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Safe and Sensitive Antiviral Screening Platform Based on Recombinant Human Coronavirus OC43 Expressing the Luciferase Reporter Gene. Antimicrob Agents Chemother 2016; 60:5492-503. [PMID: 27381385 DOI: 10.1128/aac.00814-16] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 06/27/2016] [Indexed: 12/14/2022] Open
Abstract
Human coronaviruses (HCoVs) cause 15 to 30% of mild upper respiratory tract infections. However, no specific antiviral drugs are available to prevent or treat HCoV infections to date. Here, we developed four infectious recombinant HCoVs-OC43 (rHCoVs-OC43) which express the Renilla luciferase (Rluc) reporter gene. Among these four rHCoVs-OC43, rOC43-ns2DelRluc (generated by replacing ns2 with the Rluc gene) showed robust luciferase activity with only a slight impact on its growth characteristics. Additionally, this recombinant virus remained stable for at least 10 passages in BHK-21 cells. rOC43-ns2DelRluc was comparable to its parental wild-type virus (HCoV-OC43-WT) with respect to the quantity of the antiviral activity of chloroquine and ribavirin. We showed that chloroquine strongly inhibited HCoV-OC43 replication in vitro, with a 50% inhibitory concentration (IC50) of 0.33 μM. However, ribavirin showed inhibition of HCoV-OC43 replication only at high concentrations which may not be applicable to humans in clinical treatment, with an IC50 of 10 μM. Furthermore, using a luciferase-based small interfering RNA (siRNA) screening assay, we identified double-stranded-RNA-activated protein kinase (PKR) and DEAD box RNA helicases (DDX3X) that exhibited antiviral activities, which were further verified by the use of HCoV-OC43-WT. Therefore, rOC43-ns2DelRluc represents a promising safe and sensitive platform for high-throughput antiviral screening and quantitative analysis of viral replication.
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Infectious Bronchitis Coronavirus Limits Interferon Production by Inducing a Host Shutoff That Requires Accessory Protein 5b. J Virol 2016; 90:7519-7528. [PMID: 27279618 DOI: 10.1128/jvi.00627-16] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Accepted: 06/01/2016] [Indexed: 01/08/2023] Open
Abstract
UNLABELLED During infection of their host cells, viruses often inhibit the production of host proteins, a process that is referred to as host shutoff. By doing this, viruses limit the production of antiviral proteins and increase production capacity for viral proteins. Coronaviruses from the genera Alphacoronavirus and Betacoronavirus, such as severe acute respiratory syndrome coronavirus (SARS-CoV), establish host shutoff via their nonstructural protein 1 (nsp1). The Gammacoronavirus and Deltacoronavirus genomes, however, do not encode nsp1, and it has been suggested that these viruses do not induce host shutoff. Here, we show that the Gammacoronavirus infectious bronchitis virus (IBV) does induce host shutoff, and we find that its accessory protein 5b is indispensable for this function. Importantly, we found that 5b-null viruses, unlike wild-type viruses, induce production of high concentrations of type I interferon protein in vitro, indicating that host shutoff by IBV plays an important role in antagonizing the host's innate immune response. Altogether, we demonstrate that 5b is a functional equivalent of nsp1, thereby answering the longstanding question of whether lack of nsp1 in gammacoronaviruses is compensated for by another viral protein. As such, our study is a significant step forward in the understanding of coronavirus biology and closes a gap in the understanding of some IBV virulence strategies. IMPORTANCE Many viruses inhibit protein synthesis by their host cell to enhance virus replication and to antagonize antiviral defense mechanisms. This process is referred to as host shutoff. We studied gene expression and protein synthesis in chicken cells infected with the important poultry pathogen infectious bronchitis virus (IBV). We show that IBV inhibits synthesis of host proteins, including that of type I interferon, a key component of the antiviral response. The IBV-induced host shutoff, however, does not require degradation of host RNA. Furthermore, we demonstrate that accessory protein 5b of IBV plays a crucial role in the onset of host shutoff. Our findings suggest that inhibition of host protein synthesis is a common feature of coronaviruses and primarily serves to inhibit the antiviral response of the host.
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Lim YX, Ng YL, Tam JP, Liu DX. Human Coronaviruses: A Review of Virus-Host Interactions. Diseases 2016; 4:E26. [PMID: 28933406 PMCID: PMC5456285 DOI: 10.3390/diseases4030026] [Citation(s) in RCA: 368] [Impact Index Per Article: 46.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 07/18/2016] [Accepted: 07/18/2016] [Indexed: 12/19/2022] Open
Abstract
Human coronaviruses (HCoVs) are known respiratory pathogens associated with a range of respiratory outcomes. In the past 14 years, the onset of severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV) have thrust HCoVs into spotlight of the research community due to their high pathogenicity in humans. The study of HCoV-host interactions has contributed extensively to our understanding of HCoV pathogenesis. In this review, we discuss some of the recent findings of host cell factors that might be exploited by HCoVs to facilitate their own replication cycle. We also discuss various cellular processes, such as apoptosis, innate immunity, ER stress response, mitogen-activated protein kinase (MAPK) pathway and nuclear factor kappa B (NF-κB) pathway that may be modulated by HCoVs.
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Affiliation(s)
- Yvonne Xinyi Lim
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
| | - Yan Ling Ng
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
| | - James P Tam
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
| | - Ding Xiang Liu
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
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Fung TS, Liao Y, Liu DX. Regulation of Stress Responses and Translational Control by Coronavirus. Viruses 2016; 8:v8070184. [PMID: 27384577 PMCID: PMC4974519 DOI: 10.3390/v8070184] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 06/21/2016] [Accepted: 06/28/2016] [Indexed: 01/02/2023] Open
Abstract
Similar to other viruses, coronavirus infection triggers cellular stress responses in infected host cells. The close association of coronavirus replication with the endoplasmic reticulum (ER) results in the ER stress responses, which impose a challenge to the viruses. Viruses, in turn, have come up with various mechanisms to block or subvert these responses. One of the ER stress responses is inhibition of the global protein synthesis to reduce the amount of unfolded proteins inside the ER lumen. Viruses have evolved the capacity to overcome the protein translation shutoff to ensure viral protein production. Here, we review the strategies exploited by coronavirus to modulate cellular stress response pathways. The involvement of coronavirus-induced stress responses and translational control in viral pathogenesis will also be briefly discussed.
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Affiliation(s)
- To Sing Fung
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
| | - Ying Liao
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Ziyue Road 518, Shanghai 200241, China.
| | - Ding Xiang Liu
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
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Zhao J, Zhao J, Mangalam AK, Channappanavar R, Fett C, Meyerholz DK, Agnihothram S, Baric RS, David CS, Perlman S. Airway Memory CD4(+) T Cells Mediate Protective Immunity against Emerging Respiratory Coronaviruses. Immunity 2016; 44:1379-91. [PMID: 27287409 PMCID: PMC4917442 DOI: 10.1016/j.immuni.2016.05.006] [Citation(s) in RCA: 389] [Impact Index Per Article: 48.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 02/14/2016] [Accepted: 03/08/2016] [Indexed: 02/06/2023]
Abstract
Two zoonotic coronaviruses (CoVs)—SARS-CoV and MERS-CoV—have crossed species to cause severe human respiratory disease. Here, we showed that induction of airway memory CD4+ T cells specific for a conserved epitope shared by SARS-CoV and MERS-CoV is a potential strategy for developing pan-coronavirus vaccines. Airway memory CD4+ T cells differed phenotypically and functionally from lung-derived cells and were crucial for protection against both CoVs in mice. Protection was dependent on interferon-γ and required early induction of robust innate and virus-specific CD8+ T cell responses. The conserved epitope was also recognized in SARS-CoV- and MERS-CoV-infected human leukocyte antigen DR2 and DR3 transgenic mice, indicating potential relevance in human populations. Additionally, this epitope was cross-protective between human and bat CoVs, the progenitors for many human CoVs. Vaccine strategies that induce airway memory CD4+ T cells targeting conserved epitopes might have broad applicability in the context of new CoVs and other respiratory virus outbreaks. Intranasal but not subcutaneous vaccination protects mice from pathogenic human CoVs Protection is mediated by airway memory CD4+ T cells IFN-γ produced by airway memory CD4+ T cells is required for protection A conserved epitope in SARS-CoV and MERS-CoV induces cross-reactive T cell responses
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Affiliation(s)
- Jincun Zhao
- State Key Laboratory of Respiratory Diseases, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou 510120, China; Department of Microbiology, University of Iowa, Iowa City, IA 52242, USA.
