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Marcocci ME, Napoletani G, Protto V, Kolesova O, Piacentini R, Li Puma DD, Lomonte P, Grassi C, Palamara AT, De Chiara G. Herpes Simplex Virus-1 in the Brain: The Dark Side of a Sneaky Infection. Trends Microbiol 2020; 28:808-820. [PMID: 32386801 DOI: 10.1016/j.tim.2020.03.003] [Citation(s) in RCA: 145] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 02/27/2020] [Accepted: 03/25/2020] [Indexed: 12/22/2022]
Abstract
Herpes simplex virus-1 (HSV-1) establishes latency preferentially in sensory neurons of peripheral ganglia. A variety of stresses can induce recurrent reactivations of the virus, which spreads and then actively replicates to the site of primary infection (usually the lips or eyes). Viral particles produced following reactivation can also reach the brain, causing a rare but severe form of diffuse acute infection, namely herpes simplex encephalitis. Most of the time, this infection is clinically asymptomatic. However, it was recently correlated with the production and accumulation of neuropathological biomarkers of Alzheimer's disease. In this review we discuss the different cellular and molecular mechanisms underlying the acute and long-term damage caused by HSV-1 infection in the brain.
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Affiliation(s)
- Maria Elena Marcocci
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Laboratory affiliated to Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Rome, Italy
| | - Giorgia Napoletani
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Laboratory affiliated to Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Rome, Italy
| | - Virginia Protto
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Laboratory affiliated to Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Rome, Italy
| | - Olga Kolesova
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Laboratory affiliated to Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Rome, Italy
| | - Roberto Piacentini
- Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy; Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Domenica Donatella Li Puma
- Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy; Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Patrick Lomonte
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U 1217, Institut NeuroMyoGène (INMG), Lyon, France
| | - Claudio Grassi
- Department of Neuroscience, Università Cattolica del Sacro Cuore, Rome, Italy; Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Anna Teresa Palamara
- Department of Public Health and Infectious Diseases, Sapienza University of Rome, Laboratory affiliated to Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Rome, Italy; San Raffaele Pisana, IRCCS, Telematic University, Rome, Italy.
| | - Giovanna De Chiara
- Institute of Translational Pharmacology, National Research Council, Rome, Italy
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An Immortalized Human Dorsal Root Ganglion Cell Line Provides a Novel Context To Study Herpes Simplex Virus 1 Latency and Reactivation. J Virol 2017; 91:JVI.00080-17. [PMID: 28404842 DOI: 10.1128/jvi.00080-17] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 04/01/2017] [Indexed: 01/20/2023] Open
Abstract
A defining characteristic of alphaherpesviruses is the establishment of lifelong latency in host sensory ganglia with occasional reactivation causing recurrent lytic infections. As an alternative to rodent models, we explored the use of an immortalized cell line derived from human dorsal root ganglia. HD10.6 cells proliferate by virtue of a transduced tetracycline-regulated v-myc oncogene. In the presence of doxycycline, HD10.6 cells mature to exhibit neuronal morphology and express sensory neuron-associated markers such as neurotrophin receptors TrkA, TrkB, TrkC, and RET and the sensory neurofilament peripherin. Infection of mature HD10.6 neurons by herpes simplex virus 1 (HSV-1) results in a delayed but productive infection. However, infection at a low multiplicity of infection (MOI) in the presence of acyclovir results in a quiescent infection resembling latency in which viral genomes are retained in a low number of neurons, viral gene expression is minimal, and infectious virus is not released. At least some of the quiescent viral genomes retain the capacity to reactivate, resulting in viral DNA replication and release of infectious virus. Reactivation can be induced by depletion of nerve growth factor; other commonly used reactivation stimuli have no significant effect.IMPORTANCE Infections by herpes simplex viruses (HSV) cause painful cold sores or genital lesions in many people; less often, they affect the eye or even the brain. After the initial infection, the virus remains inactive or latent in nerve cells that sense the region where that infection occurred. To learn how virus maintains and reactivates from latency, studies are done in neurons taken from rodents or in whole animals to preserve the full context of infection. However, some cellular mechanisms involved in HSV infection in rodents are different from those in humans. We describe the use of a human cell line that has the properties of a sensory neuron. HSV infection in these cultured cells shows the properties expected for a latent infection, including reactivation to produce newly infectious virus. Thus, we now have a cell culture model for latency that is derived from the normal host for this virus.
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Phelan D, Barrozo ER, Bloom DC. HSV1 latent transcription and non-coding RNA: A critical retrospective. J Neuroimmunol 2017; 308:65-101. [PMID: 28363461 DOI: 10.1016/j.jneuroim.2017.03.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 03/02/2017] [Accepted: 03/02/2017] [Indexed: 12/22/2022]
Abstract
Virologists have invested great effort into understanding how the herpes simplex viruses and their relatives are maintained dormant over the lifespan of their host while maintaining the poise to remobilize on sporadic occasions. Piece by piece, our field has defined the tissues in play (the sensory ganglia), the transcriptional units (the latency-associated transcripts), and the responsive genomic region (the long repeats of the viral genomes). With time, the observed complexity of these features has compounded, and the totality of viral factors regulating latency are less obvious. In this review, we compose a comprehensive picture of the viral genetic elements suspected to be relevant to herpes simplex virus 1 (HSV1) latent transcription by conducting a critical analysis of about three decades of research. We describe these studies, which largely involved mutational analysis of the notable latency-associated transcripts (LATs), and more recently a series of viral miRNAs. We also intend to draw attention to the many other less characterized non-coding RNAs, and perhaps coding RNAs, that may be important for consideration when trying to disentangle the multitude of phenotypes of the many genetic modifications introduced into recombinant HSV1 strains.
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Affiliation(s)
- Dane Phelan
- Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, United States.
| | - Enrico R Barrozo
- Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, United States.
| | - David C Bloom
- Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, United States.
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Field HJ, Thackray AM. Can Herpes Simplex Virus Latency Be Prevented Using Conventional Nucleoside Analogue Chemotherapy? ACTA ACUST UNITED AC 2016. [DOI: 10.1177/09563202970080s612] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This review summarizes work that has been published recently in several papers reporting the effects of famciclovir and valaciclovir therapy on the establishment of herpes simplex virus (HSV) latency in a murine cutaneous infection model. For both HSV-1 and HSV-2 infections, therapy with famciclovir or valaciclovir from 1 or 2 days after virus inoculation reduced the ability to reactivate infectious virus from explanted ganglia when this was attempted several weeks after the primary infection. For famciclovir, the reduced ability to reactivate virus was also apparent in mice in which the onset of therapy was delayed for up to 3–5 days after virus inoculation. When more sensitive methods were employed to detect latency, all mice were found to be positive for latent infections in the ganglia, including those from mice receiving early therapy. However, for mice that had received oral famciclovir treatment the relative number of latently infected ganglion cells, as determined by infectious centres, appeared to be greatly reduced; this is thought to explain the failure to reactivate virus by means of the explant method. These results show a marked difference in activity between famciclovir and valaciclovir in this model and suggest that prompt therapy of first episode herpes by means of famciclovir may be able to reduce the establishment of latency in humans, where the establishment of latent infections in ganglionic neurons is thought to be a slower process than that observed in mice.
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Affiliation(s)
- HJ Field
- Centre for Veterinary Science, University of Cambridge, Madingley Road, Cambridge, CB3 OES, UK
| | - AM Thackray
- Centre for Veterinary Science, University of Cambridge, Madingley Road, Cambridge, CB3 OES, UK
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Ma JZ, Russell TA, Spelman T, Carbone FR, Tscharke DC. Lytic gene expression is frequent in HSV-1 latent infection and correlates with the engagement of a cell-intrinsic transcriptional response. PLoS Pathog 2014; 10:e1004237. [PMID: 25058429 PMCID: PMC4110040 DOI: 10.1371/journal.ppat.1004237] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 05/23/2014] [Indexed: 12/11/2022] Open
Abstract
Herpes simplex viruses (HSV) are significant human pathogens that provide one of the best-described examples of viral latency and reactivation. HSV latency occurs in sensory neurons, being characterized by the absence of virus replication and only fragmentary evidence of protein production. In mouse models, HSV latency is especially stable but the detection of some lytic gene transcription and the ongoing presence of activated immune cells in latent ganglia have been used to suggest that this state is not entirely quiescent. Alternatively, these findings can be interpreted as signs of a low, but constant level of abortive reactivation punctuating otherwise silent latency. Using single cell analysis of transcription in mouse dorsal root ganglia, we reveal that HSV-1 latency is highly dynamic in the majority of neurons. Specifically, transcription from areas of the HSV genome associated with at least one viral lytic gene occurs in nearly two thirds of latently-infected neurons and more than half of these have RNA from more than one lytic gene locus. Further, bioinformatics analyses of host transcription showed that progressive appearance of these lytic transcripts correlated with alterations in expression of cellular genes. These data show for the first time that transcription consistent with lytic gene expression is a frequent event, taking place in the majority of HSV latently-infected neurons. Furthermore, this transcription is of biological significance in that it influences host gene expression. We suggest that the maintenance of HSV latency involves an active host response to frequent viral activity. Primary herpes simplex virus (HSV) infections are characterized by acute disease that resolves rapidly, but the virus persists in a latent form in sensory neurons that can be a source of renewed disease. Analyzing gene expression in single mouse neurons harboring latent HSV, we show directly that HSV latency is dynamic and heterogeneous. HSV lytic gene transcripts were frequently detected in latently infected neurons and often in combinations. Expression of selected cellular anti-viral and survival genes showed that transcriptional profiles differed between latently infected and uninfected neurons from the same ganglia. The pattern of host gene expression also differed between latently infected neurons that were and were not experiencing HSV lytic gene expression. Our study suggests that HSV latency is characterized by very frequent switching on of lytic genes and a rapid response by the host, presumably to halt progression to reactivation.
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Affiliation(s)
- Joel Z. Ma
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
- * E-mail: (JZM); (FRC); (DCT)
| | - Tiffany A. Russell
- Division of Biomedical Science and Biochemistry, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
| | - Tim Spelman
- Victorian Infectious Diseases Service, Melbourne Health, Melbourne, Victoria, Australia
- Centre of Population Health, Burnet Institute, Melbourne, Victoria, Australia
| | - Francis R. Carbone
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
- * E-mail: (JZM); (FRC); (DCT)
| | - David C. Tscharke
- Division of Biomedical Science and Biochemistry, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory, Australia
- * E-mail: (JZM); (FRC); (DCT)
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6
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Zheng B, Li M, Gao S, Wang L, Qi Y, Ma Y, Ruan Q. Characterization of a novel group of antisense transcripts in human cytomegalovirus UL83 gene region. J Med Virol 2014; 86:2033-41. [PMID: 24615924 DOI: 10.1002/jmv.23887] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/18/2013] [Indexed: 11/11/2022]
Abstract
The rapid advances in research on antisense transcripts are gradually changing our understanding of the expression of the Herpesviridae genome. In this study, the transcripts of the human cytomegalovirus (HCMV) UL83 antisense strand were investigated in three clinical isolates. Three cDNA clones containing sequences with an antisense orientation to the UL83 gene were identified in a late HCMV cDNA library. The UL83 antisense transcripts (UL83asts) were then shown to be transcribed only in the late infection phase of the three clinical HCMV strains, using rapid amplification of cDNA ends (RACE) and northern blotting. These UL83asts were identical at their 3' termini but different at 5' ends. Two open reading frames were predicted in the UL83asts.
