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Wang Y, Li Y, Li M, Wang K, Xiong J, Wang T, Wang Y, Guo Y, Kong L, Li M. A Combined Transcriptomic and Proteomic Analysis of Monkeypox Virus A23 Protein on HEK293T Cells. Int J Mol Sci 2024; 25:8678. [PMID: 39201364 PMCID: PMC11354578 DOI: 10.3390/ijms25168678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2024] [Revised: 07/30/2024] [Accepted: 08/03/2024] [Indexed: 09/02/2024] Open
Abstract
Monkeypox virus (MPXV) is a cross-kingdom pathogen infecting both humans and wildlife, which poses a significant health risk to the public. Although MPXV attracts broad attention, there is a lack of adequate studies to elucidate pathogenic mechanisms associated with viral infections. In this study, a high-throughput RNA sequencing (RNA-seq) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) approach was used to explore the transcriptional and metabolic responses of MPXV A23 protein to HEK293T cells. The protein-protein interactions and signaling pathways were conducted by GO and KEGG analyses. The localization of A23 protein in HEK293T cells was detected by immunofluorescence. A total of 648 differentially expressed genes (DEGs) were identified in cells by RNA-Seq, including 314 upregulated genes and 334 downregulated genes. Additionally, liquid chromatography-tandem mass spectrometry (LC-MS/MS) detected 115 cellular proteins that interact with the A23 proteins. Transcriptomic sequencing analysis revealed that transfection of MPXV A23 protein modulated genes primarily associated with cellular apoptosis and DNA damage repair. Proteomic analysis indicated that this protein primarily interacted with host ribosomal proteins and histones. Following the identification of the nuclear localization sequence RKKR within the A23 protein, a truncated mutant A23ΔRKKR was constructed to investigate the subcellular localization of A23 protein. The wild-type A23 protein exhibits a significantly higher nuclear-to-cytoplasmic ratio, exceeding 1.5, in contrast to the mutant A23ΔRKKR, which has a ratio of approximately 1. Immunofluorescence assays showed that the A23 protein was mainly localized in the nucleus. The integration of transcriptomics and proteomics analysis provides a comprehensive understanding of the interaction between MPXV A23 protein and the host. Our findings highlight the potential role of this enzyme in suppressing host antiviral immune responses and modulating host gene expression.
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Affiliation(s)
- Yihao Wang
- Institute of Pathogenic Microorganism, Jiangxi Agricultural University, Nanchang 330000, China; (Y.W.); (Y.L.); (M.L.); (K.W.); (J.X.); (T.W.); (Y.W.); (Y.G.)
- Nanchang City Key Laboratory of Animal Virus and Genetic Engineering, Nanchang 330000, China
- College of Bioscience and Engineering, Jiangxi Agricultural University, Nanchang 330000, China
| | - Yihan Li
- Institute of Pathogenic Microorganism, Jiangxi Agricultural University, Nanchang 330000, China; (Y.W.); (Y.L.); (M.L.); (K.W.); (J.X.); (T.W.); (Y.W.); (Y.G.)
- Nanchang City Key Laboratory of Animal Virus and Genetic Engineering, Nanchang 330000, China
- College of Bioscience and Engineering, Jiangxi Agricultural University, Nanchang 330000, China
| | - Mingzhi Li
- Institute of Pathogenic Microorganism, Jiangxi Agricultural University, Nanchang 330000, China; (Y.W.); (Y.L.); (M.L.); (K.W.); (J.X.); (T.W.); (Y.W.); (Y.G.)
- Nanchang City Key Laboratory of Animal Virus and Genetic Engineering, Nanchang 330000, China
- College of Bioscience and Engineering, Jiangxi Agricultural University, Nanchang 330000, China
| | - Keyi Wang
- Institute of Pathogenic Microorganism, Jiangxi Agricultural University, Nanchang 330000, China; (Y.W.); (Y.L.); (M.L.); (K.W.); (J.X.); (T.W.); (Y.W.); (Y.G.)
- Nanchang City Key Laboratory of Animal Virus and Genetic Engineering, Nanchang 330000, China
- College of Bioscience and Engineering, Jiangxi Agricultural University, Nanchang 330000, China
| | - Jiaqi Xiong
- Institute of Pathogenic Microorganism, Jiangxi Agricultural University, Nanchang 330000, China; (Y.W.); (Y.L.); (M.L.); (K.W.); (J.X.); (T.W.); (Y.W.); (Y.G.)
- Nanchang City Key Laboratory of Animal Virus and Genetic Engineering, Nanchang 330000, China
- College of Bioscience and Engineering, Jiangxi Agricultural University, Nanchang 330000, China
| | - Ting Wang
- Institute of Pathogenic Microorganism, Jiangxi Agricultural University, Nanchang 330000, China; (Y.W.); (Y.L.); (M.L.); (K.W.); (J.X.); (T.W.); (Y.W.); (Y.G.)
- Nanchang City Key Laboratory of Animal Virus and Genetic Engineering, Nanchang 330000, China
- College of Bioscience and Engineering, Jiangxi Agricultural University, Nanchang 330000, China
| | - Yu Wang
- Institute of Pathogenic Microorganism, Jiangxi Agricultural University, Nanchang 330000, China; (Y.W.); (Y.L.); (M.L.); (K.W.); (J.X.); (T.W.); (Y.W.); (Y.G.)
