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Zhou T, Wang M, Cheng A, Yang Q, Tian B, Wu Y, Jia R, Chen S, Liu M, Zhao XX, Ou X, Mao S, Sun D, Zhang S, Zhu D, Huang J, Gao Q, Yu Y, Zhang L. Regulation of alphaherpesvirus protein via post-translational phosphorylation. Vet Res 2022; 53:93. [PMID: 36397147 PMCID: PMC9670612 DOI: 10.1186/s13567-022-01115-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 08/22/2022] [Indexed: 11/18/2022] Open
Abstract
An alphaherpesvirus carries dozens of viral proteins in the envelope, tegument and capsid structure, and each protein plays an indispensable role in virus adsorption, invasion, uncoating and release. After infecting the host, a virus eliminates unfavourable factors via multiple mechanisms to escape or suppress the attack of the host immune system. Post-translational modification of proteins, especially phosphorylation, regulates changes in protein conformation and biological activity through a series of complex mechanisms. Many viruses have evolved mechanisms to leverage host phosphorylation systems to regulate viral protein activity and establish a suitable cellular environment for efficient viral replication and virulence. In this paper, viral protein kinases and the regulation of viral protein function mediated via the phosphorylation of alphaherpesvirus proteins are described. In addition, this paper provides new ideas for further research into the role played by the post-translational modification of viral proteins in the virus life cycle, which will be helpful for understanding the mechanisms of viral infection of a host and may lead to new directions of antiviral treatment.
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Romero N, Wuerzberger-Davis SM, Van Waesberghe C, Jansens RJ, Tishchenko A, Verhamme R, Miyamoto S, Favoreel HW. Pseudorabies Virus Infection Results in a Broad Inhibition of Host Gene Transcription. J Virol 2022; 96:e0071422. [PMID: 35730976 PMCID: PMC9278110 DOI: 10.1128/jvi.00714-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Accepted: 05/31/2022] [Indexed: 12/24/2022] Open
Abstract
Pseudorabies virus (PRV) is a porcine alphaherpesvirus that belongs to the Herpesviridae family. We showed earlier that infection of porcine epithelial cells with PRV triggers activation of the nuclear factor κB (NF-κB) pathway, a pivotal signaling axis in the early immune response. However, PRV-induced NF-κB activation does not lead to NF-κB-dependent gene expression. Here, using electrophoretic mobility shift assays (EMSAs), we show that PRV does not disrupt the ability of NF-κB to interact with its κB target sites. Assessing basal cellular transcriptional activity in PRV-infected cells by quantitation of prespliced transcripts of constitutively expressed genes uncovered a broad suppression of cellular transcription by PRV, which also affects the inducible expression of NF-κB target genes. Host cell transcription inhibition was rescued when viral genome replication was blocked using phosphonoacetic acid (PAA). Remarkably, we found that host gene expression shutoff in PRV-infected cells correlated with a substantial retention of the NF-κB subunit p65, the TATA box binding protein, and RNA polymerase II-essential factors required for (NF-κB-dependent) gene transcription-in expanding PRV replication centers in the nucleus and thereby away from the host chromatin. This study reveals a potent mechanism used by the alphaherpesvirus PRV to steer the protein production capacity of infected cells to viral proteins by preventing expression of host genes, including inducible genes involved in mounting antiviral responses. IMPORTANCE Herpesviruses are highly successful pathogens that cause lifelong persistent infections of their host. Modulation of the intracellular environment of infected cells is imperative for the success of virus infections. We reported earlier that a DNA damage response in epithelial cells infected with the alphaherpesvirus pseudorabies virus (PRV) results in activation of the hallmark proinflammatory NF-κB signaling axis but, remarkably, that this activation does not lead to NF-κB-induced (proinflammatory) gene expression. Here, we report that PRV-mediated inhibition of host gene expression stretches beyond NF-κB-dependent gene expression and in fact reflects a broad inhibition of host gene transcription, which correlates with a substantial recruitment of essential host transcription factors in viral replication compartments in the nucleus, away from the host chromatin. These data uncover a potent alphaherpesvirus mechanism to interfere with production of host proteins, including proteins involved in antiviral responses.
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Affiliation(s)
- Nicolás Romero
- Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | - Shelly M. Wuerzberger-Davis
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Cliff Van Waesberghe
- Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | - Robert J. Jansens
- Department of Pharmacology, Weill Medical College, Cornell University, New York, New York, USA
| | - Alexander Tishchenko
- Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | - Ruth Verhamme
- Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
| | - Shigeki Miyamoto
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Herman W. Favoreel
- Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent University, Ghent, Belgium
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Braspenning SE, Sadaoka T, Breuer J, Verjans GMGM, Ouwendijk WJD, Depledge DP. Decoding the Architecture of the Varicella-Zoster Virus Transcriptome. mBio 2020; 11:e01568-20. [PMID: 33024035 PMCID: PMC7542360 DOI: 10.1128/mbio.01568-20] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 08/31/2020] [Indexed: 12/14/2022] Open
Abstract
Varicella-zoster virus (VZV), a double-stranded DNA virus, causes varicella, establishes lifelong latency in ganglionic neurons, and reactivates later in life to cause herpes zoster, commonly associated with chronic pain. The VZV genome is densely packed and produces multitudes of overlapping transcripts deriving from both strands. While 71 distinct open reading frames (ORFs) have thus far been experimentally defined, the full coding potential of VZV remains unknown. Here, we integrated multiple short-read RNA sequencing approaches with long-read direct RNA sequencing on RNA isolated from VZV-infected cells to provide a comprehensive reannotation of the lytic VZV transcriptome architecture. Through precise mapping of transcription start sites, splice junctions, and polyadenylation sites, we identified 136 distinct polyadenylated VZV RNAs that encode canonical ORFs, noncanonical ORFs, and ORF fusions, as well as putative noncoding RNAs (ncRNAs). Furthermore, we determined the kinetic class of all VZV transcripts and observed, unexpectedly, that transcripts encoding the ORF62 protein, previously designated Immediate-Early, were expressed with Late kinetics. Our work showcases the complexity of the VZV transcriptome and provides a comprehensive resource that will facilitate future functional studies of coding RNAs, ncRNAs, and the biological mechanisms underlying the regulation of viral transcription and translation during lytic VZV infection.IMPORTANCE Transcription from herpesviral genomes, executed by the host RNA polymerase II and regulated by viral proteins, results in coordinated viral gene expression to efficiently produce infectious progeny. However, the complete coding potential and regulation of viral gene expression remain ill-defined for the human alphaherpesvirus varicella-zoster virus (VZV), causative agent of both varicella and herpes zoster. Here, we present a comprehensive overview of the VZV transcriptome and the kinetic class of all identified viral transcripts, using two virus strains and two biologically relevant cell types. Additionally, our data provide an overview of how VZV diversifies its transcription from one of the smallest herpesviral genomes. Unexpectedly, the transcript encoding the major viral transactivator protein (pORF62) was expressed with Late kinetics, whereas orthologous transcripts in other alphaherpesviruses are typically expressed during the immediate early phase. Therefore, our work both establishes the architecture of the VZV transcriptome and provides insight into regulation of alphaherpesvirus gene expression.