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Affiliation(s)
- Bo Zheng
- Virus Laboratory, The affiliated Shengjing Hospital, China Medical University, Shenyang, Liaoning, China
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van Velzen M, Jing L, Osterhaus ADME, Sette A, Koelle DM, Verjans GMGM. Local CD4 and CD8 T-cell reactivity to HSV-1 antigens documents broad viral protein expression and immune competence in latently infected human trigeminal ganglia. PLoS Pathog 2013; 9:e1003547. [PMID: 23966859 PMCID: PMC3744444 DOI: 10.1371/journal.ppat.1003547] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 06/26/2013] [Indexed: 11/26/2022] Open
Abstract
Herpes simplex virus type 1 (HSV-1) infection results in lifelong chronic infection of trigeminal ganglion (TG) neurons, also referred to as neuronal HSV-1 latency, with periodic reactivation leading to recrudescent herpetic disease in some persons. HSV-1 proteins are expressed in a temporally coordinated fashion during lytic infection, but their expression pattern during latent infection is largely unknown. Selective retention of HSV-1 reactive T-cells in human TG suggests their role in controlling reactivation by recognizing locally expressed HSV-1 proteins. We characterized the HSV-1 proteins recognized by virus-specific CD4 and CD8 T-cells recovered from human HSV-1–infected TG. T-cell clusters, consisting of both CD4 and CD8 T-cells, surrounded neurons and expressed mRNAs and proteins consistent with in situ antigen recognition and antiviral function. HSV-1 proteome-wide scans revealed that intra-TG T-cell responses included both CD4 and CD8 T-cells directed to one to three HSV-1 proteins per person. HSV-1 protein ICP6 was targeted by CD8 T-cells in 4 of 8 HLA-discordant donors. In situ tetramer staining demonstrated HSV-1-specific CD8 T-cells juxtaposed to TG neurons. Intra-TG retention of virus-specific CD4 T-cells, validated to the HSV-1 peptide level, implies trafficking of viral proteins from neurons to HLA class II-expressing non-neuronal cells for antigen presentation. The diversity of viral proteins targeted by TG T-cells across all kinetic and functional classes of viral proteins suggests broad HSV-1 protein expression, and viral antigen processing and presentation, in latently infected human TG. Collectively, the human TG represents an immunocompetent environment for both CD4 and CD8 T-cell recognition of HSV-1 proteins expressed during latent infection. HSV-1 proteins recognized by TG-resident T-cells, particularly ICP6 and VP16, are potential HSV-1 vaccine candidates. HSV-1 is an endemic human herpesvirus worldwide that establishes a lifelong latent infection of neurons in the trigeminal ganglion (TG), allowing intermittent reactivation resulting in recurrent disease in some persons. Studies in HSV-1 models suggest a central role of TG-infiltrating virus-specific CD8 T-cells to control reactivation. In humans, however, the functional properties and fine specificity of intra-TG T-cell responses remain enigmatic. The current study used molecular, immunological and in situ analysis platforms on human cadaveric TG obtained within hours after death to characterize the local HSV-1 specific T-cell response in latently infected human TG in detail. We identified that CD4 and CD8 T-cells were juxtaposed to TG neurons and expressed host transcripts and proteins consistent with in situ antigen recognition and antiviral function. The intra-TG T-cell response, involving both CD4 and CD8 T-cells, was directed to a limited set of HSV-1 proteins per person, which was not limited to a specific kinetic or structural class of viral proteins. Collectively, the data indicate that the human TG is an immunocompetent environment for CD4 and CD8 T-cell recognition of diverse HSV-1 proteins expressed during latent infection and that the viral antigens identified herein are rational candidates for HSV-1 subunit vaccines.
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Affiliation(s)
| | - Lichen Jing
- Department of Medicine, University of Washington, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | | | - Alessandro Sette
- La Jolla Institute for Allergy and Immunology, La Jolla, California, United States of America
| | - David M. Koelle
- Department of Medicine, University of Washington, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Department of Laboratory Medicine, University of Washington, Seattle, Washington, United States of America
- Department of Global Health, University of Washington, Seattle, Washington, United States of America
- Vaccine and Infectious Diseases Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
- Benaroya Research Institute, Seattle, Washington, United States of America
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8
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da Silva LF, Jones C. Small non-coding RNAs encoded within the herpes simplex virus type 1 latency associated transcript (LAT) cooperate with the retinoic acid inducible gene I (RIG-I) to induce beta-interferon promoter activity and promote cell survival. Virus Res 2013; 175:101-9. [PMID: 23648811 PMCID: PMC4074922 DOI: 10.1016/j.virusres.2013.04.005] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 04/04/2013] [Accepted: 04/08/2013] [Indexed: 12/23/2022]
Abstract
The herpes simplex virus type 1 (HSV-1) latency-associated transcript (LAT) is abundantly expressed in latently infected trigeminal ganglionic sensory neurons. Expression of the first 1.5 kb of LAT coding sequences restores wild type reactivation to a LAT null HSV-1 mutant. The anti-apoptosis functions of the first 1.5 kb of LAT coding sequences are important for wild type levels of reactivation from latency. Two small non-coding RNAs (sncRNAs) contained within the first 1.5 kb of LAT coding sequences are expressed in trigeminal ganglia of latently infected mice, they cooperate to inhibit apoptosis, and reduce the efficiency of productive infection. In this study, we demonstrated that LAT sncRNA1 cooperates with the RNA sensor, retinoic acid inducible gene I (RIG-I), to stimulate IFN-β promoter activity and NF-κB dependent transcription in human or mouse cells. LAT sncRNA2 stimulated RIG-I induction of NF-κB dependent transcription in mouse neuroblastoma cells (Neuro-2A) but not human 293 cells. Since it is well established that NF-κB interferes with apoptosis, we tested whether the sncRNAs cooperated with RIG-I to inhibit apoptosis. In Neuro-2A cells, both sncRNAs cooperated with RIG-I to inhibit cold-shock induced apoptosis. Double stranded RNA (PolyI:C) stimulates RIG-I dependent signaling; but enhanced cold-shock induced apoptosis. PolyI:C, but not LAT sncRNAs, interfered with protein synthesis when cotransfected with RIG-I, which correlated with increased levels of cold-shock induced apoptosis. LAT sncRNA1 appeared to interact with RIG-I in transiently transfected cells suggesting this interaction stimulates RIG-I.
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Affiliation(s)
- Leticia Frizzo da Silva
- School of Veterinary Medicine and Biomedical Sciences, Nebraska Center for Virology, University of Nebraska, Lincoln, NE 68583-0900, United States
- Morisson Life Science Center, RM234 Lincoln, NE 68583-0900, United States
| | - Clinton Jones
- School of Veterinary Medicine and Biomedical Sciences, Nebraska Center for Virology, University of Nebraska, Lincoln, NE 68583-0900, United States
- Morisson Life Science Center, RM234 Lincoln, NE 68583-0900, United States
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9
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Jones C. Bovine Herpes Virus 1 (BHV-1) and Herpes Simplex Virus Type 1 (HSV-1) Promote Survival of Latently Infected Sensory Neurons, in Part by Inhibiting Apoptosis. J Cell Death 2013; 6:1-16. [PMID: 25278776 PMCID: PMC4147773 DOI: 10.4137/jcd.s10803] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
α-Herpesvirinae subfamily members, including herpes simplex virus type 1 (HSV-1) and bovine herpes virus 1 (BHV-1), initiate infection in mucosal surfaces. BHV-1 and HSV-1 enter sensory neurons by cell-cell spread where a burst of viral gene expression occurs. When compared to non-neuronal cells, viral gene expression is quickly extinguished in sensory neurons resulting in neuronal survival and latency. The HSV-1 latency associated transcript (LAT), which is abundantly expressed in latently infected neurons, inhibits apoptosis, viral transcription, and productive infection, and directly or indirectly enhances reactivation from latency in small animal models. Three anti-apoptosis genes can be substituted for LAT, which will restore wild type levels of reactivation from latency to a LAT null mutant virus. Two small non-coding RNAs encoded by LAT possess anti-apoptosis functions in transfected cells. The BHV-1 latency related RNA (LR-RNA), like LAT, is abundantly expressed during latency. The LR-RNA encodes a protein (ORF2) and two microRNAs that are expressed in certain latently infected neurons. Wild-type expression of LR gene products is required for stress-induced reactivation from latency in cattle. ORF2 has anti-apoptosis functions and interacts with certain cellular transcription factors that stimulate viral transcription and productive infection. ORF2 is predicted to promote survival of infected neurons by inhibiting apoptosis and sequestering cellular transcription factors which stimulate productive infection. In addition, the LR encoded microRNAs inhibit viral transcription and apoptosis. In summary, the ability of BHV-1 and HSV-1 to interfere with apoptosis and productive infection in sensory neurons is crucial for the life-long latency-reactivation cycle in their respective hosts.
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Affiliation(s)
- Clinton Jones
- School of Veterinary Medicine and Biomedical Sciences, Nebraska Center for Virology, University of Nebraska, Morrison Life Science Center, Lincoln, NE
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10
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Abstract
Herpes simplex encephalitis (HSE) is a rare but severe complication of frequent and mostly benign infection with herpes simplex virus (HSV). Although rapid and sensitive diagnosis tools and active antiviral drugs are available, HSE morbidity/mortality levels remain unsatisfactory. Molecular and cellular determinants of HSE are incompletely understood. The rarity and severity of the disease have suggested an increased susceptibility of some subjects to HSV infection. Numerous experimental studies have investigated the respective role of host and viral factors in HSE. The results of these studies have illustrated the major role of the innate immune response, in particular interferons (IFNs), in limiting access of the virus into and/or virus replication in the central nervous system (CNS). In a few children with HSE, specific defects of the immune innate response have been identified, which impair the IFN-α/β and IFN-λ production of fibroblasts and/or neurons infected with HSV and render these cells more permissive to infection. The mutations affect proteins involved in the IFN pathway induced by stimulation of the TLR3 receptor. The patients' susceptibility to infection is restricted to HSV CNS invasion, underlining the major role of TLR3 in CNS protection against viral infection. The incomplete clinical penetrance of these molecular defects suggests that other factors (age, infectious dose) are involved in HSE. Whether pathogenesis of adult HSE is similar has not been investigated.
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Affiliation(s)
- F Rozenberg
- Service de virologie, pôle biologie pharmacie pathologie, hôpital Cochin, bâtiment Jean-Dausset, 27, rue du Faubourg-St-Jacques, 75679 Paris cedex 14, France.
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11
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Ma Y, Wang N, Li M, Gao S, Wang L, Ji Y, Qi Y, He R, Sun Z, Ruan Q. An antisense transcript in the human cytomegalovirus UL87 gene region. Virol J 2011; 8:515. [PMID: 22074130 PMCID: PMC3223508 DOI: 10.1186/1743-422x-8-515] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Accepted: 11/11/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Rapid advances in research on antisense transcripts are gradually changing our comprehension of genomic and gene expression aspects of the Herpesviridae. One such herpesvirus is the human cytomegalovirus (HCMV). Although transcription of the HCMV UL87 gene has not been specifically investigated, cDNA clones of UL87 antisense transcripts were found in HCMV cDNA libraries previously. In this study, the transcription of the UL87 antisense strand was investigated in three clinically isolated HCMV strains. RESULTS First, an 800 nucleotides transcript having an antisense orientation to the UL87 gene was found in a late HCMV cDNA library. Then, the UL87 antisense transcript was confirmed by Rapid amplification of cDNA ends (RACE) and Northern blot in three HCMV clinical strains. Two ORFs were predicted in the antisense transcript. The putative protein of ORF 1 showed a high degree of conservation among HCMV and other CMV strains. CONCLUSION An 800nt antisense transcript in the UL87 gene region exists in HCMV clinical strains.