- Nanchang City Key Laboratory of Animal Virus and Genetic Engineering, Nanchang 330000, China
- College of Bioscience and Engineering, Jiangxi Agricultural University, Nanchang 330000, China
| | - Yunli Guo
- Institute of Pathogenic Microorganism, Jiangxi Agricultural University, Nanchang 330000, China; (Y.W.); (Y.L.); (M.L.); (K.W.); (J.X.); (T.W.); (Y.W.); (Y.G.)
- Nanchang City Key Laboratory of Animal Virus and Genetic Engineering, Nanchang 330000, China
| | - Lingbao Kong
- Institute of Pathogenic Microorganism, Jiangxi Agricultural University, Nanchang 330000, China; (Y.W.); (Y.L.); (M.L.); (K.W.); (J.X.); (T.W.); (Y.W.); (Y.G.)
- Nanchang City Key Laboratory of Animal Virus and Genetic Engineering, Nanchang 330000, China
- College of Bioscience and Engineering, Jiangxi Agricultural University, Nanchang 330000, China
| | - Meifeng Li
- Institute of Pathogenic Microorganism, Jiangxi Agricultural University, Nanchang 330000, China; (Y.W.); (Y.L.); (M.L.); (K.W.); (J.X.); (T.W.); (Y.W.); (Y.G.)
- Nanchang City Key Laboratory of Animal Virus and Genetic Engineering, Nanchang 330000, China
- College of Bioscience and Engineering, Jiangxi Agricultural University, Nanchang 330000, China
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Venus S, Tandjigora K, Jankowsky E. The Viral Protein K7 Inhibits Biochemical Activities and Condensate Formation by the DEAD-box Helicase DDX3X. J Mol Biol 2023; 435:168217. [PMID: 37517790 PMCID: PMC10528715 DOI: 10.1016/j.jmb.2023.168217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 06/17/2023] [Accepted: 07/24/2023] [Indexed: 08/01/2023]
Abstract
The DEAD-box RNA helicase DDX3X promotes translation initiation and associates with stress granules. A range of diverse viruses produce proteins that target DDX3X, including hepatitis C, dengue, vaccinia, and influenza A. The interaction of some of these viral proteins with DDX3X has been shown to affect antiviral intracellular signaling, but it is unknown whether and how viral proteins impact the biochemical activities of DDX3X and its physical roles in cells. Here we show that the protein K7 from vaccinia virus, which binds to an intrinsically disordered region in the N-terminus of DDX3X, inhibits RNA helicase and RNA-stimulated ATPase activities, as well as liquid-liquid phase separation of DDX3X in vitro. We demonstrate in HCT 116 cells that K7 inhibits association of DDX3X with stress granules, as well as the formation of aberrant granules induced by expression of DDX3X with a point mutation linked to medulloblastoma and DDX3X syndrome. The results show that targeting of the intrinsically disordered N-terminus is an effective viral strategy to modulate the biochemical functions and subcellular localization of DDX3X. Our findings also have potential therapeutic implications for diseases linked to aberrant DDX3X granule formation.
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Affiliation(s)
- Sarah Venus
- Center for RNA Science and Therapeutics, Department of Biochemistry, Case Comprehensive Cancer Center, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44016, United States
| | - Kaba Tandjigora
- Center for RNA Science and Therapeutics, Department of Biochemistry, Case Comprehensive Cancer Center, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44016, United States
| | - Eckhard Jankowsky
- Center for RNA Science and Therapeutics, Department of Biochemistry, Case Comprehensive Cancer Center, School of Medicine, Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44016, United States.
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Hesser CR, Walsh D. YTHDF2 Is Downregulated in Response to Host Shutoff Induced by DNA Virus Infection and Regulates Interferon-Stimulated Gene Expression. J Virol 2023; 97:e0175822. [PMID: 36916936 PMCID: PMC10062140 DOI: 10.1128/jvi.01758-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 02/23/2023] [Indexed: 03/15/2023] Open
Abstract
Recent studies have begun to reveal the complex and multifunctional roles of N6-methyladenosine (m6A) modifications and their associated writer, reader, and eraser proteins in infection by diverse RNA and DNA viruses. However, little is known about their regulation and functions during infection by several viruses, including poxviruses. Here, we show that members of the YTH Domain Family (YTHDF), in particular YTHDF2, are downregulated as the prototypical poxvirus, vaccinia virus (VacV) enters later stages of replication in a variety of natural target cell types, but not in commonly used transformed cell lines wherein the control of YTHDF2 expression appears to be dysregulated. YTHDF proteins also decreased at late stages of infection by herpes simplex virus 1 (HSV-1) but not human cytomegalovirus, suggesting that YTHDF2 is downregulated in response to infections that induce host shutoff. In line with this idea, YTHDF2 was potently downregulated upon infection with a VacV mutant expressing catalytically inactive forms of the decapping enzymes, D9 and D10, which fails to degrade dsRNA and induces a protein kinase R response that itself inhibits protein synthesis. Overexpression and RNAi-mediated depletion approaches further demonstrate that YTHDF2 does not directly affect VacV replication. Instead, experimental downregulation of YTHDF2 or the related family member, YTHDF1, induces a potent increase in interferon-stimulated gene expression and establishes an antiviral state that suppresses infection by either VacV or HSV-1. Combined, our data suggest that YTHDF2 is destabilized in response to infection-induced host shutoff and serves to augment host antiviral responses. IMPORTANCE There is increasing recognition of the importance of N6-methyladenosine (m6A) modifications to both viral and host mRNAs and the complex roles this modification plays in determining the fate of infection by diverse RNA and DNA viruses. However, in many instances, the functional contributions and importance of specific m6A writer, reader, and eraser proteins remains unknown. Here, we show that natural target cells but not transformed cell lines downregulate the YTH Domain Family (YTHDF) of m6A reader proteins, in particular YTHDF2, in response to shutoff of protein synthesis upon infection with the large DNA viruses, vaccinia virus (VacV), or herpes simplex virus type 1. We further reveal that YTHDF2 downregulation also occurs as part of the host protein kinase R response to a VacV shutoff mutant and that this downregulation of YTHDF family members functions to enhance interferon-stimulated gene expression to create an antiviral state.