| | - Jingxian Zhao
- Department of Microbiology, University of Iowa, Iowa City, IA 52242, USA
| | | | | | - Craig Fett
- Department of Microbiology, University of Iowa, Iowa City, IA 52242, USA
| | - David K Meyerholz
- Department of Pathology, University of Iowa, Iowa City, IA 52242, USA
| | - Sudhakar Agnihothram
- Department of Microbiology and Immunology and Department of Epidemiology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Ralph S Baric
- Department of Microbiology and Immunology and Department of Epidemiology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Chella S David
- Department of Immunology, Mayo Clinic, Rochester, MI 55905, USA
| | - Stanley Perlman
- Department of Microbiology, University of Iowa, Iowa City, IA 52242, USA.
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Liao Y, Gu F, Mao X, Niu Q, Wang H, Sun Y, Song C, Qiu X, Tan L, Ding C. Regulation of de novo translation of host cells by manipulation of PERK/PKR and GADD34-PP1 activity during Newcastle disease virus infection. J Gen Virol 2016; 97:867-879. [PMID: 26869028 DOI: 10.1099/jgv.0.000426] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Viral infections result in cellular stress responses, which can trigger protein translation shutoff via phosphorylation of eukaryotic initiation factor 2 alpha (eIF2α). Newcastle disease virus (NDV) causes severe disease in poultry and selectively kills human tumour cells. In this report, we determined that infection of HeLa human cervical cancer cells and DF-1 chicken fibroblast cells with NDV maintained protein at early infection times, 0-12 h post-infection (p.i.), and gradually inhibited global protein translation at late infection times, 12-24 h p.i. Mechanistic studies showed that translation inhibition at late infection times was accompanied by phosphorylation of eIF2α, a checkpoint of translation initiation. Meanwhile, the eIF2α kinase, PKR, was upregulated and activated by phosphorylation and another eIF2α kinase, PERK, was phosphorylated and cleaved into two fragments. Pharmacological inhibition experiments revealed that only PKR activity was required for eIF2α phosphorylation, suggesting that recognition of viral dsRNA by PKR was responsible for translation shutoff. High levels of phospho-eIF2α led to preferential translation of the transcription factor ATF4 and an increase in GADD34 expression. Functionally, GADD34, in conjunction with PP1, dephosphorylated eIF2a and restored protein translation, benefiting virus protein synthesis. However, PP1 was degraded at late infection times, functionally counteracting the upregulation of GADD34. Taken together, our data support that NDV-induced translation shutoff at late infection times was attributed to sustaining phosphorylation of eIF2α, which is mediated by continual activation of PKR and degradation of PP1.
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Affiliation(s)
- Ying Liao
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Ziyue Road 518, Shanghai 200241, PRChina
| | - Feng Gu
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Ziyue Road 518, Shanghai 200241, PRChina
| | - Xiang Mao
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Ziyue Road 518, Shanghai 200241, PRChina
| | - Qiaona Niu
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Ziyue Road 518, Shanghai 200241, PRChina
| | - Huaxia Wang
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Ziyue Road 518, Shanghai 200241, PRChina
| | - Yingjie Sun
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Ziyue Road 518, Shanghai 200241, PRChina
| | - Cuiping Song
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Ziyue Road 518, Shanghai 200241, PRChina
| | - Xusheng Qiu
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Ziyue Road 518, Shanghai 200241, PRChina
| | - Lei Tan
- Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Ziyue Road 518, Shanghai 200241, PRChina
| | - Chan Ding
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, JiangSu 225009, PRChina.,Department of Avian Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Ziyue Road 518, Shanghai 200241, PRChina
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Wang X, Zhang H, Abel AM, Nelson E. Protein kinase R (PKR) plays a pro-viral role in porcine reproductive and respiratory syndrome virus (PRRSV) replication by modulating viral gene transcription. Arch Virol 2015; 161:327-33. [DOI: 10.1007/s00705-015-2671-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 10/31/2015] [Indexed: 01/01/2023]
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A Kinome-Wide Small Interfering RNA Screen Identifies Proviral and Antiviral Host Factors in Severe Acute Respiratory Syndrome Coronavirus Replication, Including Double-Stranded RNA-Activated Protein Kinase and Early Secretory Pathway Proteins. J Virol 2015; 89:8318-33. [PMID: 26041291 DOI: 10.1128/jvi.01029-15] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 05/22/2015] [Indexed: 12/17/2022] Open
Abstract
UNLABELLED To identify host factors relevant for severe acute respiratory syndrome-coronavirus (SARS-CoV) replication, we performed a small interfering RNA (siRNA) library screen targeting the human kinome. Protein kinases are key regulators of many cellular functions, and the systematic knockdown of their expression should provide a broad perspective on factors and pathways promoting or antagonizing coronavirus replication. In addition to 40 proteins that promote SARS-CoV replication, our study identified 90 factors exhibiting an antiviral effect. Pathway analysis grouped subsets of these factors in specific cellular processes, including the innate immune response and the metabolism of complex lipids, which appear to play a role in SARS-CoV infection. Several factors were selected for in-depth validation in follow-up experiments. In cells depleted for the β2 subunit of the coatomer protein complex (COPB2), the strongest proviral hit, we observed reduced SARS-CoV protein expression and a >2-log reduction in virus yield. Knockdown of the COPB2-related proteins COPB1 and Golgi-specific brefeldin A-resistant guanine nucleotide exchange factor 1 (GBF1) also suggested that COPI-coated vesicles and/or the early secretory pathway are important for SARS-CoV replication. Depletion of the antiviral double-stranded RNA-activated protein kinase (PKR) enhanced virus replication in the primary screen, and validation experiments confirmed increased SARS-CoV protein expression and virus production upon PKR depletion. In addition, cyclin-dependent kinase 6 (CDK6) was identified as a novel antiviral host factor in SARS-CoV replication. The inventory of pro- and antiviral host factors and pathways described here substantiates and expands our understanding of SARS-CoV replication and may contribute to the identification of novel targets for antiviral therapy. IMPORTANCE Replication of all viruses, including SARS-CoV, depends on and is influenced by cellular pathways. Although substantial progress has been made in dissecting the coronavirus replicative cycle, our understanding of the host factors that stimulate (proviral factors) or restrict (antiviral factors) infection remains far from complete. To study the role of host proteins in SARS-CoV infection, we set out to systematically identify kinase-regulated processes that influence virus replication. Protein kinases are key regulators in signal transduction, controlling a wide variety of cellular processes, and many of them are targets of approved drugs and other compounds. Our screen identified a variety of hits and will form the basis for more detailed follow-up studies that should contribute to a better understanding of SARS-CoV replication and coronavirus-host interactions in general. The identified factors could be interesting targets for the development of host-directed antiviral therapy to treat infections with SARS-CoV or other pathogenic coronaviruses.
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Liu WJ, Yang YT, Zhao MQ, Dong XY, Gou HC, Pei JJ, Chen JD. PKR activation enhances replication of classical swine fever virus in PK-15 cells. Virus Res 2015; 204:47-57. [PMID: 25899421 PMCID: PMC7114430 DOI: 10.1016/j.virusres.2015.04.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 03/25/2015] [Accepted: 04/09/2015] [Indexed: 12/22/2022]
Abstract
CSFV infection triggers PKR and eIF2α protein phosphorylation. PKR overexpression stimulates viral replication. PKR depletion blocks eIF2α phosphorylation and suppresses viral replication. PKR depletion increases IFN-β, and enhances the antiviral effect of IFN.