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Affiliation(s)
- Yanping Ma
- Virus Laboratory, The Affiliated Shengjing Hospital, China Medical University, 110004 Shenyang, Liaoning of China, China
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12
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Kramer MF, Jurak I, Pesola JM, Boissel S, Knipe DM, Coen DM. Herpes simplex virus 1 microRNAs expressed abundantly during latent infection are not essential for latency in mouse trigeminal ganglia. Virology 2011; 417:239-47. [PMID: 21782205 DOI: 10.1016/j.virol.2011.06.027] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 06/06/2011] [Accepted: 06/16/2011] [Indexed: 01/02/2023]
Abstract
Several herpes simplex virus 1 microRNAs are encoded within or near the latency associated transcript (LAT) locus, and are expressed abundantly during latency. Some of these microRNAs can repress the expression of important viral proteins and are hypothesized to play important roles in establishing and/or maintaining latent infections. We found that in lytically infected cells and in acutely infected mouse ganglia, expression of LAT-encoded microRNAs was weak and unaffected by a deletion that includes the LAT promoter. In mouse ganglia latently infected with wild type virus, the microRNAs accumulated to high levels, but deletions of the LAT promoter markedly reduced expression of LAT-encoded microRNAs and also miR-H6, which is encoded upstream of LAT and can repress expression of ICP4. Because these LAT deletion mutants establish and maintain latent infections, these microRNAs are not essential for latency, at least in mouse trigeminal ganglia, but may help promote it.
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Affiliation(s)
- Martha F Kramer
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
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13
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Dosa S, Castellanos K, Bacsa S, Gagyi E, Kovacs SK, Valyi-Nagy K, Shukla D, Dermody TS, Valyi-Nagy T. Chronic progressive deficits in neuron size, density and number in the trigeminal ganglia of mice latently infected with herpes simplex virus. Brain Pathol 2011; 21:583-93. [PMID: 21371157 DOI: 10.1111/j.1750-3639.2011.00485.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Numerous epidemiological studies have proposed a link between herpes simplex virus (HSV) infection and several common chronic neuropsychiatric and neurodegenerative diseases. Experimental HSV infection of mice can lead to chronic behavioral and neurological deficits and chronic pain. While neuron injury and loss are well-documented consequences of the acute phase of infection, the pathologic consequences of latent HSV infection are poorly understood. To determine whether latent HSV infection can cause neuronal injury in mice, trigeminal ganglia (TG) derived from adult BALB/c mice 1, 12 and 31 weeks after corneal HSV type 1 (HSV-1) inoculation were analyzed for evidence of productive or latent HSV-1 infection, inflammation and changes in neuron size, density and number. We found that latent HSV-1 infection between 12 and 31 weeks after corneal virus inoculation was associated with inflammation and progressive deficits in mean neuron diameter, neuronal nucleus diameter, neuron density and neuron number in the TG relative to mock-infected controls. The extent of neuronal injury during latent infection correlated with the extent of inflammation. These studies demonstrate that latent HSV infection is associated with progressive neuronal pathology and may lead to a better understanding of the role of HSV infections in chronic neurological diseases.
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Affiliation(s)
- Sandor Dosa
- Department of Pathology, University of Illinois at Chicago, College of Medicine, Chicago, IL 60612, USA
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Khansarinejad B, Soleimanjahi H, Ghaemi A, Tiraihi T, Pour Beiranvand S. Localization of herpes simplex virus type 1 DNA in latently infected BALB/c mice neurons using in situ polymerase chain reaction. IRANIAN BIOMEDICAL JOURNAL 2010; 14:83-88. [PMID: 21079658 PMCID: PMC3904058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Revised: 05/18/2010] [Accepted: 05/26/2010] [Indexed: 05/30/2023]
Abstract
BACKGROUND Herpes simplex virus type-1 (HSV-1) establishes a lifelong latent infection in neurons following primary infection. The existence of latent HSV-1 DNA in the trigeminal ganglia of infected BALB/c mice was examined using a direct in situ PCR technique, based on Digoxigenin-11-dUTP detection system with anti-digoxigenin-peroxidase and 3,3'-diaminobenzidine (DAB) substrate. METHODS Eight-week-old male BALB/c mice were inoculated via the eye by 104 plaque forming unit of wild type Iranian isolates of HSV-1. After establishment of latency, trigeminal ganglia were removed and examined using in situ PCR to detect HSV-1 genome. Finally, the results of in situ PCR were verified by a two-round PCR method, using amplification cocktail of in situ reaction, as a template for a conventional gel base PCR. RESULTS AND CONCLUSION The results suggest that a direct in situ PCR method using a peroxidase and DAB detection system is a useful means for detection of latent HSV-1 DNA in the latently infected ganglia.
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Affiliation(s)
| | | | | | - Taki Tiraihi
- Dept. of Anatomy, Faculty of Medical Sciences, Tarbiat Modares University, P. O. Box 14115-111, Tehran, Iran
| | - Shahram Pour Beiranvand
- Dept. of Anatomy, Faculty of Medical Sciences, Tarbiat Modares University, P. O. Box 14115-111, Tehran, Iran
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15
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Delaying the expression of herpes simplex virus type 1 glycoprotein B (gB) to a true late gene alters neurovirulence and inhibits the gB-CD8+ T-cell response in the trigeminal ganglion. J Virol 2010; 84:8811-20. [PMID: 20573821 DOI: 10.1128/jvi.00496-10] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Following herpes simplex virus type 1 (HSV-1) ocular infection of C57BL/6 mice, activated CD8(+) T cells specific for an immunodominant epitope on HSV-1 glycoprotein B (gB-CD8 cells) establish a stable memory population in HSV-1 latently infected trigeminal ganglia (TG), whereas non-HSV-specific CD8(+) T cells are lost over time. The retention and activation of gB-CD8 cells appear to be influenced by persistent viral antigenic exposure within the latently infected TG. We hypothesized that the low-level expression of gB from its native promoter before viral DNA synthesis is critical for the retention and activation of gB-CD8 cells in the TG during HSV-1 latency and for their ability to block HSV-1 reactivation from latency. To test this, we created a recombinant HSV-1 in which gB is expressed only after viral DNA synthesis from the true late gC promoter (gCp-gB). Despite minor growth differences compared to its rescuant in infected corneas, gCp-gB was significantly growth impaired in the TG and produced a reduced latent genome load. The gCp-gB- and rescuant-infected mice mounted similar gB-CD8 effector responses, but the size and activation phenotypes of the memory gB-CD8 cells were diminished in gCp-gB latently infected TG, suggesting that the stimulation of gB-CD8 cells requires gB expression before viral DNA synthesis. Surprisingly, late gB expression did not compromise the capacity of gB-CD8 cells to inhibit HSV-1 reactivation from latency in ex vivo TG cultures, suggesting that gB-CD8 cells can block HSV-1 reactivation at a very late stage in the viral life cycle. These data have implications for designing better immunogens for vaccines to prevent HSV-1 reactivation.
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16
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Henderson G, Jaber T, Carpenter D, Wechsler SL, Jones C. Identification of herpes simplex virus type 1 proteins encoded within the first 1.5 kb of the latency-associated transcript. J Neurovirol 2010; 15:439-48. [PMID: 20175695 DOI: 10.3109/13550280903296353] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Expression of the first 1.5 kb of the latency-associated transcript (LAT) that is encoded by herpes simplex virus type 1 (HSV-1) is sufficient for wild-type (wt) levels of reactivation from latency in small animal models. Peptide-specific immunoglobulin G (IgG) was generated against open reading frames (ORFs) that are located within the first 1.5 kb of LAT coding sequences. Cells stably transfected with LAT or trigeminal ganglionic neurons of mice infected with a LAT expressing virus appeared to express the L2 or L8 ORF. Only L2 ORF expression was readily detected in trigeminal ganglionic neurons of latently infected mice.
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Affiliation(s)
- Gail Henderson
- Department of Veterinary and Biomedical Sciences, Nebraska Center for Virology, University of Nebraska, Lincoln, Nebraska 68503, USA
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17
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Towards an understanding of the herpes simplex virus type 1 latency-reactivation cycle. Interdiscip Perspect Infect Dis 2010; 2010:262415. [PMID: 20169002 PMCID: PMC2822239 DOI: 10.1155/2010/262415] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2009] [Accepted: 11/30/2009] [Indexed: 12/17/2022] Open
Abstract
Infection by herpes simplex virus type 1 (HSV-1) can cause clinical symptoms in the peripheral and central nervous system. Recurrent ocular shedding can lead to corneal scarring and vision loss making HSV-1 a leading cause of corneal blindness due to an infectious agent. The primary site of HSV-1 latency is sensory neurons within trigeminal ganglia. Periodically, reactivation from latency occurs resulting in virus transmission and recurrent disease. During latency, the latency-associated transcript (LAT) is abundantly expressed. LAT expression is important for the latency-reactivation cycle in animal models, in part, because it inhibits apoptosis, viral gene expression, and productive infection. A novel transcript within LAT coding sequences (AL3) and small nonprotein coding RNAs are also expressed in trigeminal ganglia of latently infected mice. In this review, an update of viral factors that are expressed during latency and their potential roles in regulating the latency-reactivation cycle is discussed.
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18
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Komericki P, Akkilic M, Kränke B, Aberer W. Recurrent herpes simplex infection in multiple locations in an otherwise healthy boy. Pediatr Dermatol 2010; 27:113-4. [PMID: 20199435 DOI: 10.1111/j.1525-1470.2009.01045.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An 8-year-old boy developed vesicular lesions on the skin in different parts of the body, occurring four to six times a year. He had a history of eczema herpeticum as a young child. We confirmed a diagnosis of multifocal herpes simplex infection, and hypothesize that this was a result of his previous eczema herpeticum, an unusual complication, in an otherwise healthy and immunocompetent child.
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Affiliation(s)
- Peter Komericki
- Department for Environmental Dermatology and Venereology, Medical University of Graz, Graz, Austria.
