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Russell T, Lozano JM, Challinor C, Barry G. Diversifying selection identified in immune epitopes of bovine coronavirus isolates from Irish cattle. J Gen Virol 2024; 105:002019. [PMID: 39158563 PMCID: PMC11333106 DOI: 10.1099/jgv.0.002019] [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: 02/07/2024] [Accepted: 08/07/2024] [Indexed: 08/20/2024] Open
Abstract
Bovine betacoronavirus (BoCoV) is a pneumoenteric pathogen of cattle that is closely related to human coronavirus OC43. Vaccines are administered to protect against diseases caused by BoCoV, but knowledge gaps exist with regard to correlates of protection and the effect of immune evasion on driving evolution. In this study, immune epitopes were mapped onto BoCoV structural proteins, including spike and haemagglutinin esterase (HE), and then supported with targeted gene sequencing of Irish clinical isolates and selective pressure analysis. Increased prevalence of diversifying selection and amino acid changes in some mapped immune epitopes suggests that immune escape is selecting for non-synonymous mutations arising in these regions. Selection analysis and sequencing provided increased support for neutralising antibody (nAb) epitopes compared to others, suggesting that nAbs are an important arm of the immune response to BoCoV. Phylogenetic analysis of spike and HE sequences showed that Irish isolates from this study were in the European clade, except for one HE sequence that sat in the Asian/American clade, while the spike gene of this sample was in the European clade. Recombination between a European and an Asian/American isolate would give rise to such a sequence. This study has gathered evidence suggesting that pressure to evade the nAb response is contributing to BoCoV evolution.
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Affiliation(s)
- Tristan Russell
- UCD School of Veterinary Medicine, University College Dublin, Dublin, Ireland
- Centre for Experimental Pathogen Host Research (CEPHR), University College Dublin, Dublin, Dublin 4, Ireland
| | - Jose Maria Lozano
- Department of Agriculture, Food and the Marine, Central Veterinary Research Laboratory, Celbridge, Ireland
| | - Cailyn Challinor
- UCD School of Veterinary Medicine, University College Dublin, Dublin, Ireland
| | - Gerald Barry
- UCD School of Veterinary Medicine, University College Dublin, Dublin, Ireland
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2
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Kim MI, Lee C. Human Coronavirus OC43 as a Low-Risk Model to Study COVID-19. Viruses 2023; 15:v15020578. [PMID: 36851792 PMCID: PMC9965565 DOI: 10.3390/v15020578] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 02/08/2023] [Accepted: 02/16/2023] [Indexed: 02/22/2023] Open
Abstract
The coronavirus disease 2019 (COVID-19) pandemic has had irreversible and devastating impacts on every aspect of human life. To better prepare for the next similar pandemic, a clear understanding of coronavirus biology is a prerequisite. Nevertheless, the high-risk nature of the causative agent of COVID-19, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), requires the use of a cumbersome biosafety level-3 (BSL-3) confinement facility. To facilitate the development of preventive and therapeutic measures against SARS-CoV-2, one of the endemic strains of low-risk coronaviruses has gained attention as a useful research alternative: human coronavirus OC43 (HCoV-OC43). In this review, its history, classification, and clinical manifestations are first summarized. The characteristics of its viral genomes, genes, and evolution process are then further explained. In addition, the host factors necessary to support the life cycle of HCoV-OC43 and the innate, as well as adaptive, immunological responses to HCoV-OC43 infection are discussed. Finally, the development of in vitro and in vivo systems to study HCoV-OC43 and its application to the discovery of potential antivirals for COVID-19 by using HCoV-OC43 models are also presented. This review should serve as a concise guide for those who wish to use HCoV-OC43 to study coronaviruses in a low-risk research setting.
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Aamelfot M, Fosse JH, Viljugrein H, Ploss FB, Benestad SL, McBeath A, Christiansen DH, Garver K, Falk K. Destruction of the vascular viral receptor in infectious salmon anaemia provides in vivo evidence of homologous attachment interference. PLoS Pathog 2022; 18:e1010905. [PMID: 36240255 PMCID: PMC9621750 DOI: 10.1371/journal.ppat.1010905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 10/31/2022] [Accepted: 10/01/2022] [Indexed: 11/06/2022] Open
Abstract
Viral interference is a process where infection with one virus prevents a subsequent infection with the same or a different virus. This is believed to limit superinfection, promote viral genome stability, and protect the host from overwhelming infection. Mechanisms of viral interference have been extensively studied in plants, but remain poorly understood in vertebrates. We demonstrate that infection with infectious salmon anaemia virus (ISAV) strongly reduces homologous viral attachment to the Atlantic salmon, Salmo salar L. vascular surface. A generalised loss of ISAV binding was observed after infection with both high-virulent and low-virulent ISAV isolates, but with different kinetics. The loss of ISAV binding was accompanied by an increased susceptibility to sialidase, suggesting a loss of the vascular 4-O-sialyl-acetylation that mediates ISAV attachment and simultaneously protects the sialic acid from cleavage. Moreover, the ISAV binding capacity of cultured cells dramatically declined 3 days after ISAV infection, accompanied by reduced cellular permissiveness to infection with a second antigenically distinct isolate. In contrast, neither infection with infectious haematopoietic necrosis virus nor stimulation with the viral mimetic poly I:C restricted subsequent cellular ISAV attachment, revealing an ISAV-specific mechanism rather than a general cellular antiviral response. Our study demonstrates homologous ISAV attachment interference by de-acetylation of sialic acids on the vascular surface. This is the first time the kinetics of viral receptor destruction have been mapped throughout the full course of an infection, and the first report of homologous attachment interference by the loss of a vascular viral receptor. Little is known about the biological functions of vascular O-sialyl-acetylation. Our findings raise the question of whether this vascular surface modulation could be linked to the breakdown of central vascular functions that characterises infectious salmon anaemia. Viral interference, also referred to as superinfection exclusion, is a process that supports viral genome integrity and protects the host from overwhelming infection. Here, we demonstrate that infection of Atlantic salmon with infectious salmon anaemia virus (ISAV) results in the destruction of the viral vascular surface receptor, thus preventing virus attachment. We also observed that the loss of viral receptor strongly restricted the extent of a second ISAV infection in cultured cells, suggesting viral interference. To our knowledge, this is the first time the kinetics of viral receptor destruction has been explored in an infected host. This is important, because we know little of how such responses develop in animals and humans. Our study therefore improves the general understanding of how viral infections progress. Finally, our findings raise the question of whether modulation of the vascular surface by ISAV and other viruses may contribute to the pathogenesis of viral disease.
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Affiliation(s)
| | | | | | | | | | | | | | - Kyle Garver
- Fisheries and Oceans Canada Pacific Biological Station, Nanaimo, British Columbia, Canada
| | - Knut Falk
- Norwegian Veterinary Institute, Ås, Norway
- * E-mail:
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4
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Thoner TW, Meloy MM, Long JM, Diller JR, Slaughter JC, Ogden KM. Reovirus Efficiently Reassorts Genome Segments during Coinfection and Superinfection. J Virol 2022; 96:e0091022. [PMID: 36094315 PMCID: PMC9517712 DOI: 10.1128/jvi.00910-22] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 08/21/2022] [Indexed: 11/20/2022] Open
Abstract
Reassortment, or genome segment exchange, increases diversity among viruses with segmented genomes. Previous studies on the limitations of reassortment have largely focused on parental incompatibilities that restrict generation of viable progeny. However, less is known about whether factors intrinsic to virus replication influence reassortment. Mammalian orthoreovirus (reovirus) encapsidates a segmented, double-stranded RNA (dsRNA) genome, replicates within cytoplasmic factories, and is susceptible to host antiviral responses. We sought to elucidate the influence of infection multiplicity, timing, and compartmentalized replication on reovirus reassortment in the absence of parental incompatibilities. We used an established post-PCR genotyping method to quantify reassortment frequency between wild-type and genetically barcoded type 3 reoviruses. Consistent with published findings, we found that reassortment increased with infection multiplicity until reaching a peak of efficient genome segment exchange during simultaneous coinfection. However, reassortment frequency exhibited a substantial decease with increasing time to superinfection, which strongly correlated with viral transcript abundance. We hypothesized that physical sequestration of viral transcripts within distinct virus factories or superinfection exclusion also could influence reassortment frequency during superinfection. Imaging revealed that transcripts from both wild-type and barcoded viruses frequently co-occupied factories, with superinfection time delays up to 16 h. Additionally, primary infection progressively dampened superinfecting virus transcript levels with greater time delay to superinfection. Thus, in the absence of parental incompatibilities and with short times to superinfection, reovirus reassortment proceeds efficiently and is largely unaffected by compartmentalization of replication and superinfection exclusion. However, reassortment may be limited by superinfection exclusion with greater time delays to superinfection. IMPORTANCE Reassortment, or genome segment exchange between viruses, can generate novel virus genotypes and pandemic virus strains. For viruses to reassort their genome segments, they must replicate within the same physical space by coinfecting the same host cell. Even after entry into the host cell, many viruses with segmented genomes synthesize new virus transcripts and assemble and package their genomes within cytoplasmic replication compartments. Additionally, some viruses can interfere with subsequent infection of the same host or cell. However, spatial and temporal influences on reassortment are only beginning to be explored. We found that infection multiplicity and transcript abundance are important drivers of reassortment during coinfection and superinfection, respectively, for reovirus, which has a segmented, double-stranded RNA genome. We also provide evidence that compartmentalization of transcription and packaging is unlikely to influence reassortment, but the length of time between primary and subsequent reovirus infection can alter reassortment frequency.
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Affiliation(s)
- Timothy W. Thoner
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Madeline M. Meloy
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Jacob M. Long
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Julia R. Diller
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - James C. Slaughter
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Kristen M. Ogden
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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5
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Eriani G, Martin F. Viral and cellular translation during SARS‐CoV‐2 infection. FEBS Open Bio 2022; 12:1584-1601. [PMID: 35429230 PMCID: PMC9110871 DOI: 10.1002/2211-5463.13413] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 03/30/2022] [Accepted: 04/14/2022] [Indexed: 11/16/2022] Open
Abstract
SARS‐CoV‐2 is a betacoronavirus that emerged in China in December 2019 and which is the causative agent of the Covid‐19 pandemic. This enveloped virus contains a large positive‐sense single‐stranded RNA genome. In this review, we summarize the current knowledge on the molecular mechanisms for the translation of both viral transcripts and cellular messenger RNAs. Non‐structural proteins are encoded by the genomic RNA and are produced in the early steps of infection. In contrast, the structural proteins are produced from subgenomic RNAs that are translated in the late phase of the infectious program. Non‐structural protein 1 (NSP1) is a key molecule that regulates both viral and cellular translation. In addition, NSP1 interferes with multiple steps of the interferon I pathway and thereby blocks host antiviral responses. Therefore, NSP1 is a drug target of choice for the development of antiviral therapies.
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Affiliation(s)
- Gilbert Eriani
- Université de Strasbourg Institut de Biologie Moléculaire et Cellulaire Architecture et Réactivité de l’ARN CNRS UPR9002 2, allée Konrad Roentgen F‐67084 Strasbourg France
| | - Franck Martin
- Université de Strasbourg Institut de Biologie Moléculaire et Cellulaire Architecture et Réactivité de l’ARN CNRS UPR9002 2, allée Konrad Roentgen F‐67084 Strasbourg France
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6
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Bartak M, Słońska A, Bańbura MW, Cymerys J. SDAV, the Rat Coronavirus-How Much Do We Know about It in the Light of Potential Zoonoses. Viruses 2021; 13:1995. [PMID: 34696425 PMCID: PMC8537196 DOI: 10.3390/v13101995] [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: 08/25/2021] [Revised: 09/30/2021] [Accepted: 10/01/2021] [Indexed: 12/11/2022] Open
Abstract
Sialodacryoadenitis virus (SDAV) is known to be an etiological agent, causing infections in laboratory rats. Until now, its role has only been considered in studies on respiratory and salivary gland infections. The scant literature data, consisting mainly of papers from the last century, do not sufficiently address the topic of SDAV infections. The ongoing pandemic has demonstrated, once again, the role of the Coronaviridae family as extremely dangerous etiological agents of human zoonoses. The ability of coronaviruses to cross the species barrier and change to hosts commonly found in close proximity to humans highlights the need to characterize SDAV infections. The main host of the infection is the rat, as mentioned above. Rats inhabit large urban agglomerations, carrying a vast epidemic threat. Of the 2277 existing rodent species, 217 are reservoirs for 66 zoonotic diseases caused by viruses, bacteria, fungi, and protozoa. This review provides insight into the current state of knowledge of SDAV characteristics and its likely zoonotic potential.