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Affiliation(s)
| | - Tomohiko Sadaoka
- Division of Clinical Virology, Center for Infectious Diseases, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Judith Breuer
- Department of Infection and Immunity, University College London, London, United Kingdom
| | | | | | - Daniel P Depledge
- Department of Medicine, New York University School of Medicine, New York, New York, USA
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Interferon Gamma Inhibits Varicella-Zoster Virus Replication in a Cell Line-Dependent Manner. J Virol 2019; 93:JVI.00257-19. [PMID: 30918075 DOI: 10.1128/jvi.00257-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 03/21/2019] [Indexed: 01/29/2023] Open
Abstract
The major immediate early 62 (IE62) protein of varicella-zoster virus (VZV) is delivered to newly infected cell nuclei, where it initiates VZV replication by transactivating viral immediate early (IE), early (E), and late (L) genes. Interferon gamma (IFN-γ) is a potent cytokine produced following primary VZV infection. Furthermore, VZV reactivation correlates with a decline in IFN-γ-producing immune cells. Our results showed that treatment with 20 ng/ml of IFN-γ completely reduced intracellular VZV yield in A549 lung epithelial cells, MRC-5 lung fibroblasts, and ARPE-19 retinal epithelial cells at 4 days post-VZV infection. However, IFN-γ reduced virus yield only 2-fold in MeWo melanoma cells compared to that of untreated cells. IFN-β significantly inhibited VZV replication in both ARPE-19 and MeWo cells. In luciferase assays with VZV open reading frame 61 (ORF61) promoter reporter plasmid, IFN-γ abrogated the transactivation activity of IE62 by 95%, 97%, and 89% in A549, ARPE-19, and MRC-5 cells, respectively. However, IFN-γ abrogated IE62's transactivation activity by 16% in MeWo cells, indicating that IFN-γ inhibits VZV replication as well as IE62-mediated transactivation in a cell line-dependent manner. The expression of VZV IE62 and ORF63 suppressed by IFN-γ was restored by JAK1 inhibitor treatment, indicating that the inhibition of VZV replication is mediated by JAK/STAT1 signaling. In the presence of IFN-γ, knockdown of interferon response factor 1 (IRF1) increased VZV replication. Ectopic expression of IRF1 reduced VZV yields 4,000-fold in MRC-5 and ARPE-19 cells but 3-fold in MeWo cells. These results suggest that IFN-γ blocks VZV replication by inhibiting IE62 function in a cell line-dependent manner.IMPORTANCE Our results showed that IFN-γ significantly inhibited VZV replication in a cell line-dependent manner. IFN-γ inhibited VZV gene expression after the immediate early stage of infection and abrogated IE62-mediated transactivation. These results suggest that IFN-γ blocks VZV replication by inhibiting IE62 function in a cell line-dependent manner. Understanding the mechanisms by which IFN-γ plays a role in VZV gene programming may be important in determining the tissue restriction of VZV.
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Liver X Receptors Suppress Activity of Cholesterol and Fatty Acid Synthesis Pathways To Oppose Gammaherpesvirus Replication. mBio 2018; 9:mBio.01115-18. [PMID: 30018108 PMCID: PMC6050960 DOI: 10.1128/mbio.01115-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Gammaherpesviruses are oncogenic pathogens that persist in ~95% of the adult population. Cellular metabolic pathways have emerged as important regulators of many viral infections, including infections by gammaherpesviruses that require several lipid synthetic pathways for optimal replication. Liver X receptors (LXRs) are transcription factors that are critical regulators of cellular fatty acid and cholesterol synthesis pathways. Not surprisingly, LXRs are attractive therapeutic targets in cardiovascular disease. Here we describe an antiviral role for LXRs in the context of gammaherpesvirus infection of primary macrophages. We show that type I interferon increased LXR expression following infection. Surprisingly, there was not a corresponding induction of LXR target genes. Rather, LXRs suppressed the expression of target genes, leading to decreased fatty acid and cholesterol synthesis, two metabolic pathways that support gammaherpesvirus replication. This report defines LXR-mediated restriction of cholesterol and lipid synthesis as an intrinsic metabolic mechanism to restrict viral replication in innate immune cells.IMPORTANCE Fatty acid and cholesterol synthesis pathways of the host play important roles in diverse biological systems. Importantly, these two metabolic pathways are also usurped by a number of viruses to facilitate viral replication. In this report, we show that suppression of these pathways by liver X receptors in primary macrophages creates an intrinsic antiviral state that attenuates gammaherpesvirus replication by limiting viral access to the two metabolic pathways.
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Depledge DP, Sadaoka T, Ouwendijk WJD. Molecular Aspects of Varicella-Zoster Virus Latency. Viruses 2018; 10:v10070349. [PMID: 29958408 PMCID: PMC6070824 DOI: 10.3390/v10070349] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 06/19/2018] [Accepted: 06/27/2018] [Indexed: 02/07/2023] Open
Abstract
Primary varicella-zoster virus (VZV) infection causes varicella (chickenpox) and the establishment of a lifelong latent infection in ganglionic neurons. VZV reactivates in about one-third of infected individuals to cause herpes zoster, often accompanied by neurological complications. The restricted host range of VZV and, until recently, a lack of suitable in vitro models have seriously hampered molecular studies of VZV latency. Nevertheless, recent technological advances facilitated a series of exciting studies that resulted in the discovery of a VZV latency-associated transcript (VLT) and provide novel insights into our understanding of VZV latency and factors that may initiate reactivation. Deducing the function(s) of VLT and the molecular mechanisms involved should now be considered a priority to improve our understanding of factors that govern VZV latency and reactivation. In this review, we summarize the implications of recent discoveries in the VZV latency field from both a virus and host perspective and provide a roadmap for future studies.
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Affiliation(s)
- Daniel P Depledge
- Department of Microbiology, New York University School of Medicine, New York, NY 10016, USA.
| | - Tomohiko Sadaoka
- Division of Clinical Virology, Center for Infectious Diseases, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.
| | - Werner J D Ouwendijk
- Department of Viroscience, Erasmus Medical Centre, 3015 CN Rotterdam, The Netherlands.
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Majima R, Shindoh K, Yamaguchi T, Inoue N. Characterization of a thienylcarboxamide derivative that inhibits the transactivation functions of cytomegalovirus IE2 and varicella zoster virus IE62. Antiviral Res 2017; 140:142-150. [PMID: 28161581 DOI: 10.1016/j.antiviral.2017.01.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 01/20/2017] [Accepted: 01/25/2017] [Indexed: 11/15/2022]
Abstract
Previously we established reporter cell lines for human cytomegalovirus (HCMV) and varicella zoster virus (VZV) and identified several antiviral compounds against these viruses using the reporter cells. In this study, we found that one of the identified anti-HCMV compounds, a thienylcarboxamide derivative (coded as 133G4), was effective against not only HCMV but also VZV. The following findings indicate that 133G4 inhibits the activation of early gene promoters by HCMV IE2 and VZV IE62: i) 133G4 decreased the expression of HCMV early and late genes but not that of HCMV IE1/IE2 in HCMV-infected cells, ii) 133G4 inhibited the activation of several HCMV early gene promoters of transiently-transfected plasmids in HCMV-infected cells, and iii) in transient transfection assays, 133G4 decreased the activation of HCMV (or VZV) early gene promoters by HCMV IE2 (or VZV IE62) in the absence of other viral protein expression. The inhibition of early gene activation was observed in the human and African green monkey cell lines but not in the rodent cell lines, and the compound was not effective against murine CMV. In addition, VZV IE62 activated HCMV early promoters, and 133G4 still inhibited such promoter activation. Therefore, we hypothesized that 133G4 targets a cellular factor used commonly in activation of human herpesvirus promoters and examined whether 133G4 affects the functions of cellular proteins USF1, TBP, Med25 and EAP, the involvement of which in VZV IE62-dependent viral gene activation has been well characterized. Our experimental results using one-hybrid and bimolecular fluorescence complementation assays demonstrated that 133G4 did not inhibit the recruitment of USF1 or TBP to their binding sites, nor inhibited the direct interactions of VZV IE62 with Med25 and EAP. Thus, 133G4 is a unique anti-VZV and -HCMV compound, which warrants further studies to find out its inhibitory mechanism.
