1
|
Lefebvre V, Leon Foun Lin R, Cole L, Cosset FL, Fogeron ML, Böckmann A. Do NSm Virulence Factors in the Bunyavirales Viral Order Originate from Gn Gene Duplication? Viruses 2024; 16:90. [PMID: 38257790 PMCID: PMC10819786 DOI: 10.3390/v16010090] [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: 11/22/2023] [Revised: 12/29/2023] [Accepted: 01/03/2024] [Indexed: 01/24/2024] Open
Abstract
One-third of the nine WHO shortlisted pathogens prioritized for research and development in public health emergencies belong to the Bunyavirales order. Several Bunyavirales species carry an NSm protein that acts as a virulence factor. We predicted the structures of these NSm proteins and unexpectedly found that in two families, their cytosolic domain was inferred to have a similar fold to that of the cytosolic domain of the viral envelope-forming glycoprotein N (Gncyto) encoded on the same genome fragment. We show that although the sequence identity between the NSmcyto and the Gncyto domains is low, the conservation of the two zinc finger-forming CysCysHisCys motifs explains the predicted structural conservation. Importantly, our predictions provide a first glimpse into the long-unknown structure of NSm. Also, these predictions suggest that NSm is the result of a gene duplication event in the Bunyavirales Nairoviridae and Peribunyaviridae families and that such events may be common in the recent evolutionary history of RNA viruses.
Collapse
Affiliation(s)
- Victor Lefebvre
- MMSB—Molecular Microbiology and Structural Biochemistry, Université de Lyon 1, CNRS UMR 5086, F-69367 Lyon, France; (V.L.); (R.L.F.L.)
| | - Ravy Leon Foun Lin
- MMSB—Molecular Microbiology and Structural Biochemistry, Université de Lyon 1, CNRS UMR 5086, F-69367 Lyon, France; (V.L.); (R.L.F.L.)
| | - Laura Cole
- MMSB—Molecular Microbiology and Structural Biochemistry, Université de Lyon 1, CNRS UMR 5086, F-69367 Lyon, France; (V.L.); (R.L.F.L.)
| | - François-Loïc Cosset
- CIRI—Centre International de Recherche en Infectiologie, Université de Lyon 1, ENS de Lyon, Inserm U1111, CNRS UMR 5308, F-69007 Lyon, France
| | - Marie-Laure Fogeron
- MMSB—Molecular Microbiology and Structural Biochemistry, Université de Lyon 1, CNRS UMR 5086, F-69367 Lyon, France; (V.L.); (R.L.F.L.)
| | - Anja Böckmann
- MMSB—Molecular Microbiology and Structural Biochemistry, Université de Lyon 1, CNRS UMR 5086, F-69367 Lyon, France; (V.L.); (R.L.F.L.)
| |
Collapse
|
2
|
Okajima M, Takenaka-Uema A, Fujii Y, Izumi F, Kojima I, Ozawa M, Naitou K, Suda Y, Nishiyama S, Murakami S, Horimoto T, Ito N, Shirafuji H, Yanase T, Masatani T. Differential role of NSs genes in the neurovirulence of two genogroups of Akabane virus causing postnatal encephalomyelitis. Arch Virol 2023; 169:7. [PMID: 38082138 DOI: 10.1007/s00705-023-05929-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 10/14/2023] [Indexed: 12/18/2023]
Abstract
Akabane virus (AKAV) is a member of the genus Orthobunyavirus, family Peribunyaviridae. In addition to AKAV strains that cause fetal Akabane disease, which is characterized by abortion in ruminants, some AKAV strains cause postnatal infection characterized by nonsuppurative encephalomyelitis in ruminants. Here, we focused on the NSs protein, a virulence factor for most viruses belonging to the genus Orthobunyavirus, and we hypothesized that this protein would act as a neurovirulence factor in AKAV strains causing postnatal encephalomyelitis. We generated AKAV strains that were unable to produce the NSs protein, derived from two different genogroups, genogroups I and II, and then examined the role of their NSs proteins by inoculating mice intracerebrally with these modified viruses. Our results revealed that the neurovirulence of genogroup II strains is dependent on the NSs protein, whereas that of genogroup I strains is independent of this protein. Notably, infection of primary cultured bovine cells with these viruses suggested that the NSs proteins of both genogroups suppress innate immune-related gene expression with equal efficiency. These results indicate differences in the determinants of virulence of orthobunyaviruses.