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Affiliation(s)
- Charles R. Hesser
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Derek Walsh
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
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Wood JJ, White IJ, Samolej J, Mercer J. Acrylamide inhibits vaccinia virus through vimentin-independent anti-viral granule formation. Cell Microbiol 2021; 23:e13334. [PMID: 33792166 DOI: 10.1111/cmi.13334] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 03/23/2021] [Accepted: 03/29/2021] [Indexed: 11/28/2022]
Abstract
The replication and assembly of vaccinia virus (VACV), the prototypic poxvirus, occurs exclusively in the cytoplasm of host cells. While the role of cellular cytoskeletal components in these processes remains poorly understood, vimentin-a type III intermediate filament-has been shown to associate with viral replication sites and to be incorporated into mature VACV virions. Here, we employed chemical and genetic approaches to further investigate the role of vimentin during the VACV lifecycle. The collapse of vimentin filaments, using acrylamide, was found to inhibit VACV infection at the level of genome replication, intermediate- and late-gene expression. However, we found that CRISPR-mediated knockout of vimentin did not impact VACV replication. Combining these tools, we demonstrate that acrylamide treatment results in the formation of anti-viral granules (AVGs) known to mediate translational inhibition of many viruses. We conclude that vimentin is dispensable for poxvirus replication and assembly and that acrylamide, as a potent inducer of AVGs during VACV infection, serves to bolster cell's anti-viral response to poxvirus infection.
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Affiliation(s)
- Jennifer J Wood
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Ian J White
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Jerzy Samolej
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Jason Mercer
- MRC Laboratory for Molecular Cell Biology, University College London, London, UK.,Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
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Alakunle E, Moens U, Nchinda G, Okeke MI. Monkeypox Virus in Nigeria: Infection Biology, Epidemiology, and Evolution. Viruses 2020; 12:E1257. [PMID: 33167496 PMCID: PMC7694534 DOI: 10.3390/v12111257] [Citation(s) in RCA: 353] [Impact Index Per Article: 88.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 10/22/2020] [Accepted: 10/30/2020] [Indexed: 12/16/2022] Open
Abstract
Monkeypox is a zoonotic disease caused by monkeypox virus (MPXV), which is a member of orthopoxvirus genus. The reemergence of MPXV in 2017 (at Bayelsa state) after 39 years of no reported case in Nigeria, and the export of travelers' monkeypox (MPX) from Nigeria to other parts of the world, in 2018 and 2019, respectively, have raised concern that MPXV may have emerged to occupy the ecological and immunological niche vacated by smallpox virus. This review X-rays the current state of knowledge pertaining the infection biology, epidemiology, and evolution of MPXV in Nigeria and worldwide, especially with regard to the human, cellular, and viral factors that modulate the virus transmission dynamics, infection, and its maintenance in nature. This paper also elucidates the role of recombination, gene loss and gene gain in MPXV evolution, chronicles the role of signaling in MPXV infection, and reviews the current therapeutic options available for the treatment and prevention of MPX. Additionally, genome-wide phylogenetic analysis was undertaken, and we show that MPXV isolates from recent 2017 outbreak in Nigeria were monophyletic with the isolate exported to Israel from Nigeria but do not share the most recent common ancestor with isolates obtained from earlier outbreaks, in 1971 and 1978, respectively. Finally, the review highlighted gaps in knowledge particularly the non-identification of a definitive reservoir host animal for MPXV and proposed future research endeavors to address the unresolved questions.
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Affiliation(s)
- Emmanuel Alakunle
- Department of Natural and Environmental Sciences, Biomedical Science Concentration, School of Arts and Sciences, American University of Nigeria, 98 Lamido Zubairu Way, PMB 2250 Yola, Nigeria;
| | - Ugo Moens
- Molecular Inflammation Research Group, Institute of Medical Biology, University i Tromsø (UIT)—The Arctic University of Norway, N-9037 Tromsø, Norway;
| | - Godwin Nchinda
- Laboratory of Vaccinology and Immunology, The Chantal Biya International Reference Center for Research on the Prevention and Management HIV/AIDS (CIRCB), P.O Box 3077 Yaoundé-Messa, Cameroon;
- Department of Pharmaceutical Microbiology & Biotechnology, Faculty of Pharmaceutical Sciences, Nnamdi Azikiwe University, P.O Box 420110 Awka, Nigeria
| | - Malachy Ifeanyi Okeke
- Department of Natural and Environmental Sciences, Biomedical Science Concentration, School of Arts and Sciences, American University of Nigeria, 98 Lamido Zubairu Way, PMB 2250 Yola, Nigeria;
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Riad S, Xiang Y, AlDaif B, Mercer AA, Fleming SB. Rescue of a Vaccinia Virus Mutant Lacking IFN Resistance Genes K1L and C7L by the Parapoxvirus Orf Virus. Front Microbiol 2020; 11:1797. [PMID: 32903701 PMCID: PMC7438785 DOI: 10.3389/fmicb.2020.01797] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Accepted: 07/09/2020] [Indexed: 12/17/2022] Open
Abstract
Type 1 interferons induce the upregulation of hundreds of interferon-stimulated genes (ISGs) that combat viral replication. The parapoxvirus orf virus (ORFV) induces acute pustular skin lesions in sheep and goats and can reinfect its host, however, little is known of its ability to resist IFN. Vaccinia virus (VACV) encodes a number of factors that modulate the IFN response including the host-range genes C7L and K1L. A recombinant VACV-Western Reserve (WR) strain in which the K1L and C7L genes have been deleted does not replicate in cells treated with IFN-β nor in HeLa cells in which the IFN response is constitutive and is inhibited at the level of intermediate gene expression. Furthermore C7L is conserved in almost all poxviruses. We provide evidence that shows that although ORFV is more sensitive to IFN-β compared with VACV, and lacks homologues of KIL and C7L, it nevertheless has the ability to rescue a VACV KIL- C7L- gfp+ mutant in which gfp is expressed from a late promoter. Co-infection of HeLa cells with the mutant and ORFV demonstrated that ORFV was able to overcome the block in translation of intermediate transcripts in the mutant virus, allowing it to progress to late gene expression and new viral particles. Our findings strongly suggest that ORFV encodes a factor(s) that, although different in structure to C7L or KIL, targets an anti-viral cellular mechanism that is a highly potent at killing poxviruses.