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Affiliation(s)
- Ryuichi Majima
- Department of Microbiology and Immunology, Gifu Pharmaceutical University, Gifu, Japan
| | - Keiko Shindoh
- Department of Virology I, National Institute of Infectious Diseases, Tokyo, Japan; Department of Biosciences, Teikyo University of Science and Technology, Yamanashi, Japan
| | - Toyofumi Yamaguchi
- Department of Biosciences, Teikyo University of Science and Technology, Yamanashi, Japan
| | - Naoki Inoue
- Department of Microbiology and Immunology, Gifu Pharmaceutical University, Gifu, Japan; Department of Virology I, National Institute of Infectious Diseases, Tokyo, Japan.
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Functional Characterization of the Serine-Rich Tract of Varicella-Zoster Virus IE62. J Virol 2015; 90:959-71. [PMID: 26537679 DOI: 10.1128/jvi.02096-15] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 10/27/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The immediate early 62 protein (IE62) of varicella-zoster virus (VZV), a major viral trans-activator, initiates the virus life cycle and is a key component of pathogenesis. The IE62 possesses several domains essential for trans-activation, including an acidic trans-activation domain (TAD), a serine-rich tract (SRT), and binding domains for USF, TFIIB, and TATA box binding protein (TBP). Transient-transfection assays showed that the VZV IE62 lacking the SRT trans-activated the early VZV ORF61 promoter at only 16% of the level of the full-length IE62. When the SRT of IE62 was replaced with the SRT of equine herpesvirus 1 (EHV-1) IEP, its trans-activation activity was completely restored. Herpes simplex virus 1 (HSV-1) ICP4 that lacks a TAD very weakly (1.5-fold) trans-activated the ORF61 promoter. An IE62 TAD-ICP4 chimeric protein exhibited trans-activation ability (10.2-fold), indicating that the IE62 TAD functions with the SRT of HSV-1 ICP4 to trans-activate viral promoters. When the serine and acidic residues of the SRT were replaced with Ala, Leu, and Gly, trans-activation activities of the modified IE62 proteins IE62-SRTΔSe and IE62-SRTΔAc were reduced to 46% and 29% of wild-type activity, respectively. Bimolecular complementation assays showed that the TAD of IE62, EHV-1 IEP, and HSV-1 VP16 interacted with Mediator 25 in human melanoma MeWo cells. The SRT of IE62 interacted with the nucleolar-ribosomal protein EAP, which resulted in the formation of globular structures within the nucleus. These results suggest that the SRT plays an important role in VZV viral gene expression and replication. IMPORTANCE The immediate early 62 protein (IE62) of varicella-zoster virus (VZV) is a major viral trans-activator and is essential for viral growth. Our data show that the serine-rich tract (SRT) of VZV IE62, which is well conserved within the alphaherpesviruses, is needed for trans-activation mediated by the acidic trans-activation domain (TAD). The TADs of IE62, EHV-1 IEP, and HSV-1 VP16 interacted with cellular Mediator 25 in bimolecular complementation assays. The interaction of the IE62 SRT with nucleolar-ribosomal protein EAP resulted in the formation of globular structures within the nucleus. Understanding the mechanisms by which the TAD and SRT of IE62 contribute to the function of this essential regulatory protein is important in understanding the gene program of this human pathogen.
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Khalil MI, Ruyechan WT, Hay J, Arvin A. Differential effects of Sp cellular transcription factors on viral promoter activation by varicella-zoster virus (VZV) IE62 protein. Virology 2015; 485:47-57. [PMID: 26207799 PMCID: PMC4619144 DOI: 10.1016/j.virol.2015.06.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 05/08/2015] [Accepted: 06/25/2015] [Indexed: 12/12/2022]
Abstract
The immediate early (IE) 62 protein is the major varicella-zoster virus (VZV) regulatory factor. Analysis of the VZV genome revealed 40 predicted GC-rich boxes within 36 promoters. We examined effects of ectopic expression of Sp1-Sp4 on IE62- mediated transactivation of three viral promoters. Ectopic expression of Sp3 and Sp4 enhanced IE62 activation of ORF3 and gI promoters while Sp3 reduced IE62 activation of ORF28/29 promoter and VZV DNA replication. Sp2 reduced IE62 transactivation of gI while Sp1 had no significant influence on IE62 activation with any of these viral promoters. Electrophoretic mobility shift assays (EMSA) confirmed binding of Sp1 and Sp3 but not Sp2 and Sp4 to the gI promoter. Sp1-4 bound to IE62 and amino acids 238-258 of IE62 were important for the interaction with Sp3 and Sp4 as well as Sp1. This work shows that Sp family members have differential effects on IE62-mediated transactivation in a promoter-dependent manner.
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Affiliation(s)
- Mohamed I Khalil
- Departments of Pediatrics and Microbiology & Immunology, Stanford University School of Medicine, Stanford, CA, United States; Department of Molecular Biology, National Research Center EL-Buhouth St., Dokki, Cairo, Egypt.
| | - William T Ruyechan
- Department of Microbiology and Immunology and the Witebsky Center for Microbial Pathogenesis and Immunology, University at Buffalo, Buffalo, NY, United States
| | - John Hay
- Department of Microbiology and Immunology and the Witebsky Center for Microbial Pathogenesis and Immunology, University at Buffalo, Buffalo, NY, United States
| | - Ann Arvin
- Departments of Pediatrics and Microbiology & Immunology, Stanford University School of Medicine, Stanford, CA, United States
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Khalil MI, Sommer M, Arvin A, Hay J, Ruyechan WT. Cellular transcription factor YY1 mediates the varicella-zoster virus (VZV) IE62 transcriptional activation. Virology 2014; 449:244-53. [PMID: 24418559 DOI: 10.1016/j.virol.2013.11.029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 08/19/2013] [Accepted: 11/20/2013] [Indexed: 12/12/2022]
Abstract
Several cellular transcription factors have been shown to be involved in IE62-mediated activation. The YY1 cellular transcription factor has activating and repressive effects on gene transcription. Analysis of the VZV genome revealed 19 postulated YY1 binding sites located within putative promoters of 16 VZV genes. Electrophoretic mobility shift assays (EMSA) confirmed the binding of YY1 to ORF10, ORF28/29 and gI promoters and the mutation of these binding sites inhibited YY1 binding and the promoter activation by IE62 alone or following VZV infection. Mutation of the ORF28/29 YY1 site in the VZV genome displayed insignificant influence on virus growth in melanoma cells; but it inhibited the virus replication significantly at day 5 and 6 post infection in HELF cells. This work suggests a novel role for the cellular factor YY1 in VZV replication through the mediation of IE62 activation of viral gene expression.
