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Virus Association with Gastric Inflammation and Cancer: An Updated Overview. JOURNAL OF MEDICAL MICROBIOLOGY AND INFECTIOUS DISEASES 2022. [DOI: 10.52547/jommid.10.4.163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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2
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Ykema M, Tao YJ. Structural Insights into the Human Astrovirus Capsid. Viruses 2021; 13:v13050821. [PMID: 34062934 PMCID: PMC8147390 DOI: 10.3390/v13050821] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 04/26/2021] [Accepted: 04/28/2021] [Indexed: 12/11/2022] Open
Abstract
Astroviruses (AstVs) are non-enveloped, positive single-stranded RNA viruses that cause a wide range of inflammatory diseases in mammalian and avian hosts. The T = 3 viral capsid is unique in its ability to infect host cells in a process driven by host proteases. Intercellular protease cleavages allow for viral egress from a cell, while extracellular cleavages allow for the virus to enter a new host cell to initiate infection. High-resolution models of the capsid core indicate a large, exposed region enriched with protease cleavage sites. The virus spike protein allows for binding to target cells and is the major target for naturally occurring and engineered neutralizing antibodies. During maturation, the capsid goes through significant structural changes including the loss of many surface spikes. The capsid interacts with host membranes during the virus life cycle at multiple stages such as assembly, host cell entry and exit. This review will cover recent findings and insights related to the structure of the capsid and its function. Further understanding of the viral capsid structure and maturation process can contribute to new vaccines, gastric therapeutics, and viral engineering applications.
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3
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Owusu IA, Quaye O, Passalacqua KD, Wobus CE. Egress of non-enveloped enteric RNA viruses. J Gen Virol 2021; 102:001557. [PMID: 33560198 PMCID: PMC8515858 DOI: 10.1099/jgv.0.001557] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Accepted: 01/04/2021] [Indexed: 12/27/2022] Open
Abstract
A long-standing paradigm in virology was that non-enveloped viruses induce cell lysis to release progeny virions. However, emerging evidence indicates that some non-enveloped viruses exit cells without inducing cell lysis, while others engage both lytic and non-lytic egress mechanisms. Enteric viruses are transmitted via the faecal-oral route and are important causes of a wide range of human infections, both gastrointestinal and extra-intestinal. Virus cellular egress, when fully understood, may be a relevant target for antiviral therapies, which could minimize the public health impact of these infections. In this review, we outline lytic and non-lytic cell egress mechanisms of non-enveloped enteric RNA viruses belonging to five families: Picornaviridae, Reoviridae, Caliciviridae, Astroviridae and Hepeviridae. We discuss factors that contribute to egress mechanisms and the relevance of these mechanisms to virion stability, infectivity and transmission. Since most data were obtained in traditional two-dimensional cell cultures, we will further attempt to place them into the context of polarized cultures and in vivo pathogenesis. Throughout the review, we highlight numerous knowledge gaps to stimulate future research into the egress mechanisms of these highly prevalent but largely understudied viruses.
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Affiliation(s)
- Irene A. Owusu
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109-5620, USA
- West African Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Accra, Ghana
| | - Osbourne Quaye
- West African Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Accra, Ghana
| | - Karla D. Passalacqua
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109-5620, USA
- Henry Ford Health System, Detroit, MI 48202, USA
| | - Christiane E. Wobus
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109-5620, USA
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Perez Gaudio D, Mozo J, Martínez G, Fernández Paggi M, Decundo J, Romanelli A, Dieguez S, Soraci A. Fosfomycin protects intestinal cells from nuclear changes suggestive of deoxynivalenol-induced apoptosis. JOURNAL OF REPORTS IN PHARMACEUTICAL SCIENCES 2020. [DOI: 10.4103/jrptps.jrptps_124_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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5
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Chen Q, Xu X, Yu Z, Sui C, Zuo K, Zhi G, Ji J, Yao L, Kan Y, Bi Y, Xie Q. Characterization and genomic analysis of emerging astroviruses causing fatal gout in goslings. Transbound Emerg Dis 2019; 67:865-876. [PMID: 31680474 DOI: 10.1111/tbed.13410] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 10/21/2019] [Accepted: 10/30/2019] [Indexed: 12/25/2022]
Abstract
Since February 2017, severe outbreaks of fatal gout caused by novel gosling astroviruses (GoAstVs) have occurred in several Chinese provinces, causing a considerable economic impact on the poultry industry. To assess the infection status of GoAstVs causing gout, 165 clinical samples were collected from goslings from seven farms located in different Chinese provinces, and they were screened for viral infection. Seven GoAstV strains were completely sequenced. The positive infection rates of GoAstV, goose parvovirus, reovirus, goose haemorrhagic polyomavirus and Tembusu virus were 100%, 9.69%, 3.64%, 0% and 0%, respectively, indicating the role of GoAstV in gout. The genomes of all seven GoAstV strains were 7170-nt long and encoded three open reading frames (ORFs), namely, ORF1a, ORF1b and ORF2. Sequence and phylogenetic analyses of the seven GoAstV strains showed that these were avastroviruses and were closely related to viruses classified within Avastrovirus 3 and turkey astrovirus 2. Moreover, the mutation rates of ORF1a and ORF2 were high, and ORF1a was highly mutated at amino acid loci 545-580. The tertiary structure of the mutated ORF2 protein was smooth, and its antigenic epitope was highly mutated, which may be related to the pathogenicity of the virus and caused by antibody pressure from the host. These findings enrich our understanding of the evolution of novel GoAstVs causing gout and their circulation as well as lay the foundation for the selection of vaccine strains.
