploufragan, France.
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153
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Mohr I. To replicate or not to replicate: achieving selective oncolytic virus replication in cancer cells through translational control. Oncogene 2005; 24:7697-709. [PMID: 16299530 DOI: 10.1038/sj.onc.1209053] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
To ensure that their mRNAs are translated and that the viral proteins necessary for assembling the next generation of infectious progeny are produced, viruses must effectively seize control of the translational machinery within their host cells. In many cases, the ability to productively engage host translational components can determine if a given cell type can support viral replication, illustrating the critical importance of this task in the viral life cycle. Failure to interface properly with the host translational apparatus can compromise the productive growth cycle, resulting in an abortive infection and radically restricting viral replication. Not only have viruses become facile at commandeering this machinery, they are also particularly adept at manipulating cellular translation control pathways for their own ends. In this review, the mechanisms by which numerous viruses manipulate host translational control circuits are discussed. Furthermore, particular attention is devoted to understanding how interfering with the ability of a virus to properly regulate translation in its host can be exploited to generate oncolytic strains that selectively replicate in cancer cells.
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Affiliation(s)
- Ian Mohr
- Department of Microbiology, New York University School of Medicine, NY 10016, USA.
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154
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Narita T, Ando A, Mikami Y, Taniyama T. Overexpression of CIN85 suppresses the growth of herpes simplex virus in HeLa cells. Exp Cell Res 2005; 311:265-71. [PMID: 16223483 DOI: 10.1016/j.yexcr.2005.09.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2005] [Revised: 09/12/2005] [Accepted: 09/14/2005] [Indexed: 10/25/2022]
Abstract
The adaptor protein CIN85 is widely distributed in different tissues and has three Src homology 3 (SH3) domains, a proline-rich region (PRR), and a coiled-coil domain. During studies on the function of CIN85, it was reported to form a complex with herpes simplex virus 1 (HSV-1) infected cell protein 0 (ICP0), which plays a key role in enabling viral replication. Here, we demonstrate that plaque formation by HSV-1 is reduced on HeLa cells expressing CIN85 ectopically. The PRR of CIN85 was found to be essential for the inhibition of virus growth, whereas the three SH3 domains were not required. CIN85 also suppressed HSV-1 growth in Chinese hamster ovary (CHO) cells expressing the receptor for herpes simplex virus entry (herpes virus entry mediator A; HVEM). However, immunoprecipitation experiments showed that CIN85 did not interact with HVEM directly, indicating that CIN85 is not involved in the HSV-1 cell-entry pathway, but rather in another downstream pathway. Collectively, our data indicate that CIN85 might play an important role in HSV-1 infection.
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Affiliation(s)
- Tadashi Narita
- Laboratory of Bacterial Infection and Immunity, Department of Immunology, National Institute of Infectious Diseases, 1-23-1, Toyama, Shinjuku, Tokyo 162-8640, Japan
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155
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Pomeranz LE, Reynolds AE, Hengartner CJ. Molecular biology of pseudorabies virus: impact on neurovirology and veterinary medicine. Microbiol Mol Biol Rev 2005; 69:462-500. [PMID: 16148307 PMCID: PMC1197806 DOI: 10.1128/mmbr.69.3.462-500.2005] [Citation(s) in RCA: 580] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Pseudorabies virus (PRV) is a herpesvirus of swine, a member of the Alphaherpesvirinae subfamily, and the etiological agent of Aujeszky's disease. This review describes the contributions of PRV research to herpesvirus biology, neurobiology, and viral pathogenesis by focusing on (i) the molecular biology of PRV, (ii) model systems to study PRV pathogenesis and neurovirulence, (iii) PRV transsynaptic tracing of neuronal circuits, and (iv) veterinary aspects of pseudorabies disease. The structure of the enveloped infectious particle, the content of the viral DNA genome, and a step-by-step overview of the viral replication cycle are presented. PRV infection is initiated by binding to cellular receptors to allow penetration into the cell. After reaching the nucleus, the viral genome directs a regulated gene expression cascade that culminates with viral DNA replication and production of new virion constituents. Finally, progeny virions self-assemble and exit the host cells. Animal models and neuronal culture systems developed for the study of PRV pathogenesis and neurovirulence are discussed. PRV serves asa self-perpetuating transsynaptic tracer of neuronal circuitry, and we detail the original studies of PRV circuitry mapping, the biology underlying this application, and the development of the next generation of tracer viruses. The basic veterinary aspects of pseudorabies management and disease in swine are discussed. PRV infection progresses from acute infection of the respiratory epithelium to latent infection in the peripheral nervous system. Sporadic reactivation from latency can transmit PRV to new hosts. The successful management of PRV disease has relied on vaccination, prevention, and testing.
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Affiliation(s)
- Lisa E Pomeranz
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08540, USA.
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156
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Minaker RL, Mossman KL, Smiley JR. Functional inaccessibility of quiescent herpes simplex virus genomes. Virol J 2005; 2:85. [PMID: 16300675 PMCID: PMC1310514 DOI: 10.1186/1743-422x-2-85] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2005] [Accepted: 11/21/2005] [Indexed: 12/17/2022] Open
Abstract
Background Newly delivered herpes simplex virus genomes are subject to repression during the early stages of infection of human fibroblasts. This host defence strategy can limit virus replication and lead to long-term persistence of quiescent viral genomes. The viral immediate-early protein ICP0 acts to negate this negative regulation, thereby facilitating the onset of the viral replication cycle. Although few mechanistic details are available, the host repression machinery has been proposed to assemble the viral genome into a globally inaccessible configuration analogous to heterochromatin, blocking access to most or all trans-acting factors. The strongest evidence for this hypothesis is that ICP0-deficient virus is unable to reactivate quiescent viral genomes, despite its ability to undergo productive infection given a sufficiently high multiplicity of infection. However, recent studies have shown that quiescent infection induces a potent antiviral state, and that ICP0 plays a key role in disarming such host antiviral responses. These findings raise the possibility that cells containing quiescent viral genomes may be refractory to superinfection by ICP0-deficient virus, potentially providing an alternative explanation for the inability of such viruses to trigger reactivation. We therefore asked if ICP0-deficient virus is capable of replicating in cells that contain quiescent viral genomes. Results We found that ICP0-deficient herpes simplex virus is able to infect quiescently infected cells, leading to expression and replication of the superinfecting viral genome. Despite this productive infection, the resident quiescent viral genome was neither expressed nor replicated, unless ICP0 was provided in trans. Conclusion These data document that quiescent HSV genomes fail to respond to the virally modified host transcriptional apparatus or viral DNA replication machinery provided in trans by productive HSV infection in the absence of ICP0. These results point to global repression as the basis for HSV genome quiescence, and indicate that ICP0 induces reactivation by overcoming this global barrier to the access of trans-acting factors.