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Affiliation(s)
- Mohamed I Khalil
- Departments of Pediatrics and Microbiology & Immunology, Stanford University School of Medicine, Stanford, CA 94305, United States; Department of Molecular Biology, National Research Center, Dokki, Cairo, Egypt.
| | - Marvin Sommer
- Departments of Pediatrics and Microbiology & Immunology, Stanford University School of Medicine, Stanford, CA 94305, United States
| | - Ann Arvin
- Departments of Pediatrics and Microbiology & Immunology, Stanford University School of Medicine, Stanford, CA 94305, United States
| | - John Hay
- Department of Microbiology and Immunology and the Witebsky Center for Microbial Pathogenesis and Immunology, University at Buffalo, Buffalo, NY, United States
| | - William T Ruyechan
- Department of Microbiology and Immunology and the Witebsky Center for Microbial Pathogenesis and Immunology, University at Buffalo, Buffalo, NY, United States
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Khalil MI, Sommer M, Arvin A, Hay J, Ruyechan WT. Regulation of the varicella-zoster virus ORF3 promoter by cellular and viral factors. Virology 2013; 440:171-81. [PMID: 23523134 DOI: 10.1016/j.virol.2013.02.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 02/20/2013] [Accepted: 02/24/2013] [Indexed: 11/18/2022]
Abstract
The varicella zoster virus (VZV) immediate early 62 protein (IE62) activates most if not all identified promoters of VZV genes and also some minimum model promoters that contain only a TATA box element. Analysis of the DNA elements that function in IE62 activation of the VZV ORF3 promoter revealed that the 100 nucleotides before the translation start site of the ORF3 gene contains the promoter elements. This promoter lacks any functional TATA box element. Cellular transcription factors Sp1, Sp3 and YY1 bind to the promoter, and mutation of their binding sites inhibited ORF3 gene expression. VZV regulatory proteins, IE63 and ORF29, ORF61 and ORF10 proteins inhibited IE62-mediated activation of this promoter. Mutation of the Sp1/Sp3 binding site in the VZV genome did not alter VZV replication kinetics. This work suggests that Sp family proteins contribute to the activation of VZV promoters by IE62 in the absence of functional TATA box.
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Affiliation(s)
- Mohamed I Khalil
- Departments of Pediatrics and Microbiology & Immunology, Stanford University School of Medicine, Stanford, CA 94305, United States.
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12
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Gray WL. The simian varicella virus ORF A is expressed in infected cells but is non-essential for replication in cell culture. Arch Virol 2012; 157:1803-6. [PMID: 22678718 PMCID: PMC3560413 DOI: 10.1007/s00705-012-1367-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 04/25/2012] [Indexed: 10/28/2022]
Abstract
The simian varicella virus (SVV) genome encodes ORF A, a truncated homolog of SVV ORF 4. The SVV ORF A was expressed as a 1.0-kb transcript in SVV-infected Vero cells. The ORF A promoter was active in infected Vero cells and was stimulated by the SVV immediate-early gene ORF 62 product (IE62), a viral transactivator of SVV genes. The SVV ORF A did not transactivate SVV IE, early, or late gene promoters in transfected Vero cells and was unable to augment IE62-mediated transactivation of SVV promoters. A SVV mutant lacking ORF A replicated as efficiently as wild-type SVV in infected Vero cells, indicating that ORF A expression is not essential for in vitro replication.
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Affiliation(s)
- Wayne L Gray
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, 4301 West Markham Street, Slot 511, Little Rock, AR 72205, USA.
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13
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An Sp1/Sp3 site in the downstream region of varicella-zoster virus (VZV) oriS influences origin-dependent DNA replication and flanking gene transcription and is important for VZV replication in vitro and in human skin. J Virol 2012; 86:13070-80. [PMID: 22933283 DOI: 10.1128/jvi.01538-12] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The distribution and orientation of origin-binding protein (OBP) sites are the main architectural contrasts between varicella-zoster virus (VZV) and herpes simplex virus (HSV) origins of DNA replication (oriS). One important difference is the absence of a downstream OBP site in VZV, raising the possibility that an alternative cis element may replace its function. Our previous work established that Sp1, Sp3, and YY1 bind to specific sites within the downstream region of VZV oriS; we hypothesize that one or both of these sites may be the alternative cis element(s). Here, we show that the mutation of the Sp1/Sp3 site decreases DNA replication and transcription from the adjacent ORF62 and ORF63 promoters following superinfection with VZV. In contrast, in the absence of DNA replication or in transfection experiments with ORF62, only ORF63 transcription is affected. YY1 site mutations had no significant effect on either process. Recombinant viruses containing these mutations were then constructed. The Sp1/Sp3 site mutant exhibited a significant decrease in virus growth in MeWo cells and in human skin xenografts, while the YY1 site mutant virus grew as well as the wild type in MeWo cells, even showing a late increase in VZV replication in skin xenografts following infection. These results suggest that the Sp1/Sp3 site plays an important role in both VZV origin-dependent DNA replication and ORF62 and ORF63 transcription and that, in contrast to HSV, these events are linked during virus replication.
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Che X, Oliver SL, Sommer MH, Rajamani J, Reichelt M, Arvin AM. Identification and functional characterization of the Varicella zoster virus ORF11 gene product. Virology 2011; 412:156-66. [PMID: 21276599 DOI: 10.1016/j.virol.2010.12.055] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Revised: 11/17/2010] [Accepted: 12/27/2010] [Indexed: 11/18/2022]
Abstract
The deletion of ORF11 severely impaired VZV infection of human skin xenografts. Here, we investigate the characteristics and functions of the ORF11 gene product. ORF11 is expressed as a 118kDa polypeptide in VZV-infected cells; the protein is present in the nucleus and cytoplasm and is incorporated into VZ virions. Although ORF11 had little effect in transactivating VZV gene promoters in transfection assays, deleting ORF11 from the virus was associated with reduced expression of immediate early proteins IE4, IE62 and IE63, and the major glycoprotein, gE. ORF11 was identified as an RNA binding protein and its RNA binding domain was defined. However, disrupting the ORF11 RNA binding domain did not affect skin infection, indicating that RNA binding capacity, conserved among the alphaherpesviruses homologues, is not essential while the contribution of ORF11 to the expression of the IE proteins and gE may be required for VZV pathogenesis in skin in vivo.
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Affiliation(s)
- Xibing Che
- Departments of Pediatrics and Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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15
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Abstract
Varicella zoster virus (VZV) is the causative agent of chickenpox and shingles. During productive infection the complete VZV proteome consisting of some 68 unique gene products is expressed through interaction of a small number of viral transcriptional activators with the general transcription apparatus of the host cell. Recent work has shown that the major viral transactivator, commonly designated the IE62 protein, interacts with the human Mediator of transcription. This interaction requires direct contact between the MED25 subunit of Mediator and the acidic N-terminal transactivation domain of IE62. A second cellular factor, host cell factor-1, has been shown to be the common element in two mechanisms of activation of the promoter driving expression of the gene encoding IE62. Finally, the ubiquitous cellular transcription factors Sp1, Sp3, and YY1 have been shown to interact with sequences near the VZV origin of DNA replication and in the case of Sp1/Sp3 to influence replication efficiency.
