1
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Adly AN, Bi M, Carlson CR, Syed AM, Ciling A, Doudna JA, Cheng Y, Morgan DO. Assembly of SARS-CoV-2 ribonucleosomes by truncated N ∗ variant of the nucleocapsid protein. J Biol Chem 2023; 299:105362. [PMID: 37863261 PMCID: PMC10665939 DOI: 10.1016/j.jbc.2023.105362] [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: 08/18/2023] [Revised: 10/05/2023] [Accepted: 10/11/2023] [Indexed: 10/22/2023] Open
Abstract
The nucleocapsid (N) protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) compacts the RNA genome into viral ribonucleoprotein (vRNP) complexes within virions. Assembly of vRNPs is inhibited by phosphorylation of the N protein serine/arginine (SR) region. Several SARS-CoV-2 variants of concern carry N protein mutations that reduce phosphorylation and enhance the efficiency of viral packaging. Variants of the dominant B.1.1 viral lineage also encode a truncated N protein, termed N∗ or Δ(1-209), that mediates genome packaging despite lacking the N-terminal RNA-binding domain and SR region. Here, we use mass photometry and negative stain electron microscopy to show that purified Δ(1-209) and viral RNA assemble into vRNPs that are remarkably similar in size and shape to those formed with full-length N protein. We show that assembly of Δ(1-209) vRNPs requires the leucine-rich helix of the central disordered region and that this helix promotes N protein oligomerization. We also find that fusion of a phosphomimetic SR region to Δ(1-209) inhibits RNA binding and vRNP assembly. Our results provide new insights into the mechanisms by which RNA binding promotes N protein self-association and vRNP assembly, and how this process is modulated by phosphorylation.
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Affiliation(s)
- Armin N Adly
- Department of Physiology, University of California, San Francisco, California, USA
| | - Maxine Bi
- Department of Biochemistry & Biophysics, University of California, San Francisco, California, USA
| | | | - Abdullah M Syed
- J. David Gladstone Institutes, San Francisco, California, USA
| | - Alison Ciling
- J. David Gladstone Institutes, San Francisco, California, USA
| | - Jennifer A Doudna
- J. David Gladstone Institutes, San Francisco, California, USA; Department of Molecular and Cell Biology, University of California, Berkeley, California, USA; Howard Hughes Medical Institute, University of California, Berkeley, California, USA; Innovative Genomics Institute, University of California, Berkeley, California, USA; California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, California, USA; MBIB Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
| | - Yifan Cheng
- Department of Biochemistry & Biophysics, University of California, San Francisco, California, USA; Howard Hughes Medical Institute, University of California, San Francisco, California, USA
| | - David O Morgan
- Department of Physiology, University of California, San Francisco, California, USA.
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2
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Castillo G, Mora-Díaz JC, Breuer M, Singh P, Nelli RK, Giménez-Lirola LG. Molecular mechanisms of human coronavirus NL63 infection and replication. Virus Res 2023; 327:199078. [PMID: 36813239 PMCID: PMC9944649 DOI: 10.1016/j.virusres.2023.199078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 02/16/2023] [Accepted: 02/17/2023] [Indexed: 02/24/2023]
Abstract
Human coronavirus NL63 (HCoV-NL63) is spread globally, causing upper and lower respiratory tract infections mainly in young children. HCoV-NL63 shares a host receptor (ACE2) with severe acute respiratory syndrome coronavirus (SARS-CoV) and SARS-CoV-2 but, unlike them, HCoV-NL63 primarily develops into self-limiting mild to moderate respiratory disease. Although with different efficiency, both HCoV-NL63 and SARS-like CoVs infect ciliated respiratory cells using ACE2 as receptor for binding and cell entry. Working with SARS-like CoVs require access to BSL-3 facilities, while HCoV-NL63 research can be performed at BSL-2 laboratories. Thus, HCoV-NL63 could be used as a safer surrogate for comparative studies on receptor dynamics, infectivity and virus replication, disease mechanism, and potential therapeutic interventions against SARS-like CoVs. This prompted us to review the current knowledge on the infection mechanism and replication of HCoV-NL63. Specifically, after a brief overview on the taxonomy, genomic organization and virus structure, this review compiles the current HCoV-NL63-related research in virus entry and replication mechanism, including virus attachment, endocytosis, genome translation, and replication and transcription. Furthermore, we reviewed cumulative knowledge on the susceptibility of different cells to HCoV-NL63 infection in vitro, which is essential for successful virus isolation and propagation, and contribute to address different scientific questions from basic science to the development and assessment of diagnostic tools, and antiviral therapies. Finally, we discussed different antiviral strategies that have been explored to suppress replication of HCoV-NL63, and other related human coronaviruses, by either targeting the virus or enhancing host antiviral mechanisms.