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Affiliation(s)
- Michalina Bartak
- Division of Microbiology, Department of Preclinical Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences—SGGW, Ciszewskiego 8, 02-786 Warsaw, Poland; (A.S.); (M.W.B.)
| | | | | | - Joanna Cymerys
- Division of Microbiology, Department of Preclinical Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences—SGGW, Ciszewskiego 8, 02-786 Warsaw, Poland; (A.S.); (M.W.B.)
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7
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Visser EA, Moons SJ, Timmermans SBPE, de Jong H, Boltje TJ, Büll C. Sialic acid O-acetylation: From biosynthesis to roles in health and disease. J Biol Chem 2021; 297:100906. [PMID: 34157283 PMCID: PMC8319020 DOI: 10.1016/j.jbc.2021.100906] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 06/16/2021] [Accepted: 06/18/2021] [Indexed: 02/06/2023] Open
Abstract
Sialic acids are nine-carbon sugars that frequently cap glycans at the cell surface in cells of vertebrates as well as cells of certain types of invertebrates and bacteria. The nine-carbon backbone of sialic acids can undergo extensive enzymatic modification in nature and O-acetylation at the C-4/7/8/9 position in particular is widely observed. In recent years, the detection and analysis of O-acetylated sialic acids have advanced, and sialic acid-specific O-acetyltransferases (SOATs) and O-acetylesterases (SIAEs) that add and remove O-acetyl groups, respectively, have been identified and characterized in mammalian cells, invertebrates, bacteria, and viruses. These advances now allow us to draw a more complete picture of the biosynthetic pathway of the diverse O-acetylated sialic acids to drive the generation of genetically and biochemically engineered model cell lines and organisms with altered expression of O-acetylated sialic acids for dissection of their roles in glycoprotein stability, development, and immune recognition, as well as discovery of novel functions. Furthermore, a growing number of studies associate sialic acid O-acetylation with cancer, autoimmunity, and infection, providing rationale for the development of selective probes and inhibitors of SOATs and SIAEs. Here, we discuss the current insights into the biosynthesis and biological functions of O-acetylated sialic acids and review the evidence linking this modification to disease. Furthermore, we discuss emerging strategies for the design, synthesis, and potential application of unnatural O-acetylated sialic acids and inhibitors of SOATs and SIAEs that may enable therapeutic targeting of this versatile sialic acid modification.
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Affiliation(s)
- Eline A Visser
- Institute for Molecules and Materials, Department of Synthetic Organic Chemistry, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Sam J Moons
- Institute for Molecules and Materials, Department of Synthetic Organic Chemistry, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Suzanne B P E Timmermans
- Institute for Molecules and Materials, Department of Synthetic Organic Chemistry, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Heleen de Jong
- Institute for Molecules and Materials, Department of Synthetic Organic Chemistry, Radboud University Nijmegen, Nijmegen, the Netherlands
| | - Thomas J Boltje
- Institute for Molecules and Materials, Department of Synthetic Organic Chemistry, Radboud University Nijmegen, Nijmegen, the Netherlands.
| | - Christian Büll
- Copenhagen Center for Glycomics, Departments of Cellular and Molecular Medicine, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark; Hubrecht Institute, Utrecht, the Netherlands.
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8
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Colina SE, Serena MS, Echeverría MG, Metz GE. Clinical and molecular aspects of veterinary coronaviruses. Virus Res 2021; 297:198382. [PMID: 33705799 PMCID: PMC7938195 DOI: 10.1016/j.virusres.2021.198382] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 12/20/2020] [Accepted: 03/04/2021] [Indexed: 12/12/2022]
Abstract
Coronaviruses are a large group of RNA viruses that infect a wide range of animal species. The replication strategy of coronaviruses involves recombination and mutation events that lead to the possibility of cross-species transmission. The high plasticity of the viral receptor due to a continuous modification of the host species habitat may be the cause of cross-species transmission that can turn into a threat to other species including the human population. The successive emergence of highly pathogenic coronaviruses such as the Severe Acute Respiratory Syndrome (SARS) in 2003, the Middle East Respiratory Syndrome Coronavirus in 2012, and the recent SARS-CoV-2 has incentivized a number of studies on the molecular basis of the coronavirus and its pathogenesis. The high degree of interrelatedness between humans and wild and domestic animals and the modification of animal habitats by human urbanization, has favored new viral spreads. Hence, knowledge on the main clinical signs of coronavirus infection in the different hosts and the distinctive molecular characteristics of each coronavirus is essential to prevent the emergence of new coronavirus diseases. The coronavirus infections routinely studied in veterinary medicine must be properly recognized and diagnosed not only to prevent animal disease but also to promote public health.
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Affiliation(s)
- Santiago Emanuel Colina
- Virology, Faculty of Veterinary Sciences, National University of La Plata, La Plata, Argentina; CONICET (National Scientific and Technical Research Council), CCT La Plata, Argentina
| | - María Soledad Serena
- Virology, Faculty of Veterinary Sciences, National University of La Plata, La Plata, Argentina; CONICET (National Scientific and Technical Research Council), CCT La Plata, Argentina
| | - María Gabriela Echeverría
- Virology, Faculty of Veterinary Sciences, National University of La Plata, La Plata, Argentina; CONICET (National Scientific and Technical Research Council), CCT La Plata, Argentina
| | - Germán Ernesto Metz
- Virology, Faculty of Veterinary Sciences, National University of La Plata, La Plata, Argentina; CONICET (National Scientific and Technical Research Council), CCT La Plata, Argentina.
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Spadera L, Viola P, Pisani D, Scarpa A, Malanga D, Sorrentino G, Madini E, Laria C, Aragona T, Leopardi G, Maggiore G, Ciriolo M, Boccuto L, Pizzolato R, Abenavoli L, Cassandro C, Ralli M, Cassandro E, Chiarella G. Sudden olfactory loss as an early marker of COVID-19: a nationwide Italian survey. Eur Arch Otorhinolaryngol 2021; 278:247-255. [PMID: 32749606 PMCID: PMC7399588 DOI: 10.1007/s00405-020-06252-9] [Citation(s) in RCA: 13] [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: 05/09/2020] [Accepted: 07/27/2020] [Indexed: 01/29/2023]
Abstract
PURPOSE The presence of many asymptomatic COVID-19 cases may increase the risks of disease dissemination, mainly for physicians. There are numerous reports on the frequent findings of sudden anosmia or hyposmia, before or at the same time of the typical COVID-19 symptoms onset. The aim of this study was to verify the association of olfactory impairment and COVID-19, providing a basis for subsequent research in the field of COVID-19 clinical heterogeneity. METHODS We developed a 15-item online questionnaire on "Sudden Olfactory Loss (SOL) and COVID-19" that was administered during March 2020 to Italian general practitioners registered to a social media group. RESULTS One hundred and eighty responses were received. SOL was identified as a significant sign of infection in COVID-19 patients, mainly aged between 30 and 40 years, even in the absence of other symptoms. SOL was present as an initial symptom in 46.7% of subjects, and in 16.7%, it was the only symptom. Among the COVID-19 confirmed cases, SOL occurred as the only symptom in 19.2% of patients. CONCLUSION SOL could represent a possible early symptom in otherwise asymptomatic COVID-19 subjects. Subjects affected by SOL should be considered as potential COVID-19 cases. LEVEL OF EVIDENCE 4.
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Affiliation(s)
- Lucrezia Spadera
- Otolaryngology, San Leonardo Hospital, Castellammare di Stabia, Naples, Italy
| | - Pasquale Viola
- Unit of Audiology, Department of Experimental and Clinical Medicine, Regional Centre for Cochlear Implants and ENT Diseases, Magna Graecia University, Catanzaro, Italy
| | - Davide Pisani
- Unit of Audiology, Department of Experimental and Clinical Medicine, Regional Centre for Cochlear Implants and ENT Diseases, Magna Graecia University, Catanzaro, Italy
| | - Alfonso Scarpa
- Department of Medicine and Surgery, University of Salerno, Salerno, Italy
| | - Donatella Malanga
- Laboratory of Molecular Oncology, Department of Experimental and Clinical Medicine, Magna Graecia University, Catanzaro, Italy
- Interdepartmental Center of Services (CIS), University Magna Graecia of Catanzaro, Catanzaro, Italy
| | - Gerardo Sorrentino
- Otolaryngology, San Leonardo Hospital, Castellammare di Stabia, Naples, Italy
| | | | - Carla Laria
- Unit of Audiology, Department of Neurosciences, Reproductives and Odontostomatologic Sciences, University of Naples “Federico II”, Naples, Italy
| | | | | | | | - Marco Ciriolo
- Unit of Audiology, Department of Experimental and Clinical Medicine, Regional Centre for Cochlear Implants and ENT Diseases, Magna Graecia University, Catanzaro, Italy
| | - Luigi Boccuto
- Greenwood Genetic Center, Greenwood, SC USA
- Clemson University, Clemson, SC USA
| | - Raffaella Pizzolato
- Department of Neurology, University of Massachusetts, Medical School, Worcester, MA USA
| | - Ludovico Abenavoli
- Department of Health Sciences, University Magna Graecia, Catanzaro, Italy
| | | | - Massimo Ralli
- Department of Sense Organs, Sapienza University of Rome, Rome, Italy
| | - Ettore Cassandro
- Department of Medicine and Surgery, University of Salerno, Salerno, Italy
| | - Giuseppe Chiarella
- Unit of Audiology, Department of Experimental and Clinical Medicine, Regional Centre for Cochlear Implants and ENT Diseases, Magna Graecia University, Catanzaro, Italy
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10
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Engin AB, Engin ED, Engin A. Dual function of sialic acid in gastrointestinal SARS-CoV-2 infection. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2020; 79:103436. [PMID: 32562764 PMCID: PMC7833001 DOI: 10.1016/j.etap.2020.103436] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 06/15/2020] [Indexed: 05/11/2023]
Abstract
Recent analysis concerning the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)- angiotensin converting enzyme (ACE) receptor interaction in enterocytes, the definition of gut-lung axis, as well as the molecular basis of sialic acid-related dual recognition concept in gastrointestinal SARS-CoV-2 infection, have brought a new perspective to potential therapeutic targets. In this review evolving research and clinical data on gastrointestinal SARS-CoV-2 infection are discussed in the context of viral fusion and entry mechanisms, focusing on the different triggers used by coronaviruses. Furthermore, it is emphasized that the viral spike protein is prevented from binding gangliosides, which are composed of a glycosphingolipid with one or more sialic acids, in the presence of chloroquine or hydroxychloroquine. In gastrointestinal SARS-CoV-2 infection the efficiency of these repositioned drugs is debated.