Classical swine fever (CSF) is a highly contagious swine disease that is responsible for economic losses worldwide. Protein kinase R (PK)R is an important protein in the host viral response; however, the role of PKR in CSFV infection remains unknown. This issue was addressed in the present study using the PK-15 swine kidney cell line. We found that CSFV infection increased the phosphorylation of eukaryotic translation initiation factor (eIF)2α and its kinase PKR. However, the expression of viral proteins continued to increase. Furthermore, PKR overexpression enhanced CSFV replication, while PKR inhibition resulted in reduced CSFV replication and an increase in interferon (IFN) induction. In addition, PKR was responsible for eIF2α phosphorylation in CSFV-infected cells. These results suggest that the activation of PKR during CSFV infection is beneficial to the virus. The virus is able to commandeer the host cell's translation machinery for viral protein synthesis while evading innate immune defenses.
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Affiliation(s)
- Wen-Jun Liu
- College of Veterinary Medicine, South China Agricultural University, 483 Wu Shan Road, Tian He District, Guangzhou 510642, China
| | - You-Tian Yang
- College of Veterinary Medicine, South China Agricultural University, 483 Wu Shan Road, Tian He District, Guangzhou 510642, China
| | - Ming-Qiu Zhao
- College of Veterinary Medicine, South China Agricultural University, 483 Wu Shan Road, Tian He District, Guangzhou 510642, China
| | - Xiao-Ying Dong
- College of Veterinary Medicine, South China Agricultural University, 483 Wu Shan Road, Tian He District, Guangzhou 510642, China
| | - Hong-Chao Gou
- College of Veterinary Medicine, South China Agricultural University, 483 Wu Shan Road, Tian He District, Guangzhou 510642, China
| | - Jing-Jing Pei
- College of Veterinary Medicine, South China Agricultural University, 483 Wu Shan Road, Tian He District, Guangzhou 510642, China
| | - Jin-Ding Chen
- College of Veterinary Medicine, South China Agricultural University, 483 Wu Shan Road, Tian He District, Guangzhou 510642, China.
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Fung TS, Huang M, Liu DX. Coronavirus-induced ER stress response and its involvement in regulation of coronavirus-host interactions. Virus Res 2014; 194:110-23. [PMID: 25304691 PMCID: PMC7114476 DOI: 10.1016/j.virusres.2014.09.016] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 09/25/2014] [Accepted: 09/28/2014] [Indexed: 12/11/2022]
Abstract
Coronavirus replication is structurally and functionally associated with the endoplasmic reticulum (ER), a major site of protein synthesis, folding, modification and sorting in the eukaryotic cells. Disturbance of ER homeostasis may occur under various physiological or pathological conditions. In response to the ER stress, signaling pathways of the unfolded protein response (UPR) are activated. UPR is mediated by three ER transmembrane sensors, namely the PKR-like ER protein kinase (PERK), the inositol-requiring protein 1 (IRE1) and the activating transcriptional factor 6 (ATF6). UPR facilitates adaptation to ER stress by reversible translation attenuation, enhancement of ER protein folding capacity and activation of ER-associated degradation (ERAD). In cells under prolonged and irremediable ER stress, UPR can also trigger apoptotic cell death. Accumulating evidence has shown that coronavirus infection causes ER stress and induces UPR in the infected cells. UPR is closely associated with a number of major signaling pathways, including autophagy, apoptosis, the mitogen-activated protein (MAP) kinase pathways, innate immunity and pro-inflammatory response. Therefore, studies on the UPR are pivotal in elucidating the complicated issue of coronavirus-host interaction. In this paper, we present the up-to-date knowledge on coronavirus-induced UPR and discuss its potential involvement in regulation of innate immunity and apoptosis.
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Affiliation(s)
- To Sing Fung
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551
| | - Mei Huang
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551
| | - Ding Xiang Liu
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551.
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Activation of the chicken type I interferon response by infectious bronchitis coronavirus. J Virol 2014; 89:1156-67. [PMID: 25378498 DOI: 10.1128/jvi.02671-14] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
UNLABELLED Coronaviruses from both the Alphacoronavirus and Betacoronavirus genera interfere with the type I interferon (IFN) response in various ways, ensuring the limited activation of the IFN response in most cell types. Of the gammacoronaviruses that mainly infect birds, little is known about the activation of the host immune response. We show that the prototypical Gammacoronavirus, infectious bronchitis virus (IBV), induces a delayed activation of the IFN response in primary renal cells, tracheal epithelial cells, and a chicken cell line. In fact, Ifnβ expression is delayed with respect to the peak of viral replication and the accompanying accumulation of double-stranded RNA (dsRNA). In addition, we demonstrate that MDA5 is the primary sensor for Gammacoronavirus infections in chicken cells. Furthermore, we provide evidence that accessory proteins 3a and 3b of IBV modulate the response at the transcriptional and translational levels. Finally, we show that, despite the lack of activation of the IFN response during the early phase of IBV infection, the signaling of nonself dsRNA through both MDA5 and TLR3 remains intact in IBV-infected cells. Taken together, this study provides the first comprehensive analysis of host-virus interactions of a Gammacoronavirus with avian innate immune responses. IMPORTANCE Our results demonstrate that IBV has evolved multiple strategies to avoid the activation of the type I interferon response. Taken together, the present study closes a gap in the understanding of host-IBV interaction and paves the way for further characterization of the mechanisms underlying immune evasion strategies as well as the pathogenesis of gammacoronaviruses.
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Zhao F, Han Z, Zhang T, Shao Y, Kong X, Ma H, Liu S. Genomic characteristics and changes of avian infectious bronchitis virus strain CK/CH/LDL/97I after serial passages in chicken embryos. Intervirology 2014; 57:319-30. [PMID: 25195733 PMCID: PMC7179551 DOI: 10.1159/000365193] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 06/07/2014] [Indexed: 12/12/2022] Open
Abstract
Background We previously attenuated the infectious bronchitis virus (IBV) strain CK/CH/LDL/97I and found that it can convey protection against the homologous pathogenic virus. Objective To compare the full-length genome sequences of the Chinese IBV strain CK/CH/LDL/97I and its embryo-passaged, attenuated level to identify sequence substitutions responsible for the attenuation and define markers of attenuation. Methods The full-length genomes of CK/CH/LDL/97I P5 and P115 were amplified and sequenced. The sequences were assembled and compared using the MEGALIGN program (DNAStar) and a phylogenetic tree was constructed using MEGA4 software. Results The CK/CH/LDL/97I virus population contained subpopulations with a mixture of genetic mutants. Changes were observed in nsp4, nsp9, nsp11/12, nsp14, nsp15, nsp16, and ORF3a, but these did not result in amino acid substitutions or did not show functional variations. Amino acid substitutions occurred in the remaining genes between P5 and P115; most were found in the S region, and some of the nucleotide mutations resulted in amino acid substitutions. Among the 9 nsps in the ORF1 region, nsp3 contained the most nucleotide substitutions. Conclusions Sequence variations in different genes, especially the S gene and nsp3, in the genomes of CK/CH/LDL/97I viruses might contribute to differences in viral replication, pathogenicity, antigenicity, immunogenicity, and tissue tropism.