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Folster JM, Jensen NJ, Ruyechan WT, Inoue N, Schmid DS. Regulation of the expression of the varicella-zoster virus open reading frame 66 gene. Virus Res 2010; 155:334-42. [PMID: 21074584 DOI: 10.1016/j.virusres.2010.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 11/01/2010] [Accepted: 11/04/2010] [Indexed: 11/18/2022]
Abstract
The varicella-zoster virus (VZV) open reading frame (ORF) 66 encodes a serine/threonine kinase that phosphorylates the major viral transactivator protein, immediate-early (IE) 62, preventing its nuclear importation. Cytoplasmic sequestration of IE62 may alter viral gene transcription and could serve as a mechanism for maintaining VZV latency. We examined the regulation of expression of the ORF66 gene by mapping the promoter region, which was localized to within 150 bases of the start codon. The ORF66 promoter was activated by two viral regulatory proteins, IE62 and IE63. We evaluated the binding of viral regulatory proteins and cellular transcription factors based on recognized cellular transcription factor binding sites identified within the ORF66 promoter. These included Sp1 and TBP binding sites, several of which were essential for optimal promoter activity. Site-directed mutations in Sp1 and TBP binding sites led to varying degrees of impairment of ORF66 gene expression in the context of VZV infection. We also examined the effect of Sp1 and TBP mutations on IE62, Sp1, and TBP binding. These studies reveal that host cell-derived and viral factors contribute to and cooperate in the expression of this important viral kinase gene.
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Affiliation(s)
- Jennifer M Folster
- Division of Viral Diseases, Measles, Mumps, Rubella, and Herpesvirus Laboratory Branch, Centers for Disease Control and Prevention, Office of Infectious Diseases, National Center for Immunizations and Respiratory Diseases, Atlanta, GA 30333, USA.
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17
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The alphaherpesvirus US3/ORF66 protein kinases direct phosphorylation of the nuclear matrix protein matrin 3. J Virol 2010; 85:568-81. [PMID: 20962082 DOI: 10.1128/jvi.01611-10] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The protein kinase found in the short region of alphaherpesviruses, termed US3 in herpes simplex virus type 1 (HSV-1) and pseudorabies virus (PRV) and ORF66 in varicella-zoster virus (VZV), affects several viral and host cell processes, and its specific targets remain an area of active investigation. Reports suggesting that HSV-1 US3 substrates overlap with those of cellular protein kinase A (PKA) prompted the use of an antibody specific for phosphorylated PKA substrates to identify US3/ORF66 targets. HSV-1, VZV, and PRV induced very different substrate profiles that were US3/ORF66 kinase dependent. The predominant VZV-phosphorylated 125-kDa species was identified as matrin 3, one of the major nuclear matrix proteins. Matrin 3 was also phosphorylated by HSV-1 and PRV in a US3 kinase-dependent manner and by VZV ORF66 kinase at a novel residue (KRRRT150EE). Since VZV-directed T150 phosphorylation was not blocked by PKA inhibitors and was not induced by PKA activation, and since PKA predominantly targeted matrin 3 S188, it was concluded that phosphorylation by VZV was PKA independent. However, purified VZV ORF66 kinase did not phosphorylate matrin 3 in vitro, suggesting that additional cellular factors were required. In VZV-infected cells in the absence of the ORF66 kinase, matrin 3 displayed intranuclear changes, while matrin 3 showed a pronounced cytoplasmic distribution in late-stage cells infected with US3-negative HSV-1 or PRV. This work identifies phosphorylation of the nuclear matrix protein matrin 3 as a new conserved target of this kinase group.
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18
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Erazo A, Kinchington PR. Varicella-zoster virus open reading frame 66 protein kinase and its relationship to alphaherpesvirus US3 kinases. Curr Top Microbiol Immunol 2010; 342:79-98. [PMID: 20186610 DOI: 10.1007/82_2009_7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The varicella-zoster virus (VZV) open reading frame (ORF) 66 encodes a basophilic kinase orthologous to the US3 protein kinases found in all alphaherpesviruses. This review summarizes current information on the ORF66 kinase, and outlines apparent differences from other US3 kinases, as well as some of the conserved functions. One critical difference is the VZV ORF66 kinase targeting of the major regulatory VZV IE62 protein to control its nuclear import and assembly into the VZV virion, which is so far unprecedented in the alphaherpesviruses. However, ORF66 targets some cellular targets which are also targeted by US3 kinases of other herpesviruses, including the histone deacetylase-1 and 2 proteins, pathways that lead to changes in actin dynamics, and the targeting of substrates of protein kinase A, including the nuclear matrix protein matrin 3.
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Affiliation(s)
- Angela Erazo
- Graduate Program in Molecular Virology and Microbiology, School of Medicine, University of Pittsbusrgh, Pittsburgh, PA, USA
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19
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Regulation of the ORF61 promoter and ORF61 functions in varicella-zoster virus replication and pathogenesis. J Virol 2009; 83:7560-72. [PMID: 19457996 DOI: 10.1128/jvi.00118-09] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Varicella-zoster virus (VZV) open reading frame 61 (ORF61) encodes a protein that transactivates viral and cellular promoters in transient-transfection assays and is the ortholog of herpes simplex virus ICP0. In this report, we mapped the ORF61 promoter and investigated its regulation by viral and cellular proteins in transient-expression experiments and by mutagenesis of the VZV genome (parent Oka strain). The 5' boundary of the minimal ORF61 promoter required for IE62 transactivation was mapped to position -95 relative to the mRNA start site, and three noncanonical GT-rich Sp1-binding sites were documented to occur within the region comprising positions -95 to -45. Contributions of the three Sp1-binding-site motifs, designated Sp1a, Sp1b, and Sp1c, to ORF61 expression and viral replication were varied despite their similar sequences. Two sites, Sp1a and Sp1c, functioned synergistically. When both sites were mutated in the pOka genome to produce pOka-61proDeltaSp1ac, the mutant virus expressed significantly less ORF61 protein. Using this mutant to investigate ORF61 functions resulted in reductions in the expression levels of IE proteins, viral kinases ORF47 and ORF66, and the major glycoprotein gE, with the most impact on gE. Virion morphogenesis appeared to be intact despite minimal ORF61 expression. Pretreating melanoma cells with sodium butyrate enhanced titers of pOka-61proDeltaSp1ac but not pOka, suggesting that ORF61 has a role in histone deacetylase inhibition. Growth of pOka-61proDeltaSp1ac was impaired in SCIDhu skin xenografts, indicating that the regulation of the ORF61 promoter by Sp1 family proteins is important for ORF61 expression in vivo and that ORF61 contributes to VZV virulence at skin sites of replication.