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Affiliation(s)
- Ayse Basak Engin
- Gazi University, Faculty of Pharmacy, Department of Toxicology, Ankara, Turkey.
| | - Evren Doruk Engin
- Ankara University, Biotechnology Institute, Gumusdere Campus, Kecioren, Ankara, Turkey
| | - Atilla Engin
- Gazi University, Faculty of Medicine, Department of General Surgery, Ankara, Turkey
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11
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Coronavirus hemagglutinin-esterase and spike proteins coevolve for functional balance and optimal virion avidity. Proc Natl Acad Sci U S A 2020; 117:25759-25770. [PMID: 32994342 DOI: 10.1073/pnas.2006299117] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Human coronaviruses OC43 and HKU1 are respiratory pathogens of zoonotic origin that have gained worldwide distribution. OC43 apparently emerged from a bovine coronavirus (BCoV) spillover. All three viruses attach to 9-O-acetylated sialoglycans via spike protein S with hemagglutinin-esterase (HE) acting as a receptor-destroying enzyme. In BCoV, an HE lectin domain promotes esterase activity toward clustered substrates. OC43 and HKU1, however, lost HE lectin function as an adaptation to humans. Replaying OC43 evolution, we knocked out BCoV HE lectin function and performed forced evolution-population dynamics analysis. Loss of HE receptor binding selected for second-site mutations in S, decreasing S binding affinity by orders of magnitude. Irreversible HE mutations led to cooperativity in virus swarms with low-affinity S minority variants sustaining propagation of high-affinity majority phenotypes. Salvageable HE mutations induced successive second-site substitutions in both S and HE. Apparently, S and HE are functionally interdependent and coevolve to optimize the balance between attachment and release. This mechanism of glycan-based receptor usage, entailing a concerted, fine-tuned activity of two envelope protein species, is unique among CoVs, but reminiscent of that of influenza A viruses. Apparently, general principles fundamental to virion-sialoglycan interactions prompted convergent evolution of two important groups of human and animal pathogens.
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12
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Llanes A, Restrepo CM, Caballero Z, Rajeev S, Kennedy MA, Lleonart R. Betacoronavirus Genomes: How Genomic Information has been Used to Deal with Past Outbreaks and the COVID-19 Pandemic. Int J Mol Sci 2020; 21:E4546. [PMID: 32604724 PMCID: PMC7352669 DOI: 10.3390/ijms21124546] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 06/22/2020] [Accepted: 06/23/2020] [Indexed: 12/22/2022] Open
Abstract
In the 21st century, three highly pathogenic betacoronaviruses have emerged, with an alarming rate of human morbidity and case fatality. Genomic information has been widely used to understand the pathogenesis, animal origin and mode of transmission of coronaviruses in the aftermath of the 2002-2003 severe acute respiratory syndrome (SARS) and 2012 Middle East respiratory syndrome (MERS) outbreaks. Furthermore, genome sequencing and bioinformatic analysis have had an unprecedented relevance in the battle against the 2019-2020 coronavirus disease 2019 (COVID-19) pandemic, the newest and most devastating outbreak caused by a coronavirus in the history of mankind. Here, we review how genomic information has been used to tackle outbreaks caused by emerging, highly pathogenic, betacoronavirus strains, emphasizing on SARS-CoV, MERS-CoV and SARS-CoV-2. We focus on shared genomic features of the betacoronaviruses and the application of genomic information to phylogenetic analysis, molecular epidemiology and the design of diagnostic systems, potential drugs and vaccine candidates.
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Affiliation(s)
- Alejandro Llanes
- Centro de Biología Celular y Molecular de Enfermedades, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Panama City 0801, Panama; (A.L.); (C.M.R.); (Z.C.)
| | - Carlos M. Restrepo
- Centro de Biología Celular y Molecular de Enfermedades, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Panama City 0801, Panama; (A.L.); (C.M.R.); (Z.C.)
| | - Zuleima Caballero
- Centro de Biología Celular y Molecular de Enfermedades, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Panama City 0801, Panama; (A.L.); (C.M.R.); (Z.C.)
| | - Sreekumari Rajeev
- College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA;
| | - Melissa A. Kennedy
- College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996, USA;
| | - Ricardo Lleonart
- Centro de Biología Celular y Molecular de Enfermedades, Instituto de Investigaciones Científicas y Servicios de Alta Tecnología (INDICASAT AIP), Panama City 0801, Panama; (A.L.); (C.M.R.); (Z.C.)
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13
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Robson B. Bioinformatics studies on a function of the SARS-CoV-2 spike glycoprotein as the binding of host sialic acid glycans. Comput Biol Med 2020; 122:103849. [PMID: 32658736 PMCID: PMC7278709 DOI: 10.1016/j.compbiomed.2020.103849] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 06/04/2020] [Accepted: 06/04/2020] [Indexed: 02/08/2023]
Abstract
SARS-CoV and SARS-CoV-2 do not appear to have functions of a hemagglutinin and neuraminidase. This is a mystery, because sugar binding activities appear essential to many other viruses including influenza and even most other coronaviruses in order to bind to and escape from the glycans (sugars, oligosaccharides or polysaccharides) characteristic of cell surfaces and saliva and mucin. The S1 N terminal Domains (S1-NTD) of the spike protein, largely responsible for the bulk of the characteristic knobs at the end of the spikes of SARS-CoV and SARS-CoV-2, are here predicted to be “hiding” sites for recognizing and binding glycans containing sialic acid. This may be important for infection and the ability of the virus to locate ACE2 as its known main host cell surface receptor, and if so it becomes a pharmaceutical target. It might even open up the possibility of an alternative receptor to ACE2. The prediction method developed, which uses amino acid residue sequence alone to predict domains or proteins that bind to sialic acids, is naïve, and will be advanced in future work. Nonetheless, it was surprising that such a very simple approach was so useful, and it can easily be reproduced in a very few lines of computer program to help make quick comparisons between SARS-CoV-2 sequences and to consider the effects of viral mutations. This paper extends the studies of the author's previous SARS-CoV-2 papers. Designing vaccine and drugs must seek to avoid escape mutations. Strangely, SARS-CoV and SARS-CoV-2 appear to lack sialic acid binding functions. Sequence motifs are found, but they require a simple prediction method.
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Affiliation(s)
- B Robson
- Ingine Inc. Cleveland Ohio USA and the Dirac Foundation, Oxfordshire, UK.
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14
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Axonal Transport Enables Neuron-to-Neuron Propagation of Human Coronavirus OC43. J Virol 2018; 92:JVI.00404-18. [PMID: 29925652 DOI: 10.1128/jvi.00404-18] [Citation(s) in RCA: 305] [Impact Index Per Article: 50.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 06/08/2018] [Indexed: 02/08/2023] Open
Abstract
Human coronaviruses (HCoVs) are recognized respiratory pathogens for which accumulating evidence indicates that in vulnerable patients the infection can cause more severe pathologies. HCoVs are not always confined to the upper respiratory tract and can invade the central nervous system (CNS) under still unclear circumstances. HCoV-induced neuropathologies in humans are difficult to diagnose early enough to allow therapeutic interventions. Making use of our already described animal model of HCoV neuropathogenesis, we describe the route of neuropropagation from the nasal cavity to the olfactory bulb and piriform cortex and then the brain stem. We identified neuron-to-neuron propagation as one underlying mode of virus spreading in cell culture. Our data demonstrate that both passive diffusion of released viral particles and axonal transport are valid propagation strategies used by the virus. We describe for the first time the presence along axons of viral platforms whose static dynamism is reminiscent of viral assembly sites. We further reveal that HCoV OC43 modes of propagation can be modulated by selected HCoV OC43 proteins and axonal transport. Our work, therefore, identifies processes that may govern the severity and nature of HCoV OC43 neuropathogenesis and will make possible the development of therapeutic strategies to prevent occurrences.IMPORTANCE Coronaviruses may invade the CNS, disseminate, and participate in the induction of neurological diseases. Their neuropathogenicity is being increasingly recognized in humans, and the presence and persistence of human coronaviruses (HCoV) in human brains have been proposed to cause long-term sequelae. Using our mouse model relying on natural susceptibility to HCoV OC43 and neuronal cell cultures, we have defined the most relevant path taken by HCoV OC43 to access and spread to and within the CNS toward the brain stem and spinal cord and studied in cell culture the underlying modes of intercellular propagation to better understand its neuropathogenesis. Our data suggest that axonal transport governs HCoV OC43 egress in the CNS, leading to the exacerbation of neuropathogenesis. Exploiting knowledge on neuroinvasion and dissemination will enhance our ability to control viral infection within the CNS, as it will shed light on underlying mechanisms of neuropathogenesis and uncover potential druggable molecular virus-host interfaces.
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15
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Maginnis MS. Virus-Receptor Interactions: The Key to Cellular Invasion. J Mol Biol 2018; 430:2590-2611. [PMID: 29924965 PMCID: PMC6083867 DOI: 10.1016/j.jmb.2018.06.024] [Citation(s) in RCA: 196] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2018] [Revised: 06/04/2018] [Accepted: 06/08/2018] [Indexed: 11/05/2022]
Abstract
Virus–receptor interactions play a key regulatory role in viral host range, tissue tropism, and viral pathogenesis. Viruses utilize elegant strategies to attach to one or multiple receptors, overcome the plasma membrane barrier, enter, and access the necessary host cell machinery. The viral attachment protein can be viewed as the “key” that unlocks host cells by interacting with the “lock”—the receptor—on the cell surface, and these lock-and-key interactions are critical for viruses to successfully invade host cells. Many common themes have emerged in virus–receptor utilization within and across virus families demonstrating that viruses often target particular classes of molecules in order to mediate these events. Common viral receptors include sialylated glycans, cell adhesion molecules such as immunoglobulin superfamily members and integrins, and phosphatidylserine receptors. The redundancy in receptor usage suggests that viruses target particular receptors or “common locks” to take advantage of their cellular function and also suggests evolutionary conservation. Due to the importance of initial virus interactions with host cells in viral pathogenesis and the redundancy in viral receptor usage, exploitation of these strategies would be an attractive target for new antiviral therapeutics. Viral receptors are key regulators of host range, tissue tropism, and viral pathogenesis. Many viruses utilize common viral receptors including sialic acid, cell adhesion molecules such as immunoglobulin superfamily members and integrins, and phosphatidylserine receptors. Detailed molecular interactions between viruses and receptors have been defined through elegant biochemical analyses including glycan array screens, structural–functional analyses, and cell-based approaches providing tremendous insights into these initial events in viral infection. Commonalities in virus–receptor interactions present promising targets for the development of broad-spectrum antiviral therapies.
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Affiliation(s)
- Melissa S Maginnis
- Department of Molecular and Biomedical Sciences, The University of Maine, Orono, ME 04469-5735, USA.
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16
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Böttcher-Friebertshäuser E, Garten W, Klenk HD. Priming Time: How Cellular Proteases Arm Coronavirus Spike Proteins. ACTIVATION OF VIRUSES BY HOST PROTEASES 2018. [PMCID: PMC7122371 DOI: 10.1007/978-3-319-75474-1_4] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Coronaviruses are enveloped RNA viruses that infect mammals and birds. Infection of humans with globally circulating human coronaviruses is associated with the common cold. In contrast, transmission of animal coronaviruses to humans can result in severe disease: The severe acute respiratory syndrome (SARS) and the Middle East respiratory syndrome (MERS) are responsible for hundreds of deaths in Asia and the Middle East, respectively, and are both caused by members of the genus Betacoronavirus, SARS-CoV, and MERS-CoV that were zoonotically transmitted from an animal host to humans. At present, neither vaccines nor specific treatment is available to combat coronavirus infection in humans, and novel antiviral strategies are urgently sought. The viral spike protein (S) mediates the first essential step in coronavirus infection, viral entry into target cells. For this, the S protein critically depends on priming by host cell proteases, and the responsible enzymes are potential targets for antiviral intervention. Recent studies revealed that the endosomal cysteine protease cathepsin L and the serine proteases furin and TMPRSS2 prime the S proteins of SARS-CoV and MERS-CoV and provided evidence that successive S protein cleavage at two sites is required for S protein priming. Moreover, mechanisms that control protease choice were unraveled, and insights were obtained into which enzyme promotes viral spread in the host. Here, we will provide basic information on S protein function and proteolytic priming, and we will then discuss recent progress in our understanding of the priming of the S proteins of SARS-CoV and MERS-CoV.