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Affiliation(s)
- Qinxi Chen
- Henan Provincial Engineering Laboratory of Insects Bio-reactor, Henan Provincial Engineering and Technology Center of Health Products for Livestock and Poultry, Nanyang Normal University, Nanyang, China
| | - Xin Xu
- Henan Provincial Engineering Laboratory of Insects Bio-reactor, Henan Provincial Engineering and Technology Center of Health Products for Livestock and Poultry, Nanyang Normal University, Nanyang, China
| | - Zhengli Yu
- Henan Provincial Engineering Laboratory of Insects Bio-reactor, Henan Provincial Engineering and Technology Center of Health Products for Livestock and Poultry, Nanyang Normal University, Nanyang, China
| | - Chaoge Sui
- Henan Provincial Engineering Laboratory of Insects Bio-reactor, Henan Provincial Engineering and Technology Center of Health Products for Livestock and Poultry, Nanyang Normal University, Nanyang, China
| | - Kejing Zuo
- Veterinary Laboratory, Guangzhou Zoo, Guangzhou, China
| | - Guanglin Zhi
- Veterinary Laboratory, Guangzhou Zoo, Guangzhou, China
| | - Jun Ji
- Henan Provincial Engineering Laboratory of Insects Bio-reactor, Henan Provincial Engineering and Technology Center of Health Products for Livestock and Poultry, Nanyang Normal University, Nanyang, China
| | - Lunguang Yao
- Henan Provincial Engineering Laboratory of Insects Bio-reactor, Henan Provincial Engineering and Technology Center of Health Products for Livestock and Poultry, Nanyang Normal University, Nanyang, China
| | - Yunchao Kan
- Henan Provincial Engineering Laboratory of Insects Bio-reactor, Henan Provincial Engineering and Technology Center of Health Products for Livestock and Poultry, Nanyang Normal University, Nanyang, China
| | - Yingzuo Bi
- College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Qingmei Xie
- College of Animal Science, South China Agricultural University, Guangzhou, China
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Zhao W, Tao XL, Liu N, Lu HZ, Zheng CH, Li XY, Yu M, Li YG. Host protein CD63 promotes viral RNA replication by interacting with human astrovirus non-structural protein nsP1a/4. J Gen Virol 2019; 100:616-628. [DOI: 10.1099/jgv.0.001231] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Affiliation(s)
- Wei Zhao
- 1College of Basic Medical Sciences, Jinzhou Medical University, Jinzhou 121200, Liaoning, PR China
- 2Biological Anthropology institute, Jinzhou Medical University, Jinzhou 121200, Liaoning, PR China
| | - Xiao Li Tao
- 1College of Basic Medical Sciences, Jinzhou Medical University, Jinzhou 121200, Liaoning, PR China
| | - Nian Liu
- 1College of Basic Medical Sciences, Jinzhou Medical University, Jinzhou 121200, Liaoning, PR China
- 2Biological Anthropology institute, Jinzhou Medical University, Jinzhou 121200, Liaoning, PR China
| | - Heng Zhang Lu
- 1College of Basic Medical Sciences, Jinzhou Medical University, Jinzhou 121200, Liaoning, PR China
| | - Chun Hong Zheng
- 1College of Basic Medical Sciences, Jinzhou Medical University, Jinzhou 121200, Liaoning, PR China
| | - Xiang Yu Li
- 1College of Basic Medical Sciences, Jinzhou Medical University, Jinzhou 121200, Liaoning, PR China
| | - Man Yu
- 1College of Basic Medical Sciences, Jinzhou Medical University, Jinzhou 121200, Liaoning, PR China
| | - Yong Gang Li
- 1College of Basic Medical Sciences, Jinzhou Medical University, Jinzhou 121200, Liaoning, PR China
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Isobe T, Tange S, Tasaki H, Kanamori K, Kato A, Nakanishi A. Upregulation of CHOP participates in caspase activation and virus release in human astrovirus-infected cells. J Gen Virol 2019; 100:778-792. [PMID: 30912739 DOI: 10.1099/jgv.0.001250] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Human astroviruses (HAstVs), non-enveloped RNA viruses with positive-sense RNA genomes, are an important cause of acute gastroenteritis in young children, although the processes that produce infectious virions are not clearly defined. To track the viral replication complex (RC) upon HAstV1 infection, the subcellular distribution of double-stranded (ds) RNA and of ORF1b, a viral RNA polymerase, was examined by immunocytochemistry. Foci that were positive for dsRNA and for ORF1b were co-localized, and both foci were also co-localized with resident proteins of the endoplasmic reticulum (ER). Focusing on the association between the HAstV RC and ER, we examined the expression of unfolded protein response (UPR) markers and found that targets of eukaryotic translation initiation factor 2α (eIF2α)-activating transcription factor 4 (ATF4), including CCAAT/enhancer-binding protein homologous protein (CHOP), a proapoptotic transcription factor, were upregulated at the late phase in HAstV-infected cells. Consistently, eIF2α was phosphorylated at the late phase of HAstV infection. The formation of foci resembling stress granules, another known downstream response to eIF2α phosphorylation, was also observed at the same period. Phosphorylation of eIF2α was attenuated in protein kinase R (PKR)-knockdown cells, suggesting that, unlike the canonical ER stress response, PKR was involved in eIF2α phosphorylation in response to HAstV infection. Studies have indicated that immature HAstV capsid protein is processed by caspases, and caspase cleavage is integral to particle release. Inhibition of CHOP upregulation reduced caspase activation and the release of HAstV RNA from cells during HAstV infection. Our results suggest that the eIF2α-ATF4-CHOP pathway participates in HAstV propagation.
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Affiliation(s)
- Tomoyasu Isobe
- 1Section of Gene Therapy, Department of Aging Intervention, National Center for Geriatrics and Gerontology, Obu, Aichi, 474-8522, Japan
| | - Shoichiro Tange
- 2Department of Medical Genome Sciences, Research Institute for Frontier Medicine, Sapporo Medical University, Sapporo, 060-8556, Japan
| | | | - Kumiko Kanamori
- 1Section of Gene Therapy, Department of Aging Intervention, National Center for Geriatrics and Gerontology, Obu, Aichi, 474-8522, Japan
| | - Akiko Kato
- 4Laboratory of Radiation Safety, National Center for Geriatrics and Gerontology, Obu, Aichi, 474-8522, Japan
| | - Akira Nakanishi
- 1Section of Gene Therapy, Department of Aging Intervention, National Center for Geriatrics and Gerontology, Obu, Aichi, 474-8522, Japan.,4Laboratory of Radiation Safety, National Center for Geriatrics and Gerontology, Obu, Aichi, 474-8522, Japan
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The Ubiquitin-Proteasome System Is Necessary for Efficient Replication of Human Astrovirus. J Virol 2018; 92:JVI.01809-17. [PMID: 29093085 DOI: 10.1128/jvi.01809-17] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 10/18/2017] [Indexed: 12/25/2022] Open
Abstract
Astroviruses, members of the family Astroviridae, represent an important cause of human gastroenteritis in the world. The cellular factors required for astrovirus replication have been poorly studied. In this work, we evaluated the relevance of the ubiquitin-proteasome system (UPS) in the replication of Yuc8, a human astrovirus serotype 8 strain. We found that proteasome inhibitors decrease the production of infectious viral progeny at a step in the replication cycle subsequent to virus entry. The inhibition of proteasome activity decreases viral RNA levels and viral protein synthesis; similarly, the inhibition of ubiquitination by chemical inhibitors or RNA interference (RNAi) reduces the production of viral progeny as well as viral protein synthesis. The effect on viral progeny production induced by proteasome inhibitors is not explained by a reduction in the pool of monoubiquitin or the induction of early apoptosis or autophagy. Our observations are consistent with the need of the proteolytic activity of the UPS for the efficient replication of the virus and suggest that UPS is necessary for the production of genomic and subgenomic RNA but not for antigenomic RNA.IMPORTANCE Astroviruses are a major cause of gastroenteritis in young humans and animals, and recently, it was associated with fatal encephalitis in humans. The role of the ubiquitin-proteasome system in the replication of these viruses has not been studied previously. In this work, we present evidence that supports that the proteolytic activity of the proteasome is necessary for efficient viral progeny production and that this proteolytic system is required for the accumulation of both genomic and subgenomic viral RNAs.