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19
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Two small RNAs encoded within the first 1.5 kilobases of the herpes simplex virus type 1 latency-associated transcript can inhibit productive infection and cooperate to inhibit apoptosis. J Virol 2009; 83:9131-9. [PMID: 19587058 DOI: 10.1128/jvi.00871-09] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The herpes simplex virus type 1 (HSV-1) latency-associated transcript (LAT) is abundantly expressed in latently infected trigeminal ganglionic sensory neurons. Expression of the first 1.5 kb of LAT coding sequences is sufficient for the wild-type reactivation phenotype in small animal models of infection. The ability of the first 1.5 kb of LAT coding sequences to inhibit apoptosis is important for the latency-reactivation cycle. Several studies have also concluded that LAT inhibits productive infection. To date, a functional LAT protein has not been identified, suggesting that LAT is a regulatory RNA. Two small RNAs (sRNAs) were previously identified within the first 1.5 kb of LAT coding sequences. In this study, we demonstrated that both LAT sRNAs were expressed in the trigeminal ganglia of mice latently infected with an HSV-1 strain that expresses LAT but not when mice were infected with a LAT null mutant. LAT sRNA1 and sRNA2 cooperated to inhibit cold shock-induced apoptosis in mouse neuroblastoma cells. LAT sRNA1, but not LAT sRNA2, inhibited apoptosis less efficiently than both sRNAs. When rabbit skin cells were cotransfected with plasmids that express LAT sRNA1 and HSV-1 genomic DNA, the amount of infectious virus released was reduced approximately 3 logs. Although LAT sRNA2 was less effective at inhibiting virus production, it inhibited expression of infected cell protein 4 (ICP4). Neither LAT sRNA had an obvious effect on ICP0 expression. These studies suggested that expression of two LAT sRNAs plays a role in the latency-reactivation cycle by inhibiting apoptosis and productive infection.
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20
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Jaber T, Henderson G, Li S, Perng GC, Carpenter D, Wechsler SL, Jones C. Identification of a novel herpes simplex virus type 1 transcript and protein (AL3) expressed during latency. J Gen Virol 2009; 90:2342-2352. [PMID: 19570955 DOI: 10.1099/vir.0.013318-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The herpes simplex virus type 1 (HSV-1) latency-associated transcript (LAT) is abundantly expressed in latently infected sensory neurons. In small animal models of infection, expression of the first 1.5 kb of LAT coding sequences is necessary and sufficient for wild-type reactivation from latency. The ability of LAT to inhibit apoptosis is important for reactivation from latency. Within the first 1.5 kb of LAT coding sequences and LAT promoter sequences, additional transcripts have been identified. For example, the anti-sense to LAT transcript (AL) is expressed in the opposite direction to LAT from the 5' end of LAT and LAT promoter sequences. In addition, the upstream of LAT (UOL) transcript is expressed in the LAT direction from sequences in the LAT promoter. Further examination of the first 1.5 kb of LAT coding sequences revealed two small ORFs that are anti-sense with respect to LAT (AL2 and AL3). A transcript spanning AL3 was detected in productively infected cells, mouse neuroblastoma cells stably expressing LAT and trigeminal ganglia (TG) of latently infected mice. Peptide-specific IgG directed against AL3 specifically recognized a protein migrating near 15 kDa in cells stably transfected with LAT, mouse neuroblastoma cells transfected with a plasmid containing the AL3 ORF and TG of latently infected mice. The inability to detect the AL3 protein during productive infection may have been because the 5' terminus of the AL3 transcript was downstream of the first in-frame methionine of the AL3 ORF during productive infection.
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Affiliation(s)
- Tareq Jaber
- School of Biological Sciences, Nebraska Center for Virology, University of Nebraska, Lincoln, NE 68503, USA
| | - Gail Henderson
- Department of Veterinary and Biomedical Sciences, Nebraska Center for Virology, University of Nebraska, Lincoln, NE 68503, USA
| | - Sumin Li
- Department of Veterinary and Biomedical Sciences, Nebraska Center for Virology, University of Nebraska, Lincoln, NE 68503, USA
| | - Guey-Chuen Perng
- Department of Pathology and Laboratory Medicine, Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Dale Carpenter
- The Gavin Herbert Eye Institute, School of Medicine, University of California Irvine, Irvine, CA 92697-4375, USA
| | - Steven L Wechsler
- Center for Virus Research, University of California Irvine, Irvine, CA 92697, USA
- Department of Microbiology and Molecular Genetics, School of Medicine, University of California Irvine, Irvine, CA 92697, USA
- The Gavin Herbert Eye Institute, School of Medicine, University of California Irvine, Irvine, CA 92697-4375, USA
| | - Clinton Jones
- Department of Veterinary and Biomedical Sciences, Nebraska Center for Virology, University of Nebraska, Lincoln, NE 68503, USA
- School of Biological Sciences, Nebraska Center for Virology, University of Nebraska, Lincoln, NE 68503, USA
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21
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Goins WF, Marconi P, Krisky D, Wolfe D, Glorioso JC, Ramakrishnan R, Fink DJ. Construction of replication-defective herpes simplex virus vectors. ACTA ACUST UNITED AC 2008; Chapter 12:Unit 12.11. [PMID: 18428322 DOI: 10.1002/0471142905.hg1211s33] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Advances in identification and characterization of gene products responsible for specific diseases of the nervous system have opened opportunities for novel therapies using gene transfer vectors for gene replacement. Herpes simplex virus (HSV)-based vectors are particularly well suited for gene delivery to neurons of the central and peripheral nervous systems. The authors have developed methods to delete HSV-1 IE gene functions and to subsequently introduce foreign genes into the HSV-1 genome using homologous recombination. This unit describes methods for generating cell lines that complement multiple essential gene deletion mutants as well for generating such replication-defective virus recombinants and inserting foreign DNA sequences into replication-defective viral genomes, the last step in preparing a vector. Three support protocols describe methods for preparing virus stocks, titering virus, and preparing viral DNA.
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Affiliation(s)
- William F Goins
- University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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22
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Chromatin control of herpes simplex virus lytic and latent infection. Nat Rev Microbiol 2008; 6:211-21. [PMID: 18264117 DOI: 10.1038/nrmicro1794] [Citation(s) in RCA: 320] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Herpes simplex viruses (HSV) can undergo a lytic infection in epithelial cells and a latent infection in sensory neurons. During latency the virus persists until reactivation, which leads to recurrent productive infection and transmission to a new host. How does HSV undergo such different types of infection in different cell types? Recent research indicates that regulation of the assembly of chromatin on HSV DNA underlies the lytic versus latent decision of HSV. We propose a model for the decision to undergo a lytic or a latent infection in which HSV encodes gene products that modulate chromatin structure towards either euchromatin or heterochromatin, and we discuss the implications of this model for the development of therapeutics for HSV infections.
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23
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Tischer BK, Kaufer BB, Sommer M, Wussow F, Arvin AM, Osterrieder N. A self-excisable infectious bacterial artificial chromosome clone of varicella-zoster virus allows analysis of the essential tegument protein encoded by ORF9. J Virol 2007; 81:13200-8. [PMID: 17913822 PMCID: PMC2169085 DOI: 10.1128/jvi.01148-07] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In order to facilitate the generation of mutant viruses of varicella-zoster virus (VZV), the agent causing varicella (chicken pox) and herpes zoster (shingles), we generated a full-length infectious bacterial artificial chromosome (BAC) clone of the P-Oka strain. First, mini-F sequences were inserted into a preexisting VZV cosmid, and the SuperCos replicon was removed. Subsequently, mini-F-containing recombinant virus was generated from overlapping cosmid clones, and full-length VZV DNA recovered from the recombinant virus was established in Escherichia coli as an infectious BAC. An inverted duplication of VZV genomic sequences within the mini-F replicon resulted in markerless excision of vector sequences upon virus reconstitution in eukaryotic cells. Using the novel tool, the role in VZV replication of the major tegument protein encoded by ORF9 was investigated. A markerless point mutation introduced in the start codon by two-step en passant Red mutagenesis abrogated ORF9 expression and resulted in a dramatic growth defect that was not observed in a revertant virus. The essential nature of ORF9 for VZV replication was ultimately confirmed by restoration of the growth of the ORF9-deficient mutant virus using trans-complementation via baculovirus-mediated gene transfer.
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Affiliation(s)
- B Karsten Tischer
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
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24
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Zhang G, Raghavan B, Kotur M, Cheatham J, Sedmak D, Cook C, Waldman J, Trgovcich J. Antisense transcription in the human cytomegalovirus transcriptome. J Virol 2007; 81:11267-81. [PMID: 17686857 PMCID: PMC2045512 DOI: 10.1128/jvi.00007-07] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Human cytomegalovirus (HCMV) infections are prevalent in human populations and can cause serious diseases, especially in those with compromised or immature immune systems. The HCMV genome of 230 kb is among the largest of the herpesvirus genomes. Although the entire sequence of the laboratory-adapted AD169 strain of HCMV has been available for 18 years, the precise number of viral genes is still in question. We undertook an analysis of the HCMV transcriptome as an approach to enumerate and analyze the gene products of HCMV. Transcripts of HCMV-infected fibroblasts were isolated at different times after infection and used to generate cDNA libraries representing different temporal classes of viral genes. cDNA clones harboring viral sequences were selected and subjected to sequence analysis. Of the 604 clones analyzed, 45% were derived from genomic regions predicted to be noncoding. Additionally, at least 55% of the cDNA clones in this study were completely or partially antisense to known or predicted HCMV genes. The remarkable accumulation of antisense transcripts during infection suggests that currently available genomic maps based on open-reading-frame and other in silico analyses may drastically underestimate the true complexity of viral gene products. These findings also raise the possibility that aspects of both the HCMV life cycle and genome organization are influenced by antisense transcription. Correspondingly, virus-derived noncoding and antisense transcripts may shed light on HCMV pathogenesis and may represent a new class of targets for antiviral therapies.
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Affiliation(s)
- Guojuan Zhang
- The Ohio State University, Department of Pathology, 4162 Graves Hall, 333 West 10th Avenue, Columbus, OH 43210, USA
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25
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Jones C, Inman M, Peng W, Henderson G, Doster A, Perng GC, Angeletti AK. The herpes simplex virus type 1 locus that encodes the latency-associated transcript enhances the frequency of encephalitis in male BALB/c mice. J Virol 2006; 79:14465-9. [PMID: 16254383 PMCID: PMC1280208 DOI: 10.1128/jvi.79.22.14465-14469.2005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Herpes simplex virus type 1 (HSV-1) is the leading cause of virus-induced encephalitis; however, the viral genes that regulate encephalitis have not been well characterized. In this study, we tested whether the LAT (latency-associated transcript) locus regulates the frequency of encephalitis in male or female mice. Male BALB/c mice are more susceptible to HSV-1-induced encephalitis than age-matched female BALB/c mice. Deletion of LAT coding sequences reduced the frequency of encephalitis. A recombinant virus containing the first 1.5 kb of the LAT coding sequence induces levels of encephalitis in male BALB/c mice similar to those induced by wild-type HSV-1.
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Affiliation(s)
- Clinton Jones
- Department of Veterinary and Biomedical Sciences, Nebraska Center for Virology, University of Nebraska, Fair Street at East Campus Loop, Rm. 104, Lincoln 68583-0905, USA.