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Affiliation(s)
- Fei Zhao
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, PR China
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The endoplasmic reticulum stress sensor IRE1α protects cells from apoptosis induced by the coronavirus infectious bronchitis virus. J Virol 2014; 88:12752-64. [PMID: 25142592 DOI: 10.1128/jvi.02138-14] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
UNLABELLED The unfolded-protein response (UPR) is a signal transduction cascade triggered by perturbation of the homeostasis of the endoplasmic reticulum (ER). UPR resolves ER stress by activating a cascade of cellular responses, including the induction of molecular chaperones, translational attenuation, ER-associated degradation, and other mechanisms. Under prolonged and irremediable ER stress, however, the UPR can also trigger apoptosis. Here, we report that in cells infected with the avian coronavirus infectious bronchitis virus (IBV), ER stress was induced and the IRE1α-XBP1 pathway of UPR was activated. Knockdown and overexpression experiments demonstrated that IRE1α protects infected cells from IBV-induced apoptosis, which required both its kinase and RNase activities. Our data also suggest that splicing of XBP1 mRNA by IRE1α appears to convert XBP1 from a proapoptotic XBP1u protein to a prosurvival XBP1s protein. Moreover, IRE1α antagonized IBV-induced apoptosis by modulating the phosphorylation status of the proapoptotic c-Jun N-terminal kinase (JNK) and the prosurvival RAC-alpha serine/threonine-protein kinase (Akt). Taken together, the data indicate that the ER stress sensor IRE1α is activated in IBV-infected cells and serves as a survival factor during coronavirus infection. IMPORTANCE Animal coronaviruses are important veterinary viruses, which could cross the species barrier, becoming severe human pathogens. Molecular characterization of the interactions between coronaviruses and host cells is pivotal to understanding the pathogenicity and species specificity of coronavirus infection. It has been well established that the endoplasmic reticulum (ER) is closely associated with coronavirus replication. Here, we report that inositol-requiring protein 1 alpha (IRE1α), a key sensor of ER stress, is activated in cells infected with the avian coronavirus infectious bronchitis virus (IBV). Moreover, IRE1α is shown to protect the infected cells from apoptosis by modulating the unfolded-protein response (UPR) and two kinases related to cell survival. This study demonstrates that UPR activation constitutes a major aspect of coronavirus-host interactions. Manipulations of the coronavirus-induced UPR may provide novel therapeutic targets for the control of coronavirus infection and pathogenesis.
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Fung TS, Liu DX. Coronavirus infection, ER stress, apoptosis and innate immunity. Front Microbiol 2014; 5:296. [PMID: 24987391 PMCID: PMC4060729 DOI: 10.3389/fmicb.2014.00296] [Citation(s) in RCA: 199] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 05/29/2014] [Indexed: 12/27/2022] Open
Abstract
The replication of coronavirus, a family of important animal and human pathogens, is closely associated with the cellular membrane compartments, especially the endoplasmic reticulum (ER). Coronavirus infection of cultured cells was previously shown to cause ER stress and induce the unfolded protein response (UPR), a process that aims to restore the ER homeostasis by global translation shutdown and increasing the ER folding capacity. However, under prolonged ER stress, UPR can also induce apoptotic cell death. Accumulating evidence from recent studies has shown that induction of ER stress and UPR may constitute a major aspect of coronavirus–host interaction. Activation of the three branches of UPR modulates a wide variety of signaling pathways, such as mitogen-activated protein (MAP) kinase activation, autophagy, apoptosis, and innate immune response. ER stress and UPR activation may therefore contribute significantly to the viral replication and pathogenesis during coronavirus infection. In this review, we summarize the current knowledge on coronavirus-induced ER stress and UPR activation, with emphasis on their cross-talking to apoptotic signaling.
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Affiliation(s)
- To S Fung
- School of Biological Sciences, Nanyang Technological University Singapore, Singapore
| | - Ding X Liu
- School of Biological Sciences, Nanyang Technological University Singapore, Singapore
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65
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Sun J, Han Z, Shao Y, Cao Z, Kong X, Liu S. Comparative proteome analysis of tracheal tissues in response to infectious bronchitis coronavirus, Newcastle disease virus, and avian influenza virus H9 subtype virus infection. Proteomics 2014; 14:1403-23. [PMID: 24610701 PMCID: PMC7167649 DOI: 10.1002/pmic.201300404] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2013] [Revised: 02/16/2014] [Accepted: 03/04/2014] [Indexed: 01/29/2023]
Abstract
Infectious bronchitis coronavirus (IBV), Newcastle disease virus (NDV), and avian influenza virus (AIV) H9 subtype are major pathogens of chickens causing serious respiratory tract disease and heavy economic losses. To better understand the replication features of these viruses in their target organs and molecular pathogenesis of these different viruses, comparative proteomic analysis was performed to investigate the proteome changes of primary target organ during IBV, NDV, and AIV H9 infections, using 2D‐DIGE followed MALDI‐TOF/TOF‐MS. In total, 44, 39, 41, 48, and 38 proteins were identified in the tracheal tissues of the chickens inoculated with IBV (ck/CH/LDL/97I, H120), NDV (La Sota), and AIV H9, and between ck/CH/LDL/97I and H120, respectively. Bioinformatics analysis showed that IBV, NDV, and AIV H9 induced similar core host responses involved in biosynthetic, catabolic, metabolic, signal transduction, transport, cytoskeleton organization, macromolecular complex assembly, cell death, response to stress, and immune system process. Comparative analysis of host response induced by different viruses indicated differences in protein expression changes induced by IBV, NDV, and AIV H9 may be responsible for the specific pathogenesis of these different viruses. Our result reveals specific host response to IBV, NDV, and AIVH9 infections and provides insights into the distinct pathogenic mechanisms of these avian respiratory viruses.
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Affiliation(s)
- Junfeng Sun
- Division of Avian Infectious Diseases, State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, The Chinese Academy of Agricultural Sciences, Harbin, P. R. China
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Zhang S, Sun Y, Chen H, Dai Y, Zhan Y, Yu S, Qiu X, Tan L, Song C, Ding C. Activation of the PKR/eIF2α signaling cascade inhibits replication of Newcastle disease virus. Virol J 2014; 11:62. [PMID: 24684861 PMCID: PMC3994276 DOI: 10.1186/1743-422x-11-62] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 03/27/2014] [Indexed: 12/15/2022] Open
Abstract
Background Newcastle Disease virus (NDV) causes severe and economically significant disease in almost all birds. However, factors that affect NDV replication in host cells are poorly understood. NDV generates long double-stranded RNA (dsRNA) molecules during transcription of single-stranded genomic RNA. Protein kinase R (PKR) is activated by dsRNA. The aim of this study was to elucidate the role of PKR in NDV infection. Results NDV infection led to the activation of dsRNA-dependent PKR and phosphorylation of its substrate, translation initiation factor eIF2α, in a dose-dependent manner by either the lentogenic strain LaSota or a velogenic strain Herts/33. PKR activation coincided with the accumulation of dsRNA induced by NDV infection. PKR knockdown remarkably decreased eIF2α phosphorylation as well as IFN-β mRNA levels, leading to the augmentation of extracellular virus titer. Furthermore, siRNA knockdown or phosphorylation of eIF2α or okadaic acid treatment significantly impaired NDV replication, indicating the critical role of the PKR/eIF2α signaling cascade in NDV infection. Conclusion PKR is activated by dsRNA generated by NDV infection and inhibits NDV replication by eIF2α phosphorylation. This study provides insight into NDV-host interactions for the development of candidate antiviral strategies.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Chan Ding
- Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, No,518 Ziyue Road, Shanghai 200241, China.