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Crystal Structure of the Human Astrovirus Capsid Protein. J Virol 2016; 90:9008-17. [PMID: 27466429 PMCID: PMC5044835 DOI: 10.1128/jvi.00694-16] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Accepted: 07/20/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Human astrovirus (HAstV) is a leading cause of viral diarrhea in infants and young children worldwide. HAstV is a nonenveloped virus with a T=3 capsid and a positive-sense RNA genome. The capsid protein (CP) of HAstV is synthesized as a 90-kDa precursor (VP90) that can be divided into three linear domains: a conserved N-terminal domain, a hypervariable domain, and an acidic C-terminal domain. Maturation of HAstV requires proteolytic processing of the astrovirus CP both inside and outside the host cell, resulting in the removal of the C-terminal domain and the breakdown of the rest of the CP into three predominant protein species with molecular masses of ∼34, 27/29, and 25/26 kDa, respectively. We have now solved the crystal structure of VP90(71-415) (amino acids [aa] 71 to 415 of VP90) of human astrovirus serotype 8 at a 2.15-Å resolution. VP90(71-415) encompasses the conserved N-terminal domain of VP90 but lacks the hypervariable domain, which forms the capsid surface spikes. The structure of VP90(71-415) is comprised of two domains: an S domain, which adopts the typical jelly-roll β-barrel fold, and a P1 domain, which forms a squashed β-barrel consisting of six antiparallel β-strands similar to what was observed in the hepatitis E virus (HEV) capsid structure. Fitting of the VP90(71-415) structure into the cryo-electron microscopy (EM) maps of HAstV produced an atomic model for a continuous, T=3 icosahedral capsid shell. Our pseudoatomic model of the human HAstV capsid shell provides valuable insights into intermolecular interactions required for capsid assembly and trypsin-mediated proteolytic maturation needed for virus infectivity. Such information has potential applications in the development of a virus-like particle (VLP) vaccine as well as small-molecule drugs targeting astrovirus assembly/maturation. IMPORTANCE Human astrovirus (HAstV) is a leading cause of viral diarrhea in infants and young children worldwide. As a nonenveloped virus, HAstV exhibits an intriguing feature in that its maturation requires extensive proteolytic processing of the astrovirus capsid protein (CP) both inside and outside the host cell. Mature HAstV contains three predominant protein species, but the mechanism for acquired infectivity upon maturation is unclear. We have solved the crystal structure of VP90(71-415) of human astrovirus serotype 8. VP90(71-415) encompasses the conserved N-terminal domain of the viral CP. Fitting of the VP90(71-415) structure into the cryo-EM maps of HAstV produced an atomic model for the T=3 icosahedral capsid. Our model of the HAstV capsid provides valuable insights into intermolecular interactions required for capsid assembly and trypsin-mediated proteolytic maturation. Such information has potential applications in the development of a VLP vaccine as well as small-molecule drugs targeting astrovirus assembly/maturation.
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Vu DL, Cordey S, Brito F, Kaiser L. Novel human astroviruses: Novel human diseases? J Clin Virol 2016; 82:56-63. [PMID: 27434149 DOI: 10.1016/j.jcv.2016.07.004] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 06/28/2016] [Accepted: 07/10/2016] [Indexed: 10/21/2022]
Abstract
Astroviruses are small, non-enveloped, single-stranded positive RNA viruses that belong to the Astroviridae family. While classical human astroviruses (HAstV) are a well-recognized cause of acute non-bacterial diarrhea among young children worldwide, novel astroviruses, named HAstV-MLB and HAstV-VA/HMO, have been identified recently in humans by molecular assays. They are phylogenetically more related to animal astroviruses than to classical human astroviruses, thus suggesting cross-species transmission. Serological studies demonstrated a surprisingly high seroprevalence in certain populations and highlighted a high infection rate in the early years of life. Although their pathogenic role has not yet been clearly determined, novel astrovirus RNA sequences have been identified in different biological specimens of symptomatic patients, including the feces, plasma, cerebrospinal fluid, and brain biopsies. Thus, there is evidence that they could contribute not only to digestive tract infection, but also to unexpected clinical syndromes, notably encephalitis and meningitis. Severe infections affect mainly immunocompromised patients. These findings indicate that novel astroviruses should be considered in the differential diagnosis of immunocompromised patients with meningitis or encephalitis of unknown origin.
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Affiliation(s)
- Diem-Lan Vu
- Laboratory of Virology, Division of Laboratory Medicine and Division of Infectious Diseases, University of Geneva Hospitals, 4 Rue Gabrielle Perret-Gentil, 1211 Geneva 14, Switzerland; University of Geneva Medical School, 1 Rue Michel-Servet, 1211 Geneva 4, Switzerland.
| | - Samuel Cordey
- Laboratory of Virology, Division of Laboratory Medicine and Division of Infectious Diseases, University of Geneva Hospitals, 4 Rue Gabrielle Perret-Gentil, 1211 Geneva 14, Switzerland; University of Geneva Medical School, 1 Rue Michel-Servet, 1211 Geneva 4, Switzerland.
| | - Francisco Brito
- Swiss Institute of Bioinformatics, University of Geneva Medical School, 1 Rue Michel-Servet, 1211 Geneva 4, Switzerland.
| | - Laurent Kaiser
- Laboratory of Virology, Division of Laboratory Medicine and Division of Infectious Diseases, University of Geneva Hospitals, 4 Rue Gabrielle Perret-Gentil, 1211 Geneva 14, Switzerland; University of Geneva Medical School, 1 Rue Michel-Servet, 1211 Geneva 4, Switzerland.