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Affiliation(s)
| | - Wolfgang Garten
- Institut für Virologie, Philipps Universität, Marburg, Germany
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17
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Coronavirus receptor switch explained from the stereochemistry of protein-carbohydrate interactions and a single mutation. Proc Natl Acad Sci U S A 2016; 113:E3111-9. [PMID: 27185912 DOI: 10.1073/pnas.1519881113] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Hemagglutinin-esterases (HEs) are bimodular envelope proteins of orthomyxoviruses, toroviruses, and coronaviruses with a carbohydrate-binding "lectin" domain appended to a receptor-destroying sialate-O-acetylesterase ("esterase"). In concert, these domains facilitate dynamic virion attachment to cell-surface sialoglycans. Most HEs (type I) target 9-O-acetylated sialic acids (9-O-Ac-Sias), but one group of coronaviruses switched to using 4-O-Ac-Sias instead (type II). This specificity shift required quasisynchronous adaptations in the Sia-binding sites of both lectin and esterase domains. Previously, a partially disordered crystal structure of a type II HE revealed how the shift in lectin ligand specificity was achieved. How the switch in esterase substrate specificity was realized remained unresolved, however. Here, we present a complete structure of a type II HE with a receptor analog in the catalytic site and identify the mutations underlying the 9-O- to 4-O-Ac-Sia substrate switch. We show that (i) common principles pertaining to the stereochemistry of protein-carbohydrate interactions were at the core of the transition in lectin ligand and esterase substrate specificity; (ii) in consequence, the switch in O-Ac-Sia specificity could be readily accomplished via convergent intramolecular coevolution with only modest architectural changes in lectin and esterase domains; and (iii) a single, inconspicuous Ala-to-Ser substitution in the catalytic site was key to the emergence of the type II HEs. Our findings provide fundamental insights into how proteins "see" sugars and how this affects protein and virus evolution.
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18
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Abstract
Neurotropic strains of the mouse hepatitis virus (MHV) cause a range of diseases in infected mice ranging from mild encephalitis with clearance of the virus followed by demyelination to rapidly fatal encephalitis. This chapter discusses the structure, life cycle, transmission, and pathology of neurotropic coronaviruses, as well as the immune response to coronavirus infection. Mice infected with neurotropic strains of MHV have provided useful systems in which to study processes of virus- and immune-mediated demyelination and virus clearance and/or persistence in the CNS, and the mechanisms of virus evasion of the immune system.
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19
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Baumann AMT, Bakkers MJG, Buettner FFR, Hartmann M, Grove M, Langereis MA, de Groot RJ, Mühlenhoff M. 9-O-Acetylation of sialic acids is catalysed by CASD1 via a covalent acetyl-enzyme intermediate. Nat Commun 2015; 6:7673. [PMID: 26169044 PMCID: PMC4510713 DOI: 10.1038/ncomms8673] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 06/01/2015] [Indexed: 12/13/2022] Open
Abstract
Sialic acids, terminal sugars of glycoproteins and glycolipids, play important roles in development, cellular recognition processes and host–pathogen interactions. A common modification of sialic acids is 9-O-acetylation, which has been implicated in sialoglycan recognition, ganglioside biology, and the survival and drug resistance of acute lymphoblastic leukaemia cells. Despite many functional implications, the molecular basis of 9-O-acetylation has remained elusive thus far. Following cellular approaches, including selective gene knockout by CRISPR/Cas genome editing, we here show that CASD1—a previously identified human candidate gene—is essential for sialic acid 9-O-acetylation. In vitro assays with the purified N-terminal luminal domain of CASD1 demonstrate transfer of acetyl groups from acetyl-coenzyme A to CMP-activated sialic acid and formation of a covalent acetyl-enzyme intermediate. Our study provides direct evidence that CASD1 is a sialate O-acetyltransferase and serves as key enzyme in the biosynthesis of 9-O-acetylated sialoglycans. 9-O-Acetylation is one of the most common modifications of sialic acids, implicated in sialoglycan recognition and ganglioside biology. Here, the authors show that the key enzyme for the biosynthesis of 9-O-acetylated sialoglycans is CASD1, which uses CMP-activated sialic acid as acceptor substrate.![]()
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Affiliation(s)
- Anna-Maria T Baumann
- Institute of Cellular Chemistry, Hannover Medical School, D-30623 Hannover, Germany
| | - Mark J G Bakkers
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Falk F R Buettner
- Institute of Cellular Chemistry, Hannover Medical School, D-30623 Hannover, Germany
| | - Maike Hartmann
- Institute of Cellular Chemistry, Hannover Medical School, D-30623 Hannover, Germany
| | - Melanie Grove
- Institute of Cellular Chemistry, Hannover Medical School, D-30623 Hannover, Germany
| | - Martijn A Langereis
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Raoul J de Groot
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Martina Mühlenhoff
- Institute of Cellular Chemistry, Hannover Medical School, D-30623 Hannover, Germany
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20
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Liu DX, Fung TS, Chong KKL, Shukla A, Hilgenfeld R. Accessory proteins of SARS-CoV and other coronaviruses. Antiviral Res 2014; 109:97-109. [PMID: 24995382 PMCID: PMC7113789 DOI: 10.1016/j.antiviral.2014.06.013] [Citation(s) in RCA: 292] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 06/17/2014] [Accepted: 06/23/2014] [Indexed: 01/21/2023]
Abstract
The huge RNA genome of SARS coronavirus comprises a number of open reading frames that code for a total of eight accessory proteins. Although none of these are essential for virus replication, some appear to have a role in virus pathogenesis. Notably, some SARS-CoV accessory proteins have been shown to modulate the interferon signaling pathways and the production of pro-inflammatory cytokines. The structural information on these proteins is also limited, with only two (p7a and p9b) having their structures determined by X-ray crystallography. This review makes an attempt to summarize the published knowledge on SARS-CoV accessory proteins, with an emphasis on their involvement in virus-host interaction. The accessory proteins of other coronaviruses are also briefly discussed. This paper forms part of a series of invited articles in Antiviral Research on "From SARS to MERS: 10 years of research on highly pathogenic human coronaviruses" (see Introduction by Hilgenfeld and Peiris (2013)).
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Affiliation(s)
- Ding Xiang Liu
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
| | - To Sing Fung
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Kelvin Kian-Long Chong
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Aditi Shukla
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany; German Center for Infection Research (DZIF), University of Lübeck, Germany
| | - Rolf Hilgenfeld
- Institute of Biochemistry, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany; German Center for Infection Research (DZIF), University of Lübeck, Germany
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21
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Interferon induction of IFITM proteins promotes infection by human coronavirus OC43. Proc Natl Acad Sci U S A 2014; 111:6756-61. [PMID: 24753610 DOI: 10.1073/pnas.1320856111] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
IFNs are a family of cytokines that are essential for the antiviral response in vertebrates. Not surprisingly, viruses have adapted to encode virulence factors to cope with the IFN response. Intriguingly, we show here that all three types of interferons, IFN-α, IFN-γ, and IFN-λ, efficiently promote infection by a human coronavirus, HCoV-OC43, one of the major etiological agents of common cold, through the induction of IFN-inducible transmembrane (IFITM) proteins. IFITMs typically exert their antiviral function by inhibiting the entry of a broad spectrum of viruses into their host cells, presumably by trapping and degrading invading virions within the endocytic compartments. In contrast, HCoV-OC43 uses IFN-induced human IFITM2 or IFITM3 as an entry factor to facilitate its infection of host cells. Reverse genetics analyses suggest that the structural motifs critical for the IFITM proteins' enhancement of HCoV-OC43 infection are distinct from those required for inhibiting infection by other viruses. We also present evidence showing that IFITM family members work as homo- and hetero-oligomers to modulate virus entry. The observed enhancement of HCoV-OC43 infection by IFNs may underlie the propensity of the virus to invade the lower respiratory tract under inflammatory conditions.
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22
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Lan Y, Zhao K, Wang G, Dong B, Zhao J, Tang B, Lu H, Gao W, Chang L, Jin Z, Gao F, He W. Porcine hemagglutinating encephalomyelitis virus induces apoptosis in a porcine kidney cell line via caspase-dependent pathways. Virus Res 2013; 176:292-7. [PMID: 23770152 PMCID: PMC7114423 DOI: 10.1016/j.virusres.2013.05.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 05/23/2013] [Accepted: 05/27/2013] [Indexed: 01/17/2023]
Abstract
Porcine hemagglutinating encephalomyelitis is an acute, highly contagious disease in piglets that is caused by the porcine hemagglutinating encephalomyelitis virus (PHEV). However, the pathogenesis of PHEV and the relationship between PHEV and the host cells are not fully understood. In this study, we investigated whether the PHEV-induced cytopathic effect (CPE) was caused by apoptosis. Replication of PHEV in a porcine kidney-derived cell line (PK-15 cells) caused an extensive CPE, leading to the destruction of the entire monolayer and the death of the infected cells. Staining with Hoechst 33,342 revealed morphological changes in the nuclei and chromatin fragmentation. In addition, PHEV caused DNA fragmentation detectable by agarose gel electrophoresis 48h post-infection, increasing with the incubation time. The percentage of apoptotic cells increased with the incubation time and reached a maximum at 96h post-infection, as determined using flow cytometry and fluorescence microscopy of cells that were stained with annexin V-FITC and propidium iodide (PI). Moreover, as is commonly observed for coronavirus infections of other animals, the activities of the effecter caspase, caspase-3, and the initiator caspases, caspase-8 and caspase-9, which are representative factors in the death receptor-mediated apoptotic pathway and the mitochondrial apoptotic pathway, respectively, were increased in PHEV-infected PK-15 cells. Moreover, the tripeptide pan-ICE (caspase) inhibitor Z-VAD-FMK blocked PHEV-induced apoptosis but did not have an effect on virus production by 96h post-infection. These results suggested that PHEV induces apoptosis in PK-15 cells via a caspase-dependent pathway. Apoptotic death of infected cells is detrimental to animals because it causes cell and tissue destruction. Although the pathological characteristics of PHEV are largely unknown, apoptosis may be the pathological basis of the lesions resulting from PHEV infection.
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Affiliation(s)
- Yungang Lan
- Key Laboratory of Zoonosis, Ministry of Education, College of Veterinary Medicine, Jilin University, Changchun 130062, China
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23
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Hoffmann M, Müller MA, Drexler JF, Glende J, Erdt M, Gützkow T, Losemann C, Binger T, Deng H, Schwegmann-Weßels C, Esser KH, Drosten C, Herrler G. Differential sensitivity of bat cells to infection by enveloped RNA viruses: coronaviruses, paramyxoviruses, filoviruses, and influenza viruses. PLoS One 2013; 8:e72942. [PMID: 24023659 PMCID: PMC3758312 DOI: 10.1371/journal.pone.0072942] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 07/16/2013] [Indexed: 11/19/2022] Open
Abstract
Bats (Chiroptera) host major human pathogenic viruses including corona-, paramyxo, rhabdo- and filoviruses. We analyzed six different cell lines from either Yinpterochiroptera (including African flying foxes and a rhinolophid bat) or Yangochiroptera (genera Carollia and Tadarida) for susceptibility to infection by different enveloped RNA viruses. None of the cells were sensitive to infection by transmissible gastroenteritis virus (TGEV), a porcine coronavirus, or to infection mediated by the Spike (S) protein of SARS-coronavirus (SARS-CoV) incorporated into pseudotypes based on vesicular stomatitis virus (VSV). The resistance to infection was overcome if cells were transfected to express the respective cellular receptor, porcine aminopeptidase N for TGEV or angiotensin-converting enzyme 2 for SARS-CoV. VSV pseudotypes containing the S proteins of two bat SARS-related CoV (Bg08 and Rp3) were unable to infect any of the six tested bat cell lines. By contrast, viral pseudotypes containing the surface protein GP of Marburg virus from the family Filoviridae infected all six cell lines though at different efficiency. Notably, all cells were sensitive to infection by two paramyxoviruses (Sendai virus and bovine respiratory syncytial virus) and three influenza viruses from different subtypes. These results indicate that bat cells are more resistant to infection by coronaviruses than to infection by paramyxoviruses, filoviruses and influenza viruses. Furthermore, these results show a receptor-dependent restriction of the infection of bat cells by CoV. The implications for the isolation of coronaviruses from bats are discussed.