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Affiliation(s)
- Gino Castillo
- Department of Veterinary Diagnostic and Production Animal Medicine, Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Iowa State University, 1850 Christensen Drive, Ames, IA 50011, USA
| | - Juan Carlos Mora-Díaz
- Department of Veterinary Diagnostic and Production Animal Medicine, Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Iowa State University, 1850 Christensen Drive, Ames, IA 50011, USA
| | - Mary Breuer
- Department of Veterinary Diagnostic and Production Animal Medicine, Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Iowa State University, 1850 Christensen Drive, Ames, IA 50011, USA
| | - Pallavi Singh
- Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115, USA
| | - Rahul K Nelli
- Department of Veterinary Diagnostic and Production Animal Medicine, Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Iowa State University, 1850 Christensen Drive, Ames, IA 50011, USA
| | - Luis G Giménez-Lirola
- Department of Veterinary Diagnostic and Production Animal Medicine, Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Iowa State University, 1850 Christensen Drive, Ames, IA 50011, USA.
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3
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Abstract
Coronaviruses have caused devastation in both human and animal populations, affecting both health and the economy. Amidst the emergence and re-emergence of coronaviruses, humans need to surmount the health and economic threat of coronaviruses through science and evidence-based approaches. One of these approaches is through biotechnology, particularly the heterologous production of biopharmaceutical proteins. This review article briefly describes the genome, general virion morphology, and key structural proteins of different coronaviruses affecting animals and humans. In addition, this review paper also presents the different systems in recombinant protein technology such as bacteria, yeasts, plants, mammalian cells, and insect/insect cells systems used to express key structural proteins in the development of countermeasures such as diagnostics, prophylaxis, and therapeutics in the challenging era of coronaviruses.
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4
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Zhang B, Tian J, Zhang Q, Xie Y, Wang K, Qiu S, Lu K, Liu Y. Comparing the Nucleocapsid Proteins of Human Coronaviruses: Structure, Immunoregulation, Vaccine, and Targeted Drug. Front Mol Biosci 2022; 9:761173. [PMID: 35573742 PMCID: PMC9099148 DOI: 10.3389/fmolb.2022.761173] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 03/28/2022] [Indexed: 01/08/2023] Open
Abstract
The seven pathogenic human coronaviruses (HCoVs) include HCoV-229E, HCoV-OC43, HCoV-NL63, and HCoV-HKU1, which usually cause mild upper respiratory tract diseases, and SARS-CoV, MERS-CoV, and SARS-CoV-2, which cause a severe acute respiratory syndrome. The nucleocapsid (N) protein, as the dominant structural protein from coronaviruses that bind to the genomic RNA, participates in various vital activities after virus invasion and will probably become a promising target of antiviral drug design. Therefore, a comprehensive literature review of human coronavirus’ pathogenic mechanism and therapeutic strategies is necessary for the control of the pandemic. Here, we give a systematic summary of the structures, immunoregulation, and potential vaccines and targeted drugs of the HCoVs N protein. First, we provide a general introduction to the fundamental structures and molecular function of N protein. Next, we outline the N protein mediated immune regulation and pathogenesis mechanism. Finally, we comprehensively summarize the development of potential N protein-targeted drugs and candidate vaccines to treat coronavirus disease 2019 (COVID-19). We believe this review provides insight into the virulence and transmission of SARS-CoV-2 as well as support for further study on epidemic control of COVID-19.
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Affiliation(s)
- Bo Zhang
- College of Basic Medicine, Zunyi Medical University, Zunyi, China
- *Correspondence: Yang Liu, ; Keyu Lu, ; Bo Zhang,
| | - Junjie Tian
- College of Basic Medicine, Zunyi Medical University, Zunyi, China
| | - Qintao Zhang
- College of Basic Medicine, Zunyi Medical University, Zunyi, China
| | - Yan Xie
- School of Public Health, Zunyi Medical University, Zunyi, China
| | - Kejia Wang
- Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Sciences/Institute of Agro-bioengineering, Guizhou University, Guiyang, China
| | - Shuyi Qiu
- Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Sciences/Institute of Agro-bioengineering, Guizhou University, Guiyang, China
| | - Keyu Lu
- College of Basic Medicine, Zunyi Medical University, Zunyi, China
- *Correspondence: Yang Liu, ; Keyu Lu, ; Bo Zhang,
| | - Yang Liu
- School of Public Health, Zunyi Medical University, Zunyi, China
- Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Sciences/Institute of Agro-bioengineering, Guizhou University, Guiyang, China
- *Correspondence: Yang Liu, ; Keyu Lu, ; Bo Zhang,
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5
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Chen JC, Xie TA, Lin ZZ, Li YQ, Xie YF, Li ZW, Guo XG. Identification of Key Pathways and Genes in SARS-CoV-2 Infecting Human Intestines by Bioinformatics Analysis. Biochem Genet 2021; 60:1076-1094. [PMID: 34787756 PMCID: PMC8596852 DOI: 10.1007/s10528-021-10144-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 10/21/2021] [Indexed: 12/20/2022]
Abstract
COVID-19 is a serious infectious disease that has recently swept the world, and research on its causative virus, SARS-CoV-2, remains insufficient. Therefore, this study uses bioinformatics analysis techniques to explore the human digestive tract diseases that may be caused by SARS-CoV-2 infection. The gene expression profile data set, numbered GSE149312, is from the Gene Expression Omnibus (GEO) database and is divided into a 24-h group and a 60-h group. R software is used to analyze and screen out differentially expressed genes (DEGs) and then gene ontology (GO) term and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses are performed. In KEGG, the pathway of non-alcoholic fatty liver disease exists in both the 24-h group and 60-h group. STRING is used to establish a protein–protein interaction (PPI) network, and Cytoscape is then used to visualize the PPI and define the top 12 genes of the node as the hub genes. Through verification, nine statistically significant hub genes are identified: AKT1, TIMP1, NOTCH, CCNA2, RRM2, TTK, BUB1B, KIF20A, and PLK1. In conclusion, the results of this study can provide a certain direction and basis for follow-up studies of SARS-CoV-2 infection of the human digestive tract and provide new insights for the prevention and treatment of diseases caused by SARS-CoV-2.