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Affiliation(s)
- Sherief Riad
- Virus Research Unit, Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Yan Xiang
- Department of Microbiology, Immunology and Molecular Genetics, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Basheer AlDaif
- Virus Research Unit, Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Andrew A Mercer
- Virus Research Unit, Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Stephen B Fleming
- Virus Research Unit, Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
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Eiermann N, Haneke K, Sun Z, Stoecklin G, Ruggieri A. Dance with the Devil: Stress Granules and Signaling in Antiviral Responses. Viruses 2020; 12:v12090984. [PMID: 32899736 PMCID: PMC7552005 DOI: 10.3390/v12090984] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/31/2020] [Accepted: 08/31/2020] [Indexed: 02/07/2023] Open
Abstract
Cells have evolved highly specialized sentinels that detect viral infection and elicit an antiviral response. Among these, the stress-sensing protein kinase R, which is activated by double-stranded RNA, mediates suppression of the host translation machinery as a strategy to limit viral replication. Non-translating mRNAs rapidly condensate by phase separation into cytosolic stress granules, together with numerous RNA-binding proteins and components of signal transduction pathways. Growing evidence suggests that the integrated stress response, and stress granules in particular, contribute to antiviral defense. This review summarizes the current understanding of how stress and innate immune signaling act in concert to mount an effective response against virus infection, with a particular focus on the potential role of stress granules in the coordination of antiviral signaling cascades.
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Affiliation(s)
- Nina Eiermann
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; (N.E.); (K.H.); (G.S.)
| | - Katharina Haneke
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; (N.E.); (K.H.); (G.S.)
| | - Zhaozhi Sun
- Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Disease Research (CIID), University of Heidelberg, 69120 Heidelberg, Germany;
| | - Georg Stoecklin
- Division of Biochemistry, Mannheim Institute for Innate Immunoscience (MI3), Medical Faculty Mannheim, Heidelberg University, 68167 Mannheim, Germany; (N.E.); (K.H.); (G.S.)
| | - Alessia Ruggieri
- Department of Infectious Diseases, Molecular Virology, Center for Integrative Infectious Disease Research (CIID), University of Heidelberg, 69120 Heidelberg, Germany;
- Correspondence:
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Myxoma Virus-Encoded Host Range Protein M029: A Multifunctional Antagonist Targeting Multiple Host Antiviral and Innate Immune Pathways. Vaccines (Basel) 2020; 8:vaccines8020244. [PMID: 32456120 PMCID: PMC7349962 DOI: 10.3390/vaccines8020244] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/19/2020] [Accepted: 05/22/2020] [Indexed: 12/21/2022] Open
Abstract
Myxoma virus (MYXV) is the prototypic member of the Leporipoxvirus genus of the Poxviridae family of viruses. In nature, MYXV is highly restricted to leporids and causes a lethal disease called myxomatosis only in European rabbits (Oryctologous cuniculus). However, MYXV has been shown to also productively infect various types of nonrabbit transformed and cancer cells in vitro and in vivo, whereas their normal somatic cell counterparts undergo abortive infections. This selective tropism of MYXV for cancer cells outside the rabbit host has facilitated its development as an oncolytic virus for the treatment of different types of cancers. Like other poxviruses, MYXV possesses a large dsDNA genome which encodes an array of dozens of immunomodulatory proteins that are important for host and cellular tropism and modulation of host antiviral innate immune responses, some of which are rabbit-specific and others can function in nonrabbit cells as well. This review summarizes the functions of one such MYXV host range protein, M029, an ortholog of the larger superfamily of poxvirus encoded E3-like dsRNA binding proteins. M029 has been identified as a multifunctional protein involved in MYXV cellular and host tropism, antiviral responses, and pathogenicity in rabbits.