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Affiliation(s)
- Rebecca L Minaker
- Department of Medical Microbiology & Immunology, University of Alberta, Edmonton, Alberta, T6G 2S2, Canada
| | - Karen L Mossman
- Department of Medical Microbiology & Immunology, University of Alberta, Edmonton, Alberta, T6G 2S2, Canada
- Center for Gene Therapeutics, Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, L8N 3Z5, Canada
| | - James R Smiley
- Department of Medical Microbiology & Immunology, University of Alberta, Edmonton, Alberta, T6G 2S2, Canada
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157
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Mohr I. Phosphorylation and dephosphorylation events that regulate viral mRNA translation. Virus Res 2005; 119:89-99. [PMID: 16305812 DOI: 10.1016/j.virusres.2005.10.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2005] [Revised: 08/30/2005] [Accepted: 10/20/2005] [Indexed: 10/25/2022]
Abstract
As they are completely dependent upon the protein synthesis machinery resident in the cells of their host to translate their mRNAs, it is imperative that viruses are able to effectively manipulate the elaborate cellular regulatory network that controls translation. Indeed, this exquisite dependence on host functions has made viral models attractive systems to explore translational regulatory mechanisms operative in eukaryotic cells. Central among these are an intricate array of phosphorylation and dephosphorylation events that have far reaching consequences on the activity of cellular translation factors. Not only do these modulate the activity of a given factor, but they can also determine if the translation of host proteins persists in infected cells, the efficiency with which viral mRNAs are translated and the outcome of a systemic host anti-viral response. In this review, we discuss how various viruses manipulate the phosphorylation state of key cellular translation factors, illustrating the critical nature these interactions play in virus replication, pathogenesis and innate host defense.
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Affiliation(s)
- Ian Mohr
- Department of Microbiology, MSB 214, NYU Cancer Institute, New York University School of Medicine, 550 First Avenue, New York, NY 10016, USA.
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158
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Naito J, Mott KR, Osorio N, Jin L, Perng GC. Herpes simplex virus type 1 immediate-early protein ICP0 diffuses out of infected rabbit corneas. J Gen Virol 2005; 86:2979-2988. [PMID: 16227219 DOI: 10.1099/vir.0.81246-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Herpes stromal keratitis (HSK) results from infection of herpes simplex virus (HSV) in the cornea. Recurrent HSV infection is a leading cause of corneal scarring and visual loss. Although it is generally thought that HSK is the result of an immune response to one or more viral proteins, no viral proteins have been detected in HSK corneas. Thus, the viral proteins involved in HSK, if any, remain undetermined. In contrast, it is reported here that when HSK corneal buttons from latently infected rabbits were fixed using standard procedures, the important immediate-early HSV-1 protein ICP0 was readily detected in the fixative by Western blotting. Similarly, when HSK corneal buttons were soaked in buffer (rather than fixative), ICP0 was readily detected in the soaking buffer. Other HSV-1 proteins were not detected either in the fixative or in the soaking buffer. It is also reported here that ICP0 was consistently detected in virus-free tears from the eyes of rabbits acutely infected with HSV-1. These results suggest that ICP0 rapidly diffuses out of the cornea and may explain why ICP0 was detected in the fixative of HSK corneas and in the soaking buffer of acutely infected corneas.
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Affiliation(s)
- Julie Naito
- Department of Ophthalmology, School of Medicine, University of California at Irvine, Irvine, CA 92697, USA
| | - Kevin R Mott
- Department of Ophthalmology, School of Medicine, University of California at Irvine, Irvine, CA 92697, USA
| | - Nelson Osorio
- Department of Ophthalmology, School of Medicine, University of California at Irvine, Irvine, CA 92697, USA
| | - Ling Jin
- Department of Ophthalmology, School of Medicine, University of California at Irvine, Irvine, CA 92697, USA
| | - Guey-Chuen Perng
- Department of Ophthalmology, School of Medicine, University of California at Irvine, Irvine, CA 92697, USA
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159
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Boutell C, Canning M, Orr A, Everett RD. Reciprocal activities between herpes simplex virus type 1 regulatory protein ICP0, a ubiquitin E3 ligase, and ubiquitin-specific protease USP7. J Virol 2005; 79:12342-54. [PMID: 16160161 PMCID: PMC1211536 DOI: 10.1128/jvi.79.19.12342-12354.2005] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Herpes simplex virus type 1 (HSV-1) regulatory protein ICP0 stimulates lytic infection and the reactivation of quiescent viral genomes. These roles of ICP0 require its RING finger E3 ubiquitin ligase domain, which induces the degradation of several cellular proteins, including components of promyelocytic leukemia nuclear bodies and centromeres. ICP0 also interacts very strongly with the cellular ubiquitin-specific protease USP7 (also known as HAUSP). We have shown previously that ICP0 induces its own ubiquitination and degradation in a RING finger-dependent manner, and that its interaction with USP7 regulates this process. In the course of these studies we found and report here that ICP0 also targets USP7 for ubiquitination and proteasome-dependent degradation. The reciprocal activities of the two proteins reveal an intriguing situation that poses the question of the balance of the two processes during productive HSV-1 infection. Based on a thorough analysis of the properties of an HSV-1 mutant virus that expresses forms of ICP0 that are unable to bind to USP7, we conclude that USP7-mediated stabilization of ICP0 is dominant over ICP0-induced degradation of USP7 during productive HSV-1 infection. We propose that the biological significance of the ICP0-USP7 interaction may be most pronounced in natural infection situations, in which limited amounts of ICP0 are expressed.