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Affiliation(s)
- Ji-Chun Chen
- Department of Clinical Medicine, The Third Clinical School of Guangzhou Medical University, Guangzhou, 510150, China
| | - Tian-Ao Xie
- Department of Clinical Medicine, The Third Clinical School of Guangzhou Medical University, Guangzhou, 510150, China
| | - Zhen-Zong Lin
- Department of Clinical Medicine, The Third Clinical School of Guangzhou Medical University, Guangzhou, 510150, China
| | - Yi-Qing Li
- Department of Clinical Medicine, The Third Clinical School of Guangzhou Medical University, Guangzhou, 510150, China
| | - Yu-Fei Xie
- Department of Clinical Medicine, The Third Clinical School of Guangzhou Medical University, Guangzhou, 510150, China
| | - Zhong-Wei Li
- Department of Clinical Medicine, The Third Clinical School of Guangzhou Medical University, Guangzhou, 510150, China
| | - Xu-Guang Guo
- Department of Clinical Medicine, The Third Clinical School of Guangzhou Medical University, Guangzhou, 510150, China. .,Department of Clinical Laboratory Medicine, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, China. .,Key Laboratory for Major Obstetric Diseases of Guangdong Province, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, China. .,Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510150, China.
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6
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Benzigar MR, Bhattacharjee R, Baharfar M, Liu G. Current methods for diagnosis of human coronaviruses: pros and cons. Anal Bioanal Chem 2021; 413:2311-2330. [PMID: 33219449 PMCID: PMC7679240 DOI: 10.1007/s00216-020-03046-0] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 10/14/2020] [Accepted: 11/04/2020] [Indexed: 12/13/2022]
Abstract
The current global fight against coronavirus disease (COVID-19) to flatten the transmission curve is put forth by the World Health Organization (WHO) as there is no immediate diagnosis or cure for COVID-19 so far. In order to stop the spread, researchers worldwide are working around the clock aiming to develop reliable tools for early diagnosis of severe acute respiratory syndrome (SARS-CoV-2) understanding the infection path and mechanisms. Currently, nucleic acid-based molecular diagnosis (real-time reverse transcription polymerase chain reaction (RT-PCR) test) is considered the gold standard for early diagnosis of SARS-CoV-2. Antibody-based serology detection is ineffective for the purpose of early diagnosis, but a potential tool for serosurveys, providing people with immune certificates for clearance from COVID-19 infection. Meanwhile, there are various blooming methods developed these days. In this review, we summarise different types of coronavirus discovered which can be transmitted between human beings. Methods used for diagnosis of the discovered human coronavirus (SARS, MERS, COVID-19) including nucleic acid detection, gene sequencing, antibody detection, antigen detection, and clinical diagnosis are presented. Their merits, demerits and prospects are discussed which can help the researchers to develop new generation of advanced diagnostic tools for accurate and effective control of human coronavirus transmission in the communities and hospitals.
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Affiliation(s)
- Mercy R Benzigar
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, 2052, Australia
- Australian Centre for NanoMedicine, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Ripon Bhattacharjee
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, 2052, Australia
- Australian Centre for NanoMedicine, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Mahroo Baharfar
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, 2052, Australia
- Australian Centre for NanoMedicine, University of New South Wales, Sydney, NSW, 2052, Australia
| | - Guozhen Liu
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
- Australian Centre for NanoMedicine, University of New South Wales, Sydney, NSW, 2052, Australia.
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7
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Hönemann M, Lück C, Maier M, Pietsch C, Dietze N, Berthold T, Encalada MVN, Grünewald T, Neumeister V, Dalpke A, Liebert UG. Comprehensive evaluation of eight commercial SARS-CoV-2 IgG assays. Diagn Microbiol Infect Dis 2021; 100:115382. [PMID: 33930691 PMCID: PMC7983330 DOI: 10.1016/j.diagmicrobio.2021.115382] [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: 11/02/2020] [Revised: 03/16/2021] [Accepted: 03/16/2021] [Indexed: 12/27/2022]
Abstract
Sensitivity and specificity of serological assays are key parameters for the accurate estimation of SARS-CoV-2 sero-prevalence. The aim of this study was to compare 8 readily available IgG antibody tests using a panel of well-defined serum samples of prepandemic and pandemic origin. A cross-reaction panel included samples of patients with recent infection with either of the endemic Coronaviruses 229E, NL63, HKU1, or OC43. Additionally, samples with high antibody levels against influenza virus, adenovirus, and during acute EBV infection were included. Previous infection with endemic coronaviruses caused a significant amount of cross-reactivity in two of the assays. In contrast, the confidence intervals for the assays of Abbott, DiaSorin, Euroimmun and Roche encompassed the value of 98% for samples with a previous endemic HCoV infection. For all assays, sensitivities were between 91.3% and 98.8%. Assay performance was independent of the usage of either nucleocapsid or spike proteins.