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Dedeurwaerder A, Olyslaegers DAJ, Desmarets LMB, Roukaerts IDM, Theuns S, Nauwynck HJ. ORF7-encoded accessory protein 7a of feline infectious peritonitis virus as a counteragent against IFN-α-induced antiviral response. J Gen Virol 2013; 95:393-402. [PMID: 24189622 DOI: 10.1099/vir.0.058743-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The type I IFN-mediated immune response is the first line of antiviral defence. Coronaviruses, like many other viruses, have evolved mechanisms to evade this innate response, ensuring their survival. Several coronavirus accessory genes play a central role in these pathways, but for feline coronaviruses this has never to our knowledge been studied. As it has been demonstrated previously that ORF7 is essential for efficient replication in vitro and virulence in vivo of feline infectious peritonitis virus (FIPV), the role of this ORF in the evasion of the IFN-α antiviral response was investigated. Deletion of ORF7 from FIPV strain 79-1146 (FIPV-Δ7) rendered the virus more susceptible to IFN-α treatment. Given that ORF7 encodes two proteins, 7a and 7b, it was further explored which of these proteins is active in this mechanism. Providing 7a protein in trans rescued the mutant FIPV-Δ7 from IFN sensitivity, which was not achieved by addition of 7b protein. Nevertheless, addition of protein 7a to FIPV-Δ3Δ7, a FIPV mutant deleted in both ORF3 and ORF7, could no longer increase the replication capacity of this mutant in the presence of IFN. These results indicate that FIPV 7a protein is a type I IFN antagonist and protects the virus from the antiviral state induced by IFN, but it needs the presence of ORF3-encoded proteins to exert its antagonistic function.
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Affiliation(s)
- Annelike Dedeurwaerder
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium
| | - Dominique A J Olyslaegers
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium
| | - Lowiese M B Desmarets
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium
| | - Inge D M Roukaerts
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium
| | - Sebastiaan Theuns
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium
| | - Hans J Nauwynck
- Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820 Merelbeke, Belgium
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Upregulation of CHOP/GADD153 during coronavirus infectious bronchitis virus infection modulates apoptosis by restricting activation of the extracellular signal-regulated kinase pathway. J Virol 2013; 87:8124-34. [PMID: 23678184 DOI: 10.1128/jvi.00626-13] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Induction of the unfolded protein response (UPR) is an adaptive cellular response to endoplasmic reticulum (ER) stress that allows a cell to reestablish ER homeostasis. However, under severe and persistent ER stress, prolonged UPR may activate unique pathways that lead to cell death. In this study, we investigated the activation of the protein kinase R-like ER kinase (PERK) pathway of UPR in cells infected with the coronavirus infectious bronchitis virus (IBV) and its relationship with IBV-induced apoptosis. The results showed moderate induction of PERK phosphorylation in IBV-infected cells. Meanwhile, activating transcription factor 4 (ATF4) was upregulated at the protein level in the infected cells, resulting in the induction in trans of the transcription factor ATF3 and the proapoptotic growth arrest and DNA damage-inducible protein GADD153. Knockdown of PERK by small interfering RNA (siRNA) suppressed the activation of GADD153 and the IBV-induced apoptosis. Interestingly, knockdown of protein kinase R (PKR) by siRNA and inhibition of the PKR kinase activity by 2-aminopurine (2-AP) also reduced the IBV-induced upregulation of GADD153 and apoptosis induction. In GADD153-knockdown cells, IBV-induced apoptosis was suppressed and virus replication inhibited, revealing a key role of GADD153 in IBV-induced cell death and virus replication. Analysis of the pathways downstream of GADD153 revealed much more activation of the extracellular signal-related kinase (ERK) pathway in GADD153-knockdown cells during IBV infection, indicating that GADD153 may modulate apoptosis through suppression of the pathway. This study provides solid evidence that induction of GADD153 by PERK and PKR plays an important regulatory role in the apoptotic process triggered by IBV infection.
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Nallagatla SR, Jones CN, Ghosh SKB, Sharma SD, Cameron CE, Spremulli LL, Bevilacqua PC. Native tertiary structure and nucleoside modifications suppress tRNA's intrinsic ability to activate the innate immune sensor PKR. PLoS One 2013; 8:e57905. [PMID: 23483938 PMCID: PMC3587421 DOI: 10.1371/journal.pone.0057905] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 01/28/2013] [Indexed: 11/17/2022] Open
Abstract
Interferon inducible protein kinase PKR is an essential component of innate immunity. It is activated by long stretches of dsRNA and provides the first line of host defense against pathogens by inhibiting translation initiation in the infected cell. Many cellular and viral transcripts contain nucleoside modifications and/or tertiary structure that could affect PKR activation. We have previously demonstrated that a 5'-end triphosphate-a signature of certain viral and bacterial transcripts-confers the ability of relatively unstructured model RNA transcripts to activate PKR to inhibit translation, and that this activation is abrogated by certain modifications present in cellular RNAs. In order to understand the biological implications of native RNA tertiary structure and nucleoside modifications on PKR activation, we study here the heavily modified cellular tRNAs and the unmodified or the lightly modified mitochondrial tRNAs (mt-tRNA). We find that both a T7 transcript of yeast tRNA(Phe) and natively extracted total bovine liver mt-tRNA activate PKR in vitro, whereas native E. coli, bovine liver, yeast, and wheat tRNA(Phe) do not, nor do a variety of base- or sugar-modified T7 transcripts. These results are further supported by activation of PKR by a natively folded T7 transcript of tRNA(Phe)in vivo supporting the importance of tRNA modification in suppressing PKR activation in cells. We also examine PKR activation by a T7 transcript of the A14G pathogenic mutant of mt-tRNA(Leu), which is known to dimerize, and find that the misfolded dimeric form activates PKR in vitro while the monomeric form does not. Overall, the in vitro and in vivo findings herein indicate that tRNAs have an intrinsic ability to activate PKR and that nucleoside modifications and native RNA tertiary folding may function, at least in part, to suppress such activation, thus serving to distinguish self and non-self tRNA in innate immunity.
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Affiliation(s)
- Subba Rao Nallagatla
- Department of Chemistry and Center for RNA Molecular Biology, The Pennsylvania State University, University Park, PA, USA
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70
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Recent progress in studies of arterivirus- and coronavirus-host interactions. Viruses 2012; 4:980-1010. [PMID: 22816036 PMCID: PMC3397358 DOI: 10.3390/v4060980] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 05/30/2012] [Accepted: 06/14/2012] [Indexed: 12/15/2022] Open
Abstract
Animal coronaviruses, such as infectious bronchitis virus (IBV), and arteriviruses, such as porcine reproductive and respiratory syndrome virus (PRRSV), are able to manifest highly contagious infections in their specific native hosts, thereby arising in critical economic damage to animal industries. This review discusses recent progress in studies of virus-host interactions during animal and human coronavirus and arterivirus infections, with emphasis on IBV-host cell interactions. These interactions may be directly involved in viral replication or lead to the alteration of certain signaling pathways, such as cell stress response and innate immunity, to facilitate viral replication and pathogenesis.
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71
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Rotavirus-host cell interactions: an arms race. Curr Opin Virol 2012; 2:389-98. [PMID: 22658208 DOI: 10.1016/j.coviro.2012.05.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Revised: 05/02/2012] [Accepted: 05/08/2012] [Indexed: 12/21/2022]
Abstract
As obligate parasites, viruses depend on the synthetic machinery of the cell to translate their proteins and on the cell's energy and building blocks to replicate their genomes. Cells respond to virus invasions by eliciting diverse responses to eliminate the incoming parasitic agents. In turn, to establish a successful infection, viruses have developed different strategies to take over the cellular metabolic machinery and to cope with the defense mechanisms of the cell. The characterization of this battle has allowed the discovery of the different elements that viruses and cells have developed in the attempt to overcome the enemy. Here some of the strategies used by rotaviruses to hijack the protein synthesis apparatus of the cell to ensure the translation of their mRNAs, and to deal with the cellular stress and antiviral responses will be reviewed.