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Affiliation(s)
- Chris Boutell
- MRC Virology Unit, Institute of Virology, Church Street, Glasgow G11 5JR, Scotland, United Kingdom
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160
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Abstract
For many years, the generally accepted model for the replication of the double-stranded DNA genome of herpes simplex virus type 1 (HSV-1) incorporated initial circularization of linear molecules in the cell nucleus. Ensuing DNA synthesis resulted in the generation of head-to-tail concatemers which were subsequently cleaved into monomeric units and packaged into the nascent viral capsid. Recently, however, it has been proposed that circularization of HSV-1 genomes does not occur at the onset of lytic infection and moreover that this event is specifically inhibited by the HSV-1 transcriptional transactivator, ICP0 (S.A. Jackson and N.A. DeLuca, Proc. Natl. Acad. Sci. USA 100:7871-7876, 2003). To further investigate genome circularization, we have generated HSV-1 derivatives in which the viral a sequences, which contain the cleavage-packaging signals, have been replaced by a minimal packaging element located in the thymidine kinase gene. In contrast to wild-type HSV-1, fusion of the genomic termini of these viruses produces a novel fragment in circular or concatemeric DNA which can be detected by Southern blot hybridization. Utilizing these viruses, we demonstrate that fusion of the genomic termini occurred rapidly upon infection and in the presence of inhibitors of viral DNA or protein synthesis. We provide evidence indicating that the end joining represented circularization rather than concatemerization of input molecules and that circularized molecules functioned as templates for replication. Since the termini of these viruses lack direct repeats, our findings indicate that circularization can be mediated by direct end-to-end ligation of linear input genomes.
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Affiliation(s)
- Blair L Strang
- MRC Virology Unit, Institute of Virology, University of Glasgow, Church St., Glasgow G11 5JR, United Kingdom
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161
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Ling PD, Peng RS, Nakajima A, Yu JH, Tan J, Moses SM, Yang WH, Zhao B, Kieff E, Bloch KD, Bloch DB. Mediation of Epstein-Barr virus EBNA-LP transcriptional coactivation by Sp100. EMBO J 2005; 24:3565-75. [PMID: 16177824 PMCID: PMC1276704 DOI: 10.1038/sj.emboj.7600820] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2005] [Accepted: 08/25/2005] [Indexed: 12/15/2022] Open
Abstract
The Epstein-Barr virus (EBV) EBNA-LP protein is important for EBV-mediated B-cell immortalization and is a potent gene-specific coactivator of the viral transcriptional activator, EBNA2. The mechanism(s) by which EBNA-LP functions as a coactivator remains an important question in the biology of EBV-induced B-cell immortalization. In this study, we found that EBNA-LP interacts with the promyelocytic leukemia nuclear body (PML NB)-associated protein Sp100 and displaces Sp100 and heterochromatin protein 1alpha (HP1alpha) from PML NBs. Interaction between EBNA-LP and Sp100 was mediated through conserved region 3 in EBNA-LP and the PML NB targeting domain in Sp100. Overexpression of Sp100 lacking the N-terminal PML NB targeting domain, but not a mutant form of Sp100 lacking the HP1alpha interaction domain, was sufficient to coactivate EBNA2 in a gene-specific manner independent of EBNA-LP. These findings suggest that Sp100 is a major mediator of EBNA-LP coactivation. These studies indicate that modulation of PML NB-associated proteins may be important for establishment of latent viral infections, and also identify a convenient model system to investigate the functions of Sp100.
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Affiliation(s)
- Paul D Ling
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Rong Sheng Peng
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Ayako Nakajima
- Department of Medicine, Harvard Medical School and Center for Immunology and Inflammatory Diseases of the General Medical Services, Massachusetts General Hospital, Boston, MA, USA
| | - Jiang H Yu
- Department of Medicine, Harvard Medical School and Center for Immunology and Inflammatory Diseases of the General Medical Services, Massachusetts General Hospital, Boston, MA, USA
| | - Jie Tan
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Stephanie M Moses
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, USA
| | - Wei-Hong Yang
- Department of Medicine, Harvard Medical School and Center for Immunology and Inflammatory Diseases of the General Medical Services, Massachusetts General Hospital, Boston, MA, USA
| | - Bo Zhao
- Departments of Medicine and Microbiology and Molecular Genetics, Channing Laboratory, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Elliott Kieff
- Departments of Medicine and Microbiology and Molecular Genetics, Channing Laboratory, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Kenneth D Bloch
- Department of Medicine, Harvard Medical School and Cardiovascular Research Center of the General Medical Services, Massachusetts General Hospital, Boston, MA, USA
| | - Donald B Bloch
- Department of Medicine, Harvard Medical School and Center for Immunology and Inflammatory Diseases of the General Medical Services, Massachusetts General Hospital, Boston, MA, USA
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162
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Abstract
The ability of viruses to co-opt cell signalling pathways has, over millions of years of co-evolution, come to pervade nearly every facet of cellular functions. Recognition of the extent to which the ubiquitin–proteasome system can be directed or subverted by viruses is relatively recent. Viral products interact with, and adjust, the ubiquitin–proteasome machinery precisely and at many levels, and they do so at distinct stages of viral life-cycles. The implications for both cells and viruses are fundamental, and understanding viral strategies in this context opens up fascinating new areas for research that span from basic cell biology to therapeutic interventions against both viruses and malignancies.
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163
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Abstract
Replication-selective oncolytic viruses have emerged as a new treatment platform for cancers. However, selectivity and potency need to be improved before virotherapy can become a standard treatment modality. In addition, mechanisms that can be incorporated to enable targeting a broad range of cancer types are highly desirable. Cancer cells are well known to have multiple blocks in apoptosis pathways. On the other hand, viruses have evolved to express numerous antiapoptotic genes to antagonize apoptosis induced upon infection. Viruses with deletions in antiapoptotic genes can therefore be complemented by antiapoptotic genetic changes in cancer cells for efficient replication and oncolysis. In this review, we summarize the recent development of this concept, the potential obstacles, and future directions for optimization.