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Detection of a mammalian-like astrovirus in bird, European roller (Coracias garrulus). INFECTION GENETICS AND EVOLUTION 2015; 34:114-21. [DOI: 10.1016/j.meegid.2015.06.020] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Revised: 06/04/2015] [Accepted: 06/17/2015] [Indexed: 12/29/2022]
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Guix S, Pérez-Bosque A, Miró L, Moretó M, Bosch A, Pintó RM. Type I interferon response is delayed in human astrovirus infections. PLoS One 2015; 10:e0123087. [PMID: 25837699 PMCID: PMC4383485 DOI: 10.1371/journal.pone.0123087] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 02/27/2015] [Indexed: 12/24/2022] Open
Abstract
Type I interferon (IFN) activation and its subsequent effects are important in the response to viral infections. Here we show that human astroviruses (HAstVs), which are important agents of acute gastroenteritis in children, induce a mild and delayed IFN response upon infecting CaCo-2 cells. Although IFN-β mRNA is detected within infected cells and supernatant from infected cells show antiviral activity against the replication of other well-known IFN-sensitive viruses, these responses occur at late stages of infection once genome replication has taken place. On the other hand, HAstV replication can be partially reduced by the addition of exogenous IFN, and inhibition of IFN activation by BX795 enhances viral replication, indicating that HAstVs are IFN-sensitive viruses. Finally, different levels of IFN response were observed in cells infected with different HAstV mutants with changes in the hypervariable region of nsP1a/4, suggesting that nsP1a/4 genotype may potentially have clinical implications due to its correlation with the viral replication phenotype and the antiviral responses induced within infected cells.
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Affiliation(s)
- Susana Guix
- Enteric Virus Group, Department of Microbiology, University of Barcelona, Barcelona, Spain
- Nutrition and Food Safety Research Institute (INSA-UB), University of Barcelona, Santa Coloma de Gramanet, Spain
- * E-mail:
| | - Anna Pérez-Bosque
- Nutrition and Food Safety Research Institute (INSA-UB), University of Barcelona, Santa Coloma de Gramanet, Spain
- Digestive Physiology and Nutritional Adaptations Group, Department of Physiology, University of Barcelona, Barcelona, Spain
| | - Lluïsa Miró
- Nutrition and Food Safety Research Institute (INSA-UB), University of Barcelona, Santa Coloma de Gramanet, Spain
- Digestive Physiology and Nutritional Adaptations Group, Department of Physiology, University of Barcelona, Barcelona, Spain
| | - Miquel Moretó
- Nutrition and Food Safety Research Institute (INSA-UB), University of Barcelona, Santa Coloma de Gramanet, Spain
- Digestive Physiology and Nutritional Adaptations Group, Department of Physiology, University of Barcelona, Barcelona, Spain
| | - Albert Bosch
- Enteric Virus Group, Department of Microbiology, University of Barcelona, Barcelona, Spain
- Nutrition and Food Safety Research Institute (INSA-UB), University of Barcelona, Santa Coloma de Gramanet, Spain
| | - Rosa M. Pintó
- Enteric Virus Group, Department of Microbiology, University of Barcelona, Barcelona, Spain
- Nutrition and Food Safety Research Institute (INSA-UB), University of Barcelona, Santa Coloma de Gramanet, Spain
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Abstract
Human astroviruses (HAtVs) are positive-sense single-stranded RNA viruses that were discovered in 1975. Astroviruses infecting other species, particularly mammalian and avian, were identified and classified into the genera Mamastrovirus and Avastrovirus. Through next-generation sequencing, many new astroviruses infecting different species, including humans, have been described, and the Astroviridae family shows a high diversity and zoonotic potential. Three divergent groups of HAstVs are recognized: the classic (MAstV 1), HAstV-MLB (MAstV 6), and HAstV-VA/HMO (MAstV 8 and MAstV 9) groups. Classic HAstVs contain 8 serotypes and account for 2 to 9% of all acute nonbacterial gastroenteritis in children worldwide. Infections are usually self-limiting but can also spread systemically and cause severe infections in immunocompromised patients. The other groups have also been identified in children with gastroenteritis, but extraintestinal pathologies have been suggested for them as well. Classic HAstVs may be grown in cells, allowing the study of their cell cycle, which is similar to that of caliciviruses. The continuous emergence of new astroviruses with a potential zoonotic transmission highlights the need to gain insights on their biology in order to prevent future health threats. This review focuses on the basic virology, pathogenesis, host response, epidemiology, diagnostic assays, and prevention strategies for HAstVs.
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Affiliation(s)
- Albert Bosch
- Enteric Virus Laboratory, Department of Microbiology and Institute of Nutrition and Food Safety, University of Barcelona, Barcelona, Spain
| | - Rosa M Pintó
- Enteric Virus Laboratory, Department of Microbiology and Institute of Nutrition and Food Safety, University of Barcelona, Barcelona, Spain
| | - Susana Guix
- Enteric Virus Laboratory, Department of Microbiology and Institute of Nutrition and Food Safety, University of Barcelona, Barcelona, Spain
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Liu C, Liu WH, Kan LL, Li X, Li YG, Zhao W. Production of polyclonal antibody to a recombinant non-structural protein Nsp1a of human astrovirus. J Virol Methods 2014; 209:82-5. [PMID: 25239369 DOI: 10.1016/j.jviromet.2014.09.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 09/02/2014] [Accepted: 09/09/2014] [Indexed: 11/17/2022]
Abstract
Human astrovirus (HAstV) are important pathogens that cause acute viral diarrhea in infants. Little is known about the mechanisms of astrovirus-induced diarrhea. Previous studies have suggested that an apoptosis inducer may be encoded in the non-structural protein (nsP1a) of astrovirus and contribute to virus-induced diarrhea. To study the biological function of nsP1a and to gain further insight into nsP1a protein-host cell interactions, good quality antibodies must be produced. The nsP1agene of HAstV-1 was cloned into a bacterial expression vector Pgex-6P-1. The recombinant plasmid Pgex-6P-nsP1a was transformed into Escherichia coli BL21 (DE3) and expressed as a fusion protein that contains N-terminal GST tags. The expressed recombinant protein was purified and used as an antigen to produce an nsP1a antiserum in rabbits. ELISA was used to detect the titer of specific antibodies. Specificity activity was detected by Western blot and immunofluorescence analysis. The titer of specific antibodies was up to 1:30,000. Western blotting and immunofluorescence analysis indicated that the polyclonal antibody could recognize specifically the HAstV-1 nsP1a protein.