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Affiliation(s)
- Mario Hönemann
- Institute of Virology, Leipzig University, Leipzig, Germany.
| | - Christian Lück
- Institute of Medical Microbiology and Virology, Technische Universität Dresden, Dresden, Germany
| | - Melanie Maier
- Institute of Virology, Leipzig University, Leipzig, Germany
| | | | - Nadine Dietze
- Institute of Medical Microbiology, Leipzig University, Leipzig, Germany
| | - Tom Berthold
- Institute of Virology, Leipzig University, Leipzig, Germany
| | | | - Thomas Grünewald
- Clinic for Infectious Diseases and Tropical Medicine, Klinikum Chemnitz, Chemnitz
| | - Volker Neumeister
- Institute for Clinical Chemistry and Laboratory Medicine, Technische Universität Dresden, Dresden, Germany
| | - Alexander Dalpke
- Institute of Medical Microbiology and Virology, Technische Universität Dresden, Dresden, Germany
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8
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Lee P, Kim CU, Seo SH, Kim DJ. Current Status of COVID-19 Vaccine Development: Focusing on Antigen Design and Clinical Trials on Later Stages. Immune Netw 2021; 21:e4. [PMID: 33728097 PMCID: PMC7937514 DOI: 10.4110/in.2021.21.e4] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 02/17/2021] [Accepted: 02/17/2021] [Indexed: 12/23/2022] Open
Abstract
The global outbreak of coronavirus disease 2019 (COVID-19) is still threatening human health, economy, and social life worldwide. As a counteraction for this devastating disease, a number of vaccines are being developed with unprecedented speed combined with new technologies. As COVID-19 vaccines are being developed in the absence of a licensed human coronavirus vaccine, there remain further questions regarding the long-term efficacy and safety of the vaccines, as well as immunological mechanisms in depth. This review article discusses the current status of COVID-19 vaccine development, mainly focusing on antigen design, clinical trials in later stages, and immunological considerations for further study.
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Affiliation(s)
- Pureum Lee
- Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
- Department of Bioscience, University of Science and Technology (UST), Daejeon 34113, Korea
| | - Chang-Ung Kim
- Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
- Department of Biochemistry, Chungnam National University, Daejeon 34134, Korea
| | | | - Doo-Jin Kim
- Infectious Disease Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
- Department of Bioscience, University of Science and Technology (UST), Daejeon 34113, Korea
- Department of Biochemistry, Chungnam National University, Daejeon 34134, Korea
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9
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Yang M, He S, Chen X, Huang Z, Zhou Z, Zhou Z, Chen Q, Chen S, Kang S. Structural Insight Into the SARS-CoV-2 Nucleocapsid Protein C-Terminal Domain Reveals a Novel Recognition Mechanism for Viral Transcriptional Regulatory Sequences. Front Chem 2021; 8:624765. [PMID: 33511102 PMCID: PMC7835709 DOI: 10.3389/fchem.2020.624765] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 12/08/2020] [Indexed: 11/22/2022] Open
Abstract
Coronavirus disease 2019 (COVID-19) has caused massive disruptions to society and the economy, and the transcriptional regulatory mechanisms behind the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are poorly understood. Herein, we determined the crystal structure of the SARS-CoV-2 nucleocapsid protein C-terminal domain (CTD) at a resolution of 2.0 Å, and demonstrated that the CTD has a comparable distinct electrostatic potential surface to equivalent domains of other reported CoVs, suggesting that the CTD has novel roles in viral RNA binding and transcriptional regulation. Further in vitro biochemical assays demonstrated that the viral genomic intergenic transcriptional regulatory sequences (TRSs) interact with the SARS-CoV-2 nucleocapsid protein CTD with a flanking region. The unpaired adeno dinucleotide in the TRS stem-loop structure is a major determining factor for their interactions. Taken together, these results suggested that the nucleocapsid protein CTD is responsible for the discontinuous viral transcription mechanism by recognizing the different patterns of viral TRS during transcription.