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Affiliation(s)
- Ta-Chiang Liu
- Molecular Neurosurgery Laboratory, Massachusetts General Hospital and Harvard Medical School, MA, USA.
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164
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Abstract
The survival strategy of herpes simplex virus centres on the establishment of latency in sensory neurons innervating the site of primary infection followed by periodic reactivation to facilitate transmission. This is a highly evolved and efficient survival mechanism, which despite being the subject of intense research, has proven remarkably difficult to dissect at a molecular level. This review will focus on data, emerging from both in vitro and in vivo model systems, which provide a framework for a mechanistic understanding of latency and the existence and possible significance of non-uniform latent states.
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Affiliation(s)
- S Efstathiou
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK
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165
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Tanaka M, Nishiyama Y, Sata T, Kawaguchi Y. The role of protein kinase activity expressed by the UL13 gene of herpes simplex virus 1: the activity is not essential for optimal expression of UL41 and ICP0. Virology 2005; 341:301-12. [PMID: 16095647 DOI: 10.1016/j.virol.2005.07.010] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2005] [Revised: 06/17/2005] [Accepted: 07/07/2005] [Indexed: 11/21/2022]
Abstract
Herpes simplex virus 1 (HSV-1) UL13 is a viral protein kinase that is packaged into virions and regulates optimal expression of ICP0 and a subset of late (gamma) proteins, including UL41 in infected cells. In the present study, we investigated the role(s) of the protein kinase activity of UL13 in viral replication using a recombinant virus expressing enzymatically inactive UL13 after an amino acid substitution in the invariant lysine of UL13. The recombinant virus carrying this mutation formed smaller plaques yielded 10-fold less progeny than wild-type virus but could not be differentiated from wild-type virus with respect to accumulation of UL41 and ICP0 in infected cells. These results indicate that the protein kinase activity of UL13 plays a role in viral replication in cell culture, but the activity is not essential for the optimal expression of UL41 and ICP0.
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Affiliation(s)
- Michiko Tanaka
- Department of Pathology, National Institute of Infectious Disease, Shinjuku-ku, Tokyo 162-8640, Japan
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166
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Hadjipanayis CG, DeLuca NA. Inhibition of DNA repair by a herpes simplex virus vector enhances the radiosensitivity of human glioblastoma cells. Cancer Res 2005; 65:5310-6. [PMID: 15958578 DOI: 10.1158/0008-5472.can-04-3793] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Expression of the herpes simplex virus (HSV) protein, ICP0, from the viral genome, rendered two radioresistant human glioblastoma multiforme cell lines more sensitive to the effects of ionizing radiation. Using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and clonogenic survival assays, U87-MG and T98 cell survival was more greatly decreased as a function of ionizing radiation dose when ICP0 was preexpressed in cells compared with when ICP0 was not expressed. Consistent with previous results, we found that the catalytic subunit of DNA-dependent protein kinase was degraded as a function of ICP0 in both cell types. This most likely resulted in the inhibition of DNA repair as inferred by the persistence of gammaH2AX foci or DNA double-strand breaks. Enhanced apoptosis was also found to occur following irradiation of U87-MG cells preinfected with the ICP0-producing HSV-1 mutant, d106. Our results suggest that expression of ICP0 in human glioblastoma multiforme cells inhibits the repair of DNA double-strand breaks after ionizing radiation treatment, decreasing the survival of these cells in part by induction of apoptosis.
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Affiliation(s)
- Costas G Hadjipanayis
- Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA
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167
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Ellermann-Eriksen S. Macrophages and cytokines in the early defence against herpes simplex virus. Virol J 2005; 2:59. [PMID: 16076403 PMCID: PMC1215526 DOI: 10.1186/1743-422x-2-59] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2005] [Accepted: 08/03/2005] [Indexed: 11/12/2022] Open
Abstract
Herpes simplex virus (HSV) type 1 and 2 are old viruses, with a history of evolution shared with humans. Thus, it is generally well-adapted viruses, infecting many of us without doing much harm, and with the capacity to hide in our neurons for life. In rare situations, however, the primary infection becomes generalized or involves the brain. Normally, the primary HSV infection is asymptomatic, and a crucial element in the early restriction of virus replication and thus avoidance of symptoms from the infection is the concerted action of different arms of the innate immune response. An early and light struggle inhibiting some HSV replication will spare the host from the real war against huge amounts of virus later in infection. As far as such a war will jeopardize the life of the host, it will be in both interests, including the virus, to settle the conflict amicably. Some important weapons of the unspecific defence and the early strikes and beginning battle during the first days of a HSV infection are discussed in this review. Generally, macrophages are orchestrating a multitude of anti-herpetic actions during the first hours of the attack. In a first wave of responses, cytokines, primarily type I interferons (IFN) and tumour necrosis factor are produced and exert a direct antiviral effect and activate the macrophages themselves. In the next wave, interleukin (IL)-12 together with the above and other cytokines induce production of IFN-gamma in mainly NK cells. Many positive feed-back mechanisms and synergistic interactions intensify these systems and give rise to heavy antiviral weapons such as reactive oxygen species and nitric oxide. This results in the generation of an alliance against the viral enemy. However, these heavy weapons have to be controlled to avoid too much harm to the host. By IL-4 and others, these reactions are hampered, but they are still allowed in foci of HSV replication, thus focusing the activity to only relevant sites. So, no hero does it alone. Rather, an alliance of cytokines, macrophages and other cells seems to play a central role. Implications of this for future treatment modalities are shortly considered.
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Affiliation(s)
- Svend Ellermann-Eriksen
- Department of Clinical Microbiology, Aarhus University Hospital, Skejby Sygehus, Brendstrupgaardsvej 100, DK-8200 Aarhus N., Denmark.