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20
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Cellular transcription factors Sp1 and Sp3 suppress varicella-zoster virus origin-dependent DNA replication. J Virol 2008; 82:11723-33. [PMID: 18815296 DOI: 10.1128/jvi.01322-08] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The varicella-zoster virus (VZV) origin of DNA replication (oriS) contains a 46-bp AT-rich palindrome and three consensus binding sites for the VZV origin binding protein (OBP) encoded by VZV ORF51. All three OBP binding sites are upstream of the palindrome in contrast to the sequence of the herpes simplex virus oriS, which has required OBP binding sites upstream and downstream of the AT-rich region. We are investigating the roles that sequences downstream of the palindrome play in VZV oriS-dependent DNA replication. Computer analysis identified two GC boxes, GC box 1 and GC box 2, in the downstream region which were predicted to be binding sites for the cellular transcription factor Sp1. Electrophoretic mobility shift assay and supershift assays showed that two members of the Sp family (Sp1 and Sp3) stably bind to GC box 1, but not to GC box 2. A predicted binding site for the cellular factor Yin Yang 1 (YY1) that overlaps with GC box 2 was also identified. Supershift and mutational analyses confirmed the binding of YY1 to this site. Mutation of GC box 1 resulted in loss of Sp1 and Sp3 binding and an increase in origin-dependent replication efficiency in DpnI replication assays. In contrast, mutation of the YY1 site had a statistically insignificant effect. These results suggest a model where origin-dependent DNA replication and viral transcription are coupled by the binding of Sp1 and Sp3 to the downstream region of the VZV replication origin during lytic infection. They may also have implications regarding establishment or reactivation of viral latency.
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Cyclin-dependent kinase 1/cyclin B1 phosphorylates varicella-zoster virus IE62 and is incorporated into virions. J Virol 2008; 82:12116-25. [PMID: 18799590 DOI: 10.1128/jvi.00153-08] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Varicella-zoster virus (VZV), an alphaherpesvirus restricted to humans, infects differentiated cells in vivo, including T lymphocytes, keratinocytes, and neurons, and spreads rapidly in confluent cultured dermal fibroblasts (HFFs). In VZV-infected HFFs, atypical expression of cyclins D3 and B1 occurs along with the induction of cyclin-dependent kinase (CDK) activity. A specific CDK1 inhibitor blocked VZV spread, indicating an important function for this cellular kinase in VZV replication. CDK activity assays of infected cells revealed a large viral phosphoprotein that was identified as being the major immediate-early transactivator, IE62. Since IE62 colocalized with CDK1/cyclin B1 by confocal microscopy, we investigated whether this cellular kinase complex interacts with IE62. Using recombinant fragments of IE62 spanning the entire amino acid sequence, we found that purified CDK1/cyclin B1 phosphorylated IE62 at residues T10, S245, and T680 in vitro. Immunoprecipitation of cyclin B1 from VZV-infected HFFs indicated that IE62 was included in the complex within infected cells. The full-length IE62 protein, obtained by immunoprecipitation from infected cells, was also phosphorylated by purified CDK1/cyclin B1. Based on IE62/CDK1/cyclin B1 colocalization near viral assembly regions, we hypothesized that these cellular proteins could be incorporated into VZV virions with IE62. Purified virions were analyzed by immunoblotting for the presence of CDK1 and cyclin B1, and active CDK1 and cyclin B1 were present in the VZV tegument with IE62 and were sensitive to detergent treatment. Thus, IE62 is a substrate for CDK1/cyclin B1, and virions could deliver the active cellular kinase to nondividing cells that normally do not express it.
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Berarducci B, Sommer M, Zerboni L, Rajamani J, Arvin AM. Cellular and viral factors regulate the varicella-zoster virus gE promoter during viral replication. J Virol 2007; 81:10258-67. [PMID: 17634217 PMCID: PMC2045477 DOI: 10.1128/jvi.00553-07] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Varicella-zoster virus (VZV) glycoprotein E (gE) is essential for viral replication and is involved in cell-to-cell spread, secondary envelopment, and entry. We created a set of mutations in the gE promoter to investigate the role of viral and cellular transcriptional factors in regulation of the gE promoter. Deletion or point mutation of the two Sp1 sites in the gE promoter abolished Sp1 binding and IE62-mediated transactivation of the gE promoter in vitro. Incorporation of the deletion or the point mutations disrupting both of the Sp1 binding sites into the VZV genome was not compatible with viral replication. A point mutation altering the atypical Sp1 binding site was lethal, while altering the second site impaired VZV replication significantly, indicating functional differences between the two Sp1 binding sites. Deletions in the gE promoter that abolished putative binding sites for cellular transcriptional factors other than Sp1, identified by bioinformatics analysis, were inserted in the VZV genome. Replication of the viruses with mutations of the gE promoter did not differ from control recombinants in melanoma cells or primary human tonsil T cells in vitro. These deletions did not affect infection of human skin xenografts in SCIDhu mice. These results indicate that Sp1 is required for IE62-mediated transactivation of the gE promoter and that this transcriptional factor appears to be the only cellular factor essential for regulation of the gE promoter.
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Affiliation(s)
- Barbara Berarducci
- Department of Pediatrics, Stanford University School of Medicine, 300 Pasteur Dr., Rm. G312, Stanford, CA 94305-5208, USA.
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23
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Narayanan A, Ruyechan WT, Kristie TM. The coactivator host cell factor-1 mediates Set1 and MLL1 H3K4 trimethylation at herpesvirus immediate early promoters for initiation of infection. Proc Natl Acad Sci U S A 2007; 104:10835-40. [PMID: 17578910 PMCID: PMC1894567 DOI: 10.1073/pnas.0704351104] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Originally identified as an essential component of the herpes simplex virus immediate early (IE) gene enhancer complex, the transcriptional coactivator host cell factor-1 (HCF-1) has been implicated in a broad range of cellular regulatory circuits. The protein mediates activation through multiple interactions with transcriptional activators, coactivators, and chromatin remodeling complexes. However, the mechanisms involved in HCF-1-dependent transcriptional stimulation were undefined. By using a minimal HCF-1-dependent promoter and a model activator, the varicella zoster IE62 protein, it was determined that HCF-1 was not required for the assembly of the RNAPII basal complex, which depended solely on IE62 in conjunction with the cellular factor Sp1. In contrast, HCF-1 was required for recruitment of the histone methyltransferases Set1 and MLL1 (mixed-lineage leukemia 1), leading to histone H3K4 trimethylation and transcriptional activation. Similarly, in a varicella zoster virus lytic infection, HCF-1, Set1, and MLL1 were recruited to the viral genomic IE promoter, suggesting an essential role for HCF-1 in chromatin modification and remodeling during initiation of lytic infection. The results indicate that one biological rationale for the incorporation of the viral IE activators in the viral particle is to recruit HCF-1/histone methyltransferase complexes and promote assembly of the viral IE gene promoters into transcriptionally active chromatin. These studies also contribute to the model whereby the induced nuclear transport of HCF-1 in sensory neurons may be critical to the reactivation of latent herpesviruses by promoting the activation of chromatin modifications.