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Affiliation(s)
- Markus Hoffmann
- Institute of Virology, University of Veterinary Medicine Hannover, Hannover, Germany
| | | | - Jan Felix Drexler
- Institute of Virology, University of Bonn Medical Centre, Bonn, Germany
| | - Jörg Glende
- Institute of Virology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Meike Erdt
- Institute of Virology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Tim Gützkow
- Institute of Virology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Christoph Losemann
- Institute of Virology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Tabea Binger
- Institute of Virology, University of Bonn Medical Centre, Bonn, Germany
| | - Hongkui Deng
- Department of Cell Biology and Genetics, College of Life Sciences, Peking University, Beijing, P. R. China
| | | | - Karl-Heinz Esser
- Institute of Zoology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Christian Drosten
- Institute of Virology, University of Bonn Medical Centre, Bonn, Germany
| | - Georg Herrler
- Institute of Virology, University of Veterinary Medicine Hannover, Hannover, Germany
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24
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Abstract
Sialic acid linked to glycoproteins and gangliosides is used by many viruses as a receptor for cell entry. These viruses include important human and animal pathogens, such as influenza, parainfluenza, mumps, corona, noro, rota, and DNA tumor viruses. Attachment to sialic acid is mediated by receptor binding proteins that are constituents of viral envelopes or exposed at the surface of non-enveloped viruses. Some of these viruses are also equipped with a neuraminidase or a sialyl-O-acetyl-esterase. These receptor-destroying enzymes promote virus release from infected cells and neutralize sialic acid-containing soluble proteins interfering with cell surface binding of the virus. Variations in the receptor specificity are important determinants for host range, tissue tropism, pathogenicity, and transmissibility of these viruses.
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Affiliation(s)
| | - Philippe Delannoy
- Lille University of Science and Technology, Villeneuve d'Ascq Cedex, France
| | - Mark von Itzstein
- Institute for Glycomics, Griffith University, Southport, Queensland Australia
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25
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The acetyl-esterase activity of the hemagglutinin-esterase protein of human coronavirus OC43 strongly enhances the production of infectious virus. J Virol 2013; 87:3097-107. [PMID: 23283955 DOI: 10.1128/jvi.02699-12] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Most betacoronaviruses possess an hemagglutinin-esterase (HE) protein, which appears to play a role in binding to or release from the target cell. Since this HE protein possesses an acetyl-esterase activity that removes acetyl groups from O-acetylated sialic acid, a role as a receptor-destroying enzyme has been postulated. However, the precise function of HE and of its enzymatic activity remains poorly understood. Making use of neutralizing antibody and of molecular clones of recombinant human coronavirus OC43 (HCoV-OC43), our results suggest that the HE protein of this HCoV could be associated with infection of target cells and, most notably, is important in the production of infectious viral particles. Indeed, after transfecting BHK-21 cells with various cDNA infectious clones of HCoV-OC43, either lacking the HE protein or bearing an HE protein with a nonfunctional acetyl-esterase enzymatic activity, we were reproducibly unable to detect recombinant infectious viruses compared to the reference infectious HCoV-OC43 clone pBAC-OC43(FL). Complementation experiments, using BHK-21 cells expressing wild-type HE, either transiently or in a stable ectopic expression, demonstrate that this protein plays a very significant role in the production of infectious recombinant coronaviral particles that can subsequently more efficiently infect susceptible epithelial and neuronal cells. Even though the S protein is the main viral factor influencing coronavirus infection of susceptible cells, our results taken together indicate that a functionally active HE protein enhances the infectious properties of HCoV-OC43 and contributes to efficient virus dissemination in cell culture.
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26
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Abstract
Sialic acids are a diverse family of monosaccharides widely expressed on all cell surfaces of vertebrates and so-called "higher" invertebrates, and on certain bacteria that interact with vertebrates. This overview surveys examples of biological roles of sialic acids in immunity, with emphasis on an evolutionary perspective. Given the breadth of the subject, the treatment of individual topics is brief. Subjects discussed include biophysical effects regulation of factor H; modulation of leukocyte trafficking via selectins; Siglecs in immune cell activation; sialic acids as ligands for microbes; impact of microbial and endogenous sialidases on immune cell responses; pathogen molecular mimicry of host sialic acids; Siglec recognition of sialylated pathogens; bacteriophage recognition of microbial sialic acids; polysialic acid modulation of immune cells; sialic acids as pathogen decoys or biological masks; modulation of immunity by sialic acid O-acetylation; sialic acids as antigens and xeno-autoantigens; antisialoglycan antibodies in reproductive incompatibility; and sialic-acid-based blood groups.
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Affiliation(s)
- Ajit Varki
- Glycobiology Research and Training Center, Department of Medicine, University of California at San Diego, La Jolla, 92093-0687, USA.
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27
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Abstract
Sialic acids have a pivotal functional impact in many biological interactions such as virus attachment, cellular adhesion, regulation of proliferation, and apoptosis. A common modification of sialic acids is O-acetylation. O-Acetylated sialic acids occur in bacteria and parasites and are also receptor determinants for a number of viruses. Moreover, they have important functions in embryogenesis, development, and immunological processes. O-Acetylated sialic acids represent cancer markers, as shown for acute lymphoblastic leukemia, and they are known to play significant roles in the regulation of ganglioside-mediated apoptosis. Expression of O-acetylated sialoglycans is regulated by sialic acid-specific O-acetyltransferases and O-acetylesterases. Recent developments in the identification of the enigmatic sialic acid-specific O-acetyltransferase are discussed.
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Affiliation(s)
- Chitra Mandal
- Cancer and Cell Biology, Council of Scientific and Industrial Research - Indian Institute of Chemical Biology, 4 Raja S.C. Mallick Road, Kolkata, 700 032 India
| | - Reinhard Schwartz-Albiez
- Department of Translational Immunology, German Cancer Research Center, 69120 Heidelberg, Germany
| | - Reinhard Vlasak
- Department of Molecular Biology, University Salzburg, Billrothstr 11, 5020 Salzburg, Austria
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28
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Abstract
Coronaviruses infect many species of animals including humans, causing acute and chronic diseases. This review focuses primarily on the pathogenesis of murine coronavirus mouse hepatitis virus (MHV) and severe acute respiratory coronavirus (SARS-CoV). MHV is a collection of strains, which provide models systems for the study of viral tropism and pathogenesis in several organs systems, including the central nervous system, the liver, and the lung, and has been cited as providing one of the few animal models for the study of chronic demyelinating diseases such as multiple sclerosis. SARS-CoV emerged in the human population in China in 2002, causing a worldwide epidemic with severe morbidity and high mortality rates, particularly in older individuals. We review the pathogenesis of both viruses and the several reverse genetics systems that made much of these studies possible. We also review the functions of coronavirus proteins, structural, enzymatic, and accessory, with an emphasis on roles in pathogenesis. Structural proteins in addition to their roles in virion structure and morphogenesis also contribute significantly to viral spread in vivo and in antagonizing host cell responses. Nonstructural proteins include the small accessory proteins that are not at all conserved between MHV and SARS-CoV and the 16 conserved proteins encoded in the replicase locus, many of which have enzymatic activities in RNA metabolism or protein processing in addition to functions in antagonizing host response.
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Affiliation(s)
- Susan R Weiss
- Department of Microbiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, USA
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29
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Lan Y, Lu H, Zhao K, He W, Chen K, Wang G, Song D, Gao F. In vitro inhibition of porcine hemagglutinating encephalomyelitis virus replication with siRNAs targeting the spike glycoprotein and replicase polyprotein genes. Intervirology 2011; 55:53-61. [PMID: 21372550 PMCID: PMC7179546 DOI: 10.1159/000323523] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Accepted: 11/24/2010] [Indexed: 12/22/2022] Open
Abstract
Objective The specific effect of RNA interference on the replication of porcine hemagglutinating encephalomyelitis virus (PHE-CoV) was explored. Methods Four species of small interfering RNA (siRNA), targeting different regions of the PHE-CoV spike glycoprotein and replicase polyprotein genes, were prepared by in vitro transcription. After transfection of PK-15 cells with each of the siRNAs followed by infection with PHE-CoV, the cytopathic effect (CPE) was examined by phase-contrast microscope, and viral proliferation within cells was examined by indirect immunofluorescence microscopy, hemagglutination (HA) test, TCID50 assay and real-time RT-PCR. Results Examination of CPE demonstrated that the four siRNAs were capable of protecting cells against PHE-CoV invasion with very high specificity and efficiency. At 48 h post-infection, only a few siRNA-treated cells were positive for viral antigen staining, whereas most untreated virus-infected cells were positive. Transfection with siRNAs also suppressed the production of infectious virus by up to 18- to 32-fold as assessed by a HA test and 93- to 494-fold as assessed by TCID50 assay. Furthermore, treatment with siRNAs caused a 53-91% reduction in the viral genome copy number as assessed by real-time RT-PCR. Conclusion These results suggested that the four species of siRNAs can efficiently inhibit PHE-CoV genome replication and infectious virus production.
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Affiliation(s)
- Yungang Lan
- College of Animal Science and Veterinary Medicine, Jilin University, Changchun, China
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30
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Abstract
Coronaviruses infect many species of animals including humans, causing acute and chronic diseases. This review focuses primarily on the pathogenesis of murine coronavirus mouse hepatitis virus (MHV) and severe acute respiratory coronavirus (SARS-CoV). MHV is a collection of strains, which provide models systems for the study of viral tropism and pathogenesis in several organs systems, including the central nervous system, the liver, and the lung, and has been cited as providing one of the few animal models for the study of chronic demyelinating diseases such as multiple sclerosis. SARS-CoV emerged in the human population in China in 2002, causing a worldwide epidemic with severe morbidity and high mortality rates, particularly in older individuals. We review the pathogenesis of both viruses and the several reverse genetics systems that made much of these studies possible. We also review the functions of coronavirus proteins, structural, enzymatic, and accessory, with an emphasis on roles in pathogenesis. Structural proteins in addition to their roles in virion structure and morphogenesis also contribute significantly to viral spread in vivo and in antagonizing host cell responses. Nonstructural proteins include the small accessory proteins that are not at all conserved between MHV and SARS-CoV and the 16 conserved proteins encoded in the replicase locus, many of which have enzymatic activities in RNA metabolism or protein processing in addition to functions in antagonizing host response.
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Affiliation(s)
- Susan R Weiss
- Department of Microbiology, University of Pennsylvania, Perelman School of Medicine, Philadelphia, USA
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31
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Attachment of mouse hepatitis virus to O-acetylated sialic acid is mediated by hemagglutinin-esterase and not by the spike protein. J Virol 2010; 84:8970-4. [PMID: 20538854 DOI: 10.1128/jvi.00566-10] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The members of Betacoronavirus phylocluster A possess two types of surface projections, one comprised of the spike protein (S) and the other of hemagglutinin-esterase (HE). Purportedly, these viruses bind to O-acetylated sialic acids (O-Ac-Sias) primarily through S, with HE serving merely as receptor-destroying enzyme. Here, we show that, in apparent contrast to human and ungulate host range variants of Betacoronavirus-1, murine coronaviruses actually bind to O-Ac-Sias via HE exclusively. Apparently, expansion of group A betacoronaviruses into new hosts and niches was accompanied by changes in HE ligand and substrate preference and in the roles of HE and S in Sia receptor usage.
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32
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Structural basis for ligand and substrate recognition by torovirus hemagglutinin esterases. Proc Natl Acad Sci U S A 2009; 106:15897-902. [PMID: 19721004 DOI: 10.1073/pnas.0904266106] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Hemagglutinin esterases (HEs), closely related envelope glycoproteins in influenza C and corona- and toroviruses, mediate reversible attachment to O-acetylated sialic acids (Sias). They do so by acting both as lectins and as receptor-destroying enzymes, functions exerted by separate protein domains. HE divergence was accompanied by changes in quaternary structure and in receptor and substrate specificity. The selective forces underlying HE diversity and the molecular basis for Sia specificity are poorly understood. Here we present crystal structures of porcine and bovine torovirus HEs in complex with receptor analogs. Torovirus HEs form homodimers with sialate-O-acetylesterase domains almost identical to corresponding domains in orthomyxo- and coronavirus HEs, but with unique lectin sites. Structure-guided biochemical analysis of the esterase domains revealed that a functionally, but not structurally conserved arginine-Sia carboxylate interaction is critical for the binding and positioning of glycosidically bound Sias in the catalytic pocket. Although essential for efficient de-O-acetylation of Sias, this interaction is not required for catalysis nor does it affect substrate specificity. In fact, the distinct preference of the porcine torovirus enzyme for 9-mono- over 7,9-di-O-acetylated Sias can be explained from a single-residue difference with HEs of more promiscuous specificity. Apparently, esterase and lectin pockets coevolved; also the porcine torovirus HE receptor-binding site seems to have been designed to use 9-mono- and exclude di-O-acetylated Sias, possibly as an adaptation to replication in swine. Our findings shed light on HE evolution and provide fundamental insight into mechanisms of substrate binding, substrate recognition, and receptor selection in this important class of virion proteins.