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168
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Prechtel AT, Turza NM, Kobelt DJ, Eisemann JI, Coffin RS, McGrath Y, Hacker C, Ju X, Zenke M, Steinkasserer A. Infection of mature dendritic cells with herpes simplex virus type 1 dramatically reduces lymphoid chemokine-mediated migration. J Gen Virol 2005; 86:1645-1657. [PMID: 15914842 DOI: 10.1099/vir.0.80852-0] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Herpes simplex virus type 1 (HSV-1) is able to establish latency in infected individuals. In order to characterize potential new immune-escape mechanisms, mature dendritic cells (DCs) were infected with HSV-1 and total cellular RNA was isolated from infected and mock-infected populations at different time points. RNA profiling on Affymetrix Human Genome U133A arrays demonstrated a dramatic downregulation of the migration-mediating surface molecules CCR7 and CXCR4, an observation that was further confirmed by RT-PCR and fluorescence-activated cell sorting analyses. Furthermore, migration assays revealed that, upon infection of mature DCs, CCR7- and CXCR4-mediated migration towards the corresponding CCL19 and CXCL12 chemokine gradients was strongly reduced. It is noteworthy that the infection of immature DCs with HSV-1 prior to maturation led to a failure of CCR7 and CXCR4 upregulation during DC maturation and, as a consequence, also induced a block in their migratory capacity. Additional migration assays with a Δvhs mutant virus lacking the virion host shutoff (vhs) gene, which is known to degrade cellular mRNAs, suggested a vhs-independent mechanism. These results indicate that HSV-1-infected mature DCs are limited in their capacity to migrate to secondary lymphoid organs, the areas of antigen presentation and T-cell stimulation, thus inhibiting an antiviral immune response. This represents a novel, previously unrecognized mechanism for HSV-1 to escape the human immune system.
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Affiliation(s)
- Alexander T Prechtel
- Department of Dermatology, University Hospital Erlangen, Hartmannstrasse 14, D-91052 Erlangen, Germany
| | - Nadine M Turza
- Department of Dermatology, University Hospital Erlangen, Hartmannstrasse 14, D-91052 Erlangen, Germany
| | - Dieter J Kobelt
- Department of Dermatology, University Hospital Erlangen, Hartmannstrasse 14, D-91052 Erlangen, Germany
| | - Jutta I Eisemann
- Department of Dermatology, University Hospital Erlangen, Hartmannstrasse 14, D-91052 Erlangen, Germany
| | - Robert S Coffin
- BioVex Ltd, Oxford OX14 4RX, UK
- Department of Immunology and Molecular Pathology, University College London, London W1P 6DB, UK
| | | | - Christine Hacker
- Max Delbruck Center for Molecular Medicine, MDC, Robert-Rossle-Str. 10, 13092 Berlin, Germany
| | - Xinsheng Ju
- Institute for Biomedical Technology, Department of Cell Biology, University Hospital Aachen, Aachen, Germany
- Max Delbruck Center for Molecular Medicine, MDC, Robert-Rossle-Str. 10, 13092 Berlin, Germany
| | - Martin Zenke
- Institute for Biomedical Technology, Department of Cell Biology, University Hospital Aachen, Aachen, Germany
- Max Delbruck Center for Molecular Medicine, MDC, Robert-Rossle-Str. 10, 13092 Berlin, Germany
| | - Alexander Steinkasserer
- Department of Dermatology, University Hospital Erlangen, Hartmannstrasse 14, D-91052 Erlangen, Germany
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169
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Gu H, Liang Y, Mandel G, Roizman B. Components of the REST/CoREST/histone deacetylase repressor complex are disrupted, modified, and translocated in HSV-1-infected cells. Proc Natl Acad Sci U S A 2005; 102:7571-6. [PMID: 15897453 PMCID: PMC1140450 DOI: 10.1073/pnas.0502658102] [Citation(s) in RCA: 159] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The infected cell protein (ICP)0 enables gene expression and the replication of herpes simplex virus (HSV)-1 in cells infected at low multiplicities and enhances the expression of genes introduced into cells by transfection or infection. We report that a short sequence of ICP0 is similar to a sequence in the amino terminus of CoREST, a corepressor that exists in complexes with the repressor REST and histone deacetylases (HDACs) 1 or 2 to repress cellular gene expression. In wild-type-virus-infected cells, HDAC1 dissociates from the CoREST/REST complex, CoREST and HDAC1 are phosphorylated by a process mediated by viral protein kinases, and CoREST and HDAC1 are partially translocated to the cytoplasm. In cells infected with a virus mutant (DeltaICP4), in which ICP0 accumulates, but post-alpha gene expression is blocked, HDAC1 is dissociated from the CoREST/REST complex, but translocation to the cytoplasm does not occur. After infection with a mutant virus from which ICP0 is deleted, the complex remains intact, but, under conditions of productive infection, the complex is partially translocated to the cytoplasm. These results suggest that, at low multiplicities of infection, ICP0 blocks CoREST-mediated silencing of viral genes by dissociation of HDAC1, whereas subsequent modifications and translocation of the components of the complex are the functions of other viral gene products made later in infection.
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Affiliation(s)
- Haidong Gu
- Marjorie B. Kovler Viral Oncology Laboratories, University of Chicago, Chicago, IL 60637, USA
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170
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Morency E, Couté Y, Thomas J, Texier P, Lomonte P. The protein ICP0 of herpes simplex virus type 1 is targeted to nucleoli of infected cells. Arch Virol 2005; 150:2387-95. [PMID: 15883654 DOI: 10.1007/s00705-005-0546-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2005] [Accepted: 03/23/2005] [Indexed: 10/25/2022]
Abstract
This study describes the nucleolar localization of the viral protein ICP0 of herpes simplex virus type 1. We show that the RING finger domain of ICP0 is essential for ICP0 to localize in nucleoli of transfected and 4 hour-infected cells. ICP0 forms particular intranucleolar domains that do not correspond to any known nucleolar domains. This distribution was confirmed by immunoblots performed on fractionated infected cells. Quantitative RT-PCR experiments indicated that ICP0 did not increase the transcription from the RNA polymerase I (Pol I) promoter in transfected cells, an effect opposite to that observed on viral and cellular Pol II promoters. Nucleoli are thus, after PML bodies and centromeres, a novel nuclear structure targeted by ICP0.