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Clavarino G, Cláudio N, Couderc T, Dalet A, Judith D, Camosseto V, Schmidt EK, Wenger T, Lecuit M, Gatti E, Pierre P. Induction of GADD34 is necessary for dsRNA-dependent interferon-β production and participates in the control of Chikungunya virus infection. PLoS Pathog 2012; 8:e1002708. [PMID: 22615568 PMCID: PMC3355096 DOI: 10.1371/journal.ppat.1002708] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Accepted: 04/03/2012] [Indexed: 01/08/2023] Open
Abstract
Nucleic acid sensing by cells is a key feature of antiviral responses, which generally result in type-I Interferon production and tissue protection. However, detection of double-stranded RNAs in virus-infected cells promotes two concomitant and apparently conflicting events. The dsRNA-dependent protein kinase (PKR) phosphorylates translation initiation factor 2-alpha (eIF2α) and inhibits protein synthesis, whereas cytosolic DExD/H box RNA helicases induce expression of type I-IFN and other cytokines. We demonstrate that the phosphatase-1 cofactor, growth arrest and DNA damage-inducible protein 34 (GADD34/Ppp1r15a), an important component of the unfolded protein response (UPR), is absolutely required for type I-IFN and IL-6 production by mouse embryonic fibroblasts (MEFs) in response to dsRNA. GADD34 expression in MEFs is dependent on PKR activation, linking cytosolic microbial sensing with the ATF4 branch of the UPR. The importance of this link for anti-viral immunity is underlined by the extreme susceptibility of GADD34-deficient fibroblasts and neonate mice to Chikungunya virus infection. Nucleic acids detection by multiple molecular sensors results in type-I interferon production, which protects cells and tissues from viral infections. At the intracellular level, the detection of double-stranded RNA by one of these sensors, the dsRNA-dependent protein kinase also leads to the profound inhibition of protein synthesis. We describe here that the inducible phosphatase 1 co-factor Ppp1r15a/GADD34, a well known player in the endoplasmic reticulum unfolded protein response (UPR), is activated during double-stranded RNA detection and is absolutely necessary to allow cytokine production in cells exposed to poly I:C or Chikungunya virus. Our data shows that the cellular response to nucleic acids can reveal unanticipated connections between innate immunity and fundamental stress pathways, such as the ATF4 branch of the UPR.
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Affiliation(s)
- Giovanna Clavarino
- Centre d'Immunologie de Marseille-Luminy, UM2, Aix-Marseille Université, Marseille, France
- INSERM, U1104, Marseille, France
- CNRS, UMR 7280, Marseille, France
| | - Nuno Cláudio
- Centre d'Immunologie de Marseille-Luminy, UM2, Aix-Marseille Université, Marseille, France
- INSERM, U1104, Marseille, France
- CNRS, UMR 7280, Marseille, France
| | - Thérèse Couderc
- Institut Pasteur, ‘Microbes and host barriers’ Group, Paris, France
- Inserm, Equipe avenir U604, Paris, France
| | - Alexandre Dalet
- Centre d'Immunologie de Marseille-Luminy, UM2, Aix-Marseille Université, Marseille, France
- INSERM, U1104, Marseille, France
- CNRS, UMR 7280, Marseille, France
| | - Delphine Judith
- Institut Pasteur, ‘Microbes and host barriers’ Group, Paris, France
- Inserm, Equipe avenir U604, Paris, France
| | - Voahirana Camosseto
- Centre d'Immunologie de Marseille-Luminy, UM2, Aix-Marseille Université, Marseille, France
- INSERM, U1104, Marseille, France
- CNRS, UMR 7280, Marseille, France
| | - Enrico K. Schmidt
- Centre d'Immunologie de Marseille-Luminy, UM2, Aix-Marseille Université, Marseille, France
- INSERM, U1104, Marseille, France
- CNRS, UMR 7280, Marseille, France
| | - Till Wenger
- Centre d'Immunologie de Marseille-Luminy, UM2, Aix-Marseille Université, Marseille, France
- INSERM, U1104, Marseille, France
- CNRS, UMR 7280, Marseille, France
| | - Marc Lecuit
- Institut Pasteur, ‘Microbes and host barriers’ Group, Paris, France
- Inserm, Equipe avenir U604, Paris, France
- Université Paris Descartes, Hôpital Necker-Enfants malades, Service des Maladies Infectieuses et Tropicales, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Evelina Gatti
- Centre d'Immunologie de Marseille-Luminy, UM2, Aix-Marseille Université, Marseille, France
- INSERM, U1104, Marseille, France
- CNRS, UMR 7280, Marseille, France
- * E-mail: (EG) (EG); (PP) (PP)
| | - Philippe Pierre
- Centre d'Immunologie de Marseille-Luminy, UM2, Aix-Marseille Université, Marseille, France
- INSERM, U1104, Marseille, France
- CNRS, UMR 7280, Marseille, France
- * E-mail: (EG) (EG); (PP) (PP)
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Jackwood MW, Hall D, Handel A. Molecular evolution and emergence of avian gammacoronaviruses. INFECTION GENETICS AND EVOLUTION 2012; 12:1305-11. [PMID: 22609285 PMCID: PMC7106068 DOI: 10.1016/j.meegid.2012.05.003] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Revised: 05/08/2012] [Accepted: 05/09/2012] [Indexed: 12/20/2022]
Abstract
Coronaviruses, which are single stranded, positive sense RNA viruses, are responsible for a wide variety of existing and emerging diseases in humans and other animals. The gammacoronaviruses primarily infect avian hosts. Within this genus of coronaviruses, the avian coronavirus infectious bronchitis virus (IBV) causes a highly infectious upper-respiratory tract disease in commercial poultry. IBV shows rapid evolution in chickens, frequently producing new antigenic types, which adds to the multiple serotypes of the virus that do not cross protect. Rapid evolution in IBV is facilitated by strong selection, large population sizes and high genetic diversity within hosts, and transmission bottlenecks between hosts. Genetic diversity within a host arises primarily by mutation, which includes substitutions, insertions and deletions. Mutations are caused both by the high error rate, and limited proof reading capability, of the viral RNA-dependent RNA-polymerase, and by recombination. Recombination also generates new haplotype diversity by recombining existing variants. Rapid evolution of avian coronavirus IBV makes this virus extremely difficult to diagnose and control, but also makes it an excellent model system to study viral genetic diversity and the mechanisms behind the emergence of coronaviruses in their natural host.
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Affiliation(s)
- Mark W Jackwood
- Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, United States.
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The IE180 protein of pseudorabies virus suppresses phosphorylation of translation initiation factor eIF2α. J Virol 2012; 86:7235-40. [PMID: 22532685 DOI: 10.1128/jvi.06929-11] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
We have previously shown that the porcine alphaherpesvirus pseudorabies virus (PRV) efficiently interferes with phosphorylation of the eukaryotic translation initiation factor eIF2α. Inhibition of phosphorylation of eIF2α has been reported earlier for the closely related alphaherpesvirus herpes simplex virus 1 (HSV-1) through its ICP34.5 and US11 proteins. PRV, however, does not encode an ICP34.5 or US11 orthologue. Assays using cycloheximide, UV-inactivated PRV, or phosphonoacetic acid (PAA) showed that de novo expression of one or more (immediate) early viral protein(s) is required for interference with eIF2α phosphorylation. In line with this, a time course assay showed that eIF2α phosphorylation was abolished within 2 h after PRV inoculation. PRV encodes only one immediate-early protein, IE180, the orthologue of HSV-1 ICP4. As reported earlier, a combinational treatment of cells with cycloheximide and actinomycin D allowed expression of IE180 without detectable expression of the US3 early protein in PRV-infected cells. This led to a substantial reduction in eIF2α phosphorylation levels, indicative for an involvement of IE180. In support of this, transfection of IE180 also potently reduced eIF2α phosphorylation. IE180-mediated interference with eIF2α phosphorylation was not cell type dependent, as it occurred both in rat neuronal 50B11 cells and in swine testicle cells. Inhibition of the cellular phosphatase PP1 impaired PRV-mediated interference with eIF2α phosphorylation, indicating that PP1 is involved in this process. In conclusion, the immediate-early IE180 protein of PRV has the previously uncharacterized ability to suppress phosphorylation levels of the eukaryotic translation initiation factor eIF2α.