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33
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Mayr J, Haselhorst T, Langereis MA, Dyason JC, Huber W, Frey B, Vlasak R, de Groot RJ, von Itzstein M. Influenza C virus and bovine coronavirus esterase reveal a similar catalytic mechanism: new insights for drug discovery. Glycoconj J 2008; 25:393-9. [PMID: 18196455 PMCID: PMC7088442 DOI: 10.1007/s10719-007-9094-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2007] [Revised: 10/30/2007] [Accepted: 11/21/2007] [Indexed: 11/04/2022]
Abstract
Both, the influenza C (INF-C) virus haemagglutinin esterase fusion and bovine coronavirus (BCoV) haemagglutinin esterase surface glycoproteins exhibit a lectin binding capability and a receptor-destroying 9-O-acetyl esterase activity that recognise 9-O-acetyl-N-acetylneuraminic acid (Neu5,9Ac(2))-containing glycans. Here we report nuclear magnetic resonance and molecular modelling studies on the 9-O-acetyl esterase showing that the alpha-configured Neu5,9Ac(2) is strictly preferred by the INF-C and BCoV esterases. Interestingly, we have discovered that the INF-C esterase function releases acetate independently of the chemical nature of the aglycon moiety, whereas subtle differences in substrate recognition were found for BCoV esterase. Analysis of the apo and complexed X-ray crystal structure of INF-C esterase revealed that binding of 9-O-acetylated N-acetylneuraminic acids is a dynamic process that involves conformational rearrangement of serine-57 in the esterase active site. This study provides valuable insights towards the design of drugs to combat INF-C virus and coronavirus infections causing outbreaks of upper respiratory infections and severe diarrhea in calves, respectively.
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Affiliation(s)
- Juliane Mayr
- Applied Biotechnology, Department of Cell Biology, University of Salzburg, 5020 Salzburg, Austria
| | - Thomas Haselhorst
- Institute for Glycomics, Gold Coast Campus, Griffith University, Parklands, Queensland 4222 Australia
| | - Martijn A. Langereis
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, the Netherlands
| | - Jeffrey C. Dyason
- Institute for Glycomics, Gold Coast Campus, Griffith University, Parklands, Queensland 4222 Australia
| | - Wolfgang Huber
- Applied Biotechnology, Department of Cell Biology, University of Salzburg, 5020 Salzburg, Austria
| | - Barbara Frey
- Institute for Glycomics, Gold Coast Campus, Griffith University, Parklands, Queensland 4222 Australia
| | - Reinhard Vlasak
- Applied Biotechnology, Department of Cell Biology, University of Salzburg, 5020 Salzburg, Austria
| | - Raoul J. de Groot
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, the Netherlands
| | - Mark von Itzstein
- Institute for Glycomics, Gold Coast Campus, Griffith University, Parklands, Queensland 4222 Australia
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Zeng Q, Langereis MA, van Vliet ALW, Huizinga EG, de Groot RJ. Structure of coronavirus hemagglutinin-esterase offers insight into corona and influenza virus evolution. Proc Natl Acad Sci U S A 2008; 105:9065-9. [PMID: 18550812 PMCID: PMC2449365 DOI: 10.1073/pnas.0800502105] [Citation(s) in RCA: 185] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Indexed: 11/18/2022] Open
Abstract
The hemagglutinin-esterases (HEs) are a family of viral envelope glycoproteins that mediate reversible attachment to O-acetylated sialic acids by acting both as lectins and as receptor-destroying enzymes (RDEs). Related HEs occur in influenza C, toro-, and coronaviruses, apparently as a result of relatively recent lateral gene transfer events. Here, we report the crystal structure of a coronavirus (CoV) HE in complex with its receptor. We show that CoV HE arose from an influenza C-like HE fusion protein (HEF). In the process, HE was transformed from a trimer into a dimer, whereas remnants of the fusion domain were adapted to establish novel monomer-monomer contacts. Whereas the structural design of the RDE-acetylesterase domain remained unaltered, the HE receptor-binding domain underwent remodeling to such extent that the ligand is now bound in opposite orientation. This is surprising, because the architecture of the HEF site was preserved in influenza A HA over a much larger evolutionary distance, a switch in receptor specificity and extensive antigenic variation notwithstanding. Apparently, HA and HEF are under more stringent selective constraints than HE, limiting their exploration of alternative binding-site topologies. We attribute the plasticity of the CoV HE receptor-binding site to evolutionary flexibility conferred by functional redundancy between HE and its companion spike protein S. Our findings offer unique insights into the structural and functional consequences of independent protein evolution after interviral gene exchange and open potential avenues to broad-spectrum antiviral drug design.
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Affiliation(s)
- Qinghong Zeng
- *Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Faculty of Sciences, and
| | - Martijn A. Langereis
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL, Utrecht, The Netherlands
| | - Arno L. W. van Vliet
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL, Utrecht, The Netherlands
| | - Eric G. Huizinga
- *Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Faculty of Sciences, and
| | - Raoul J. de Groot
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL, Utrecht, The Netherlands
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Infection of the tracheal epithelium by infectious bronchitis virus is sialic acid dependent. Microbes Infect 2007; 10:367-73. [PMID: 18396435 PMCID: PMC7110564 DOI: 10.1016/j.micinf.2007.12.009] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2007] [Revised: 12/05/2007] [Accepted: 12/19/2007] [Indexed: 11/25/2022]
Abstract
Avian Infectious bronchitis virus (IBV) is a coronavirus that infects chickens via the respiratory epithelium as primary target cells. The binding of coronaviruses to the cell surface is mediated by the viral surface protein S. Recently we demonstrated that α2,3-linked sialic acid serves as a receptor determinant for IBV on Vero cells and primary chicken embryo kidney cells. Here we analyze the importance of the sialic acid binding activity for the infection of tracheal organ cultures (TOCs) by different IBV strains. Our results show that α2,3-linked sialic acid also serves as a receptor determinant on chicken TOCs. Infection of TOCs by IBV results in ciliostasis. Desialylation induced by neuraminidase treatment of tracheal organ cultures prior to infection by IBV delayed the ciliostatic effect or resulted in partial loss of ciliary activity. This effect was observed with both respiratory and nephropathogenic strains. Inhibition of ciliostasis was also observed when TOCs were pretreated with an α2,3-specific neuraminidase. Analysis of the tracheal epithelium for reactivity with lectins revealed that the susceptible cells in the epithelium abundantly express α2,3-linked sialic acid. These results indicate that α2,3-linked sialic acid plays an important role for infection of the respiratory epithelium by IBV.
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36
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Abstract
Among coronaviruses, several members are able to interact with sialic acids. For bovine coronavirus (BCoV) and related viruses, binding to cell surface components containing
N-acetyl-9-
O-acetylneuraminic acid is essential for initiation of an infection. These viruses resemble influenza C viruses because they share not only the receptor determinant, but also the presence of an acetylesterase that releases the 9-
O-acetyl group from sialic acid and thus abolishes the ability of the respective sialoglycoconjugate to function as a receptor for BCoV. As in the case of influenza viruses, the receptor-destroying enzyme of BCoV is believed to facilitate the spread of virus infection by removing receptor determinants from the surface of infected cells and by preventing the formation of virus aggregates. Another coronavirus, porcine transmissible gastroenteritis virus (TGEV) preferentially recognizes
N-glycolylneuraminic acid. TGEV does not contain a receptor-destroying enzyme and does not depend on the sialic acid binding activity for infection of cultured cells. However, binding to sialic acids is required for the enteropathogenicity of TGEV. Interaction with sialoglycoconjugates may help the virus to pass through the sialic acid-rich mucus layer that covers the viral target cells in the epithelium of the small intestine. We discuss that the BCoV group of viruses may have evolved from a TGEV-like ancestor by acquiring an acetylesterase gene through heterologous recombination.
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Affiliation(s)
- Christel Schwegmann-Weßels
- Institut für Virologie, Stiftung Tierärztliche Hochschule Hannover, Bünteweg 17, 30559 Hannover, Germany
| | - Georg Herrler
- Institut für Virologie, Stiftung Tierärztliche Hochschule Hannover, Bünteweg 17, 30559 Hannover, Germany
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37
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Rinninger A, Richet C, Pons A, Kohla G, Schauer R, Bauer HC, Zanetta JP, Vlasak R. Localisation and distribution of O-acetylated N-acetylneuraminic acids, the endogenous substrates of the hemagglutinin-esterases of murine coronaviruses, in mouse tissue. Glycoconj J 2006; 23:73-84. [PMID: 16575524 PMCID: PMC7088067 DOI: 10.1007/s10719-006-5439-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Infections by mouse hepatitis viruses result in disease of the liver, the gastrointestinal tract, respiratory tract, and the central nervous system. Coronaviruses related to mouse hepatitis virus express a hemagglutinin-esterase surface glycoprotein, which specifically hydrolyses either 5-N-acetyl-4-O-acetyl neuraminic acid (Neu4,5Ac2) or 5-N-acetyl-9-O-acetyl neuraminic acid (Neu5,9Ac2). Moreover, these sialic acids represent potential cellular receptor determinants for murine coronaviruses. Until now, the distribution of these sialic acids in mouse brain was not thoroughly investigated. Particularly Neu4,5Ac2 was not yet found in mouse brain. Using a sensitive method of gas chromatography coupled to mass spectrometry in the electron impact mode of ionization this manuscript demonstrates the occurrence of 13 different sialic acids varying in their alkyl and acyl substituents in mouse tissues including 5-N-acetyl-4-O-acetyl-9-O-lactyl-neuraminic acid (Neu4,5Ac29Lt), 5-N-acetyl-9-O-lactyl-neuraminic acid (Neu5Ac9Lt), 5-N-acetyl-8-O-methyl-neuraminic acid (Neu5Ac8Me) and the 1,7-lactone (Neu5Ac1,7L) of neuraminic acid. Neu4,5Ac2, relatively abundant in the gut, was present as a minor compound in all tissues, including liver, olfactory lobe, telencephalon, metencephalon and hippocampus. Neu5,9Ac2 was also found in these tissues, except in the liver. It is suggested that these sialic acids represent the endogenous substrate and receptor determinants for murine coronaviruses.