Collapse
Affiliation(s)
- Misuzu Okajima
- Joint Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
| | - Akiko Takenaka-Uema
- Laboratory of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Yuji Fujii
- Joint Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
| | - Fumiki Izumi
- Joint Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
| | - Isshu Kojima
- Joint Graduate School of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
| | - Makoto Ozawa
- Joint Graduate School of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
- Laboratory of Animal Hygiene, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
- Transboundary Animal Diseases Research Center, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
| | - Kiyotada Naitou
- Department of Basic Veterinary Science, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima, Japan
| | - Yuto Suda
- Kagoshima Research Station, National Institute of Animal Health, NARO, Kagoshima, Japan
| | - Shoko Nishiyama
- Laboratory of Zoonotic Diseases, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan
| | - Shin Murakami
- Laboratory of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Taisuke Horimoto
- Laboratory of Veterinary Microbiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Naoto Ito
- Joint Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
- Laboratory of Zoonotic Diseases, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan
- Center for One Medicine Innovative Translational Research (COMIT), Gifu University, Gifu, Japan
| | - Hiroaki Shirafuji
- Kagoshima Research Station, National Institute of Animal Health, NARO, Kagoshima, Japan
| | - Tohru Yanase
- Kagoshima Research Station, National Institute of Animal Health, NARO, Kagoshima, Japan
| | - Tatsunori Masatani
- Joint Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan.
- Laboratory of Zoonotic Diseases, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan.
- Center for One Medicine Innovative Translational Research (COMIT), Gifu University, Gifu, Japan.
| |
Collapse
|
3
|
Barker J, daSilva LLP, Crump CM. Mechanisms of bunyavirus morphogenesis and egress. J Gen Virol 2023; 104. [PMID: 37083579 DOI: 10.1099/jgv.0.001845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023] Open
Abstract
Unlike many segmented negative-sense RNA viruses, most members of the Bunyavirales bud at Golgi membranes, as opposed to the plasma membrane. Central players in this assembly process are the envelope glycoproteins, Gn and Gc, which upon translation undergo proteolytic processing, glycosylation and trafficking to the Golgi, where they interact with ribonucleoprotein genome segments and bud into Golgi-derived compartments. The processes involved in genome packaging during virion assembly can lead to the generation of reassorted viruses, if a cell is co-infected with two different bunyaviruses, due to mismatching of viral genome segment packaging. This can lead to viruses with high pathogenic potential, as demonstrated by the emergence of Schmallenberg virus. This review focuses on the assembly pathways of tri-segmented bunyaviruses, highlighting some areas in need of further research to understand these important pathogens with zoonotic potential.