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Zhao Y, Zhao L, Huang P, Ren J, Zhang P, Tian H, Tan W. Non-replicating Vaccinia Virus TianTan Strain (NTV) Translation Arrest of Viral Late Protein Synthesis Associated With Anti-viral Host Factor SAMD9. Front Cell Infect Microbiol 2020; 10:116. [PMID: 32266167 PMCID: PMC7098914 DOI: 10.3389/fcimb.2020.00116] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 03/02/2020] [Indexed: 11/13/2022] Open
Abstract
NTV is a highly attenuated virus that was created by genetically deleting 26 genes related to host range and virulence from TianTan strain. Since NTV is highly attenuated, it has been used widely as an optimizing viral vector. In this study, we explored the biological characteristics in vitro and the host restriction mechanism of NTV. Most cell lines do not support sufficient dissemination and replication of NTV, and in non-permissive cell line HeLa, the replication block of NTV occurred at the translation stage of viral late protein expression. Lack of PKR activity was not sufficient to rescue expression of viral late proteins and replication, even though the phosphorylation level of eIF2α increased in NTV-infected HeLa cells. Moreover, the translation inhibition of NTV in HeLa cells was dependent upon a SAMD9 signaling pathway, as demonstrated by silencing SAMD9 expression with siRNA and observing the colocalization of SAMD9 and AVGs. Reinserting C7L or K1L into NTV rescued the late viral protein expression and replication of NTV in HeLa cells. Among the genes deleted in NTV, C7L or/and K1L gene was mainly responsible for its replication defect. Protein C7 interacted with SAMD9, which antagonized the antiviral response of SAMD9 to ensure viral protein translation and replication of NTV in non-permissive cell lines. Our finding will serve as a baseline for modification of NTV in future application.
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Affiliation(s)
- Ying Zhao
- NHC Key Laboratory of Medical Virology and Viral Disease, Chinese Center for Disease Control and Prevention, National Institute for Viral Disease Control and Prevention, Beijing, China
| | - Li Zhao
- NHC Key Laboratory of Medical Virology and Viral Disease, Chinese Center for Disease Control and Prevention, National Institute for Viral Disease Control and Prevention, Beijing, China
| | - Panpan Huang
- NHC Key Laboratory of Medical Virology and Viral Disease, Chinese Center for Disease Control and Prevention, National Institute for Viral Disease Control and Prevention, Beijing, China.,Shenzhen Research Institute, City University of Hong Kong, Shenzhen, China
| | - Jiao Ren
- NHC Key Laboratory of Medical Virology and Viral Disease, Chinese Center for Disease Control and Prevention, National Institute for Viral Disease Control and Prevention, Beijing, China
| | - Peng Zhang
- NHC Key Laboratory of Medical Virology and Viral Disease, Chinese Center for Disease Control and Prevention, National Institute for Viral Disease Control and Prevention, Beijing, China
| | - Houwen Tian
- NHC Key Laboratory of Medical Virology and Viral Disease, Chinese Center for Disease Control and Prevention, National Institute for Viral Disease Control and Prevention, Beijing, China
| | - Wenjie Tan
- NHC Key Laboratory of Medical Virology and Viral Disease, Chinese Center for Disease Control and Prevention, National Institute for Viral Disease Control and Prevention, Beijing, China
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Weber S, Jeske K, Ulrich RG, Imholt C, Jacob J, Beer M, Hoffmann D. In Vivo Characterization of a Bank Vole-Derived Cowpox Virus Isolate in Natural Hosts and the Rat Model. Viruses 2020; 12:v12020237. [PMID: 32093366 PMCID: PMC7077282 DOI: 10.3390/v12020237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 02/18/2020] [Accepted: 02/18/2020] [Indexed: 12/04/2022] Open
Abstract
Cowpox virus (CPXV) belongs to the genus Orthopoxvirus in the Poxviridae family and is endemic in western Eurasia. Based on seroprevalence studies in different voles from continental Europe and UK, voles are suspected to be the major reservoir host. Recently, a CPXV was isolated from a bank vole (Myodes glareolus) in Germany that showed a high genetic similarity to another isolate originating from a Cotton-top tamarin (Saguinus oedipus). Here we characterize this first bank vole-derived CPXV isolate in comparison to the related tamarin-derived isolate. Both isolates grouped genetically within the provisionally called CPXV-like 3 clade. Previous phylogenetic analysis indicated that CPXV is polyphyletic and CPXV-like 3 clade represents probably a different species if categorized by the rules used for other orthopoxviruses. Experimental infection studies with bank voles, common voles (Microtusarvalis) and Wistar rats showed very clear differences. The bank vole isolate was avirulent in both common voles and Wistar rats with seroconversion seen only in the rats. In contrast, inoculated bank voles exhibited viral shedding and seroconversion for both tested CPXV isolates. In addition, bank voles infected with the tamarin-derived isolate experienced a marked weight loss. Our findings allow for the conclusion that CPXV isolates might differ in their replication capacity in different vole species and rats depending on their original host. Moreover, the results indicate host-specific differences concerning CPXV-specific virulence. Further experiments are needed to identify individual virulence and host factors involved in the susceptibility and outcome of CPXV-infections in the different reservoir hosts.
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Affiliation(s)
- Saskia Weber
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (S.W.); (K.J.)
| | - Kathrin Jeske
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (S.W.); (K.J.)
- Institute of Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany;
| | - Rainer G. Ulrich
- Institute of Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany;
| | - Christian Imholt
- Vertebrate Research, Institute for Plant Protection in Horticulture and Forests, Julius Kühn-Institute, Toppheideweg 88, 48161 Münster, Germany; (C.I.); (J.J.)
| | - Jens Jacob
- Vertebrate Research, Institute for Plant Protection in Horticulture and Forests, Julius Kühn-Institute, Toppheideweg 88, 48161 Münster, Germany; (C.I.); (J.J.)
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (S.W.); (K.J.)