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Affiliation(s)
- E Morency
- Centre de Génétique Moléculaire et Cellulaire, UMR5534-CNRS, Equipe Silencing Viral et Remodelage de la Chromatine Université Claude Bernard Lyon 1, Villeurbanne, France
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171
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Peng R, Moses SC, Tan J, Kremmer E, Ling PD. The Epstein-Barr virus EBNA-LP protein preferentially coactivates EBNA2-mediated stimulation of latent membrane proteins expressed from the viral divergent promoter. J Virol 2005; 79:4492-505. [PMID: 15767449 PMCID: PMC1061541 DOI: 10.1128/jvi.79.7.4492-4505.2005] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The mechanistic contribution of the Epstein-Barr virus (EBV) EBNA-LP protein to B-cell immortalization remains an enigma. However, previous studies have indicated that EBNA-LP may contribute to immortalization by enhancing EBNA2-mediated transcriptional activation of the LMP-1 gene. To gain further insight into the potential role EBNA-LP has in EBV-mediated B-cell immortalization, we asked whether it is a global or gene-specific coactivator of EBNA2 and whether coactivation requires interaction between these proteins. In type I Burkitt's lymphoma cells, we found that EBNA-LP strongly coactivated EBNA2 stimulation of LMP-1 and LMP2B RNAs, which are expressed from the viral divergent promoter. Surprisingly, the viral LMP2A gene and cellular CD21 and Hes-1 genes were induced by EBNA2 but showed no further induction after EBNA-LP coexpression. We also found that EBNA-LP did not stably interact with EBNA2 in coimmunoprecipitation assays, even though the conditions were adequate to observe specific interactions between EBNA2 and its cellular cofactor, CBF1. Colocalization between EBNA2 and EBNA-LP was not detectable in EBV-transformed cell lines or transfected type I Burkitt's cells. Finally, no significant interactions between EBNA2 and EBNA-LP were found with mammalian two-hybrid assays. From this data, we conclude that EBNA-LP is not a global coactivator of EBNA2 targets, but it preferentially coactivates EBNA2 stimulation of the viral divergent promoter. While this may require specific transient interactions between these proteins that only occur in the context of the divergent promoter, our data strongly suggest that EBNA-LP also cooperates with EBNA2 through mechanisms that do not require direct or indirect complex formation between these proteins.
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Affiliation(s)
- Rongsheng Peng
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX 77030, USA
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172
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Liang Y, Kurakin A, Roizman B. Herpes simplex virus 1 infected cell protein 0 forms a complex with CIN85 and Cbl and mediates the degradation of EGF receptor from cell surfaces. Proc Natl Acad Sci U S A 2005; 102:5838-43. [PMID: 15824310 PMCID: PMC556299 DOI: 10.1073/pnas.0501253102] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Infected cell protein 0 (ICP0) is a 775-residue multifunctional herpes simplex virus protein associated with numerous functions related to transactivation of gene expression and repression of host defenses to infection. We report that an uncharted domain of ICP0 located between residues 245 and 510 contains multiple SH3 domain binding motifs similar to those required for binding to CIN85, the M(r) 85,000 protein that interacts with Cbl. CIN85 and Cbl are involved in endocytosis and negative regulation of numerous receptor tyrosine kinases. We report that ICP0 binds CIN85 in a reciprocal manner and that the complexes pulled down by ICP0 also contain Cbl. We tested the role of ICP0 in the down-regulation of receptor tyrosine kinases by using epidermal growth factor receptor (EGFR) as a prototypic receptor. In transfection assays, ICP0, in the absence of other viral genes, down-regulated EGF-dependent expression of a reporter gene (luciferase). ICP0 also down-regulated both total and cell surface levels of EGFR in EGF-independent manner. In wild-type virus-infected cells, the surface levels of EGFR were also decreased in the absence of EGF stimulation. Stimulation by EGF enhanced the decrease in surface EGFR. We conclude that ICP0 encodes SH3 domain binding sites that function to down-regulate signaling pathways associated with receptor tyrosine kinases. The results suggest that ICP0 precludes signaling to the infected cells through the receptor tyrosine kinases.
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Affiliation(s)
- Yu Liang
- The Marjorie B. Kovler Viral Oncology Laboratories, University of Chicago, 910 East 58th Street, Chicago, IL 60637, USA
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173
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Kawaguchi Y, Tanaka M. [BAC system: A novel method for manipulation of herpesvirus genomes based on bacterial genetics]. Uirusu 2005; 54:255-64. [PMID: 15745165 DOI: 10.2222/jsv.54.255] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Although methods for reverse genetics of herpesviruses have been established in early 1980s, the steps are laborious and time-consuming. In 1997, Dr. Koszinwski's group reported a novel approach for the construction of herpesvirus mutants, based on cloning the viral genome as a bacterial artificial chromosome (BAC) in E. coli. This technique allows the maintenance of viral genomes as plasmid in E. coli and the reconstitution of viral progeny by transfection of the BAC plasmid into eukaryotic cells. Any genetics modification of the viral genome in E. coli using bacterial genetics is possible, thereby facilitating the introduction of mutagenesis into herpesvirus genome. This 'BAC system' has opened new avenues for reverse and forward genetics of herpesviruses in basic research and in vector development for human therapy. Here we describe the principle of the 'BAC system' in herpesvirus researches.
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Affiliation(s)
- Yasushi Kawaguchi
- Department of Virology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya, Japan.
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174
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Preston CM, Nicholl MJ. Human cytomegalovirus tegument protein pp71 directs long-term gene expression from quiescent herpes simplex virus genomes. J Virol 2005; 79:525-35. [PMID: 15596845 PMCID: PMC538741 DOI: 10.1128/jvi.79.1.525-535.2005] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The human cytomegalovirus tegument protein pp71 is important for transactivation of immediate-early (IE) gene expression and for the efficient initiation of virus replication. We have analyzed the properties of pp71 by assaying its effects on gene expression from the genome of in1312, a herpes simplex virus type 1 (HSV-1) mutant devoid of functional VP16, ICP0, and ICP4. Upon infection of human fibroblasts, in1312-derived viruses are repressed and retained in a quiescent state, but the presence of pp71 prevented the quiescent state from being attained. Reporter gene cassettes cloned into the in1312 genome, in addition to the endogenous IE promoters, remained active for at least 12 days postinfection, and infected cells were viable and morphologically normal. Cells expressing pp71 remained responsive to the HSV-1 transactivating factors VP16 and ICP4 and to trichostatin A. The C-terminal 61 amino acids, but not the LACSD motif, were required for pp71 activity. In addition to preventing attainment of quiescence, pp71 was able to disrupt the quiescent state of in1312 derivatives and promote the resumption of viral gene expression after a lag of approximately 3 days. The results extend the functional analysis of pp71 and suggest a degree of similarity with the HSV-1 IE protein ICP0. The ability to provoke slow reactivation of quiescent genomes, in conjunction with cell survival, represents a novel property for a viral structural protein.