Collapse
Affiliation(s)
- Jake Barker
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, UK
| | - Luis L P daSilva
- Departamento de Biologia Celular e Molecular, Centro de Pesquisa em Virologia, Faculdade de Medicina de Ribeirão Preto, University of São Paulo, State of São Paulo, Brazil
| | - Colin M Crump
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, UK
| |
Collapse
|
4
|
Hellert J, Aebischer A, Haouz A, Guardado-Calvo P, Reiche S, Beer M, Rey FA. Structure, function, and evolution of the Orthobunyavirus membrane fusion glycoprotein. Cell Rep 2023; 42:112142. [PMID: 36827185 DOI: 10.1016/j.celrep.2023.112142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Revised: 12/29/2022] [Accepted: 02/07/2023] [Indexed: 02/24/2023] Open
Abstract
La Crosse virus, responsible for pediatric encephalitis in the United States, and Schmallenberg virus, a highly teratogenic veterinary virus in Europe, belong to the large Orthobunyavirus genus of zoonotic arthropod-borne pathogens distributed worldwide. Viruses in this under-studied genus cause CNS infections or fever with debilitating arthralgia/myalgia syndromes, with no effective treatment. The main surface antigen, glycoprotein Gc (∼1,000 residues), has a variable N-terminal half (GcS) targeted by the patients' antibody response and a conserved C-terminal moiety (GcF) responsible for membrane fusion during cell entry. Here, we report the X-ray structure of post-fusion La Crosse and Schmallenberg virus GcF, revealing the molecular determinants for hairpin formation and trimerization required to drive membrane fusion. We further experimentally confirm the role of residues in the fusion loops and in a vestigial endoplasmic reticulum (ER) translocation sequence at the GcS-GcF junction. The resulting knowledge provides essential molecular underpinnings for future development of potential therapeutic treatments and vaccines.
Collapse
Affiliation(s)
- Jan Hellert
- Structural Virology Unit, Institut Pasteur - Université Paris-Cité, CNRS UMR 3569, 25-28 rue du Dr. Roux, 75015 Paris, France; Centre for Structural Systems Biology (CSSB), Leibniz-Institut für Virologie (LIV), Notkestraße 85, 22607 Hamburg, Germany
| | - Andrea Aebischer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald, Germany; Department of Experimental Animal Facilities and Biorisk Management, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald, Germany
| | - Ahmed Haouz
- Crystallography Platform C2RT, Institut Pasteur, CNRS UMR 3528, 25-28 rue du Dr. Roux, 75015 Paris, France
| | - Pablo Guardado-Calvo
- Structural Virology Unit, Institut Pasteur - Université Paris-Cité, CNRS UMR 3569, 25-28 rue du Dr. Roux, 75015 Paris, France
| | - Sven Reiche
- Department of Experimental Animal Facilities and Biorisk Management, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald, Germany
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald, Germany.
| | - Félix A Rey
- Structural Virology Unit, Institut Pasteur - Université Paris-Cité, CNRS UMR 3569, 25-28 rue du Dr. Roux, 75015 Paris, France.
| |
Collapse
|
5
|
Abstract
Oropouche virus (OROV; genus Orthobunyavirus) is the etiological agent of Oropouche fever, a debilitating febrile illness common in South America. We used recombinant expression of the OROV M polyprotein, which encodes the surface glycoproteins Gn and Gc plus the nonstructural protein NSm, to probe the cellular determinants for OROV assembly and budding. Gn and Gc self-assemble and are secreted independently of NSm. Mature OROV Gn has two predicted transmembrane domains that are crucial for glycoprotein translocation to the Golgi complex and glycoprotein secretion, and unlike related orthobunyaviruses, both transmembrane domains are retained during Gn maturation. Disruption of Golgi function using the drugs brefeldin A and monensin inhibits glycoprotein secretion. Infection studies have previously shown that the cellular endosomal sorting complexes required for transport (ESCRT) machinery is recruited to Golgi membranes during OROV assembly and that ESCRT activity is required for virus secretion. A dominant-negative form of the ESCRT-associated ATPase VPS4 significantly reduces recombinant OROV glycoprotein secretion and blocks virus release from infected cells, and VPS4 partly colocalizes with OROV glycoproteins and membranes costained with Golgi markers. Furthermore, immunoprecipitation and fluorescence microscopy experiments demonstrate that OROV glycoproteins interact with the ESCRT-III component CHMP6, with overexpression of a dominant-negative form of CHMP6 significantly reducing OROV glycoprotein secretion. Taken together, our data highlight differences in M polyprotein processing across orthobunyaviruses, indicate that Golgi and ESCRT function are required for glycoprotein secretion, and identify CHMP6 as an ESCRT-III component that interacts with OROV glycoproteins. IMPORTANCE Oropouche virus causes Oropouche fever, a debilitating illness common in South America that is characterized by high fever, headache, myalgia, and vomiting. The tripartite genome of this zoonotic virus is capable of reassortment, and there have been multiple epidemics of Oropouche fever in South America over the last 50 years, making Oropouche virus infection a significant threat to public health. However, the molecular characteristics of this arbovirus are poorly understood. We developed a recombinant protein expression system to investigate the cellular determinants of OROV glycoprotein maturation and secretion. We show that the proteolytic processing of the M polypeptide, which encodes the surface glycoproteins (Gn and Gc) plus a nonstructural protein (NSm), differs between OROV and its close relative Bunyamwera virus. Furthermore, we demonstrate that OROV M glycoprotein secretion requires the cellular endosomal sorting complexes required for transport (ESCRT) membrane-remodeling machinery and identify that the OROV glycoproteins interact with the ESCRT protein CHMP6.