- Correspondence: (M.B.); (D.H.); Tel.: +49-38351-7-1200 (M.B.); +49-38351-7-1627 (D.H.)
| | - Donata Hoffmann
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Südufer 10, 17493 Greifswald-Insel Riems, Germany; (S.W.); (K.J.)
- Correspondence: (M.B.); (D.H.); Tel.: +49-38351-7-1200 (M.B.); +49-38351-7-1627 (D.H.)
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11
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Gaete-Argel A, Márquez CL, Barriga GP, Soto-Rifo R, Valiente-Echeverría F. Strategies for Success. Viral Infections and Membraneless Organelles. Front Cell Infect Microbiol 2019; 9:336. [PMID: 31681621 PMCID: PMC6797609 DOI: 10.3389/fcimb.2019.00336] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 09/18/2019] [Indexed: 12/12/2022] Open
Abstract
Regulation of RNA homeostasis or “RNAstasis” is a central step in eukaryotic gene expression. From transcription to decay, cellular messenger RNAs (mRNAs) associate with specific proteins in order to regulate their entire cycle, including mRNA localization, translation and degradation, among others. The best characterized of such RNA-protein complexes, today named membraneless organelles, are Stress Granules (SGs) and Processing Bodies (PBs) which are involved in RNA storage and RNA decay/storage, respectively. Given that SGs and PBs are generally associated with repression of gene expression, viruses have evolved different mechanisms to counteract their assembly or to use them in their favor to successfully replicate within the host environment. In this review we summarize the current knowledge about the viral regulation of SGs and PBs, which could be a potential novel target for the development of broad-spectrum antiviral therapies.
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Affiliation(s)
- Aracelly Gaete-Argel
- Molecular and Cellular Virology Laboratory, Virology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,HIV/AIDS Workgroup, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Chantal L Márquez
- Molecular and Cellular Virology Laboratory, Virology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,HIV/AIDS Workgroup, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Gonzalo P Barriga
- Emerging Viruses Laboratory, Virology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Ricardo Soto-Rifo
- Molecular and Cellular Virology Laboratory, Virology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,HIV/AIDS Workgroup, Faculty of Medicine, Universidad de Chile, Santiago, Chile
| | - Fernando Valiente-Echeverría
- Molecular and Cellular Virology Laboratory, Virology Program, Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile.,HIV/AIDS Workgroup, Faculty of Medicine, Universidad de Chile, Santiago, Chile
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12
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Chicken Embryonic-Stem Cells Are Permissive to Poxvirus Recombinant Vaccine Vectors. Genes (Basel) 2019; 10:genes10030237. [PMID: 30897824 PMCID: PMC6471371 DOI: 10.3390/genes10030237] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 03/14/2019] [Accepted: 03/15/2019] [Indexed: 12/17/2022] Open
Abstract
The discovery of mammalian pluripotent embryonic stem cells (ESC) has revolutionised cell research and regenerative medicine. More recently discovered chicken ESC (cESC), though less intensively studied, are increasingly popular as vaccine substrates due to a dearth of avian cell lines. Information on the comparative performance of cESC with common vaccine viruses is limited. Using RNA-sequencing, we compared cESC transcriptional programmes elicited by stimulation with chicken type I interferon or infection with vaccine viruses routinely propagated in primary chicken embryo fibroblasts (CEF). We used poxviruses (fowlpox virus (FWPV) FP9, canarypox virus (CNPV), and modified vaccinia virus Ankara (MVA)) and a birnavirus (infectious bursal disease virus (IBDV) PBG98). Interferon-stimulated genes (ISGs) were induced in cESC to levels comparable to those in CEF and immortalised chicken fibroblast DF-1 cells. cESC are permissive (with distinct host transcriptional responses) to MVA, FP9, and CNPV but, surprisingly, not to PBG98. MVA, CNPV, and FP9 suppressed innate immune responses, while PBG98 induced a subset of ISGs. Dysregulation of signalling pathways (i.e., NFκB, TRAF) was observed, which might affect immune responses and viral replication. In conclusion, we show that cESC are an attractive alternative substrate to study and propagate poxvirus recombinant vaccine vectors.
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13
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Wong PS, Sutejo R, Chen H, Ng SH, Sugrue RJ, Tan BH. A System Based-Approach to Examine Cytokine Response in Poxvirus-Infected Macrophages. Viruses 2018; 10:v10120692. [PMID: 30563103 PMCID: PMC6316232 DOI: 10.3390/v10120692] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 11/29/2018] [Accepted: 11/30/2018] [Indexed: 02/07/2023] Open
Abstract
The poxviruses are large, linear, double-stranded DNA viruses about 130 to 230 kbp, that have an animal origin and evolved to infect a wide host range. Variola virus (VARV), the causative agent of smallpox, is a poxvirus that infects only humans, but other poxviruses such as monkey poxvirus and cowpox virus (CPXV) have crossed over from animals to infect humans. Therefore understanding the biology of poxviruses can devise antiviral strategies to prevent these human infections. In this study we used a system-based approach to examine the host responses to three orthopoxviruses, CPXV, vaccinia virus (VACV), and ectromelia virus (ECTV) in the murine macrophage RAW 264.7 cell line. Overall, we observed a significant down-regulation of gene expressions for pro-inflammatory cytokines, chemokines, and related receptors. There were also common and virus-specific changes in the immune-regulated gene expressions for each poxvirus-infected RAW cells. Collectively our results showed that the murine macrophage RAW 264.7 cell line is a suitable cell-based model system to study poxvirus host response.