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Clavarino G, Cláudio N, Dalet A, Terawaki S, Couderc T, Chasson L, Ceppi M, Schmidt EK, Wenger T, Lecuit M, Gatti E, Pierre P. Protein phosphatase 1 subunit Ppp1r15a/GADD34 regulates cytokine production in polyinosinic:polycytidylic acid-stimulated dendritic cells. Proc Natl Acad Sci U S A 2012; 109:3006-3011. [PMID: 22315398 PMCID: PMC3286954 DOI: 10.1073/pnas.1104491109] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/11/2023] Open
Abstract
In response to inflammatory stimulation, dendritic cells (DCs) have a remarkable pattern of differentiation that exhibits specific mechanisms to control the immune response. Here we show that in response to polyriboinosinic:polyribocytidylic acid (pI:C), DCs mount a specific integrated stress response during which the transcription factor ATF4 and the growth arrest and DNA damage-inducible protein 34 (GADD34/Ppp1r15a), a phosphatase 1 (PP1) cofactor, are expressed. In agreement with increased GADD34 levels, an extensive dephosphorylation of the translation initiation factor eIF2α was observed during DC activation. Unexpectedly, although DCs display an unusual resistance to protein synthesis inhibition induced in response to cytosolic dsRNA, GADD34 expression did not have a major impact on protein synthesis. GADD34, however, was shown to be required for normal cytokine production both in vitro and in vivo. These observations have important implications in linking further pathogen detection with the integrated stress response pathways.
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Affiliation(s)
- Giovanna Clavarino
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille University, 13288 Marseille, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U631, 13288 Marseille, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6102, 13288 Marseille, France
| | - Nuno Cláudio
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille University, 13288 Marseille, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U631, 13288 Marseille, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6102, 13288 Marseille, France
| | - Alexandre Dalet
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille University, 13288 Marseille, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U631, 13288 Marseille, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6102, 13288 Marseille, France
| | - Seigo Terawaki
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille University, 13288 Marseille, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U631, 13288 Marseille, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6102, 13288 Marseille, France
| | - Thérèse Couderc
- Microbes and Host Barriers Group, Institut Pasteur, 75015 Paris, France
- INSERM, Equipe avenir U604, 75015 Paris, France; and
| | - Lionel Chasson
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille University, 13288 Marseille, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U631, 13288 Marseille, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6102, 13288 Marseille, France
| | - Maurizio Ceppi
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille University, 13288 Marseille, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U631, 13288 Marseille, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6102, 13288 Marseille, France
| | - Enrico K. Schmidt
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille University, 13288 Marseille, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U631, 13288 Marseille, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6102, 13288 Marseille, France
| | - Till Wenger
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille University, 13288 Marseille, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U631, 13288 Marseille, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6102, 13288 Marseille, France
| | - Marc Lecuit
- Microbes and Host Barriers Group, Institut Pasteur, 75015 Paris, France
- INSERM, Equipe avenir U604, 75015 Paris, France; and
- Service des Maladies Infectieuses et Tropicales, Université Paris Descartes, Hôpital Necker-Enfants malades, Assistance Publique-Hôpitaux de Paris, 75015 Paris, France
| | - Evelina Gatti
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille University, 13288 Marseille, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U631, 13288 Marseille, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6102, 13288 Marseille, France
| | - Philippe Pierre
- Centre d'Immunologie de Marseille-Luminy, Aix-Marseille University, 13288 Marseille, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U631, 13288 Marseille, France
- Centre National de la Recherche Scientifique, Unité Mixte de Recherche 6102, 13288 Marseille, France
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76
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Zhong Y, Liao Y, Fang S, Tam JP, Liu DX. Up-regulation of Mcl-1 and Bak by coronavirus infection of human, avian and animal cells modulates apoptosis and viral replication. PLoS One 2012; 7:e30191. [PMID: 22253918 PMCID: PMC3256233 DOI: 10.1371/journal.pone.0030191] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 12/15/2011] [Indexed: 12/14/2022] Open
Abstract
Virus-induced apoptosis and viral mechanisms that regulate this cell death program are key issues in understanding virus-host interactions and viral pathogenesis. Like many other human and animal viruses, coronavirus infection of mammalian cells induces apoptosis. In this study, the global gene expression profiles are first determined in IBV-infected Vero cells at 24 hours post-infection by Affymetrix array, using avian coronavirus infectious bronchitis virus (IBV) as a model system. It reveals an up-regulation at the transcriptional level of both pro-apoptotic Bak and pro-survival myeloid cell leukemia-1 (Mcl-1). These results were further confirmed both in vivo and in vitro, in IBV-infected embryonated chicken eggs, chicken fibroblast cells and mammalian cells at transcriptional and translational levels, respectively. Interestingly, the onset of apoptosis occurred earlier in IBV-infected mammalian cells silenced with short interfering RNA targeting Mcl-1 (siMcl-1), and was delayed in cells silenced with siBak. IBV progeny production and release were increased in infected Mcl-1 knockdown cells compared to similarly infected control cells, while the contrary was observed in infected Bak knockdown cells. Furthermore, IBV infection-induced up-regulation of GADD153 regulated the expression of Mcl-1. Inhibition of the mitogen-activated protein/extracellular signal-regulated kinase (MEK/ERK) and phosphoinositide 3-kinase (PI3K/Akt) signaling pathways by chemical inhibitors and knockdown of GADD153 by siRNA demonstrated the involvement of ER-stress response in regulation of IBV-induced Mcl-1 expression. These results illustrate the sophisticated regulatory strategies evolved by a coronavirus to modulate both virus-induced apoptosis and viral replication during its replication cycle.
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Affiliation(s)
- Yanxin Zhong
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Ying Liao
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Shouguo Fang
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - James P. Tam
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Ding Xiang Liu
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
- * E-mail:
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77
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Xu LH, Huang M, Fang SG, Liu DX. Coronavirus infection induces DNA replication stress partly through interaction of its nonstructural protein 13 with the p125 subunit of DNA polymerase δ. J Biol Chem 2011; 286:39546-59. [PMID: 21918226 PMCID: PMC3234778 DOI: 10.1074/jbc.m111.242206] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 08/29/2011] [Indexed: 12/20/2022] Open
Abstract
Perturbation of cell cycle regulation is a characteristic feature of infection by many DNA and RNA viruses, including Coronavirus infectious bronchitis virus (IBV). IBV infection was shown to induce cell cycle arrest at both S and G(2)/M phases for the enhancement of viral replication and progeny production. However, the underlying mechanisms are not well explored. In this study we show that activation of cellular DNA damage response is one of the mechanisms exploited by Coronavirus to induce cell cycle arrest. An ATR-dependent cellular DNA damage response was shown to be activated by IBV infection. Suppression of the ATR kinase activity by chemical inhibitors and siRNA-mediated knockdown of ATR reduced the IBV-induced ATR signaling and inhibited the replication of IBV. Furthermore, yeast two-hybrid screens and subsequent biochemical and functional studies demonstrated that interaction between Coronavirus nsp13 and DNA polymerase δ induced DNA replication stress in IBV-infected cells. These findings indicate that the ATR signaling activated by IBV replication contributes to the IBV-induced S-phase arrest and is required for efficient IBV replication and progeny production.