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Affiliation(s)
- Andreas Rinninger
- Applied Biotechnology, Departments of Cell Biology and Organismic Biology, University Salzburg, A-5020 Salzburg, Austria
| | | | - Alexandre Pons
- CNRS Unité Mixte de Recherche 8576, Laboratoire de Glycobiologie Structurale et Fonctionnelle, Université des Sciences et Technologies de Lille, Bâtiment C9, 59655 Villeneuve d'Ascq Cedex, France
| | - Guido Kohla
- Biochemisches Institut, Christian-Albrechts-Universität zu Kiel, Olshausenstr. 40, D-24098 Kiel, Germany
| | - Roland Schauer
- Biochemisches Institut, Christian-Albrechts-Universität zu Kiel, Olshausenstr. 40, D-24098 Kiel, Germany
| | - Hans-Christian Bauer
- Applied Biotechnology, Departments of Cell Biology and Organismic Biology, University Salzburg, A-5020 Salzburg, Austria
| | - Jean-Pierre Zanetta
- CNRS Unité Mixte de Recherche 8576, Laboratoire de Glycobiologie Structurale et Fonctionnelle, Université des Sciences et Technologies de Lille, Bâtiment C9, 59655 Villeneuve d'Ascq Cedex, France
| | - Reinhard Vlasak
- Applied Biotechnology, Departments of Cell Biology and Organismic Biology, University Salzburg, A-5020 Salzburg, Austria
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38
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Park SJ, Jeong C, Yoon SS, Choy HE, Saif LJ, Park SH, Kim YJ, Jeong JH, Park SI, Kim HH, Lee BJ, Cho HS, Kim SK, Kang MI, Cho KO. Detection and characterization of bovine coronaviruses in fecal specimens of adult cattle with diarrhea during the warmer seasons. J Clin Microbiol 2006; 44:3178-88. [PMID: 16954245 PMCID: PMC1594715 DOI: 10.1128/jcm.02667-05] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bovine coronavirus (BCoV) is an etiological agent associated with winter dysentery (WD), prevalent in adult cattle during the winter. Although we previously detected, isolated, and characterized BCoV strains from adult cattle with WD (WD-BCoV strains) during the winter in South Korea, the precise epidemiology, as well as the causative agent of diarrhea in adult cattle in the warmer seasons, has not been examined. We examined 184 diarrheic fecal specimens collected from 75 herds of adult cattle from seven provinces during the spring (warm), autumn (warm), and summer (hot) seasons. Bovine coronavirus-positive reactions were detected for 107 (58.2%) diarrheic fecal samples (in 47/75 herds). Of these 107 positive samples, 90 fecal samples from 33 herds tested positive for BCoV alone and 17 fecal samples from 14 herds also tested positive for other pathogens. Biological comparisons between the 9 BCoV strains isolated in this study and the 10 previously isolated WD-BCoV strains revealed that there was no receptor-destroying enzyme (RDE) activity against mouse erythrocytes in the 9 BCoV strains but the 10 WD-BCoV strains had high RDE activity. Phylogenetic analysis of the spike (S) and hemagglutinin/esterase (HE) proteins revealed that all the Korean BCoVs clustered together regardless of season and were distinct from the other known BCoVs, suggesting a distinct evolutionary pathway for the Korean BCoVs. These and previous results revealed a high prevalence and widespread geographical distribution of BCoV, suggesting that this virus is endemic in adult cattle with diarrhea in all seasons in South Korea.
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Affiliation(s)
- Su-Jin Park
- Biotherapy Human Resources Center, College of Veterinary Medicine, Chonnam National University, Gwangju 500-757, South Korea
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Abstract
Coronaviruses are large, enveloped RNA viruses of both medical and veterinary importance. Interest in this viral family has intensified in the past few years as a result of the identification of a newly emerged coronavirus as the causative agent of severe acute respiratory syndrome (SARS). At the molecular level, coronaviruses employ a variety of unusual strategies to accomplish a complex program of gene expression. Coronavirus replication entails ribosome frameshifting during genome translation, the synthesis of both genomic and multiple subgenomic RNA species, and the assembly of progeny virions by a pathway that is unique among enveloped RNA viruses. Progress in the investigation of these processes has been enhanced by the development of reverse genetic systems, an advance that was heretofore obstructed by the enormous size of the coronavirus genome. This review summarizes both classical and contemporary discoveries in the study of the molecular biology of these infectious agents, with particular emphasis on the nature and recognition of viral receptors, viral RNA synthesis, and the molecular interactions governing virion assembly.
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Affiliation(s)
- Paul S Masters
- Wadsworth Center, New York State Department of Health, Albany, 12201, USA
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40
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Winter C, Schwegmann-Weßels C, Cavanagh D, Neumann U, Herrler G. Sialic acid is a receptor determinant for infection of cells by avian Infectious bronchitis virus. J Gen Virol 2006; 87:1209-1216. [PMID: 16603523 DOI: 10.1099/vir.0.81651-0] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The importance of sialic acid for infection by avian Infectious bronchitis virus (IBV) has been analysed. Neuraminidase treatment rendered Vero, baby hamster kidney and primary chicken kidney cells resistant to infection by the IBV-Beaudette strain. Sialic acid-dependent infection was also observed with strain M41 of IBV, which infects primary chicken kidney cells but not cells from other species. In comparison with Influenza A virus and Sendai virus, IBV was most sensitive to pre-treatment of cells with neuraminidase. This finding suggests that IBV requires a greater amount of sialic acid on the cell surface to initiate an infection compared with the other two viruses. In previous studies, with respect to the haemagglutinating activity of IBV, it has been shown that the virus preferentially recognizes α2,3-linked sialic acid. In agreement with this finding, susceptibility to infection by IBV was connected to the expression of α2,3-linked sialic acid as indicated by the reactivity with the lectin Maackia amurensis agglutinin. Here, it is discussed that binding to sialic acid may be used by IBV for primary attachment to the cell surface; tighter binding and subsequent fusion between the viral and the cellular membrane may require interaction with a second receptor.
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Affiliation(s)
- Christine Winter
- Institute for Virology and Clinic for Poultry, University of Veterinary Medicine Hannover, Bünteweg 17, 30559 Hannover, Germany
| | - Christel Schwegmann-Weßels
- Institute for Virology and Clinic for Poultry, University of Veterinary Medicine Hannover, Bünteweg 17, 30559 Hannover, Germany
| | - Dave Cavanagh
- Institute for Animal Health, Division of Microbiology, Compton Laboratory, Compton, Newbury, Berkshire RG20 7NN, UK
| | - Ulrich Neumann
- Institute for Virology and Clinic for Poultry, University of Veterinary Medicine Hannover, Bünteweg 17, 30559 Hannover, Germany
| | - Georg Herrler
- Institute for Virology and Clinic for Poultry, University of Veterinary Medicine Hannover, Bünteweg 17, 30559 Hannover, Germany
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41
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Ko CK, Kang MI, Lim GK, Kim GY, Yoon SS, Park JT, Jeong C, Park SH, Park SJ, Kim YJ, Jeong JH, Kim SK, Park SI, Kim HH, Kim KY, Cho KO. Molecular characterization of HE, M, and E genes of winter dysentery bovine coronavirus circulated in Korea during 2002-2003. Virus Genes 2006; 32:129-36. [PMID: 16604443 PMCID: PMC7089456 DOI: 10.1007/s11262-005-6867-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2005] [Accepted: 07/13/2005] [Indexed: 11/25/2022]
Abstract
The different bovine coronavirus (BCoV) strains or isolates exhibited various degrees of substitutions, resulting in altered antigenicity and pathogenicity of the virus. In the previous our study, we demonstrated that the spike glycoprotein gene of Korean winter dysentery (WD) BCoV had a genetic property of both enteric (EBCV) and respiratory BCoV (RBCV) and were significantly distinct from the ancestral enteric strains. In the present study, therefore, we analyzed the other structure genes, the hemagglutinin/esterase (HE) protein, the transmembrane (M) protein and the small membrane (E) protein to characterize 10 WD BCoV circulated in Korea during 2002-2003 and compared the nucleotide and deduced amino acid sequences with the other known BCoV. Phylogenetic analysis indicated that the HE gene among BCoV could be divided into three groups. The first group included only RBCV, while the second group contained calf diarrhea BCoV, RBCV, WD and EBCV, respectively. The third group possessed only all Korean WD strains which were more homologous to each other and were sharply distinct from the other known BCoV, suggesting Korean WD strains had evolutionary distinct pathway. In contrast, the relative conservation of the M and E proteins of BCoV including Korean WD strains and the other coronaviruses suggested that structural constraints on these proteins are rigid, resulting in more limited evolution of these proteins. In addition, BCoV and human coronavirus HCV-OC43 contained four potential O-glycosylation sites in the M gene. However, the M gene sequence of both BCoV and HCV-OC43 might not contain a signal peptide, suggesting the M protein might be unlikely to be exposed to the O-glycosylation machinery in vivo.
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Affiliation(s)
- Chin-Koo Ko
- Veterinary Medical Research Center, College of Veterinary Medicine, Chonnam National University, Gwangju, South Korea.
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42
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Lissenberg A, Vrolijk MM, van Vliet ALW, Langereis MA, de Groot-Mijnes JDF, Rottier PJM, de Groot RJ. Luxury at a cost? Recombinant mouse hepatitis viruses expressing the accessory hemagglutinin esterase protein display reduced fitness in vitro. J Virol 2006; 79:15054-63. [PMID: 16306576 PMCID: PMC1316008 DOI: 10.1128/jvi.79.24.15054-15063.2005] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Group 2 coronaviruses encode an accessory envelope glycoprotein species, the hemagglutinin esterase (HE), which possesses sialate-O-acetylesterase activity and which, presumably, promotes virus spread and entry in vivo by facilitating reversible virion attachment to O-acetylated sialic acids. While HE may provide a strong selective advantage during natural infection, many laboratory strains of mouse hepatitis virus (MHV) fail to produce the protein. Apparently, their HE genes were inactivated during cell culture adaptation. For this report, we have studied the molecular basis of this phenomenon. By using targeted RNA recombination, we generated isogenic recombinant MHVs which differ exclusively in their expression of HE and produce either the wild-type protein (HE+), an enzymatically inactive HE protein (HE0), or no HE at all. HE expression or the lack thereof did not lead to gross differences in in vitro growth properties. Yet the expression of HE was rapidly lost during serial cell culture passaging. Competition experiments with mixed infections revealed that this was not due to the enzymatic activity: MHVs expressing HE+ or HE0 propagated with equal efficiencies. During the propagation of recombinant MHV-HE+, two types of spontaneous mutants accumulated. One produced an anchorless HE, while the other had a Gly-to-Trp substitution at the predicted C-terminal residue of the HE signal peptide. Neither mutant incorporated HE into virion particles, suggesting that wild-type HE reduces the in vitro propagation efficiency, either at the assembly stage or at a postassembly level. Our findings demonstrate that the expression of "luxury" proteins may come at a fitness penalty. Apparently, under natural conditions the costs of maintaining HE are outweighed by the benefits.
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Affiliation(s)
- A Lissenberg
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands
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43
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Kazi L, Lissenberg A, Watson R, de Groot RJ, Weiss SR. Expression of hemagglutinin esterase protein from recombinant mouse hepatitis virus enhances neurovirulence. J Virol 2006; 79:15064-73. [PMID: 16306577 PMCID: PMC1316009 DOI: 10.1128/jvi.79.24.15064-15073.2005] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Murine hepatitis virus (MHV) infection provides a model system for the study of hepatitis, acute encephalitis, and chronic demyelinating disease. The spike glycoprotein, S, which mediates receptor binding and membrane fusion, plays a critical role in MHV pathogenesis. However, viral proteins other than S also contribute to pathogenicity. The JHM strain of MHV is highly neurovirulent and expresses a second spike glycoprotein, the hemagglutinin esterase (HE), which is not produced by MHV-A59, a hepatotropic but only mildly neurovirulent strain. To investigate a possible role for HE in MHV-induced neurovirulence, isogenic recombinant MHV-A59 viruses were generated that produced either (i) the wild-type protein, (ii) an enzymatically inactive HE protein, or (iii) no HE at all (A. Lissenberg, M. M. Vrolijk, A. L. W. van Vliet, M. A. Langereis, J. D. F. de Groot-Mijnes, P. J. M. Rottier, and R. J. de Groot, J. Virol. 79:15054-15063, 2005 [accompanying paper]). A second, mirror set of recombinant viruses was constructed in which, in addition, the MHV-A59 S gene had been replaced with that from MHV-JHM. The expression of HE in combination with A59 S did not affect the tropism, pathogenicity, or spread of the virus in vivo. However, in combination with JHM S, the expression of HE, regardless of whether it retained esterase activity or not, resulted in increased viral spread within the central nervous system and in increased neurovirulence. Our findings suggest that the properties of S receptor utilization and/or fusogenicity mainly determine organ and host cell tropism but that HE enhances the efficiency of infection and promotes viral dissemination, at least in some tissues, presumably by serving as a second receptor-binding protein.