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Affiliation(s)
- Pui-San Wong
- Defence Medical and Environmental Research Institute, DSO National Labs, Singapore 117510, Singapore.
| | - Richard Sutejo
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore.
| | - Hui Chen
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore.
| | - Sock-Hoon Ng
- Defence Medical and Environmental Research Institute, DSO National Labs, Singapore 117510, Singapore.
| | - Richard J Sugrue
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore.
| | - Boon-Huan Tan
- Defence Medical and Environmental Research Institute, DSO National Labs, Singapore 117510, Singapore.
- Infection and Immunity, LKC School of Medicine, Nanyang Technological University, Singapore 308232, Singapore.
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14
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Battling for Ribosomes: Translational Control at the Forefront of the Antiviral Response. J Mol Biol 2018; 430:1965-1992. [PMID: 29746850 DOI: 10.1016/j.jmb.2018.04.040] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 04/24/2018] [Accepted: 04/27/2018] [Indexed: 01/05/2023]
Abstract
In the early stages of infection, gaining control of the cellular protein synthesis machinery including its ribosomes is the ultimate combat objective for a virus. To successfully replicate, viruses unequivocally need to usurp and redeploy this machinery for translation of their own mRNA. In response, the host triggers global shutdown of translation while paradoxically allowing swift synthesis of antiviral proteins as a strategy to limit collateral damage. This fundamental conflict at the level of translational control defines the outcome of infection. As part of this special issue on molecular mechanisms of early virus-host cell interactions, we review the current state of knowledge regarding translational control during viral infection with specific emphasis on protein kinase RNA-activated and mammalian target of rapamycin-mediated mechanisms. We also describe recent technological advances that will allow unprecedented insight into how viruses and host cells battle for ribosomes.
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15
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Li C, Du S, Tian M, Wang Y, Bai J, Tan P, Liu W, Yin R, Wang M, Jiang Y, Li Y, Zhu N, Zhu Y, Li T, Wu S, Jin N, He F. The Host Restriction Factor Interferon-Inducible Transmembrane Protein 3 Inhibits Vaccinia Virus Infection. Front Immunol 2018; 9:228. [PMID: 29503647 PMCID: PMC5820317 DOI: 10.3389/fimmu.2018.00228] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Accepted: 01/26/2018] [Indexed: 11/21/2022] Open
Abstract
Interferons (IFNs) establish dynamic host defense mechanisms by inducing various IFN-stimulated genes that encodes many antiviral innate immune effectors. IFN-inducible transmembrane (IFITM) proteins have been identified as intrinsic antiviral effectors, which block the entry of a broad spectrum of enveloped RNA viruses by interrupting virus-endosomal fusion. However, antiviral activity of IFITM proteins against mammalian DNA virus has not been demonstrated till date. Here, we sought to investigate the antiviral activities and mechanisms of interferon-inducible transmembrane protein 3 (IFITM3) protein against poxvirus infection. Analysis of expression kinetics of cell endogenous IFITM3 protein indicated that vaccinia virus (VACV) infection suppressed its translation, which was independent of IRF3 phosphorylation triggered by VACV. Although silencing of endogenous IFITM proteins did not affect their baseline antiviral effects in the cell, it has reduced the IFN-α-mediated inhibition of VACV infection, and also modulated VACV-induced cell death. Moreover, we discovered that overexpression of IFITM3 significantly restricted VACV infection, replication and proliferation mainly by interfering with virus entry processes prior to the virus nucleocapsid entry into the cytoplasm. Interestingly, IFITM3 overexpression showed an impact on virus binding. Furthermore, IFITM3 interfered with the cytosolic entry of virus through low pH-dependent fashion. Taken together, our findings provide the first evidence of exogenously expressed IFITM3 protein restricting infection of an enveloped DNA virus, thus expanding their antiviral spectrum. This study further explores the complex mechanism and provides novel insights into the interaction between virus infection and host defense.
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Affiliation(s)
- Chang Li
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Institute, Academy of Military Medical Sciences, Changchun, China
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Institute of Radiation Medicine, Beijing, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
- 2nd Clinical Medical College of Jinan University, Shenzhen People’s Hospital, Shenzhen, China
| | - Shouwen Du
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Institute, Academy of Military Medical Sciences, Changchun, China
- 2nd Clinical Medical College of Jinan University, Shenzhen People’s Hospital, Shenzhen, China
| | - Mingyao Tian
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Institute, Academy of Military Medical Sciences, Changchun, China
| | - Yuhang Wang
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Institute, Academy of Military Medical Sciences, Changchun, China
| | - Jieying Bai
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Institute, Academy of Military Medical Sciences, Changchun, China
| | - Peng Tan
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Institute, Academy of Military Medical Sciences, Changchun, China
| | - Wei Liu
- State Key Laboratory of Pathogen and Biosecurity, Institute of Microbiology and Epidemiology, Academy of Military Medical Sciences, Beijing, China
| | - Ronglan Yin
- Academy of Animal Science and Veterinary Medicine in Jilin Province, Changchun, China
| | - Maopeng Wang
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Institute, Academy of Military Medical Sciences, Changchun, China
| | - Ying Jiang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Institute of Radiation Medicine, Beijing, China
| | - Yi Li
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Institute, Academy of Military Medical Sciences, Changchun, China
| | - Na Zhu
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Institute, Academy of Military Medical Sciences, Changchun, China
| | - Yilong Zhu