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26
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Peng W, Henderson G, Inman M, BenMohamed L, Perng GC, Wechsler SL, Jones C. The locus encompassing the latency-associated transcript of herpes simplex virus type 1 interferes with and delays interferon expression in productively infected neuroblastoma cells and trigeminal Ganglia of acutely infected mice. J Virol 2005; 79:6162-71. [PMID: 15858001 PMCID: PMC1091686 DOI: 10.1128/jvi.79.10.6162-6171.2005] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2004] [Accepted: 12/29/2004] [Indexed: 01/12/2023] Open
Abstract
The herpes simplex virus type 1 (HSV-1) latency-associated transcript (LAT) is the only abundant viral transcript expressed in latently infected neurons. LAT inhibits apoptosis, suggesting that it regulates latency by promoting the survival of infected neurons. The LAT locus also contains a newly described gene (AL), which is antisense to LAT and partially overlaps LAT encoding sequences. When human (SK-N-SH) or mouse (neuro-2A) neuroblastoma cells were infected with a virus that does not express LAT or AL gene products (dLAT2903), beta interferon (IFN-beta) and IFN-alpha RNA expression was detected earlier relative to the same cells infected with HSV-1 strains that express LAT and AL. Infection of neuro-2A cells with dLAT2903 also led to higher levels of IFN-beta promoter activity than in cells infected with wild-type (wt) HSV-1. In contrast, IFN RNA expression was the same when human lung fibroblasts were infected with dLAT2903 or wt HSV-1. When BALB/c mice were infected with dLAT2903, IFN-alpha and IFN-beta RNA expression was readily detected in trigeminal ganglia (TG) 4 days after infection. These transcripts were not detected in TG of mice infected with wt HSV-1 or dLAT2903R (marker-rescued dLAT2903) until 6 days postinfection. When TG single-cell suspensions from infected BALB/c mice were prepared and incubated in vitro with wt HSV-1 as a source of antigen, TG cultures prepared from mice infected with dLAT2903 produced and secreted higher levels of IFN protein than wt HSV-1 or dLAT2903R. Collectively, these studies suggest that the LAT locus interferes with and delays IFN expression.
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Affiliation(s)
- Weiping Peng
- Department of Veterinary and Biomedical Sciences, Nebraska Center for Virology, University of Nebraska, Lincoln, Fair Street at East Campus Loop, Lincoln, NE 68583-0905, USA
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27
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Bhattacharjee PS, Tran RK, Myles ME, Maruyama K, Mallakin A, Bloom DC, Hill JM. Overlapping subdeletions within a 348-bp in the 5' exon of the LAT region that facilitates epinephrine-induced reactivation of HSV-1 in the rabbit ocular model do not further define a functional element. Virology 2003; 312:151-8. [PMID: 12890628 DOI: 10.1016/s0042-6822(03)00174-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A previous study identified a 348-bp region at the 5' end of the 8.5-kb latency-associated transcript (LAT) of HSV-1 strain 17Syn+ that is necessary for maximum adrenergically induced reactivation following transcorneal iontophoresis of epinephrine (D.C. Bloom et al., 1996, J. Virol. 70, 2449-2459). In that study, the construct with complete deletion of the 348-bp region, 17delta348, failed to achieve the high reactivation frequency demonstrated by the parent (17Syn+) and rescued (17delta348R) viruses. To further characterize the function of the 348-bp region, we analyzed two genetic constructs with partial deletions in the same 348-bp region, 17delta201 and 17delta207, in the rabbit model. Both constructs exhibited the same high reactivation frequencies demonstrated by the parent 17Syn+ and the rescued 17delta348R viruses. These results suggest that the control of reactivation is distributed over a large portion of the 348-bp region, rather than being confined within a smaller, more discrete region. To assess whether the low reactivation phenotype of the 17delta348 construct was caused by a requirement for proper spacing of elements outside the 348-bp region, we constructed a virus (17delta348St) that contained a 360-bp stuffer fragment of heterologous DNA (lacZ) to maintain the proper spacing. The 17delta348St construct also displayed a low reactivation phenotype, similar to that of 17delta348, suggesting that the effect of deleting this segment of the 5' exon of LAT is obtained through a mechanism other than the disruption of spacing.
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Affiliation(s)
- Partha S Bhattacharjee
- LSU Eye Center, Department of Ophthalmology, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
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28
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Abstract
Primary infection by herpes simplex virus type 1 (HSV-1) can cause clinical symptoms in the peripheral and central nervous system, upper respiratory tract, and gastrointestinal tract. Recurrent ocular shedding leads to corneal scarring that can progress to vision loss. Consequently, HSV-1 is the leading cause of corneal blindness due to an infectious agent. Bovine herpesvirus 1 (BHV-1) has similar biological properties to HSV-1 and is a significant health concern to the cattle industry. Latency of BHV-1 and HSV-1 is established in sensory neurons of trigeminal ganglia, but latency can be interrupted periodically, leading to reactivation from latency and spread of infectious virus. The ability of HSV-1 and BHV-1 to reactivate from latency leads to virus transmission and can lead to recurrent disease in individuals latently infected with HSV-1. During latency, the only abundant HSV-1 RNA expressed is the latency-associated transcript (LAT). In latently infected cattle, the latency-related (LR) RNA is the only abundant transcript that is expressed. LAT and LR RNA are antisense to ICP0 or bICP0, viral genes that are crucial for productive infection, suggesting that LAT and LR RNA interfere with productive infection by inhibiting ICP0 or bICP0 expression. Numerous studies have concluded that LAT expression is important for the latency-reactivation cycle in animal models. The LR gene has recently been demonstrated to be required for the latency-reactivation cycle in cattle. Several recent studies have demonstrated that LAT and the LR gene inhibit apoptosis (programmed cell death) in trigeminal ganglia of infected animals and transiently transfected cells. The antiapoptotic properties of LAT map to the same sequences that are necessary for promoting reactivation from latency. This review summarizes our current knowledge of factors regulating the latency-reactivation cycle of HSV-1 and BHV-1.
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Affiliation(s)
- Clinton Jones
- Department of Veterinary and Biomedical Sciences, The Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, Nebraska 68583-0905, USA.
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29
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Ecker AD, Smith JE. Are latent, immediate-early genes of herpes simplex virus-1 essential in causing trigeminal neuralgia? Med Hypotheses 2002; 59:603-6. [PMID: 12376087 DOI: 10.1016/s0306-9877(02)00177-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The etiology and pathogenesis of major trigeminal neuralgia remain largely unknown, but are believed to result from an irritative lesion near the semilunar ganglion. We suggest that its primary cause is a single, active DNA sequence in the persistent but non-integrated genome of latent herpes simplex virus type 1 commonly observed in a few infected A-delta nerve fibers of the cheek. Facial pain occurs as a result of herpes virus reactivation and when supplies of neurotrophins controlling normal transport functions of axolemmal ion channels become depleted.
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MESH Headings
- Adult
- Antiviral Agents/pharmacology
- Antiviral Agents/therapeutic use
- Child
- DNA, Viral/genetics
- Gene Expression Regulation, Viral
- Genes, Immediate-Early
- Genes, Viral
- Herpes Simplex/complications
- Herpes Simplex/genetics
- Herpesvirus 1, Human/genetics
- Herpesvirus 1, Human/pathogenicity
- Humans
- Ion Channels
- Models, Neurological
- Nerve Growth Factor/physiology
- RNA, Viral/biosynthesis
- RNA, Viral/genetics
- Receptors, Nerve Growth Factor/physiology
- Trigeminal Ganglion/virology
- Trigeminal Neuralgia/drug therapy
- Trigeminal Neuralgia/etiology
- Trigeminal Neuralgia/physiopathology
- Trigeminal Neuralgia/virology
- Virus Latency/genetics
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Affiliation(s)
- A D Ecker
- Biology Department, Upstate Medical University, Syracuse, New York 13244-1270, USA
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30
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Chen XP, Mata M, Kelley M, Glorioso JC, Fink DJ. The relationship of herpes simplex virus latency associated transcript expression to genome copy number: a quantitative study using laser capture microdissection. J Neurovirol 2002; 8:204-10. [PMID: 12053275 DOI: 10.1080/13550280290049642] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
To investigate the quantitative relationship of latent herpes simplex virus (HSV) genomes to the expression of latency associated transcripts (LATs) we used a combination of laser capture microdissection (LCM), polymerase chain reaction (PCR), and quantitative real-time PCR to determine the number of HSV genomes in individual neurons of the mouse trigeminal ganglion (TG) during viral latency. Both LAT-positive and LAT-negative neurons detected by in situ hybridization (ISH) and lifted by LCM contained HSV genomes detected by PCR for HSV ICP47. The number of genomes/cell determined by real-time PCR with probes for HSV UL44 following LCM demonstrated a Poisson distribution with a predicted mean count of 178 genomes/LAT-positive neuron, and 68 genomes/LAT-negative neuron. The range was similar between the LAT-positive and LAT-negative neurons, and there was a substantial overlap in the distributions. These results suggest that the expression of LATs in an amount that is detectable by ISH does not depend only on the number of HSV genomes in the cell, and by implication suggests that neuron-specific factors play a role in the regulation of LAT expression during latency.
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Affiliation(s)
- Xiao-Ping Chen
- Department of Neurology, University of Pittsburgh School of Medicine, Pennsylvania, USA
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31
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Wang K, Pesnicak L, Guancial E, Krause PR, Straus SE. The 2.2-kilobase latency-associated transcript of herpes simplex virus type 2 does not modulate viral replication, reactivation, or establishment of latency in transgenic mice. J Virol 2001; 75:8166-72. [PMID: 11483762 PMCID: PMC115061 DOI: 10.1128/jvi.75.17.8166-8172.2001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
To better understand the mechanisms responsible for the observed effects of deletions in the promoter region of the latency-associated transcript (LAT) gene in impairing herpes simplex virus (HSV) reactivation, we generated mice transgenic for a 5.5-kb HSV type 2 (HSV-2) genomic fragment spanning the major LAT, along with the LAT promoter and flanking regions, in the C57BL/6 background. The mice expressed abundant 2.2-kb major LATs in trigeminal ganglia (TG) and other tissues. The effects of the transgene on HSV-2 infection, latency, and reactivation were assessed. When infected with wild-type (WT) HSV-2 or its LAT promoter deletion (LAT(-)) mutant, primary lung fibroblast lines established from normal C57BL/6 and transgenic mice supported virus growth equally well. The replication of these viruses in the mouse eye and their spread to TG and brains were similar. The quantities of latent viral DNA in TG of transgenic and normal mice, as determined by real-time PCR, were comparable. UV light-induced reactivation of the LAT(-) mutant from transgenic mice (0 to 7%) was no more frequent than that from normal mice (0 to 14%), while WT virus was reactivated from 13 to 54% of normal mice and 22 to 54% of transgenic mice. The cumulative data indicate that, when expressed transgenically, the HSV-2 major LAT cannot influence HSV-2 infection or latency and cannot complement the defect in reactivation of the LAT(-) mutant. These results imply that the phenotype of reduced reactivation associated with the LAT(-) mutant is related to a function encoded in the LAT promoter but not to the major LAT itself.
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Affiliation(s)
- K Wang
- Medical Virology Section, Laboratory of Clinical Investigation, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892, USA.