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Affiliation(s)
- Ling Hui Xu
- From the School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551
| | - Mei Huang
- From the School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551
| | - Shou Guo Fang
- From the School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551
| | - Ding Xiang Liu
- From the School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551
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78
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Cruz JLG, Sola I, Becares M, Alberca B, Plana J, Enjuanes L, Zuñiga S. Coronavirus gene 7 counteracts host defenses and modulates virus virulence. PLoS Pathog 2011; 7:e1002090. [PMID: 21695242 PMCID: PMC3111541 DOI: 10.1371/journal.ppat.1002090] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Accepted: 04/12/2011] [Indexed: 12/14/2022] Open
Abstract
Transmissible gastroenteritis virus (TGEV) genome contains three accessory genes: 3a, 3b and 7. Gene 7 is only present in members of coronavirus genus a1, and encodes a hydrophobic protein of 78 aa. To study gene 7 function, a recombinant TGEV virus lacking gene 7 was engineered (rTGEV-Δ7). Both the mutant and the parental (rTGEV-wt) viruses showed the same growth and viral RNA accumulation kinetics in tissue cultures. Nevertheless, cells infected with rTGEV-Δ7 virus showed an increased cytopathic effect caused by an enhanced apoptosis mediated by caspase activation. Macromolecular synthesis analysis showed that rTGEV-Δ7 virus infection led to host translational shut-off and increased cellular RNA degradation compared with rTGEV-wt infection. An increase of eukaryotic translation initiation factor 2 (eIF2α) phosphorylation and an enhanced nuclease, most likely RNase L, activity were observed in rTGEV-Δ7 virus infected cells. These results suggested that the removal of gene 7 promoted an intensified dsRNA-activated host antiviral response. In protein 7 a conserved sequence motif that potentially mediates binding to protein phosphatase 1 catalytic subunit (PP1c), a key regulator of the cell antiviral defenses, was identified. We postulated that TGEV protein 7 may counteract host antiviral response by its association with PP1c. In fact, pull-down assays demonstrated the interaction between TGEV protein 7, but not a protein 7 mutant lacking PP1c binding motif, with PP1. Moreover, the interaction between protein 7 and PP1 was required, during the infection, for eIF2α dephosphorylation and inhibition of cell RNA degradation. Inoculation of newborn piglets with rTGEV-Δ7 and rTGEV-wt viruses showed that rTGEV-Δ7 virus presented accelerated growth kinetics and pathology compared with the parental virus. Overall, the results indicated that gene 7 counteracted host cell defenses, and modified TGEV persistence increasing TGEV survival. Therefore, the acquisition of gene 7 by the TGEV genome most likely has provided a selective advantage to the virus.
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Affiliation(s)
- Jazmina L. G. Cruz
- Centro Nacional de Biotecnología, CNB, CSIC, Department of Molecular and Cell Biology, Darwin 3, Campus Universidad Autónoma de Madrid, Cantoblanco, Madrid, Spain
| | - Isabel Sola
- Centro Nacional de Biotecnología, CNB, CSIC, Department of Molecular and Cell Biology, Darwin 3, Campus Universidad Autónoma de Madrid, Cantoblanco, Madrid, Spain
| | - Martina Becares
- Centro Nacional de Biotecnología, CNB, CSIC, Department of Molecular and Cell Biology, Darwin 3, Campus Universidad Autónoma de Madrid, Cantoblanco, Madrid, Spain
| | | | | | - Luis Enjuanes
- Centro Nacional de Biotecnología, CNB, CSIC, Department of Molecular and Cell Biology, Darwin 3, Campus Universidad Autónoma de Madrid, Cantoblanco, Madrid, Spain
- * E-mail:
| | - Sonia Zuñiga
- Centro Nacional de Biotecnología, CNB, CSIC, Department of Molecular and Cell Biology, Darwin 3, Campus Universidad Autónoma de Madrid, Cantoblanco, Madrid, Spain
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79
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Abstract
Transmissible gastroenteritis virus (TGEV) genome contains three accessory genes: 3a, 3b and 7. Gene 7 is only present in members of coronavirus genus a1, and encodes a hydrophobic protein of 78 aa. To study gene 7 function, a recombinant TGEV virus lacking gene 7 was engineered (rTGEV-Δ7). Both the mutant and the parental (rTGEV-wt) viruses showed the same growth and viral RNA accumulation kinetics in tissue cultures. Nevertheless, cells infected with rTGEV-Δ7 virus showed an increased cytopathic effect caused by an enhanced apoptosis mediated by caspase activation. Macromolecular synthesis analysis showed that rTGEV-Δ7 virus infection led to host translational shut-off and increased cellular RNA degradation compared with rTGEV-wt infection. An increase of eukaryotic translation initiation factor 2 (eIF2α) phosphorylation and an enhanced nuclease, most likely RNase L, activity were observed in rTGEV-Δ7 virus infected cells. These results suggested that the removal of gene 7 promoted an intensified dsRNA-activated host antiviral response. In protein 7 a conserved sequence motif that potentially mediates binding to protein phosphatase 1 catalytic subunit (PP1c), a key regulator of the cell antiviral defenses, was identified. We postulated that TGEV protein 7 may counteract host antiviral response by its association with PP1c. In fact, pull-down assays demonstrated the interaction between TGEV protein 7, but not a protein 7 mutant lacking PP1c binding motif, with PP1. Moreover, the interaction between protein 7 and PP1 was required, during the infection, for eIF2α dephosphorylation and inhibition of cell RNA degradation. Inoculation of newborn piglets with rTGEV-Δ7 and rTGEV-wt viruses showed that rTGEV-Δ7 virus presented accelerated growth kinetics and pathology compared with the parental virus. Overall, the results indicated that gene 7 counteracted host cell defenses, and modified TGEV persistence increasing TGEV survival. Therefore, the acquisition of gene 7 by the TGEV genome most likely has provided a selective advantage to the virus.
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80
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Rojas M, Arias CF, López S. Protein kinase R is responsible for the phosphorylation of eIF2alpha in rotavirus infection. J Virol 2010; 84:10457-66. [PMID: 20631127 PMCID: PMC2950594 DOI: 10.1128/jvi.00625-10] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Accepted: 07/07/2010] [Indexed: 11/20/2022] Open
Abstract
The eukaryotic initiation translation factor 2 (eIF2) represents a key point in the regulation of protein synthesis. This factor delivers the initiator Met-tRNA to the ribosome, a process that is conserved in all eukaryotic cells. Many types of stress reduce global translation by triggering the phosphorylation of the α subunit of eIF2, which reduces the formation of the preinitiation translation complexes. Early during rotavirus infection, eIF2α becomes phosphorylated, and even under these conditions viral protein synthesis is not affected, while most of the cell protein synthesis is blocked. Here, we found that the kinase responsible for the phosphorylation of eIF2α in rotavirus-infected cells is PKR, since in mouse embryonic fibroblasts deficient in the kinase domain of PKR, or in MA104 cells where the expression of PKR was knocked down by RNA interference, eIF2α was not phosphorylated upon rotavirus infection. The viral component responsible for the activation of PKR seems to be viral double-stranded RNA, which is found in the cytoplasm of infected cells, outside viroplasms. Taken together, these results suggest that rotaviruses induce the PKR branch of the interferon system and have evolved a mechanism to translate its proteins, surpassing the block imposed by eIF2α phosphorylation.
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MESH Headings
- Animals
- Cell Line
- Cells, Cultured
- Enzyme Activation
- Eukaryotic Initiation Factor-2/genetics
- Eukaryotic Initiation Factor-2/metabolism
- Gene Knockdown Techniques
- Host-Pathogen Interactions/physiology
- Macaca mulatta
- Mice
- Mice, Knockout
- Mutant Proteins/antagonists & inhibitors
- Mutant Proteins/genetics
- Mutant Proteins/metabolism
- Phosphorylation
- RNA, Double-Stranded/genetics
- RNA, Double-Stranded/metabolism
- RNA, Viral/genetics
- RNA, Viral/metabolism
- Ribosome Subunits, Small, Eukaryotic/metabolism
- Ribosome Subunits, Small, Eukaryotic/virology
- Rotavirus/genetics
- Rotavirus/pathogenicity
- Rotavirus/physiology
- Rotavirus Infections/metabolism
- Transfection
- Viral Proteins/biosynthesis
- eIF-2 Kinase/antagonists & inhibitors
- eIF-2 Kinase/deficiency
- eIF-2 Kinase/genetics
- eIF-2 Kinase/metabolism
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Affiliation(s)
- Margarito Rojas
- Departamento de Génetica del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, UNAM, Cuernavaca, Morelos 62210, México
| | - Carlos F. Arias
- Departamento de Génetica del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, UNAM, Cuernavaca, Morelos 62210, México
| | - Susana López
- Departamento de Génetica del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, UNAM, Cuernavaca, Morelos 62210, México
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