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Affiliation(s)
- Mei Yang
- Guangdong Provincial Key Laboratory of Biomedical Imaging, Molecular Imaging Center, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China.,Molecular Imaging Center, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China
| | - Suhua He
- Guangdong Provincial Key Laboratory of Biomedical Imaging, Molecular Imaging Center, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China
| | - Xiaoxue Chen
- Guangdong Provincial Key Laboratory of Biomedical Imaging, Molecular Imaging Center, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China
| | - Zhaoxia Huang
- Guangdong Provincial Key Laboratory of Biomedical Imaging, Molecular Imaging Center, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China
| | - Ziliang Zhou
- Guangdong Provincial Key Laboratory of Biomedical Imaging, Molecular Imaging Center, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China
| | - Zhechong Zhou
- Guangdong Provincial Key Laboratory of Biomedical Imaging, Molecular Imaging Center, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China
| | - Qiuyue Chen
- Guangdong Provincial Key Laboratory of Biomedical Imaging, Molecular Imaging Center, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China
| | - Shoudeng Chen
- Guangdong Provincial Key Laboratory of Biomedical Imaging, Molecular Imaging Center, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China.,Molecular Imaging Center, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China
| | - Sisi Kang
- Guangdong Provincial Key Laboratory of Biomedical Imaging, Molecular Imaging Center, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China.,Molecular Imaging Center, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China
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10
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Carlson CR, Asfaha JB, Ghent CM, Howard CJ, Hartooni N, Safari M, Frankel AD, Morgan DO. Phosphoregulation of Phase Separation by the SARS-CoV-2 N Protein Suggests a Biophysical Basis for its Dual Functions. Mol Cell 2020; 80:1092-1103.e4. [PMID: 33248025 PMCID: PMC7677695 DOI: 10.1016/j.molcel.2020.11.025] [Citation(s) in RCA: 199] [Impact Index Per Article: 49.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 10/02/2020] [Accepted: 11/10/2020] [Indexed: 12/20/2022]
Abstract
The nucleocapsid (N) protein of coronaviruses serves two major functions: compaction of the RNA genome in the virion and regulation of viral gene transcription. It is not clear how the N protein mediates such distinct functions. The N protein contains two RNA-binding domains surrounded by regions of intrinsic disorder. Phosphorylation of the central disordered region promotes the protein's transcriptional function, but the underlying mechanism is not known. Here, we show that the N protein of SARS-CoV-2, together with viral RNA, forms biomolecular condensates. Unmodified N protein forms partially ordered gel-like condensates and discrete 15-nm particles based on multivalent RNA-protein and protein-protein interactions. Phosphorylation reduces these interactions, generating a more liquid-like droplet. We propose that distinct oligomeric states support the two functions of the N protein: unmodified protein forms a structured oligomer that is suited for nucleocapsid assembly, and phosphorylated protein forms a liquid-like compartment for viral genome processing.
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Affiliation(s)
- Christopher R Carlson
- Department of Physiology, University of California, San Francisco, San Francisco, CA 94143, USA; Tetrad Graduate Program, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Jonathan B Asfaha
- Department of Physiology, University of California, San Francisco, San Francisco, CA 94143, USA; Tetrad Graduate Program, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Chloe M Ghent
- Department of Physiology, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Conor J Howard
- Department of Biochemistry & Biophysics, University of California, San Francisco, San Francisco, CA 94143, USA; Tetrad Graduate Program, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Nairi Hartooni
- Department of Physiology, University of California, San Francisco, San Francisco, CA 94143, USA; Tetrad Graduate Program, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Maliheh Safari
- Department of Biochemistry & Biophysics, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Alan D Frankel
- Department of Biochemistry & Biophysics, University of California, San Francisco, San Francisco, CA 94143, USA; Tetrad Graduate Program, University of California, San Francisco, San Francisco, CA 94143, USA
| | - David O Morgan
- Department of Physiology, University of California, San Francisco, San Francisco, CA 94143, USA; Tetrad Graduate Program, University of California, San Francisco, San Francisco, CA 94143, USA.
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11
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Oliveira SC, de Magalhães MTQ, Homan EJ. Immunoinformatic Analysis of SARS-CoV-2 Nucleocapsid Protein and Identification of COVID-19 Vaccine Targets. Front Immunol 2020; 11:587615. [PMID: 33193414 PMCID: PMC7655779 DOI: 10.3389/fimmu.2020.587615] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2020] [Accepted: 10/02/2020] [Indexed: 12/23/2022] Open
Abstract
COVID-19 is a worldwide emergency; therefore, there is a critical need for foundational knowledge about B and T cell responses to SARS-CoV-2 essential for vaccine development. However, little information is available defining which determinants of SARS-CoV-2 other than the spike glycoprotein are recognized by the host immune system. In this study, we focus on the SARS-CoV-2 nucleocapsid protein as a suitable candidate target for vaccine formulations. Major B and T cell epitopes of the SARS-CoV-2 N protein are predicted and resulting sequences compared with the homolog immunological domains of other coronaviruses that infect human beings. The most dominant of B cell epitope is located between 176–206 amino acids in the SRGGSQASSRSSSRSRNSSRNSTPGSSRGTS sequence. Further, we identify sequences which are predicted to bind multiple common MHC I and MHC II alleles. Most notably there is a region of potential T cell cross-reactivity within the SARS-CoV-2 N protein position 102–110 amino acids that traverses multiple human alpha and betacoronaviruses. Vaccination strategies designed to target these conserved epitope regions could generate immune responses that are cross-reactive across human coronaviruses, with potential to protect or modulate disease. Finally, these predictions can facilitate effective vaccine design against this high priority virus.