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Affiliation(s)
- Chris M Preston
- Medical Research Council Virology Unit, Glasgow, Scotland, United Kingdom.
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175
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Kim SK, Albrecht RA, O'Callaghan DJ. A negative regulatory element (base pairs -204 to -177) of the EICP0 promoter of equine herpesvirus 1 abolishes the EICP0 protein's trans-activation of its own promoter. J Virol 2004; 78:11696-706. [PMID: 15479811 PMCID: PMC523287 DOI: 10.1128/jvi.78.21.11696-11706.2004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The early EICP0 protein is a powerful trans-activator that activates all classes of equine herpesvirus 1 (EHV-1) promoters but, unexpectedly, trans-activates its own promoter very weakly. Transient transfection assays that employed constructs harboring deletions within the EICP0 promoter indicated that EICP0 cis-acting sequences within bp -224 to -158 relative to the first ATG abolished the EICP0 protein's trans-activation of its own promoter. When inserted into the promoters of other EHV-1 genes, this sequence also downregulated activation of the immediate-early IE(-169/+73), early thymidine kinase TK(-215/+97), and late glycoprotein K gK(-83/+14) promoters, indicating that the cis-acting sequence (-224 to -158) downregulated expression of representative promoters of all classes of EHV-1 genes and contains a negative regulatory element (NRE). To define the cis-acting element(s), three synthetic oligonucleotides (Na [bp -224 to -195], Nb [bp -204 to -177], and Nc [bp -185 to -156]) were synthesized and cloned upstream of the EICP0(-157/-21) promoter. Of the three synthetic sequences, only the Nb oligonucleotide caused the downregulation of the EICP0 promoter. The NRE was identified as a 28-bp element to lie at -204 to -177 that encompassed the sequence of ([-204]AGATACAGATGTTCGATAAATTGGAACC[-177]). Gel shift assays performed with mouse L-M, rabbit RK-13, and human HeLa cell nuclear extracts and gamma-(32)P-labeled wild-type and mutant NREs demonstrated that a ubiquitous nuclear protein(s) (NRE-binding protein, NREBP) binds specifically to a sequence (bp -193 to -183) in the NRE. The NREBP is also present in the nucleus of EHV-1-infected cells; however, the amount of NREBP in EHV-1-infected L-M cells that bound to the Nb oligonucleotide was reduced compared to that in uninfected L-M cells. Transient transfection assays showed that deletions or mutations within the NREBP-binding site abolished the NRE activity of the EICP0 promoter. These results suggested that the NREBP may mediate the NRE activity of the EICP0 promoter and may function in the coordinate expression of EHV-1 genes.
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Affiliation(s)
- Seong K Kim
- Department of Microbiology and Immunology, Louisiana State University Health Sciences Center, 1501 Kings Highway, P.O. Box 33932, Shreveport, LA 71130-3932, USA
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176
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Huang J, Huang Q, Zhou X, Shen MM, Yen A, Yu SX, Dong G, Qu K, Huang P, Anderson EM, Daniel-Issakani S, Buller RML, Payan DG, Lu HH. The poxvirus p28 virulence factor is an E3 ubiquitin ligase. J Biol Chem 2004; 279:54110-6. [PMID: 15496420 DOI: 10.1074/jbc.m410583200] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A majority of the orthopoxviruses, including the variola virus that causes the dreaded smallpox disease, encode a highly conserved 28-kDa protein with a classic RING finger sequence motif (C(3)HC(4)) at their carboxyl-terminal domains. The RING domain of p28 has been shown to be a critical determinant of viral virulence for the ectromelia virus (mousepox virus) in a murine infection model (Senkevich, T. G., Koonin, E. V., and Buller, R. M. (1994) Virology 198, 118-128). Here, we demonstrate that the p28 proteins encoded by the ectromelia virus and the variola virus possess E3 ubiquitin ligase activity in biochemical assays as well as in cultured mammalian cells. Point mutations disrupting the RING finger domain of p28 completely abolish its E3 ligase activity. In addition, p28 functions cooperatively with Ubc4 and UbcH5c, the E2 conjugating enzymes involved in 26 S proteasome degradation of protein targets. Moreover, p28 catalyzes the formation of Lys-63-linked polyubiquitin chains in the presence of Ubc13/Uev1A, a heterodimeric E2 conjugating enzyme, indicating that p28 may regulate the biological activity of its cognate viral and/or host cell target(s) by Lys-63-linked ubiquitin multimers. We thus conclude that the poxvirus p28 virulence factor is a new member of the RING finger E3 ubiquitin ligase family and has a unique polyubiquitylation activity. We propose that the E3 ligase activity of the p28 virulence factor may be targeted for therapeutic intervention against infections by the variola virus and other poxviruses.
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Affiliation(s)
- Jianing Huang
- Rigel Pharmaceuticals, Inc., South San Francisco, California 94080, USA
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177
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Everett RD, Zafiropoulos A. Visualization by live-cell microscopy of disruption of ND10 during herpes simplex virus type 1 infection. J Virol 2004; 78:11411-5. [PMID: 15452264 PMCID: PMC521835 DOI: 10.1128/jvi.78.20.11411-11415.2004] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2004] [Accepted: 06/01/2004] [Indexed: 11/20/2022] Open
Abstract
ND10 structures are disrupted during herpes simplex virus type 1 (HSV-1) infection by viral regulatory protein ICP0. The significance of this effect remains controversial, partly because of a report that high-level expression of the major ND10 promyelocytic leukemia (PML) protein precludes ND10 disruption yet does not inhibit HSV-1 infection. Here we demonstrate dramatic reorganization of ND10 during HSV-1 infection by live-cell microscopy, even in the presence of overexpressed PML.