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32
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Berthomme H, Thomas J, Texier P, Epstein A, Feldman LT. Enhancer and long-term expression functions of herpes simplex virus type 1 latency-associated promoter are both located in the same region. J Virol 2001; 75:4386-93. [PMID: 11287587 PMCID: PMC114183 DOI: 10.1128/jvi.75.9.4386-4393.2001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During herpes simplex virus type 1 (HSV-1) latent infection in vivo, the latency-associated promoter (LAP) is the only promoter to remain highly active long term. In a previous attempt to characterize LAP activity in vitro and in a mouse model, we showed that a 1.5-kb fragment called the long-term expression element (LTE), located immediately downstream from the transcriptional start site of LAP, was able to (i) increase gene expression in an orientation-independent manner, regardless of the cell type or the promoter used in vitro (enhancer activity) and (ii) keep LAP active during latency in vivo (long-term expression activity) (H. Berthomme, J. Lokensgard, L. Yang, T. Margolis, and L. T. Feldman, J. Virol. 74:3613-3622, 2000). To determine if these two functions could be separated genetically, we conducted a mutational analysis on the LTE and analyzed the effect on the LAP-LTE properties in both transient expression in cell culture and mouse dorsal root ganglia lytic and latent infection. In this report, we show that the first half of the LTE sequence, corresponding to the region previously described as LAP2 or exon1, encodes the enhancer function. This same region is also required to keep the LAP active during latency. These results exclude the intron region as containing any significant enhancer activity or any ability to keep the LAP active during latency. The results also show that these two functions have not been separated, leaving open the possibility that there is no long-term expression function per se but that the enhancer itself may function to keep the LAP active during latency by raising the level of expression to a detectable one. Further mutational analysis will be required to determine if these two potential functions continue to cosegregate.
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Affiliation(s)
- H Berthomme
- Centre de Génétique Moléculaire et Cellulaire, UMR5534 CNRS, Université Claude Bernard Lyon I, Villeurbanne, France
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33
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Inman M, Perng GC, Henderson G, Ghiasi H, Nesburn AB, Wechsler SL, Jones C. Region of herpes simplex virus type 1 latency-associated transcript sufficient for wild-type spontaneous reactivation promotes cell survival in tissue culture. J Virol 2001; 75:3636-46. [PMID: 11264353 PMCID: PMC114855 DOI: 10.1128/jvi.75.8.3636-3646.2001] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The latency-associated transcript (LAT) is the only abundant herpes simplex virus type 1 (HSV-1) transcript expressed during latency. In the rabbit eye model, LAT null mutants do not reactivate efficiently from latency. We recently demonstrated that the LAT null mutant dLAT2903 induces increased levels of apoptosis in trigeminal ganglia of infected rabbits compared to LAT+ strains (G.-C. Perng, C. Jones, J. Ciacci-Zarella, M. Stone, G. Henderson, A. Yokht, S. M. Slanina, F. M. Hoffman, H. Ghiasi, A. B. Nesburn, and C. S. Wechsler, Science 287:1500-1503, 2000). The same study also demonstrated that a plasmid expressing LAT nucleotides 301 to 2659 enhanced cell survival of transfected cells after induction of apoptosis. Consequently, we hypothesized that LAT enhances spontaneous reactivation in part, because it promotes survival of infected neurons. Here we report on the ability of plasmids expressing different portions of the 5' end of LAT to promote cell survival after induction of apoptosis. A plasmid expressing the first 1.5 kb of LAT (LAT nucleotides 1 to 1499) promoted cell survival in neuro-2A (mouse neuronal) and CV-1 (monkey fibroblast) cells. A plasmid expressing just the first 811 nucleotides of LAT promoted cell survival less efficiently. Plasmids expressing the first 661 nucleotides or less of LAT did not promote cell survival. We previously showed that a mutant expressing just the first 1.5 kb of LAT has wild-type spontaneous reactivation in rabbits, and a mutant expressing just the first 811 nucleotides of LAT has a reactivation frequency higher than that of dLAT2903 but lower than that of wild-type virus. In addition, mutants reported here for the first time, expressing just the first 661 or 76 nucleotides of LAT, had spontaneous reactivation indistinguishable from that of the LAT null mutant dLAT2903. In summary, these studies provide evidence that there is a functional relationship between the ability of LAT to promote cell survival and its ability to enhance spontaneous reactivation.
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Affiliation(s)
- M Inman
- Department of Veterinary and Biomedical Sciences, University of Nebraska, Lincoln, Nebraska 68583-0905, USA
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34
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Randall G, Lagunoff M, Roizman B. Herpes simplex virus 1 open reading frames O and P are not necessary for establishment of latent infection in mice. J Virol 2000; 74:9019-27. [PMID: 10982346 PMCID: PMC102098 DOI: 10.1128/jvi.74.19.9019-9027.2000] [Citation(s) in RCA: 12] [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
Open reading frame (ORF) O and ORF P partially overlap and are located antisense to the gamma(1)34.5 gene within the domain transcribed during latency. In wild-type virus-infected cells, ORF O and ORF P are completely repressed during productive infection by ICP4, the major viral transcriptional activator/repressor. In cells infected with a mutant in which ORF P was derepressed there was a significant delay in the appearance of the viral alpha-regulatory proteins ICP0 and ICP22. The ORF O protein binds to and inhibits ICP4 binding to its cognate DNA site in vitro. These characteristics suggested a role for ORF O and ORF P in the establishment of latency. To test this hypothesis, two recombinant viruses were constructed. In the first, R7538(P-/O-), the ORF P initiator methionine codon, which also serves as the initiator methionine codon for ORF O, was replaced and a diagnostic restriction endonuclease was introduced upstream. In the second, R7543(P-/O-)R, the mutations were repaired to restore the wild-type virus sequences. We report the following. (i) The R7538(P-/O-) mutant failed to express ORF O and ORF P proteins but expressed a wild-type gamma(1)34.5 protein. (ii) R7538(P-/O-) yields were similar to that of the wild type following infection of cell culture or following infection of mice by intracerebral or ocular routes. (iii) R7538(P-/O-) virus reactivated from latency following explanation and cocultivation of murine trigeminal ganglia with Vero cells at a frequency similar to that of the wild type, herpes simplex virus 1(F). (iv) The amount of latent R7538(P-/O-) virus as assayed by quantitative PCR is eightfold less than that of the repair virus. The repaired virus could not be differentiated from the wild-type parent in any of the assays done in this study. We conclude that ORF O and ORF P are not essential for the establishment of latency in mice but may play a role in determining the quantity of latent virus maintained in sensory neurons.
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Affiliation(s)
- G Randall
- The Marjorie B. Kovler Viral Oncology Laboratories, The University of Chicago, Chicago, Illinois 60637, USA
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35
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Zhu J, Kang W, Wolfe JH, Fraser NW. Significantly increased expression of beta-glucuronidase in the central nervous system of mucopolysaccharidosis type VII mice from the latency-associated transcript promoter in a nonpathogenic herpes simplex virus type 1 vector. Mol Ther 2000; 2:82-94. [PMID: 10899831 DOI: 10.1006/mthe.2000.0093] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Herpes simplex virus (HSV) has the ability to establish life-long latent infections in postmitotic neurons and to remain transcriptionally active, continuously expressing latency-associated transcripts (LAT) while producing minimal disease. These properties have made HSV an excellent candidate for neuronal gene transfer. Previously, we have shown that in mucopolysaccharidosis type VII mice (MPS VII, beta-glucuronidase deficiency) the LAT promoter is capable of expressing beta-glucuronidase (GUSB) in the trigeminal ganglion and the brainstem after latency is established. However, the number of neurons expressing GUSB is much lower than the number expressing 2-kb LAT following a wild-type virus infection. In this study, we have evaluated the effect of the position of the coding sequence relative to the LAT promoter on beta-glucuronidase gene expression in the central nervous system (CNS). Non-neurovirulent (ICP-34.5-deleted HSV-1) vectors were used, allowing direct intracranial injection. Significantly more GUSB activity was detected in brains of MPS VII mice inoculated with a recombinant virus (HSV-LAT-GUSB-JS) in which the GUSB cDNA was inserted near the LAT promoter, compared to viruses where it was inserted farther downstream in either the LAT exon 1 or overlapping exon 1 and the 2-kb LAT intron. This vector produced more than 100 times the number of positive cells than the other constructs. During acute infection, the distribution of viral replication differed from the distribution of GUSB enzyme expression. Viral antigen was predominately present in cells around the site of injection in the caudate putamen and in ependymal cells lining the ventricles. In contrast, GUSB expression was present mainly in cells of the thalamus and hypothalamus, which did not exhibit viral antigen, suggesting that GUSB enzyme activity was expressed from latently but not acutely infected neuronal cells. This vector design should be useful for high-level expression of various genes in the CNS.
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MESH Headings
- Animals
- Blotting, Northern
- Blotting, Southern
- Brain/metabolism
- Brain/pathology
- Brain/virology
- Central Nervous System/metabolism
- Chlorocebus aethiops
- DNA, Complementary/metabolism
- Disease Models, Animal
- Exons
- Genetic Vectors
- Glucuronidase/genetics
- Glucuronidase/metabolism
- Herpesvirus 1, Human/genetics
- Immunohistochemistry
- Mice
- Mice, Mutant Strains
- Models, Genetic
- Mucopolysaccharidosis VII/genetics
- Mucopolysaccharidosis VII/metabolism
- Plasmids/metabolism
- Promoter Regions, Genetic
- RNA/metabolism
- RNA Splicing
- Recombination, Genetic
- Tissue Distribution
- Transcription, Genetic
- Vero Cells
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Affiliation(s)
- J Zhu
- Department of Microbiology, School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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36
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Pevenstein SR, Williams RK, McChesney D, Mont EK, Smialek JE, Straus SE. Quantitation of latent varicella-zoster virus and herpes simplex virus genomes in human trigeminal ganglia. J Virol 1999; 73:10514-8. [PMID: 10559370 PMCID: PMC113107 DOI: 10.1128/jvi.73.12.10514-10518.1999] [Citation(s) in RCA: 119] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Using real-time fluorescence PCR, we quantitated the numbers of copies of latent varicella-zoster virus (VZV) and herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) genomes in 15 human trigeminal ganglia. Eight (53%) and 1 (7%) of 15 ganglia were PCR positive for HSV-1 or -2 glycoprotein G genes, with means of 2,902 +/- 1,082 (standard error of the mean) or 109 genomes/10(5) cells, respectively. Eleven of 14 (79%) to 13 of 15 (87%) of the ganglia were PCR positive for VZV gene 29, 31, or 62. Pooling of the results for the three VZV genes yielded a mean of 258 +/- 38 genomes/10(5) ganglion cells. These levels of latent viral genome loads have implications for virus distribution in and reactivation from human sensory ganglia.
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Affiliation(s)
- S R Pevenstein
- Medical Virology Section, Laboratory of Clinical Investigation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
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37
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Affiliation(s)
- C Jones
- Department of Veterinary and Biomedical Sciences, University of Nebraska, Lincoln 68583-0905, USA
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38
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Chen SH, Kramer MF, Schaffer PA, Coen DM. A viral function represses accumulation of transcripts from productive-cycle genes in mouse ganglia latently infected with herpes simplex virus. J Virol 1997; 71:5878-84. [PMID: 9223477 PMCID: PMC191843 DOI: 10.1128/jvi.71.8.5878-5884.1997] [Citation(s) in RCA: 141] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Latent infections of neurons by herpes simplex virus form reservoirs of recurrent viral infections that resist cure. In latently infected neurons, viral gene expression is severely repressed; only the latency-associated transcripts (LATs) are expressed abundantly. Using sensitive reverse transcriptase PCR assays, we analyzed the effects of a deletion mutation in the LAT locus on viral gene expression in latently infected mouse trigeminal ganglia. The deletion mutation, which reduced expression of the major LATs 10(5)-fold, resulted in a approximately 5-fold increase in accumulation of transcripts from the immediate-early gene encoding ICP4, an essential transactivator of viral gene expression. The LAT deletion also resulted in a >10-fold increase in the accumulation of transcripts from the early gene encoding thymidine kinase, whose expression during productive infection stringently depends on ICP4, and positively affected the correlation of the levels of these transcripts with the levels of ICP4 transcripts. We also detected transcripts antisense to ICP4 RNA, which were in substantial excess to ICP4 transcripts in ganglia latently infected with wild-type virus. In contrast to its effects on productive-cycle transcripts, the LAT deletion reduced the accumulation of these antisense transcripts approximately 15-fold. Thus, a viral function associated with the LAT locus represses the accumulation of transcripts from at least two productive-cycle genes in latently infected mouse ganglia. We discuss possible mechanisms and consequences of this repression.