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Affiliation(s)
- Sergio C Oliveira
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.,Instituto Nacional de Ciência e Tecnologia em Doenças Tropicais (INCT-DT), Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Ministerio de Ciencia e Tecnologia (MCT), Salvador, Brazil
| | - Mariana T Q de Magalhães
- Departamento de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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Nevers Q, Albertini AA, Lagaudrière-Gesbert C, Gaudin Y. Negri bodies and other virus membrane-less replication compartments. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118831. [PMID: 32835749 PMCID: PMC7442162 DOI: 10.1016/j.bbamcr.2020.118831] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 08/14/2020] [Accepted: 08/14/2020] [Indexed: 12/25/2022]
Abstract
Viruses reshape the organization of the cell interior to achieve different steps of their cellular cycle. Particularly, viral replication and assembly often take place in viral factories where specific viral and cellular proteins as well as nucleic acids concentrate. Viral factories can be either membrane-delimited or devoid of any cellular membranes. In the latter case, they are referred as membrane-less replication compartments. The most emblematic ones are the Negri bodies, which are inclusion bodies that constitute the hallmark of rabies virus infection. Interestingly, Negri bodies and several other viral replication compartments have been shown to arise from a liquid-liquid phase separation process and, thus, constitute a new class of liquid organelles. This is a paradigm shift in the field of virus replication. Here, we review the different aspects of membrane-less virus replication compartments with a focus on the Mononegavirales order and discuss their interactions with the host cell machineries and the cytoskeleton. We particularly examine the interplay between viral factories and the cellular innate immune response, of which several components also form membrane-less condensates in infected cells. Viral factories harbor essential steps of the viral cycle. Some viral factories are devoid of membranes and have liquid organelle properties. Liquid viral factories concentrate cellular factors required for replication. Innate immunity sensors and several ISGs are found in membrane-less condensates. A subtle interplay exists between liquid viral factories and innate immunity actors.
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Affiliation(s)
- Quentin Nevers
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Aurélie A Albertini
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Cécile Lagaudrière-Gesbert
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Yves Gaudin
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette, France.
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Membrane Protein of Human Coronavirus NL63 Is Responsible for Interaction with the Adhesion Receptor. J Virol 2019; 93:JVI.00355-19. [PMID: 31315999 PMCID: PMC6744225 DOI: 10.1128/jvi.00355-19] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 07/12/2019] [Indexed: 12/11/2022] Open
Abstract
It is generally accepted that the coronaviral S protein is responsible for viral interaction with a cellular receptor. Here we show that the M protein is also an important player during early stages of HCoV-NL63 infection and that the concerted action of the two proteins (M and S) is a prerequisite for effective infection. We believe that this study broadens the understanding of HCoV-NL63 biology and may also alter the way in which we perceive the first steps of cell infection with the virus. The data presented here may also be important for future research into vaccine or drug development. Human coronavirus NL63 (HCoV-NL63) is a common respiratory virus that causes moderately severe infections. We have previously shown that the virus uses heparan sulfate proteoglycans (HSPGs) as the initial attachment factors, facilitating viral entry into the cell. In the present study, we show that the membrane protein (M) of HCoV-NL63 mediates this attachment. Using viruslike particles lacking the spike (S) protein, we demonstrate that binding to the cell is not S protein dependent. Furthermore, we mapped the M protein site responsible for the interaction with HSPG and confirmed its relevance using a viable virus. Importantly, in silico analysis of the region responsible for HSPG binding in different clinical isolates and the Amsterdam I strain did not exhibit any signs of cell culture adaptation. IMPORTANCE It is generally accepted that the coronaviral S protein is responsible for viral interaction with a cellular receptor. Here we show that the M protein is also an important player during early stages of HCoV-NL63 infection and that the concerted action of the two proteins (M and S) is a prerequisite for effective infection. We believe that this study broadens the understanding of HCoV-NL63 biology and may also alter the way in which we perceive the first steps of cell infection with the virus. The data presented here may also be important for future research into vaccine or drug development.
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Development and Evaluation of a Multiplexed Immunoassay for Simultaneous Detection of Serum IgG Antibodies to Six Human Coronaviruses. Sci Rep 2019; 9:1390. [PMID: 30718599 PMCID: PMC6362100 DOI: 10.1038/s41598-018-37747-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 12/03/2018] [Indexed: 12/26/2022] Open
Abstract
Known human coronaviruses (hCoV) usually cause mild to moderate upper-respiratory tract illnesses, except SARS-CoV and MERS-CoV, which, in addition to mild illness can also be associated with severe respiratory diseases and high mortality rates. Well-characterized multiplexed serologic assays are needed to aid in rapid detection and surveillance of hCoVs. The present study describes development and evaluation of a multiplexed magnetic microsphere immunoassay (MMIA) to simultaneously detect immunoglobulin G (IgG) antibodies specific for recombinant nucleocapsid proteins (recN) from hCoVs 229E, NL63, OC43, HKU1, SARS-CoV, and MERS-CoV. We used paired human sera to screen for IgG with reactivity against six hCoVs to determine assay sensitivity, specificity and reproducibility. We found no signal interference between monoplex and multiplex assay formats (R2 range = 0.87–0.97). Screening of paired human sera using MMIA, resulted in 92 of 106 (sensitivity: 86%) as positive and 68 of 80 (specificity: 84%) as negative. This study serves as a proof of concept that it is feasible to develop and use a multiplexed microsphere immunoassay as a next generation screening tool for use in large scale seroprevalence studies of hCoVs.