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Affiliation(s)
- Chang Liu
- 1st affiliated hospital endocrinology, Liaoning Medical University, Jinzhou, 121000 Liaoning, China
| | - Wen-Hui Liu
- Liaoning Medical University, Jinzhou, 121200 Liaoning, China
| | - Li-Li Kan
- Panjin Liaohe Oilfield General Hospital, Panjin, 124010 Liaoning, China
| | - Xin Li
- Liaoning Medical University, Jinzhou, 121200 Liaoning, China
| | - Yong-gang Li
- Liaoning Medical University, Jinzhou, 121200 Liaoning, China
| | - Wei Zhao
- Liaoning Medical University, Jinzhou, 121200 Liaoning, China.
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15
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Bidokhti MRM, Ullman K, Jensen TH, Chriél M, Mottahedin A, Munir M, Andersson AM, Detournay O, Hammer AS, Baule C. Establishment of stably transfected cells constitutively expressing the full-length and truncated antigenic proteins of two genetically distinct mink astroviruses. PLoS One 2013; 8:e82978. [PMID: 24376619 PMCID: PMC3871642 DOI: 10.1371/journal.pone.0082978] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2013] [Accepted: 11/01/2013] [Indexed: 01/06/2023] Open
Abstract
Astroviruses are becoming a growing concern in veterinary and public health. To date there are no registered vaccines against astrovirus-induced disease, mostly due to the difficulty to cultivate astroviruses to high titer for vaccine development using conventional techniques. As means to circumvent this drawback, we have developed stably transfected mink fetal cells and BHK21 cells constitutively expressing the full-length and truncated capsid proteins of two distinct genotypes of mink astrovirus. Protein expression in these stably transfected cells was demonstrated by strong signals as evaluated by in-situ PLA and IFA, and confirmed by Western blotting. The recombinant full-length and truncated proteins induced a high level of antibodies in mink, evaluated by ELISA, demonstrating their immunogenicity. In a challenge experiment in mink, a reduction in presentation clinical signs and virus shedding was observed in mink kits born from immunized females. The gene integration and protein expression were sustained through cell passage, showing that the used approach is robust and reliable for expression of functional capsid proteins for vaccine and diagnostic applications.
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Affiliation(s)
- Mehdi R. M. Bidokhti
- Joint R&D Division of Virology, Department of Virology, Immunobiology and Parasitology, The National Veterinary Institute (SVA), Uppsala, Sweden
| | - Karin Ullman
- Joint R&D Division of Virology, Department of Virology, Immunobiology and Parasitology, The National Veterinary Institute (SVA), Uppsala, Sweden
| | - Trine H. Jensen
- Division of Veterinary Diagnostics and Research, National Veterinary Institute, Technical University of Denmark, Copenhagen, Denmark
| | - Mariann Chriél
- Division of Veterinary Diagnostics and Research, National Veterinary Institute, Technical University of Denmark, Copenhagen, Denmark
| | - Amin Mottahedin
- Joint R&D Division of Virology, Department of Virology, Immunobiology and Parasitology, The National Veterinary Institute (SVA), Uppsala, Sweden
| | - Muhammad Munir
- Department of Biomedical Sciences and Veterinary Public Health, Division of Virology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Anna Maria Andersson
- The National Veterinary Institute, Department of Animal Health and Antimicrobial Resistance, Uppsala, Sweden
| | - Olivier Detournay
- Joint R&D Division of Virology, Department of Virology, Immunobiology and Parasitology, The National Veterinary Institute (SVA), Uppsala, Sweden
| | - Anne Sofie Hammer
- Division of Veterinary Diagnostics and Research, National Veterinary Institute, Technical University of Denmark, Copenhagen, Denmark
| | - Claudia Baule
- Joint R&D Division of Virology, Department of Virology, Immunobiology and Parasitology, The National Veterinary Institute (SVA), Uppsala, Sweden
- * E-mail:
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16
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Tange S, Zhou Y, Nagakui-Noguchi Y, Imai T, Nakanishi A. Initiation of human astrovirus type 1 infection was blocked by inhibitors of phosphoinositide 3-kinase. Virol J 2013; 10:153. [PMID: 23680019 PMCID: PMC3750554 DOI: 10.1186/1743-422x-10-153] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 04/23/2013] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Upon initial contact with a virus, host cells activate a series of cellular signaling cascades that facilitate viral entry and viral propagation within the cell. Little is known about how the human astrovirus (HAstV) exploits signaling cascades to establish an infection in host cells. Recent studies showed that activation of extracellular signal-regulated kinase 1/2 (ERK1/2) is important for HAstV infection, though the involvement of other signaling cascades remains unclear. METHODS A panel of kinase blockers was used to search for cellular signaling pathways important for HAstV1 infection. To determine their impact on the infectious process, we examined viral gene expression, RNA replication, and viral RNA and capsid protein release from host cells. RESULTS Inhibitors of phosphoinositide 3-kinase (PI3K) activation interfered with the infection, independent of their effect on ERK 1/2 activation. Activation of the PI3K signaling cascade occurred at an early phase of the infection, judging from the timeframe of Akt phosphorylation. PI3K inhibition at early times, but not at later times, blocked viral gene expression. However, inhibiting the downstream targets of PI3K activation, Akt and Rac1, did not block infection. Inhibition of protein kinase A (PKA) activation was found to block a later phase of HAstV1 production. CONCLUSIONS Our results reveal a previously unknown, essential role of PI3K in the life cycle of HAstV1. PI3K participates in the early stage of infection, possibly during the viral entry process. Our results also reveal the role of PKA in viral production.
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Affiliation(s)
- Shoichiro Tange
- Section of Gene Therapy, Department of Aging Intervention, National Center for Geriatrics and Gerontology, 35, Gengo, Morioka, Obu, Aichi 474-8522, Japan
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17
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Santos JV, Pina MET, Marques MPM, de Carvalho LAEB. New sustained release of Zidovudine Matrix tablets − cytotoxicity toward Caco-2 cells. Drug Dev Ind Pharm 2012; 39:1154-66. [DOI: 10.3109/03639045.2012.669129] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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18
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Finkbeiner SR, Holtz LR. New Human Astroviruses. ASTROVIRUS RESEARCH 2012. [PMCID: PMC7120454 DOI: 10.1007/978-1-4614-4735-1_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The first human astrovirus was discovered in 1975 by Madeley and Cosgrove through visualization of viral particles in stool using electron microscopy. Over the course of the next ∼20 years, an additional seven serotypes of human astroviruses were discovered. In the last decade, new technological advances in microarrays and sequencing strategies enabled more sophisticated methods for detecting viruses in clinical and environmental specimens. These methods led to the discovery of many novel viruses from a variety of virus families. They also brought about a dramatic realization that more astroviruses can be found in humans than previously recognized. In fact, the number of astroviruses associated with humans has nearly doubled within the last few years. Furthermore, the discovery of novel astroviruses in human specimens revealed that there is more diversity amongst them than was assumed based on the high level of similarity between human astroviruses 1 and 8. This chapter will describe the discovery and early characterization of the five novel astroviruses initially identified in human stool samples in 2008 and 2009.