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Affiliation(s)
- S H Chen
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
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39
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Abstract
The clinical manifestations of herpes simplex virus infection generally involve a mild and localized primary infection followed by asymptomatic (latent) infection interrupted sporadically by periods of recrudescence (reactivation) where virus replication and associated cytopathologic findings are manifest at the site of initial infection. During the latent phase of infection, viral genomes, but not infectious virus itself, can be detected in sensory and autonomic neurons. The process of latent infection and reactivation has been subject to continuing investigation in animal models and, more recently, in cultured cells. The initiation and maintenance of latent infection in neurons are apparently passive phenomena in that no virus gene products need be expressed or are required. Despite this, a single latency-associated transcript (LAT) encoded by DNA encompassing about 6% of the viral genome is expressed during latent infection in a minority of neurons containing viral DNA. This transcript is spliced, and the intron derived from this splicing is stably maintained in the nucleus of neurons expressing it. Reactivation, which can be induced by stress and assayed in several animal models, is facilitated by the expression of LAT. Although the mechanism of action of LAT-mediated facilitation of reactivation is not clear, all available evidence argues against its involving the expression of a protein. Rather, the most consistent models of action involve LAT expression playing a cis-acting role in a very early stage of the reactivation process.
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Affiliation(s)
- E K Wagner
- Department of Molecular Biology and Biochemistry, University of California, Irvine 92697-3900, USA.
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40
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Yoshikawa T, Hill JM, Stanberry LR, Bourne N, Kurawadwala JF, Krause PR. The characteristic site-specific reactivation phenotypes of HSV-1 and HSV-2 depend upon the latency-associated transcript region. J Exp Med 1996; 184:659-64. [PMID: 8760819 PMCID: PMC2192722 DOI: 10.1084/jem.184.2.659] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
After replication at sites of initial inoculation, herpes simplex virus type 1 and 2 (HSV-1 and HSV-2) establish lifelong latent infections of the sensory and autonomic neurons of the ganglia serving those sites. Periodically, the virus reactivates from these neurons, and travels centripetally along the neuronal axon to cause recurrent epithelial infection. The major clinically observed difference between infections with herpes simplex virus type 1 and type 2 is the anatomic site specificity of recurrence. HSV-1 reactivates most efficiently and frequently from trigeminal ganglia, causing recurrent ocular and oral-facial lesions, while HSV-2 reactivates primarily from sacral ganglia causing recurrent genital lesions. An intertypic recombinant virus was constructed and evaluated in animal models of recurrent ocular and genital herpes. Substitution of a 2.8-kbp region from the HSV-1 latency-associated transcript (LAT) for native HSV-2 sequences caused HSV-2 to reactivate with an HSV-1 phenotype in both animal models. The HSV-2 phenotype was restored by replacing the mutated sequences with wild-type HSV-2 LAT-region sequences. These sequences or their products must act specifically in the cellular environments of trigeminal and sacral neurons to promote the reactivation patterns characteristic of each virus.
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Affiliation(s)
- T Yoshikawa
- Division of Viral Products, Food and Drug Administration, Bethesda, Maryland, USA
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41
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Yoshikawa T, Stanberry LR, Bourne N, Krause PR. Downstream regulatory elements increase acute and latent herpes simplex virus type 2 latency-associated transcript expression but do not influence recurrence phenotype or establishment of latency. J Virol 1996; 70:1535-41. [PMID: 8627672 PMCID: PMC189975 DOI: 10.1128/jvi.70.3.1535-1541.1996] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The role of putative promoter or activator sequences downstream of the herpes simplex virus type 2 latency-associated transcript (LAT) promoter and upstream of the LAT intron was investigated in vivo by constructing and evaluating mutant viruses with deletions in this region. The deletion of LAT promoter sequences upstream of the primary LAT transcript reduced levels of LAT expression during productive infections, compared with the LAT expression level of wild-type virus, and abolished LAT expression during latency. The deletion of the putative downstream regulatory elements reduced but did not eliminate LAT expression during productive and latent infections. The deletion of both regions almost completely eliminated acute LAT transcription, although additional acute LAT-region transcription directed by sequences upstream of either region was detected by reverse transcriptase PCR. The deletion of the downstream elements did not influence the ability of the virus to reactivate from latently infected guinea pigs relative to the ability of the wild-type virus to reactivate; thus, decreased LAT expression did not affect the frequency of recurrence. The deletion of both regions did not affect the ability of the virus to establish latency. We conclude that downstream regulatory elements are necessary for maximal acute LAT expression but do not constitute an independent promoter during latency and do not play an obvious role in the establishment of our reactivation from latency.
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Affiliation(s)
- T Yoshikawa
- Division of Viral Products, Food and Drug Administration, Bethesda, Maryland, USA
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42
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Krause PR, Stanberry LR, Bourne N, Connelly B, Kurawadwala JF, Patel A, Straus SE. Expression of the herpes simplex virus type 2 latency-associated transcript enhances spontaneous reactivation of genital herpes in latently infected guinea pigs. J Exp Med 1995; 181:297-306. [PMID: 7807009 PMCID: PMC2191851 DOI: 10.1084/jem.181.1.297] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The latency-associated transcript (LAT) is the only herpes simplex virus (HSV) gene product detectable in latently infected humans and animals. In this report, we show that a 624-bp deletion in the promoter of the HSV-2 LAT had no discernable effect on viral growth in tissue culture or in acute genital infection of guinea pigs, but impaired LAT accumulation and led to a marked decrease in spontaneous genital recurrences when compared with the behavior of wild-type and rescuant strains. Differences in the ability of the mutant to replicate, or in how readily it established or maintained latency did not account for this finding. Thus, HSV LAT expression facilitates the spontaneous reactivation of latent virus.
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Affiliation(s)
- P R Krause
- Division of Viral Products, Food and Drug Administration, Bethesda, Maryland 20892
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43
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Tenser RB, Edris WA, Gaydos A, Hay KA. Secondary herpes simplex virus latent infection in transplanted ganglia. J Virol 1994; 68:7212-20. [PMID: 7933103 PMCID: PMC237160 DOI: 10.1128/jvi.68.11.7212-7220.1994] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Sensory ganglia latently infected with herpes simplex virus (HSV) were transplanted beneath the renal capsule of syngeneic recipients, and the latent infection remaining was investigated. HSV latency-associated transcript (LAT) expression and reactivation of HSV after explant of transplanted dorsal root ganglia were monitored as markers of latency. Two to four weeks after transplantation, both indicated evidence of HSV latency in transplants. At those times, infectious virus was not detected in direct ganglion homogenates. In addition, viral antigen and infected cell polypeptide 4 RNA were not detected. Taken together, the results suggested that HSV latent infection rather than persistent infection was present in transplants. From these results, two explanations seemed possible: latency was maintained in transplanted neurons, or alternatively, latency developed after transplantation, in neurons not previously latently infected. The latter was considered putative secondary latency and was investigated in three ways. First, evidence of reactivation which might serve as a source for secondary latency was evaluated. Reactivation of HSV in transplants was evident from HSV antigen expression (52% of transplants) and the presence of cell-free virus (38% of transplants) 3 to 5 days after transplantation. Second, putative secondary latency was investigated in recipients immunized with HSV prior to receiving latently infected ganglia. Reactivation was not detected 3 to 5 days after transplantation in immunized recipients, and LAT expression was rare in these recipients after 3 to 4 weeks. Lastly, the possibility of secondary latency was investigated by comparing results obtained with standard HSV and with reactivation-defective thymidine kinase-negative (TK-) HSV. Defective reactivation of TK- HSV was demonstrated by immunohistochemistry and by the inability to isolate infectious virus. Donor dorsal root ganglia latently infected with TK+ HSV showed many LAT-positive neurons 2 or more weeks after transplantation (average, 26 per transplant). However, LAT expression was undetectable or minimal > 2 weeks after transplantation in donor ganglia latently infected with TK- HSV (average, 0.2 per transplant). Impaired reactivation of TK- HSV-infected donor ganglia after transplantation, therefore, was correlated with subsequent limited LAT expression. From these results, the occurrence of secondary latency was concluded for ganglia latently infected with TK+ HSV and transplanted beneath the kidney capsule. In vivo reactivation in this transplant model may provide a more useful means to investigate HSV reactivation than in usual in vitro explant models and may complement other in vivo reactivation models. The occurrence of secondary latency was unique. The inhibition of secondary latency by the immune system may provide an avenue to evaluate immunological control of HSV latency.
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Affiliation(s)
- R B Tenser
- Department of Medicine (Neurology), Pennsylvania State University College of Medicine, Hershey 17033
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44
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Nicosia M, Deshmane SL, Zabolotny JM, Valyi-Nagy T, Fraser NW. Herpes simplex virus type 1 latency-associated transcript (LAT) promoter deletion mutants can express a 2-kilobase transcript mapping to the LAT region. J Virol 1993; 67:7276-83. [PMID: 8230451 PMCID: PMC238191 DOI: 10.1128/jvi.67.12.7276-7283.1993] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The results of studies in several laboratories suggest that a TATA box-containing promoter located in the herpes simplex virus type 1 internal long repeat and long terminal repeat elements drives expression of the latency-associated transcripts (LATs). In the present study, we show that expression of a 2-kb LAT-related transcript can occur in the absence of this LAT TATA promoter, indicating the existence of a cryptic promoter. By Northern (RNA) blot analysis, we have examined LAT expression by herpes simplex virus type 1 variant strains KOS/29 and 1704, which contain deletions of the LAT promoter region. Our data indicate that KOS/29, despite lacking the 203-bp fragment which contains the LAT TATA box, can express a 2-kb LAT-related transcript during productive infection in tissue culture and in mouse trigeminal ganglia during acute infection and reactivation. Similarly, strain 1704, which contains a larger deletion in this promoter region, also expresses a 2-kb LAT-related transcript during tissue culture infection and reactivation of latently infected trigeminal ganglia. However, LATs are not expressed with either virus during latency. Northern blot analysis with a single-stranded, oligonucleotide probe demonstrates that the 2-kb LAT and LAT-related transcript are colinear and share a large area of sequence similarity. These findings suggest the existence of a second promoter in the LAT gene which can function during lytic infection and reactivation, at least in the absence of the LAT TATA promoter. We propose that this cryptic promoter is located either in a proximal region approximately 300 bp upstream of the start site of the 2-kb LAT or in a distal region starting over 1,226 bp upstream of this site.