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Development of a Whole-Virus ELISA for Serological Evaluation of Domestic Livestock as Possible Hosts of Human Coronavirus NL63. Viruses 2019; 11:v11010043. [PMID: 30634419 PMCID: PMC6356407 DOI: 10.3390/v11010043] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 12/31/2018] [Accepted: 01/05/2019] [Indexed: 01/17/2023] Open
Abstract
Known human coronaviruses are believed to have originated in animals and made use of intermediate hosts for transmission to humans. The intermediate hosts of most of the human coronaviruses are known, but not for HCoV-NL63. This study aims to assess the possible role of some major domestic livestock species as intermediate hosts of HCoV-NL63. We developed a testing algorithm for high throughput screening of livestock sera with ELISA and confirmation with recombinant immunofluorescence assay testing for antibodies against HCoV-NL63 in livestock. Optimization of the ELISA showed a capability of the assay to significantly distinguish HCoV-NL63 from HCoV-229E (U = 27.50, p < 0.001) and HCoV-OC43 (U = 55.50, p < 0.001) in coronavirus-characterized sera. Evaluation of the assay with collected human samples showed no significant difference in mean optical density values of immunofluorescence-classified HCoV-NL63-positive and HCoV-NL63-negative samples (F (1, 215) = 0.437, p = 0.509). All the top 5% (n = 8) most reactive human samples tested by ELISA were HCoV-NL63 positive by immunofluorescence testing. In comparison, only a proportion (84%, n = 42) of the top 25% were positive by immunofluorescence testing, indicating an increased probability of the highly ELISA reactive samples testing positive by the immunofluorescence assay. None of the top 5% most ELISA reactive livestock samples were positive for HCoV-NL63-related viruses by immunofluorescence confirmation. Ghanaian domestic livestock are not likely intermediate hosts of HCoV-NL63-related coronaviruses.
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Nguyen THV, Lichière J, Canard B, Papageorgiou N, Attoumani S, Ferron F, Coutard B. Structure and oligomerization state of the C-terminal region of the Middle East respiratory syndrome coronavirus nucleoprotein. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2019; 75:8-15. [PMID: 30644840 PMCID: PMC7159728 DOI: 10.1107/s2059798318014948] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 10/22/2018] [Indexed: 12/16/2022]
Abstract
Middle East respiratory syndrome coronavirus (MERS-CoV) is a human pathogen responsible for a severe respiratory illness that emerged in 2012. Structural information about the proteins that constitute the viral particle is scarce. In order to contribute to a better understanding of the nucleoprotein (N) in charge of RNA genome encapsidation, the structure of the C-terminal domain of N from MERS-CoV obtained using single-crystal X-ray diffraction is reported here at 1.97 Å resolution. The molecule is present as a dimer in the crystal structure and this oligomerization state is confirmed in solution, as measured by additional methods including small-angle X-ray scattering measurements. Comparisons with the structures of the C-terminal domains of N from other coronaviruses reveals a high degree of structural conservation despite low sequence conservation, and differences in electrostatic potential at the surface of the protein.
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Affiliation(s)
| | - Julie Lichière
- Aix-Marseille Université, AFMB UMR 7257, 13288 Marseilles, France
| | - Bruno Canard
- Aix-Marseille Université, AFMB UMR 7257, 13288 Marseilles, France
| | | | - Sarah Attoumani
- Aix-Marseille Université, AFMB UMR 7257, 13288 Marseilles, France
| | - François Ferron
- Aix-Marseille Université, AFMB UMR 7257, 13288 Marseilles, France
| | - Bruno Coutard
- Aix-Marseille Université, AFMB UMR 7257, 13288 Marseilles, France
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Milewska A, Kindler E, Vkovski P, Zeglen S, Ochman M, Thiel V, Rajfur Z, Pyrc K. APOBEC3-mediated restriction of RNA virus replication. Sci Rep 2018; 8:5960. [PMID: 29654310 PMCID: PMC5899082 DOI: 10.1038/s41598-018-24448-2] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 04/04/2018] [Indexed: 01/13/2023] Open
Abstract
APOBEC3 family members are cytidine deaminases with roles in intrinsic responses to infection by retroviruses and retrotransposons, and in the control of other DNA viruses, such as herpesviruses, parvoviruses and hepatitis B virus. Although effects of APOBEC3 members on viral DNA have been demonstrated, it is not known whether they edit RNA genomes through cytidine deamination. Here, we investigated APOBEC3-mediated restriction of Coronaviridae. In experiments in vitro, three human APOBEC3 proteins (A3C, A3F and A3H) inhibited HCoV-NL63 infection and limited production of progeny virus, but did not cause hypermutation of the coronaviral genome. APOBEC3-mediated restriction was partially dependent on enzyme activity, and was reduced by the use of enzymatically inactive APOBEC3. Moreover, APOBEC3 proteins bound to the coronaviral nucleoprotein, and this interaction also affected viral replication. Although the precise molecular mechanism of deaminase-dependent inhibition of coronavirus replication remains elusive, our results further our understanding of APOBEC-mediated restriction of RNA virus infections.
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Affiliation(s)
- Aleksandra Milewska
- Microbiology Department, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Krakow, Poland.