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Affiliation(s)
- Aarthi Narayanan
- *Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Building 4-131, 4 Center Drive, Bethesda, MD 20892; and
| | - William T. Ruyechan
- Department of Microbiology and Immunology, University at Buffalo, State University of New York, 251 Biomedical Research Building, Buffalo, NY 14214
| | - Thomas M. Kristie
- *Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Building 4-131, 4 Center Drive, Bethesda, MD 20892; and
- To whom correspondence should be addressed. E-mail:
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Che X, Berarducci B, Sommer M, Ruyechan WT, Arvin AM. The ubiquitous cellular transcriptional factor USF targets the varicella-zoster virus open reading frame 10 promoter and determines virulence in human skin xenografts in SCIDhu mice in vivo. J Virol 2007; 81:3229-39. [PMID: 17251302 PMCID: PMC1866059 DOI: 10.1128/jvi.02537-06] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2006] [Accepted: 01/19/2007] [Indexed: 11/20/2022] Open
Abstract
Varicella-zoster virus (VZV) open reading frame 10 (ORF10) is a determinant of virulence in SCIDhu skin xenografts but not in human T cells in vivo. In this analysis of the regulation of ORF10 transcription, we have identified four ORF10-related transcripts, including a major 1.3-kb RNA spanning ORF10 only and three other read-through transcripts. Rapid-amplification-of-cDNA-ends experiments indicated that the 1.3-kb transcript of ORF10 has single initiation and termination sites. In transient expression assays, the ORF10 promoter was strongly stimulated by the major VZV transactivator, IE62. Deletion analyses revealed approximate boundaries for the full ORF10 promoter activity between -75 and -45 and between +5 and -8, relative to the ORF10 transcription start site. The recombinant virus POKA10-Deltapro, with the ORF10 promoter deletion, blocked transcription of ORF10 and also of ORF9A and ORF9 mRNAs, whereas expression of read-through ORF9A/9/10 and ORF9/10 transcripts was increased, compensating for the loss of the monocistronic mRNAs. The cellular factor USF bound specifically to its consensus site within the ORF10 promoter and was required for IE62 transactivation, whereas disrupting the predicted TATA boxes or Oct-1 binding elements had no effect. The USF binding site was disrupted in the recombinant virus, POKA10-proDeltaUSF, and no ORF10 protein was produced. Both ORF10 promoter mutants reduced VZV replication in SCIDhu skin xenografts. These observations provided further evidence of the contribution of the ORF10 protein to VZV pathogenesis in skin and demonstrated that VZV depends upon the cellular transcriptional factor USF to support its virulence in human skin in vivo.
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Affiliation(s)
- Xibing Che
- Department of Pediatrics, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94305-5208, USA.
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Abstract
VZV is a highly cell-associated member of the Herpesviridae family and one of the eight herpesviruses to infect humans. The virus is ubiquitous in most populations worldwide, primary infection with which causes varicella, more commonly known as chickenpox. Characteristic of members of the alphaherpesvirus sub-family, VZV is neurotropic and establishes latency in sensory neurones. Reactivation from latency, usually during periods of impaired cellular immunity, causes herpes zoster (shingles). Despite being one of the most genetically stable human herpesviruses, nucleotide alterations in the virus genome have been used to classify VZV strains from different geographical regions into distinct clades. Such studies have also provided evidence that, despite pre-existing immunity to VZV, subclinical reinfection and reactivation of reinfecting strains to cause zoster is also occurring. During both primary infection and reactivation, VZV infects several PBMC and skin cell lineages. Difficulties in studying the pathogenesis of VZV because of its high cell association and narrow host range have been overcome through the development of the VZV severe combined immunodeficient mouse model carrying human tissue implants. This model has provided a valuable tool for studying the importance of individual viral proteins during both the complex intracellular replication and assembly of new virions and for understanding the underlying mechanism of attenuation of the live varicella vaccine. In addition, a rat model has been developed and successfully used to uncover which viral proteins are important for both the establishment and maintenance of latent VZV infection.
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Affiliation(s)
- Mark Quinlivan
- Centre for Infectious Diseases, Institute for Cell and Molecular Science, 4 Newark Street, Whitechapel, London, E1 2AT, UK.
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Yang M, Peng H, Hay J, Ruyechan WT. Promoter activation by the varicella-zoster virus major transactivator IE62 and the cellular transcription factor USF. J Virol 2006; 80:7339-53. [PMID: 16840315 PMCID: PMC1563731 DOI: 10.1128/jvi.00309-06] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The varicella-zoster virus major transactivator, IE62, can activate expression from homologous and heterologous promoters. High levels of IE62-mediated activation appear to involve synergy with cellular transcription factors. The work presented here focuses on functional interactions of IE62 with the ubiquitously expressed cellular factor USF. We have found that USF can synergize with IE62 to a similar extent on model minimal promoters and the complex native ORF28/29 regulatory element, neither of which contains a consensus IE62 binding site. Using Gal4 fusion constructs, we have found that the activation domain of USF1 is necessary and sufficient for synergistic activation with IE62. We have mapped the regions of USF and IE62 required for direct physical interaction. Deletion of the required region within IE62 does not ablate synergistic activation but does influence its efficiency depending on promoter architecture. Both proteins stabilize/increase binding of TATA binding protein/TFIID to promoter elements. These findings suggest a novel mechanism for the observed synergistic activation which requires neither site-specific IE62 binding to the promoter nor a direct physical interaction with USF.
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Affiliation(s)
- Min Yang
- Department of Microbiology and Immunology, 138 Farber Hall, University at Buffalo, Buffalo, NY 14214-3000, USA
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Ou Y, Gray WL. Simian varicella virus gene 28 and 29 promoters share a common upstream stimulatory factor-binding site and are induced by IE62 transactivation. J Gen Virol 2006; 87:1501-1508. [PMID: 16690914 DOI: 10.1099/vir.0.81645-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Simian varicella virus (SVV) is a neurotropic alphaherpesvirus that causes a natural, varicella-like disease in non-human primates. After resolution of the primary disease, SVV, like its human counterpart, varicella-zoster virus (VZV), establishes latent infection in the neural ganglia of the host. In this study, gene expression of SVV open reading frames (ORFs) 28 and 29, which encode the viral DNA polymerase and DNA-binding protein, respectively, was characterized during lytic infection of Vero cells. The results indicate that the intergenic region controlling gene 28 and 29 expression includes overlapping, divergent promoters. The ORF 28 and 29 promoters are active in SVV-infected Vero cells, but not in uninfected cells. The SVV immediate-early gene 62 (IE62) product transactivates ORF 28 and 29 expression, and a cellular upstream stimulatory factor-binding site is important for efficient IE62 induction of genes 28 and 29. DNA sequence analysis of the 185 bp intergenic region identified putative cellular transcription factor-binding sites. Transcriptional analysis mapped ORF 28 and 29 RNA start sites. A recombinant SVV was employed to demonstrate that the ORF 29 promoter can express a heterologous gene (green fluorescent protein) when inserted into a novel site (the ORF 12/13 intergenic region) within the SVV genome. The findings demonstrate similarities between SVV and VZV ORF 28/29 expression and indicate that the simian varicella model may be useful to investigate the differential regulation of viral genes during lytic and latent infection.