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Affiliation(s)
- Roger D Everett
- MRC Virology Unit, Church Street, University of Glasgow, Glasgow G11 5JR, Scotland, United Kingdom.
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178
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Everett RD. Herpes simplex virus type 1 regulatory protein ICP0 does not protect cyclins D1 and D3 from degradation during infection. J Virol 2004; 78:9599-604. [PMID: 15331692 PMCID: PMC514960 DOI: 10.1128/jvi.78.18.9599-9604.2004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Previous reports have suggested that herpes simplex virus type 1 (HSV-1) immediate-early regulatory protein ICP0 stabilizes cyclins D1 and D3 during infection by inducing the degradation of cdc34, the E2-conjugating enzyme that is responsible for regulating the stability of these cyclins. Since ICP0 has complex effects on the progress of viral infection that vary greatly with cell type and viral dose, it can be difficult to distinguish between direct effects caused by ICP0 itself and indirect effects caused by the rate of the progression of infection in the absence of ICP0 at the chosen multiplicity of infection. This report describes the fates of cdc34 and cyclins D1 and D3 during HSV-1 infection under conditions that ensured that viral infection and gene expression were proceeding at equivalent rates in the presence and absence of ICP0. It was confirmed that both D-type cyclins were unstable during HSV-1 infection of a variety of cell types, but no effect on cdc34 was observed, even when high levels of ICP0 were expressed. Furthermore, there was no evidence that ICP0 protected either cyclin D1 or cyclin D3 from degradation. Reconstruction of the conditions of the experiments in the previous studies, using the stated cell type and multiplicities of infection, indicated that the original results could be explained by differences in the rate of progression of infection rather than by the presence or absence of ICP0. The data presented in this report are incompatible with the hypothesis that ICP0 induces the degradation of cdc34 and thereby stabilizes cyclins D1 and D3 during HSV-1 infection.
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Affiliation(s)
- Roger D Everett
- MRC Virology Unit, Church St., Glasgow G11 5JR, Scotland, United Kingdom.
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179
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Keckesova Z, Ylinen LMJ, Towers GJ. The human and African green monkey TRIM5alpha genes encode Ref1 and Lv1 retroviral restriction factor activities. Proc Natl Acad Sci U S A 2004; 101:10780-5. [PMID: 15249687 PMCID: PMC490011 DOI: 10.1073/pnas.0402474101] [Citation(s) in RCA: 291] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The rhesus macaque tripartite motif containing protein TRIM5alpha specifically restricts HIV-1 infection at an early post-entry step before reverse transcription [Stremlau, M., Owens, C. M., Perron, M. J., Kiessling, M., Autissier, P. & Sodroski, J. (2004) Nature 427, 848-853]. Here, we show that the human and African green monkey (AGM) TRIM5alpha genes encode Ref1 and Lv1 antiretroviral activities, respectively. Expression of TRIM5alpha in permissive cat cells renders them resistant to restriction-sensitive murine leukemia virus but not closely related insensitive virus. Disruption of TRIM5alpha expression in human and AGM cells with small interfering RNA rescues infectivity of restricted virus without affecting unrestricted virus. We also demonstrate that the activity of the murine restriction factor Fv1 depends on TRIM5alpha expression when Fv1 is expressed in human cells. Furthermore, a drug that modifies the behavior of the related promyelocytic leukemia protein PML specifically rescues infection by viruses restricted by human TRIM5alpha. Alignment of the TRIM5alpha proteins from rhesus macaque and AGM indicates an 18-aa insertion. We speculate that this insertion may contribute to the broader specificity of the AGM TRIM5alpha restriction as compared with the human and rhesus macaque proteins.
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Affiliation(s)
- Zuzana Keckesova
- Wohl Virion Center, Division of Infection and Immunity, University College London, London W1T 4JF, United Kingdom
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180
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Canning M, Boutell C, Parkinson J, Everett RD. A RING finger ubiquitin ligase is protected from autocatalyzed ubiquitination and degradation by binding to ubiquitin-specific protease USP7. J Biol Chem 2004; 279:38160-8. [PMID: 15247261 DOI: 10.1074/jbc.m402885200] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Herpes simplex virus type 1 immediate-early regulatory protein ICP0 stimulates lytic infection and reactivation from latency, processes that require the ubiquitin E3 ligase activity mediated by the RING finger domain in the N-terminal portion of the protein. ICP0 stimulates the production of polyubiquitin chains by the ubiquitin-conjugating enzymes UbcH5a and UbcH6 in vitro, and in infected and transfected cells it induces the proteasome-dependent degradation of a number of cellular proteins including PML, the major constituent protein of PML nuclear bodies. However, ICP0 binds strongly to the cellular ubiquitin-specific protease USP7, a member of a family of proteins that cleave polyubiquitin chains and/or ubiquitin precursors. The region of ICP0 that is required for its interaction with USP7 has been mapped, and mutations in this domain reduce the functionality of ICP0. These findings pose the question: why does ICP0 include domains that are associated with the potentially antagonistic functions of ubiquitin conjugation and deconjugation? Here we report that although neither protein affected the intrinsic activities of the other in vitro, USP7 protected ICP0 from autoubiquitination in vitro, and their interaction can greatly increase the stability of ICP0 in vivo. These results demonstrate that RING finger-mediated autoubiquitination of ICP0 is biologically relevant and can be regulated by interaction with USP7. This principle may extend to a number of cellular RING finger E3 ubiquitin ligase proteins that have analogous interactions with ubiquitin-specific cleavage enzymes.
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Affiliation(s)
- Mary Canning
- Medical Research Council Virology Unit, Church Street, Glasgow G11 5JR, Scotland, United Kingdom
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181
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Shackelford J, Pagano JS. Tumor viruses and cell signaling pathways: deubiquitination versus ubiquitination. Mol Cell Biol 2004; 24:5089-93. [PMID: 15169876 PMCID: PMC419865 DOI: 10.1128/mcb.24.12.5089-5093.2004] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Julia Shackelford
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7295, USA
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