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Abstract
Astrovirus infections cause gastroenteritis in mammals and have been identified as causative agents of diverse pathologies in birds such as hepatitis in ducks and poult enteritis mortality syndrome (PEMS), which causes enteritis and thymic and bursal atrophy in turkeys. Human astroviruses are recognized as the second leading cause of childhood viral gastroenteritis worldwide. Eight traditional astrovirus serotypes have been identified in humans, but recently novel astrovirus strains isolated from humans have been associated with diseases other than gastroenteritis. Herein we summarize our current knowledge of the astrovirus life cycle. Though there are gaps in our understanding of astrovirus replication, similarities can be drawn from Picornaviridae and Caliciviridae virus families. There are, however, unique characteristics of the astrovirus life cycle, including intracellular proteolytic processing of viral particles by cellular caspases, which has been shown to be required for the maturation and exit of viral progeny.
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Affiliation(s)
- Stacey Schultz-Cherry
- , Infectious Diseases, St Jude Children’s Research Hospital, 262 Danny Thomas Place, Memphis, 38105 Tennessee USA
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20
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The C-terminal nsP1a protein of human astrovirus is a phosphoprotein that interacts with the viral polymerase. J Virol 2011; 85:4470-9. [PMID: 21325412 DOI: 10.1128/jvi.01515-10] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human astrovirus nonstructural C-terminal nsP1a protein (nsP1a/4) colocalizes with the endoplasmic reticulum and viral RNA. It has been suggested that nsP1a/4 protein is involved in the RNA replication process in endoplasmic reticulum-derived intracellular membranes. A hypervariable region (HVR) is contained in the nsP1a/4 protein, and different replicative patterns can be distinguished depending on its variability. In the present work, both the astrovirus RNA-dependent RNA polymerase and four types (IV, V, VI, and XII) of nsP1a/4 proteins have been cloned and expressed in the baculovirus system to analyze their interactions. Different isoforms of each of the nsP1a/4 proteins exist: a nonphosphorylated isoform and different phosphorylated isoforms. While the polymerase accumulates as a monomer, the nsP1a/4 proteins accumulate as oligomers. The oligomerization domain of nsP1a/4-V is mapped between residues 176 and 209. For all studied genotypes, oligomers mainly contain the nonphosphorylated isoform. When RNA polymerase is coexpressed with nsP1a/4 proteins, they interact, likely forming heterodimers. The polymerase binding region has been mapped in the nsP1a/4-V protein between residues 88 and 176. Phosphorylated isoforms of nsP1a/4 type VI show a stronger interactive pattern with the polymerase than the nonphosphorylated isoform. This difference is not observed in genotypes IV and V, suggesting a role of the HVR in modulating the interaction of the nsP1a/4 protein with the polymerase through phosphorylation/dephosphorylation of some critical residues.
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21
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Banos-Lara MDR, Méndez E. Role of individual caspases induced by astrovirus on the processing of its structural protein and its release from the cell through a non-lytic mechanism. Virology 2010; 401:322-32. [PMID: 20347468 DOI: 10.1016/j.virol.2010.02.028] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Revised: 12/13/2009] [Accepted: 02/23/2010] [Indexed: 11/20/2022]
Abstract
Caspases (Casp) activity has been associated with the intracellular proteolytic processing of the structural protein to yield the mature capsid formed by VP70 and with the cell release of human astrovirus (HAstV). This work describes the role of individual Casp on these events. The activity of initiator (-8, -9) and executioner (-3/7) Casp was clearly detected at 12h post-infection. All these proteases were able to cleave VP90 in an in vitro assay, but this processing was blocked in cells transfected with siRNA against Casp-3, -9, but not against Casp-8. In contrast, virus release, observed in the absence of cell lysis, was more drastically affected by either silencing Casp-3 or in the presence of the inhibitor Ac-DEVD-CHO. Cleavage of VP90 to yield VP70 was mapped at motif TYVD(657). These data indicate that the processing of VP90 and the release of HAstV from the cell are two Casp-related, but apparently independent, events.
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Affiliation(s)
- Ma del Rocío Banos-Lara
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad 2001, Colonia Chamilpa, Cuernavaca, Morelos 62210, México
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22
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Finkbeiner SR, Kirkwood CD, Wang D. Complete genome sequence of a highly divergent astrovirus isolated from a child with acute diarrhea. Virol J 2008; 5:117. [PMID: 18854035 PMCID: PMC2576171 DOI: 10.1186/1743-422x-5-117] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2008] [Accepted: 10/14/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Astroviruses infect a variety of mammals and birds and are causative agents of diarrhea in humans and other animal hosts. We have previously described the identification of several sequence fragments with limited sequence identity to known astroviruses in a stool specimen obtained from a child with acute diarrhea, suggesting that a novel virus was present. RESULTS In this study, the complete genome of this novel virus isolate was sequenced and analyzed. The overall genome organization of this virus paralleled that of known astroviruses, with 3 open reading frames identified. Phylogenetic analysis of the ORFs indicated that this virus is highly divergent from all previously described animal and human astroviruses. Molecular features that are highly conserved in human serotypes 1-8, such as a 3'NTR stem-loop structure and conserved nucleotide motifs present in the 5'NTR and ORF1b/2 junction, were either absent or only partially conserved in this novel virus. CONCLUSION Based on the analyses described herein, we propose that this newly discovered virus represents a novel species in the family Astroviridae. It has tentatively been named Astrovirus MLB1.
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Affiliation(s)
- Stacy R Finkbeiner
- Departments of Molecular Microbiology and Pathology & Immunology, Washington University School of Medicine, St, Louis, MO, USA.
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23
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Abstract
Human astroviruses are nonenveloped, positive-sense single-strand RNA viruses associated with self-limiting diarrhea. Although they are recognized as a leading cause of disease in young children, the cellular factors involved in astrovirus replication are not well defined. The extracellular signal-regulated kinase (ERK) pathway has been shown to regulate many viral infections, but its role during astrovirus infection is unknown. In this report, we show that astrovirus activates ERK1/2 early in infection independently of replication. Inhibition of ERK activation with U0126, a specific ERK inhibitor, significantly reduced viral production. Investigations into the mechanism of ERK1/2 regulation revealed that all steps of the viral life cycle, including early and late protein expression as well as subgenomic and genomic RNA transcription, were diminished during U0126 treatment of monolayers. These data support a role for ERK1/2 in a postattachment step, although the precise mechanism remains under investigation.