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Affiliation(s)
- Lubna Kazi
- Department of Microbiology, University of Pennsylvania School of Medicine, 36th Street and Hamilton Walk, Philadelphia, PA 19104-6076, USA
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44
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Weiss SR, Navas-Martin S. Coronavirus pathogenesis and the emerging pathogen severe acute respiratory syndrome coronavirus. Microbiol Mol Biol Rev 2006; 69:635-64. [PMID: 16339739 PMCID: PMC1306801 DOI: 10.1128/mmbr.69.4.635-664.2005] [Citation(s) in RCA: 752] [Impact Index Per Article: 41.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Coronaviruses are a family of enveloped, single-stranded, positive-strand RNA viruses classified within the Nidovirales order. This coronavirus family consists of pathogens of many animal species and of humans, including the recently isolated severe acute respiratory syndrome coronavirus (SARS-CoV). This review is divided into two main parts; the first concerns the animal coronaviruses and their pathogenesis, with an emphasis on the functions of individual viral genes, and the second discusses the newly described human emerging pathogen, SARS-CoV. The coronavirus part covers (i) a description of a group of coronaviruses and the diseases they cause, including the prototype coronavirus, murine hepatitis virus, which is one of the recognized animal models for multiple sclerosis, as well as viruses of veterinary importance that infect the pig, chicken, and cat and a summary of the human viruses; (ii) a short summary of the replication cycle of coronaviruses in cell culture; (iii) the development and application of reverse genetics systems; and (iv) the roles of individual coronavirus proteins in replication and pathogenesis. The SARS-CoV part covers the pathogenesis of SARS, the developing animal models for infection, and the progress in vaccine development and antiviral therapies. The data gathered on the animal coronaviruses continue to be helpful in understanding SARS-CoV.
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Affiliation(s)
- Susan R Weiss
- Department of Microbiology, University of Pennsylvania School of Medicine, 36th Street and Hamilton Walk, Philadelphia, Pennsylvania 19104-6076, USA.
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45
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Abstract
Virus attachment to host cells is mediated by dedicated virion proteins, which specifically recognize one or, at most, a limited number of cell surface molecules. Receptor binding often involves protein-protein interactions, but carbohydrates may serve as receptor determinants as well. In fact, many different viruses use members of the sialic acid family either as their main receptor or as an initial attachment factor. Sialic acids (Sias) are 9-carbon negatively-charged monosaccharides commonly occurring as terminal residues of glycoconjugates. They come in a large variety and are differentially expressed in cells and tissues. By targeting specific Sia subtypes, viruses achieve host cell selectivity, but only to a certain extent. The Sia of choice might still be abundantly present on non-cell associated molecules, on non-target cells (including cells already infected) and even on virus particles themselves. This poses a hazard, as high-affinity virion binding to any of such "false'' receptors would result in loss of infectivity. Some enveloped RNA viruses deal with this problem by encoding virion-associated receptor-destroying enzymes (RDEs). These enzymes make the attachment to Sia reversible, thus providing the virus with an escape ticket. RDEs occur in two types: neuraminidases and sialate-O-acetylesterases. The latter, originally discovered in influenza C virus, are also found in certain nidoviruses, namely in group 2 coronaviruses and in toroviruses, as well as in infectious salmon anemia virus, an orthomyxovirus of teleosts. Here, the structure, function and evolution of viral sialate-O-acetylesterases is reviewed with main focus on the hemagglutinin-esterases of nidoviruses.
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Affiliation(s)
- Raoul J de Groot
- Virology Section, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, The Netherlands.
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46
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Weiss SR, Navas-Martin S. Coronavirus pathogenesis and the emerging pathogen severe acute respiratory syndrome coronavirus. Microbiol Mol Biol Rev 2005. [PMID: 16339739 DOI: 10.1128/mmbr.69.4.635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2023] Open
Abstract
Coronaviruses are a family of enveloped, single-stranded, positive-strand RNA viruses classified within the Nidovirales order. This coronavirus family consists of pathogens of many animal species and of humans, including the recently isolated severe acute respiratory syndrome coronavirus (SARS-CoV). This review is divided into two main parts; the first concerns the animal coronaviruses and their pathogenesis, with an emphasis on the functions of individual viral genes, and the second discusses the newly described human emerging pathogen, SARS-CoV. The coronavirus part covers (i) a description of a group of coronaviruses and the diseases they cause, including the prototype coronavirus, murine hepatitis virus, which is one of the recognized animal models for multiple sclerosis, as well as viruses of veterinary importance that infect the pig, chicken, and cat and a summary of the human viruses; (ii) a short summary of the replication cycle of coronaviruses in cell culture; (iii) the development and application of reverse genetics systems; and (iv) the roles of individual coronavirus proteins in replication and pathogenesis. The SARS-CoV part covers the pathogenesis of SARS, the developing animal models for infection, and the progress in vaccine development and antiviral therapies. The data gathered on the animal coronaviruses continue to be helpful in understanding SARS-CoV.
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Affiliation(s)
- Susan R Weiss
- Department of Microbiology, University of Pennsylvania School of Medicine, 36th Street and Hamilton Walk, Philadelphia, Pennsylvania 19104-6076, USA.
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47
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Woo PCY, Lau SKP, Chu CM, Chan KH, Tsoi HW, Huang Y, Wong BHL, Poon RWS, Cai JJ, Luk WK, Poon LLM, Wong SSY, Guan Y, Peiris JSM, Yuen KY. Characterization and complete genome sequence of a novel coronavirus, coronavirus HKU1, from patients with pneumonia. J Virol 2005; 79:884-95. [PMID: 15613317 PMCID: PMC538593 DOI: 10.1128/jvi.79.2.884-895.2005] [Citation(s) in RCA: 1049] [Impact Index Per Article: 55.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Despite extensive laboratory investigations in patients with respiratory tract infections, no microbiological cause can be identified in a significant proportion of patients. In the past 3 years, several novel respiratory viruses, including human metapneumovirus, severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV), and human coronavirus NL63, were discovered. Here we report the discovery of another novel coronavirus, coronavirus HKU1 (CoV-HKU1), from a 71-year-old man with pneumonia who had just returned from Shenzhen, China. Quantitative reverse transcription-PCR showed that the amount of CoV-HKU1 RNA was 8.5 to 9.6 x 10(6) copies per ml in his nasopharyngeal aspirates (NPAs) during the first week of the illness and dropped progressively to undetectable levels in subsequent weeks. He developed increasing serum levels of specific antibodies against the recombinant nucleocapsid protein of CoV-HKU1, with immunoglobulin M (IgM) titers of 1:20, 1:40, and 1:80 and IgG titers of <1:1,000, 1:2,000, and 1:8,000 in the first, second and fourth weeks of the illness, respectively. Isolation of the virus by using various cell lines, mixed neuron-glia culture, and intracerebral inoculation of suckling mice was unsuccessful. The complete genome sequence of CoV-HKU1 is a 29,926-nucleotide, polyadenylated RNA, with G+C content of 32%, the lowest among all known coronaviruses with available genome sequence. Phylogenetic analysis reveals that CoV-HKU1 is a new group 2 coronavirus. Screening of 400 NPAs, negative for SARS-CoV, from patients with respiratory illness during the SARS period identified the presence of CoV-HKU1 RNA in an additional specimen, with a viral load of 1.13 x 10(6) copies per ml, from a 35-year-old woman with pneumonia. Our data support the existence of a novel group 2 coronavirus associated with pneumonia in humans.
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Affiliation(s)
- Patrick C Y Woo
- Department of Microbiology, The University of Hong Kong, University Pathology Building, Queen Mary Hospital, Hong Kong
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Abstract
This chapter describes the interactions between the different structural components of the viruses and discusses their relevance for the process of virion formation. Two key factors determine the efficiency of the assembly process: intracellular transport and molecular interactions. Many viruses have evolved elaborate strategies to ensure the swift and accurate delivery of the virion components to the cellular compartment(s) where they must meet and form (sub) structures. Assembly of viruses starts in the nucleus by the encapsidation of viral DNA, using cytoplasmically synthesized capsid proteins; nucleocapsids then migrate to the cytosol, by budding at the inner nuclear membrane followed by deenvelopment, to pick up the tegument proteins.
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Affiliation(s)
- Cornelis A M de Haan
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands
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49
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Smits SL, Gerwig GJ, van Vliet ALW, Lissenberg A, Briza P, Kamerling JP, Vlasak R, de Groot RJ. Nidovirus sialate-O-acetylesterases: evolution and substrate specificity of coronaviral and toroviral receptor-destroying enzymes. J Biol Chem 2004; 280:6933-41. [PMID: 15507445 PMCID: PMC8062793 DOI: 10.1074/jbc.m409683200] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Many viruses achieve reversible attachment to sialic acid (Sia) by encoding envelope glycoproteins with receptor-binding and receptor-destroying activities. Toroviruses and group 2 coronaviruses bind to O-acetylated Sias, presumably via their spike proteins (S), whereas other glycoproteins, the hemagglutinin-esterases (HE), destroy Sia receptors by de-O-acetylation. Here, we present a comprehensive study of these enzymes. Sialate-9-O-acetylesterases specific for 5-N-acetyl-9-O-acetylneuraminic acid, described for bovine and human coronaviruses, also occur in equine coronaviruses and in porcine toroviruses. Bovine toroviruses, however, express novel sialate-9-O-acetylesterases, which prefer the di-O-acetylated substrate 5-N-acetyl-7(8),9-di-O-acetylneuraminic acid. Whereas most rodent coronaviruses express sialate-4-O-acetylesterases, the HE of murine coronavirus DVIM cleaves 9-O-acetylated Sias. Under the premise that HE specificity reflects receptor usage, we propose that two types of Sias serve as initial attachment factors for coronaviruses in mice. There are striking parallels between orthomyxo- and nidovirus biology. Reminiscent of antigenic shifts in orthomyxoviruses, rodent coronaviruses exchanged S and HE sequences through recombination to extents not appreciated before. As for orthomyxovirus reassortants, the fitness of nidovirus recombinant offspring probably depends both on antigenic properties and on compatibility of receptor-binding and receptor-destroying activities.
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Affiliation(s)
- Saskia L Smits
- Virology Division, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, The Netherlands
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50
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Falk K, Aspehaug V, Vlasak R, Endresen C. Identification and characterization of viral structural proteins of infectious salmon anemia virus. J Virol 2004; 78:3063-71. [PMID: 14990725 PMCID: PMC353767 DOI: 10.1128/jvi.78.6.3063-3071.2004] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Infectious salmon anemia virus (ISAV) is an unclassified Orthomyxovirus that has been shown to contain a segmented genome with eight single-stranded RNA species coding for 10 viral proteins. Four major structural proteins were characterized in the present study: two glycosylated proteins with estimated molecular masses of 42 and 50 kDa, one 66-kDa phosphoprotein, and one 22-kDa protein. Examination of lysed virions revealed the two glycoproteins and the 22-kDa protein in the soluble fraction, while the 66-kDa phosphoprotein and a minor part of the 22-kDa protein were found in the pelleted fraction. Immunofluorescence staining of infected cells demonstrated that the 22-kDa protein was a late protein accumulating in the nucleus. We conclude that the 66-kDa protein is the nucleoprotein, the 22-kDa protein is the matrix protein, and the 42- and 50-kDa proteins are the surface proteins. Radioimmunoprecipitation analysis of the 42-kDa glycoprotein, which was previously shown to represent the ISAV hemagglutinin, indicated that this protein exists at least as dimers. Further, by labeling of purified ISAV with [1,3-(3)H]diisopropyl fluorophosphate, it was also demonstrated that the viral esterase is located with the hemagglutinin. This finding was confirmed by demonstration of acetylesterase activity in affinity-purified hemagglutinin preparations. Finally, the active-site serine residue could be tentatively identified at position 32 within the amino acid sequence of the hemagglutinin of ISAV strain Glesvaer/2/90. It is proposed that the ISAV vp66 protein be termed nucleoprotein, the gp42 protein be termed HE protein, and the vp22 protein be termed matrix protein.
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Affiliation(s)
- Knut Falk
- Section for Fish Health, National Veterinary Institute, Oslo, Austria.
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