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Institute, Academy of Military Medical Sciences, Changchun, China
| | - Tiyuan Li
- 2nd Clinical Medical College of Jinan University, Shenzhen People’s Hospital, Shenzhen, China
| | - Shipin Wu
- 2nd Clinical Medical College of Jinan University, Shenzhen People’s Hospital, Shenzhen, China
| | - Ningyi Jin
- Key Laboratory of Jilin Province for Zoonosis Prevention and Control, Military Veterinary Institute, Academy of Military Medical Sciences, Changchun, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, China
- 2nd Clinical Medical College of Jinan University, Shenzhen People’s Hospital, Shenzhen, China
| | - Fuchu He
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, Institute of Radiation Medicine, Beijing, China
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16
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Combined Proteomics/Genomics Approach Reveals Proteomic Changes of Mature Virions as a Novel Poxvirus Adaptation Mechanism. Viruses 2017; 9:v9110337. [PMID: 29125539 PMCID: PMC5707544 DOI: 10.3390/v9110337] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Revised: 11/06/2017] [Accepted: 11/07/2017] [Indexed: 12/16/2022] Open
Abstract
DNA viruses, like poxviruses, possess a highly stable genome, suggesting that adaptation of virus particles to specific cell types is not restricted to genomic changes. Cowpox viruses are zoonotic poxviruses with an extraordinarily broad host range, demonstrating their adaptive potential in vivo. To elucidate adaptation mechanisms of poxviruses, we isolated cowpox virus particles from a rat and passaged them five times in a human and a rat cell line. Subsequently, we analyzed the proteome and genome of the non-passaged virions and each passage. While the overall viral genome sequence was stable during passaging, proteomics revealed multiple changes in the virion composition. Interestingly, an increased viral fitness in human cells was observed in the presence of increased immunomodulatory protein amounts. As the only minor variant with increasing frequency during passaging was located in a viral RNA polymerase subunit and, moreover, most minor variants were found in transcription-associated genes, protein amounts were presumably regulated at transcription level. This study is the first comparative proteome analysis of virus particles before and after cell culture propagation, revealing proteomic changes as a novel poxvirus adaptation mechanism.
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17
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KSHV inhibits stress granule formation by viral ORF57 blocking PKR activation. PLoS Pathog 2017; 13:e1006677. [PMID: 29084250 PMCID: PMC5679657 DOI: 10.1371/journal.ppat.1006677] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 11/09/2017] [Accepted: 10/03/2017] [Indexed: 11/18/2022] Open
Abstract
TIA-1 positive stress granules (SG) represent the storage sites of stalled mRNAs and are often associated with the cellular antiviral response. In this report, we provide evidence that Kaposi's sarcoma-associated herpesvirus (KSHV) overcomes the host antiviral response by inhibition of SG formation via a viral lytic protein ORF57. By immunofluorescence analysis, we found that B lymphocytes with KSHV lytic infection are refractory to SG induction. KSHV ORF57, an essential post-transcriptional regulator of viral gene expression and the production of new viral progeny, inhibits SG formation induced experimentally by arsenite and poly I:C, but not by heat stress. KSHV ORF37 (vSOX) bearing intrinsic endoribonuclease activity also inhibits arsenite-induced SG formation, but KSHV RTA, vIRF-2, ORF45, ORF59 and LANA exert no such function. ORF57 binds both PKR-activating protein (PACT) and protein kinase R (PKR) through their RNA-binding motifs and prevents PACT-PKR interaction in the PKR pathway which inhibits KSHV production. Consistently, knocking down PKR expression significantly promotes KSHV virion production. ORF57 interacts with PKR to inhibit PKR binding dsRNA and its autophosphorylation, leading to inhibition of eIF2α phosphorylation and SG formation. Homologous protein HSV-1 ICP27, but not EBV EB2, resembles KSHV ORF57 in the ability to block the PKR/eIF2α/SG pathway. In addition, KSHV ORF57 inhibits poly I:C-induced TLR3 phosphorylation. Altogether, our data provide the first evidence that KSHV ORF57 plays a role in modulating PKR/eIF2α/SG axis and enhances virus production during virus lytic infection.
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18
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Mekhedov SL, Makarova KS, Koonin EV. The complex domain architecture of SAMD9 family proteins, predicted STAND-like NTPases, suggests new links to inflammation and apoptosis. Biol Direct 2017; 12:13. [PMID: 28545555 PMCID: PMC5445408 DOI: 10.1186/s13062-017-0185-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 05/16/2017] [Indexed: 01/09/2023] Open
Abstract
We report a comprehensive computational dissection of the domain architecture of the SAMD9 family proteins that are involved in antivirus and antitumor response in humans. We show that the SAMD9 protein family is represented in most animals and also, unexpectedly, in bacteria, in particular actinomycetes. From the N to C terminus, the core SAMD9 family architecture includes DNA/RNA-binding AlbA domain, a variant Sir2-like domain, a STAND-like P-loop NTPase, an array of TPR repeats and an OB-fold domain with predicted RNA-binding properties. Vertebrate SAMD9 family proteins contain the eponymous SAM domain capable of polymerization, whereas some family members from other animals instead contain homotypic adaptor domains of the DEATH superfamily, known as dedicated components of apoptosis networks. Such complex domain architecture is reminiscent of the STAND superfamily NTPases that are involved in various signaling processes, including programmed cell death, in both eukaryotes and prokaryotes. These findings suggest that SAMD9 is a hub of a novel, evolutionarily conserved defense network that remains to be characterized. REVIEWERS This article was reviewed by Igor B. Zhulin and Mensur Dlakic.
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Affiliation(s)
- Sergei L Mekhedov
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, 20894, USA
| | - Kira S Makarova
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, 20894, USA
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, 20894, USA.
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