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Affiliation(s)
- Yang Ou
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, 4301 W. Markham Street, Little Rock, AR 72205, USA
| | - Wayne L Gray
- Department of Microbiology and Immunology, University of Arkansas for Medical Sciences, 4301 W. Markham Street, Little Rock, AR 72205, USA
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28
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Yang M, Hay J, Ruyechan WT. The DNA element controlling expression of the varicella-zoster virus open reading frame 28 and 29 genes consists of two divergent unidirectional promoters which have a common USF site. J Virol 2004; 78:10939-52. [PMID: 15452214 PMCID: PMC521831 DOI: 10.1128/jvi.78.20.10939-10952.2004] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The mechanism of the divergent expression of the varicella-zoster virus (VZV) ORF 28 and ORF 29 genes from a common intergenic DNA element, the ORF 28/29 promoter, is of interest based on the observation that both genes are expressed during VZV lytic infection but only the ORF 29 gene is expressed in latently infected neurons. In the work presented here, expression driven by the ORF 28/29 intergenic region was examined. We found that the promoter activity towards the ORF 29 direction is more responsive to activation by the major viral transactivator IE62 than that towards the ORF 28 direction in the context of our experimental system. Analysis of the functional DNA elements involved in IE62 activation of the bidirectional ORF 28/29 regulatory element revealed that in both transfected and VZV-superinfected cells it is a fusion of two unidirectional promoters overlapping an essential USF binding site but with distinct TATA elements. A single TATA element directs expression in the ORF 28 direction, whereas the two TATA elements directing ORF 29 gene expression are alternatively and differentially utilized for transcription initiation. We also identified an Sp1 site localized proximal to the ORF 28 gene which functions as an activator element for expression in both directions. These results indicate that the ORF 28 and ORF 29 genes can be expressed either coordinately or independently and that the observed expression of only the ORF 29 gene during VZV latency may involve neuron-specific cellular factors and/or structural aspects of the latent viral genome.
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Affiliation(s)
- Min Yang
- Department of Microbiology and Immunology, 138 Farber Hall, University at Buffalo, Buffalo, NY 14214-3000, USA
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Grose C, Tyler S, Peters G, Hiebert J, Stephens GM, Ruyechan WT, Jackson W, Storlie J, Tipples GA. Complete DNA sequence analyses of the first two varicella-zoster virus glycoprotein E (D150N) mutant viruses found in North America: evolution of genotypes with an accelerated cell spread phenotype. J Virol 2004; 78:6799-807. [PMID: 15194755 PMCID: PMC421634 DOI: 10.1128/jvi.78.13.6799-6807.2004] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Varicella-zoster virus (VZV) is considered to be one of the most genetically stable of all the herpesviruses. Yet two VZV strains with a D150N missense mutation within the gE glycoprotein were isolated in North America in 1998 and 2002. The mutant strains have an accelerated cell spread phenotype, which distinguishes them from all wild-type and laboratory viruses. Since the VZV genome contains 70 additional open reading frames (ORFs), the possibility existed that the phenotypic change was actually due to an as-yet-undiscovered mutation or deletion elsewhere in the genome. To exclude this hypothesis, the entire genomes of the two mutant viruses were sequenced and found to contain 124,883 (VZV-MSP) and 125,459 (VZV-BC) nucleotides. Coding single-nucleotide polymorphisms (SNPs) were identified in 14 ORFs. One missense mutation was discovered in gH, but none was found in gB, gI, gL, or gK. There were no coding SNPs in the major regulatory protein ORF 62. One polymorphism was discovered which could never have been anticipated based on current knowledge of herpesvirus genomics, namely, the origins of replication differed from those in the prototype strain but not in a manner expected to affect cell spread. When the two complete mutant VZV sequences were surveyed in their entirety, the most reasonable conclusion was that the increased cell spread phenotype was dependent substantially or solely on the single D150N polymorphism in glycoprotein gE. The genomic results also expanded the evolutionary database by identifying which VZV ORFs were more likely to mutate over time.
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Affiliation(s)
- Charles Grose
- Department of Pediatrics, University of Iowa, Iowa City, 52242, USA.
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Rahaus M, Desloges N, Yang M, Ruyechan WT, Wolff MH. Transcription factor USF, expressed during the entire phase of varicella-zoster virus infection, interacts physically with the major viral transactivator IE62 and plays a significant role in virus replication. J Gen Virol 2003; 84:2957-2967. [PMID: 14573800 DOI: 10.1099/vir.0.19335-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The expression of the genes of varicella-zoster virus (VZV) is regulated by self-encoded viral as well as cellular transcription factors. A potential candidate with an ability to influence the transcription of VZV genes is USF (upstream stimulatory factor), which recognizes the consensus E-box motif. Quantitative RT-PCR and immunoblot assays indicate stable expression of both USF1 and USF2 throughout infection. It was also found that USF binds to a variety of E-boxes (consensus and closely related motifs) within the promoters of ORF 8/9 (two elements), ORF 22 and ORF 67. Co-immunoprecipitation experiments and His-tag protein affinity pull-down assays indicate that a direct physical interaction occurs between USF and the major virus transactivator IE62. To study the general effects of USF in the replication of VZV, a cell line expressing a dominant-negative form of USF (A-USF), which inhibits binding of USF to its recognition sites, was created. A significant decrease in virus replication was detected when this cell line was infected with cell-free virus, indicating that USF is an important cellular factor that regulates the transcription of VZV genes.
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Affiliation(s)
- Markus Rahaus
- Institute of Microbiology and Virology, University of Witten/Herdecke, Stockumer Str. 10, D-58448 Witten, Germany
| | - Nathalie Desloges
- Institute of Microbiology and Virology, University of Witten/Herdecke, Stockumer Str. 10, D-58448 Witten, Germany
| | - Min Yang
- Department of Microbiology, State University of New York at Buffalo, 138 Farber Hall, Buffalo, NY 14214, USA
| | - William T Ruyechan
- Department of Microbiology, State University of New York at Buffalo, 138 Farber Hall, Buffalo, NY 14214, USA
| | - Manfred H Wolff
- Institute of Microbiology and Virology, University of Witten/Herdecke, Stockumer Str. 10, D-58448 Witten, Germany
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Peng H, He H, Hay J, Ruyechan WT. Interaction between the varicella zoster virus IE62 major transactivator and cellular transcription factor Sp1. J Biol Chem 2003; 278:38068-75. [PMID: 12855699 DOI: 10.1074/jbc.m302259200] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The varicella zoster virus (VZV) IE62 protein is involved in the activation of expression of all three kinetic classes of VZV proteins. Analysis of the viral promoter for VZV glycoprotein I has shown that the cellular factor Sp1 is involved in or required for the observed IE62 mediated activation. Co-immunoprecipitation experiments show that the two proteins are present in a complex in VZV-infected cells. Protein affinity pull-down assays using recombinant proteins showed that IE62 and Sp1 interact in the absence of any other viral and cellular proteins. Mapping studies using GST-fusion proteins containing truncations of IE62 and Sp1 have delimited the interacting regions to amino acids 612-778 in Sp1 and amino acids 226-299 in IE62. The region identified in Sp1 is involved in DNA-binding, synergistic Sp1 activation, and Sp1 interaction with cellular transcription factors. The interacting region identified in IE62 overlaps with or borders on sites involved in interactions with the VZV IE4 protein and the cellular factors TBP and TFIIB. Assays using wild-type and mutant promoter elements indicate that Sp1 is involved in recruitment of IE62 to the gI promoter and IE62 enhances Sp1 and TBP binding.
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Affiliation(s)
- Hua Peng
- Department of Microbiology, University at Buffalo, Buffalo, New York 14214, USA
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