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Moser LA, Carter M, Schultz-Cherry S. Astrovirus increases epithelial barrier permeability independently of viral replication. J Virol 2007; 81:11937-45. [PMID: 17699569 PMCID: PMC2168760 DOI: 10.1128/jvi.00942-07] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Astrovirus infection in a variety of species results in an age-dependent diarrhea; however, the means by which astroviruses cause diarrhea remain unknown. Studies of astrovirus-infected humans and turkeys have demonstrated few histological changes and little inflammation during infection, suggesting that intestinal damage or an overzealous immune response is not the primary mediator of astrovirus diarrhea. An alternative contributor to diarrhea is increased intestinal barrier permeability. Here, we demonstrate that astrovirus increases barrier permeability in a Caco-2 cell culture model system following apical infection. Increased permeability correlated with disruption of the tight-junction protein occludin and decreased the number of actin stress fibers in the absence of cell death. Additionally, permeability was increased when monolayers were treated with UV-inactivated virus or purified recombinant human astrovirus serotype 1 capsid in the form of virus-like particles. Together, these results demonstrate that astrovirus-induced permeability occurs independently of viral replication and is modulated by the capsid protein, a property apparently unique to astroviruses. Based on these data, we propose that the capsid contributes to diarrhea in vivo.
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Affiliation(s)
- Lindsey A Moser
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, 1300 University Avenue, Madison, WI 53706, USA
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25
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Méndez E, Aguirre-Crespo G, Zavala G, Arias CF. Association of the astrovirus structural protein VP90 with membranes plays a role in virus morphogenesis. J Virol 2007; 81:10649-58. [PMID: 17652389 PMCID: PMC2045458 DOI: 10.1128/jvi.00785-07] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
VP90, the capsid polyprotein precursor of human astrovirus Yuc8, is assembled into viral particles, and its processing at the carboxy terminus by cellular caspases, to yield VP70, has been correlated with the cell release of the virus. Here, we characterized the effect of the VP90-VP70 processing on the properties of these proteins, as well as on their intracellular distribution. VP90 was found in membrane-enriched fractions (mVP90), as well as in fractions enriched in cytosolic proteins (cVP90), while VP70 was found exclusively in the latter fractions. Upon trypsin activation, infectivity was detected in all VP90-containing fractions, confirming that both mVP90 and cVP90 are able to assemble into particles; however, the two forms of VP90 showed differential sensitivities to trypsin, especially at their carboxy termini, which in the case of mVP90 was shown to remain membrane associated after protease digestion. Structural protein oligomers were detected in purified VP70-containing viruses, as well as in membrane-enriched fractions, but they were less evident in cytosolic fractions. Ultrastructural studies of infected cells revealed different types of viral particles, some of which appeared to be associated with membranes. By immunoelectron microscopy, structural proteins were shown to form virus particles in clusters and to associate with the edges of vesicles induced during infection, which also appear to contain subviral particles inside. Nonstructural proteins and viral RNA colocalized with mVP90, but not with cVP90, suggesting that mVP90 might represent the form of the protein that is initially assembled into particles, at the sites where the virus genome is being replicated.
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Affiliation(s)
- Ernesto Méndez
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apartado Postal 510-3, Colonia Miraval, Cuernavaca, Morelos 62250, Mexico.
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26
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van Hemert FJ, Lukashov VV, Berkhout B. Different rates of (non-)synonymous mutations in astrovirus genes; correlation with gene function. Virol J 2007; 4:25. [PMID: 17343744 PMCID: PMC1828050 DOI: 10.1186/1743-422x-4-25] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2007] [Accepted: 03/07/2007] [Indexed: 11/30/2022] Open
Abstract
Background Complete genome sequences of the Astroviridae include human, non-human mammalian and avian species. A consensus topology of astroviruses has been derived from nucleotide substitutions in the full-length genomes and from non-synonymous nucleotide substitutions in each of the three ORFs. Analyses of synonymous substitutions displayed a loss of tree structure, suggesting either saturation of the substitution model or a deviant pattern of synonymous substitutions in certain virus species. Results We analyzed the complete Astroviridae family for the inference of adaptive molecular evolution at sites and in branches. High rates of synonymous mutations are observed among the non-human virus species. Deviant patterns of synonymous substitutions are found in the capsid structural genes. Purifying selection is a dominant force among all astrovirus genes and only few codon sites showed values for the dN/dS ratio that may indicate site-specific molecular adaptation during virus evolution. One of these sites is the glycine residue of a RGD motif in ORF2 of human astrovirus serotype 1. RGD or similar integrin recognition motifs are present in nearly all astrovirus species. Conclusion Phylogenetic analysis directed by maximum likelihood approximation allows the inclusion of significantly more evolutionary history and thereby, improves the estimation of dN and dS. Sites with enhanced values for dN/dS are prominent at domains in charge of environmental communication (f.i. VP27 and domain 4 in ORF1a) more than at domains dedicated to intrinsic virus functions (f.i. VP34 and ORF1b (the virus polymerase)). Integrin recognition may play a key role in astrovirus to target cell attachment.
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Affiliation(s)
- Formijn J van Hemert
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, The Netherlands
| | - Vladimir V Lukashov
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, The Netherlands
| | - Ben Berkhout
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, University of Amsterdam, The Netherlands
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27
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van Hemert FJ, Berkhout B, Lukashov VV. Host-related nucleotide composition and codon usage as driving forces in the recent evolution of the Astroviridae. Virology 2006; 361:447-54. [PMID: 17188318 PMCID: PMC7127384 DOI: 10.1016/j.virol.2006.11.021] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2006] [Revised: 10/23/2006] [Accepted: 11/14/2006] [Indexed: 01/20/2023]
Abstract
The evolutionary history of the Astroviridae comprises the ancient separation between avian and mammalian astrovirus lineages followed by diversification among mammalian astroviruses. The latter process included several cross-species transmissions. We found that the recent, but not the ancient, evolution of astroviruses was associated with a switch in nucleotide composition and codon usage among non-human mammalian versus human/avian astroviruses. Virus and hosts phylogenies based on codon usage agreed with each other and matched the hosts' evolutionary emergence order. This recent switch in driving forces acting at the synonymous level points to the adaptation of codon usage by viruses to that of their hosts after cross-species transmissions. This is the first demonstration of nucleotide composition and codon usage being active driving forces during the recent evolutionary history of a virus group in the host-parasite system.