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Affiliation(s)
- M Nicosia
- Wistar Institute, Philadelphia, Pennsylvania 19104-4268
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Yeh L, Schaffer PA. A novel class of transcripts expressed with late kinetics in the absence of ICP4 spans the junction between the long and short segments of the herpes simplex virus type 1 genome. J Virol 1993; 67:7373-82. [PMID: 7901428 PMCID: PMC238201 DOI: 10.1128/jvi.67.12.7373-7382.1993] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
A novel family of transcripts that span the junction between the long and short segments of the herpes simplex virus type 1 genome has been identified. These transcripts, designated L/S junction-spanning transcripts (L/STs), are synthesized in abundance in a variety of cells infected with mutant viruses defective in the gene for ICP4, the major transcriptional regulatory protein of the virus. Transcription of abundant 2.3- and 8.5-kb series of L/STs was shown to initiate within the same sequences as less abundant 4.2-, 7.3-, and > 9.5-kb transcripts by Northern (RNA) blot analysis. S1 nuclease analysis revealed a single 5' terminus 28 bp downstream of a TATA box and 6 bp downstream of a consensus ICP4 binding site. The location of the transcriptional start site indicates that the promoter of the L/STs likely corresponds to the bidirectional promoter described by Bohenzky et al. (R. A. Bohenzky, A. G. Papavassiliou, I. H. Gelman, and S. Silverstein, J. Virol. 67:632-642, 1993). The L/STs accumulate with late kinetics in ICP4 mutant-infected cells and are polyadenylated. Mutant viruses encoding forms of ICP4 unable to bind the consensus site, ATCGTC, exhibited abundant expression of the L/STs, whereas mutants encoding forms of ICP4 able to bind this site expressed no detectable L/STs, suggesting that ICP4 plays a critical role in repressing L/ST expression. Their synthesis in ICP4 mutant-infected cells is inhibited by the protein synthesis inhibitor cycloheximide, indicating that they are induced either by an immediate-early viral protein other than ICP4 or by a virus-induced cellular protein. Preliminary evidence indicates that the L/STs are not present in latently infected ganglia. The abundant expression of the L/STs with late kinetics only in the absence of functional ICP4 and the sensitivity of their synthesis to cycloheximide indicate that they are not members of any of the recognized kinetic classes of herpes simplex virus type 1 transcripts but constitute a new class of viral transcript.
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Affiliation(s)
- L Yeh
- Division of Molecular Genetics, Dana-Farber Cancer Institute, Boston, Massachusetts
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Steiner I, Kennedy PG. Molecular biology of herpes simplex virus type 1 latency in the nervous system. Mol Neurobiol 1993; 7:137-59. [PMID: 8396944 DOI: 10.1007/bf02935640] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Herpes simplex virus (HSV) is one of the best studied examples of viral ability to remain latent in the human nervous system and to cause recurrent disease by reactivation. Intensive effort was directed in recent years to unveil the molecular viral mechanisms and the virus-host interactions associated with latent HSV infection. The discovery of the state of the latent viral DNA in nervous tissues and of the presence of latency-associated gene expression during latent infection, both differing from the situation during viral replication, provided important clues relevant to the pathogenesis of latent HSV infection. This review summarizes the current state of knowledge on the site of latent infection, the molecular phenomena of latency, and the mechanisms of the various stages of latency: acute infection, establishment and maintenance of latency, and reactivation. This information paved the way to recent trials aiming to use herpes viruses as vectors to deliver genes into the nervous system, an issue that is also addressed in this review.
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Affiliation(s)
- I Steiner
- Department of Neurology, Hadassah University Hospital, Hebrew University-Hadassah Medical School, Jerusalem, Israel
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Batchelor AH, O'Hare P. Localization of cis-acting sequence requirements in the promoter of the latency-associated transcript of herpes simplex virus type 1 required for cell-type-specific activity. J Virol 1992; 66:3573-82. [PMID: 1316469 PMCID: PMC241139 DOI: 10.1128/jvi.66.6.3573-3582.1992] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
We have previously demonstrated (A. H. Batchelor and P. O'Hare, J. Virol. 64:3269-3279, 1990) the selective activity in human neuroblastoma cells (IMR-32) of a promoter located upstream of the latency-associated transcript of herpes simplex virus type 1. In this work, we provide evidence for the basis of the selective activity of this latency-associated promoter (LAP). Recombinant constructs containing sequences up to -143 (relative to the LAP cap site) linked to the chloramphenicol acetyltransferase gene retain strong activity in HeLa cells but exhibit extremely weak activity in IMR-32 cells. Sequences mapping within the 108 bp upstream of -143 to position -251 enhance LAP activity by over 15-fold, restoring optimal levels of expression in IMR-32 cells, but have little or no effect (1.5-fold) in HeLa cells. This cell-type-specific enhancement of promoter activity took place in two major steps, with sequences between -143 and -158 conferring a four- to fivefold effect and sequences between -177 and -251 conferring a further threefold effect. Furthermore, sequences mapping from -40 to -258 could transfer the ability to be expressed in neuroblastoma cells to the normally inactive immediate-early 110K promoter (IE110K), increasing levels of expression by 35-fold. By comparison, this region had a relatively minor effect (twofold) on the activity of the IE110K promoter in HeLa cells, even though this promoter is open to activation by other mechanisms. However, neither of the overlapping subregions from -40 to -143 or -138 to -258 could confer efficient IMR-32 cell expression on the IE110K promoter, and we present alternative models for multiple element requirements or the requirement for a critical site around -140 which is not retained in either subfragment. We provide consistent evidence for a site around -140 and demonstrate the presence selectively in IMR-32 cells of a DNA-binding factor which binds a probe spanning this region. We propose that this element and the cognate factor (IC-1) may be involved in the selective activity of the LAP in neuroblastoma cells.
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Affiliation(s)
- A H Batchelor
- Marie Curie Research Institute, Oxted, Surrey, United Kingdom
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48
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Sawtell NM, Thompson RL. Herpes simplex virus type 1 latency-associated transcription unit promotes anatomical site-dependent establishment and reactivation from latency. J Virol 1992; 66:2157-69. [PMID: 1312626 PMCID: PMC289008 DOI: 10.1128/jvi.66.4.2157-2169.1992] [Citation(s) in RCA: 195] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Defined herpes simplex virus type 1 (HSV-1) mutants KOS/1 and KOS/62 (positive and negative, respectively, for latency-associated transcripts [LATs]) express the Escherichia coli beta-galactosidase (beta-Gal) gene during latency. These mutants were employed to assess the functions of the latency-associated transcription unit on establishment and maintenance of and reactivation from the latent state. It was found that in the trigeminal ganglia, the frequencies of hyperthermia-induced reactivation of KOS/62 and an additional LATs- mutant (KOS/29) were reduced by at least 80%. Quantification of latently infected neurons expressing the beta-Gal gene revealed that the LATs- mutant KOS/62 established approximately 80% fewer latent infections in the trigeminal ganglia than did KOS/1 (LATs+). This reduction in establishment which is evident in the trigeminal ganglia could account for the reduced frequency of reactivation from this site. In striking contrast, both LATs- mutants reactivated with wild-type frequencies from lumbosacral ganglia. Quantification of beta-Gal-positive neurons at this site revealed that KOS/62 established as many as or more latent infections than the LATs+ virus, KOS/1. Colocalization of HSV antigen and beta-Gal suggested that the decreased establishment by LATs- mutants in trigeminal ganglia was the result of inefficient viral shutoff. Thus, one function of the HSV-1 LATs transcription unit is to promote the establishment of latency in trigeminal but not lumbosacral ganglia. Such a function may be relevant to understanding the distinct clinical recurrent disease patterns of HSV-1 and HSV-2.
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Affiliation(s)
- N M Sawtell
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati Medical Center, Ohio 45267-0524
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Wilcox CL, Crnic LS, Pizer LI. Replication, latent infection, and reactivation in neuronal culture with a herpes simplex virus thymidine kinase-negative mutant. Virology 1992; 187:348-52. [PMID: 1310559 DOI: 10.1016/0042-6822(92)90326-k] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Herpes simplex virus type 1 (HSV-1) mutant viruses lacking functional viral thymidine kinase activity are reported to be incapable of replication in neurons. To investigate the role of viral thymidine kinase (TK) activity in the HSV-1 infection of the neuron, we studied a thymidine kinase-negative (TK-) mutant virus engineered to eliminate TK function without affecting the other known transcripts encoded in this region of the genome. Studies using the mouse eye model demonstrated that the mutant behaved as is reported for other TK- viruses: DNA of the mutant virus was detected in the ganglia during the latent infection by polymerase chain reaction, but virus did not reactivate after explantation of the ganglia. Utilizing the neuronal cultures, we investigated the ability of the mutant virus to replicate in neurons and the capacity of the mutant virus to establish latency and reactivate. With a low multiplicity of infection (m.o.i.), replication of the TK- mutant virus in sensory neurons in culture was significantly delayed compared to that of the wild-type virus. However, when a high m.o.i. was used, the mutant and the wild-type viruses replicated with similar kinetics. The TK- mutant virus was capable of establishment of latency and reactivation from the latent infection in sensory neurons in culture. These data suggest that HSV-1 thymidine kinase activity facilitates viral replication, but that TK activity is not essential for either replication or reactivation from latent infections in neurons in vitro.
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Affiliation(s)
- C L Wilcox
- Department of Microbiology, University of Colorado School of Medicine, Denver 80262
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Spivack JG, Woods GM, Fraser NW. Identification of a novel latency-specific splice donor signal within the herpes simplex virus type 1 2.0-kilobase latency-associated transcript (LAT): translation inhibition of LAT open reading frames by the intron within the 2.0-kilobase LAT. J Virol 1991; 65:6800-10. [PMID: 1658375 PMCID: PMC250769 DOI: 10.1128/jvi.65.12.6800-6810.1991] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Herpes simplex virus type 1 establishes latent infection in trigeminal ganglia of mice infected via the eye. A family of three colinear viral transcripts (LATs), 2.0, 1.5, and 1.45 kb, is present in latently infected ganglia. To characterize these LATs, lambda gt10 cDNA libraries were constructed with RNAs isolated from the trigeminal ganglia of latently infected mice. A series of recombinant bacteriophage were isolated containing cDNA inserts covering 1.7 kb of the 2.0-kb LAT. Splice junctions of the smaller LATs and the 3' end of the 2.0-kb LAT were identified by sequence analysis of RNA polymerase chain reaction products. No splice acceptor site, which does not support the hypotheses that the 2.0-kb LAT is an intron. However, the data are consistent with the possibility of a short leader sequence or multiple LAT transcription start sites. To generate the smaller 1.5- and 1.45-kb LATs, there is a 559-nucleotide intron spliced from the 2.0-kb LAT in strain F and a 556-nucleotide intron in strain 17+. The nucleotide sequences at the 5' and 3' ends of these introns are characteristic of spliced transcripts from eukaryotic protein-encoding genes, with one significant difference; i.e., the 5' end of the LAT intron is GC instead of the consensus sequence GT. This splice donor sequence is conserved in herpes simplex virus type 1 strains F, 17+, and KOS. Processing of the 2.0-kb LAT to form the spliced LATs preserves two open reading frames (ORFs) at the 3' end of the LATs; no new ORFs are created. Splicing of the LATs positions a 276-nucleotide leader sequence close to these ORFs and removes an intron that inhibits their translation in vitro. The novel 5' structure of the intron within the 2.0-kb LAT may be part of a control mechanism for transcription processing that results in splicing of the LATs only in sensory neurons during latent infection and reactivation but not during the viral replication cycle.
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Affiliation(s)
- J G Spivack
- Wistar Institute, Philadelphia, Pennsylvania 19104
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