- Virogenetics Laboratory of Virology, Malopolska Centre of Biotechnology, Jagiellonian University, Gronostajowa 7a, 30-387, Krakow, Poland.
| | - Eveline Kindler
- Institute for Virology and Immunology, Bern and Mittelhäusern, Bern, Switzerland
- Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Länggassstrasse 122, Bern, Switzerland
| | - Philip Vkovski
- Institute for Virology and Immunology, Bern and Mittelhäusern, Bern, Switzerland
- Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Länggassstrasse 122, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Slawomir Zeglen
- Department of Cardiac Surgery and Transplantology, Silesian Center for Heart Diseases, Marii Curie-Skłodowskiej 9, 41-800, Zabrze, Poland
- Head of Histology Department, Medical Department, University of Opole, Opole, Poland
| | - Marek Ochman
- Department of Pharmacology, School of Medicine with the Division of Dentistry in Zabrze, Medical University of Silesia in Katowice, Katowice, Poland
| | - Volker Thiel
- Institute for Virology and Immunology, Bern and Mittelhäusern, Bern, Switzerland
- Department of Infectious Diseases and Pathobiology, Vetsuisse Faculty, University of Bern, Länggassstrasse 122, Bern, Switzerland
| | - Zenon Rajfur
- Institute of Physics, Faculty of Physics, Astronomy and Applied Computer Sciences, Jagiellonian University, Lojasiewicza 11, 30-348, Krakow, Poland
| | - Krzysztof Pyrc
- Microbiology Department, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Gronostajowa 7, 30-387, Krakow, Poland.
- Virogenetics Laboratory of Virology, Malopolska Centre of Biotechnology, Jagiellonian University, Gronostajowa 7a, 30-387, Krakow, Poland.
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Zhu L, Mou C, Yang X, Lin J, Yang Q. Mitophagy in TGEV infection counteracts oxidative stress and apoptosis. Oncotarget 2017; 7:27122-41. [PMID: 27027356 PMCID: PMC5053637 DOI: 10.18632/oncotarget.8345] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 03/14/2016] [Indexed: 12/14/2022] Open
Abstract
The intestinal epithelial cells contain a large number of mitochondria for persisting absorption and barrier function. Selective autophagy of mitochondria (mitophagy) plays an important role in the quality control of mitochondria and maintenance of cell homeostasis. Transmissible gastroenteritis virus (TGEV) is a porcine enteropathogenic coronavirus which induces malabsorption and lethal watery diarrhea in suckling piglets. The role of mitophagy in the pathological changes caused by TGEV infection is unclear. Here, we report that TGEV induces mitophagy to suppress oxidative stress and apoptosis induced by viral infection in porcine epithelial cells (IPEC-J2). We observe that TGEV infection induce mitochondrial injury, abnormal morphology, complete mitophagy, and without obvious apoptosis after TGEV infection. Meanwhile, TGEV also induces DJ-1 and some antioxidant genes upregulation to suppress oxidative stress induced by viral infection. Furthermore, silencing DJ-1 inhibit mitophagy and increase apoptosis after TGEV infection. In addition, we demonstrate for the first time that viral nucleocapsid protein (N) is located in mitochondria and mitophagosome during virus infection or be expressed alone. Those results provide a novel perspective for further improvement of prevention and treatment in TGEV infection. These results suggest that TGEV infection induce mitophagy to promote cell survival and possibly viral infection.
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Affiliation(s)
- Liqi Zhu
- Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China
| | - Chunxiao Mou
- Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China
| | - Xing Yang
- Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China
| | - Jian Lin
- College of Life Sciences, Nanjing Agricultural University Weigang No.1, Nanjing, Jiangsu, China
| | - Qian Yang
- Key Laboratory of Animal Physiology and Biochemistry, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, Jiangsu, People's Republic of China
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Structural Characterization of Human Coronavirus NL63 N Protein. J Virol 2017; 91:JVI.02503-16. [PMID: 28331093 DOI: 10.1128/jvi.02503-16] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 02/07/2017] [Indexed: 11/20/2022] Open
Abstract
Coronaviruses are responsible for upper and lower respiratory tract infections in humans. It is estimated that 1 to 10% of the population suffers annually from cold-like symptoms related to infection with human coronavirus NL63 (HCoV-NL63), an alphacoronavirus. The nucleocapsid (N) protein, the major structural component of the capsid, facilitates RNA packing, links the capsid to the envelope, and is also involved in multiple other processes, including viral replication and evasion of the immune system. Although the role of N protein in viral replication is relatively well described, no structural data are currently available regarding the N proteins of alphacoronaviruses. Moreover, our understanding of the mechanisms of RNA binding and nucleocapsid formation remains incomplete. In this study, we solved the crystal structures of the N- and C-terminal domains (NTD, residues 10 to 140, and CTD, residues 221 to 340, respectively) of the N protein of HCoV-NL63, both at a 1.5-Å resolution. Based on our structure of NTD solved here, we proposed and experimentally evaluated a model of RNA binding. The structure of the CTD reveals the mode of N protein dimerization. Overall, this study expands our understanding of the initial steps of N protein-nucleic acid interaction and may facilitate future efforts to control the associated infections.IMPORTANCE Coronaviruses are responsible for the common cold and other respiratory tract infections in humans. According to multiple studies, 1 to 10% of the population is infected each year with HCoV-NL63. Viruses are relatively simple organisms composed of a few proteins and the nucleic acids that carry the information determining their composition. The nucleocapsid (N) protein studied in this work protects the nucleic acid from the environmental factors during virus transmission. This study investigated the structural arrangement of N protein, explaining the first steps of its interaction with nucleic acid at the initial stages of virus structure assembly. The results expand our understanding of coronavirus physiology and may facilitate future efforts to control the associated infections.
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