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Affiliation(s)
- Formijn J van Hemert
- Laboratory of Experimental Virology, Department of Medical Microbiology, Center for Infection and Immunity Amsterdam, Academic Medical Center, University of Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, The Netherlands
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28
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Natoni A, Kass GEN, Carter MJ, Roberts LO. The mitochondrial pathway of apoptosis is triggered during feline calicivirus infection. J Gen Virol 2006; 87:357-361. [PMID: 16432022 DOI: 10.1099/vir.0.81399-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Feline calicivirus (FCV) belongs to the family Caliciviridae and is an important pathogen of the upper respiratory tract of cats. Recent studies have shown that cells infected with FCV undergo apoptosis, as evidenced by caspase activation, chromatin condensation and cleavage of poly(ADP-ribose) polymerase. Here, the upstream events were investigated in order to define the molecular mechanism of apoptosis in FCV-infected cells. It was shown that FCV induced translocation of phosphatidylserine to the cell outer membrane and release of cytochrome c from mitochondria at about 6-8 h post-infection. These events were preceded by the loss of mitochondrial membrane potential and Bax translocation from the cytosol to mitochondria between 4 and 6 h after infection. Release of cytochrome c from mitochondria triggered the activation of caspase-9 and the subsequent activation of the executioner caspase, caspase-3. These results suggest that the mitochondrial pathway of apoptosis is triggered during FCV infection.
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Affiliation(s)
- Alessandro Natoni
- School of Biomedical and Molecular Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK
| | - George E N Kass
- School of Biomedical and Molecular Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK
| | - Michael J Carter
- School of Biomedical and Molecular Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK
| | - Lisa O Roberts
- School of Biomedical and Molecular Sciences, University of Surrey, Guildford, Surrey GU2 7XH, UK
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29
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Abstract
Coat proteins of non-enveloped, icosahedral viruses must perform a variety of functions during their life cycle such as assembly of the coat protein subunits into a closed shell, specific encapsidation of the viral nucleic acid, maturation of the capsid, interaction with host receptors, and disassembly to deliver the genetic information into the newly infected cell. A thorough understanding of the multiple capsid properties at the molecular level is required in order to identify potential targets for antiviral therapy and the prevention of viral disease. The system we have chosen for study is the astrovirus, a family of icosahedral, single-stranded RNA viruses that cause disease in mammals and birds. Very little is known about what regions of the coat protein contribute to the diverse capsid functions. This review will present novel structural predictions for the coat protein sequence of different astrovirus family members. Based on these predictions, we hypothesize that the assembly and RNA packaging functions of the astrovirus coat protein constitutes an individual domain distinct from the determinants required for receptor binding and internalization. Information derived from these structural predictions will serve as an important tool in designing experiments to understand astrovirus biology.
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Affiliation(s)
- Neel K Krishna
- Department of Pediatrics and the Center for Pediatric Research, Norfolk, VA 23510, USA.
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30
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Guix S, Caballero S, Bosch A, Pintó RM. Human astrovirus C-terminal nsP1a protein is involved in RNA replication. Virology 2005; 333:124-31. [PMID: 15708598 DOI: 10.1016/j.virol.2004.12.023] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2004] [Revised: 10/07/2004] [Accepted: 12/20/2004] [Indexed: 11/23/2022]
Abstract
Human astrovirus nonstructural C-terminal nsP1a protein, which contains a hypervariable region (HVR) and colocalizes with the endoplasmic reticulum and viral RNA, has been suggested to be involved in the RNA replication process. Four viruses differing only in their C-terminal nsP1a protein, corresponding to HVR-derived genotypes IV, V, VI, and XII, were all able to replicate in CaCo-2 cells but displayed differences in their RNA replication and growth properties. Two overall patterns of replication were observed: types IV and V on one side, and types VI and XII on the other. The main detected differences were on the levels of antigenomic and subgenomic RNAs, being the latter significantly higher in types IV and V. Accordingly, quantification of viral RNA load in feces from children with gastroenteritis showed that HVR-derived genotypes IV and V occur in significantly higher numbers. In consequence, it may be concluded that the variability of the C-terminal nsP1a gene affects the virus replication phenotype.
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Affiliation(s)
- Susana Guix
- Department of Microbiology, Enteric Virus Laboratory, University of Barcelona, Diagonal 645, 08028 Barcelona, Spain
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31
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Abstract
Astroviruses are one of the leading causes of diarrhea worldwide. In spite of its impact on human health, little is known about astrovirus pathogenesis. One reason for this may be the lack of a suitable small animal model for infection. In recent years, there has been increasing information on the mechanism of astrovirus-induced disease in mammals (including humans) and birds. This review summarizes our current state of knowledge on astrovirus pathogenesis.
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Affiliation(s)
- Lindsey A Moser
- Department of Medical Microbiology and Immunology, University of Wisconsin, 1300 University Ave, Madison, WI 53575, USA
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32
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Guix S, Caballero S, Bosch A, Pintó RM. C-terminal nsP1a protein of human astrovirus colocalizes with the endoplasmic reticulum and viral RNA. J Virol 2004; 78:13627-36. [PMID: 15564473 PMCID: PMC533902 DOI: 10.1128/jvi.78.24.13627-13636.2004] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Computational and biological approaches were undertaken to characterize the role of the human astrovirus nonstructural protein nsP1a/4, located at the C-terminal fragment of nsP1a. Computer analysis reveals sequence similarities to other nonstructural viral proteins involved in RNA replication and/or transcription and allows the identification of a glutamine- and proline-rich region, the prediction of many phosphorylation and O-glycosylation sites, and the occurrence of a KKXX-like endoplasmic reticulum retention signal. Immunoprecipitation analysis with an antibody against a synthetic peptide of the nsP1a/4 sequence detected polyprotein precursors of 160, 75, and 38 to 40 kDa as well as five smaller proteins in the range of 21 to 27 kDa. Immunofluorescence labeling showed that the nsP1a/4 protein is accumulated at the perinuclear region, in association with the endoplasmic reticulum and the viral RNA. These results suggest the involvement of nsP1a/4 protein in the RNA replication process in endoplasmic reticulum-derived intracellular membranes.
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Affiliation(s)
- Susana Guix
- Enteric Virus Laboratory, Department of Microbiology, University of Barcelona, Avda Diagonal 645, 08028 Barcelona, Spain
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