Collapse
|
6
|
Schwake C, Hyon M, Chishti AH. Signal peptide peptidase: A potential therapeutic target for parasitic and viral infections. Expert Opin Ther Targets 2022; 26:261-273. [PMID: 35235480 DOI: 10.1080/14728222.2022.2047932] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Signal peptide peptidase (SPP) is a GxGD-type intramembrane-cleaving aspartyl protease responsible for clearing accumulating signal peptides in the endoplasmic reticulum. SPP is conserved among all kingdoms and is essential for maintaining cell homeostasis. Inhibition of SPP with selective inhibitors and the structurally similar HIV protease inhibitors results in signal peptide accumulation and subsequent cell death. Identification of SPP homologues in major human parasitic infections has opened a new therapeutic opportunity. Moreover, the essentiality of mammalian SPP-mediated viral protein processing during infection is emerging. AREAS COVERED This review introduces the discovery and biological function of human SPP enzymes and identify parasitic homologues as pharmacological targets of both SPP and HIV protease inhibitors. Later, the role of mammalian SPP during viral infection and how disruption of host SPP can be employed as a novel antiviral therapy are examined and discussed. EXPERT OPINION Parasitic and viral infections cause severe health and economic burden, exacerbated by the lack of new therapeutics in the pipeline. SPP has been shown to be essential for malaria parasite growth and encouraging evidence in other parasites demonstrates broad essentiality of these proteases as therapeutic targets. As drug resistant parasite and viruses emerge, SPP inhibition will provide a new generation of compounds to counter the growing threat of antimicrobial resistance.
Collapse
Affiliation(s)
- Christopher Schwake
- Department of Developmental, Molecular, and Chemical Biology, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA, USA
| | - Michael Hyon
- Department of Developmental, Molecular, and Chemical Biology, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA, USA
| | - Athar H Chishti
- Department of Developmental, Molecular, and Chemical Biology, Graduate School of Biomedical Sciences, Tufts University School of Medicine, Boston, MA, USA
| |
Collapse
|
7
|
Ghosh P, Bhattacharya M, Patra P, Sharma G, Patra BC, Lee SS, Sharma AR, Chakraborty C. Evaluation and Designing of Epitopic-Peptide Vaccine Against Bunyamwera orthobunyavirus Using M-Polyprotein Target Sequences. Int J Pept Res Ther 2021; 28:5. [PMID: 34867129 PMCID: PMC8634745 DOI: 10.1007/s10989-021-10322-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/17/2021] [Indexed: 11/30/2022]
Abstract
Bunyamwera orthobunyavirus and its serogroup can cause several diseases in humans, cattle, ruminants, and birds. The viral M-polyprotein helps the virus to enter the host body. Therefore, this protein might serve as a potential vaccine target against Bunyamwera orthobunyavirus. The present study applied the immunoinformatics technique to design an epitopic vaccine component that could protect against Bunyamwera infection. Phylogenetic analysis revealed the presence of conserved patterns of M-polyprotein within the viral serogroup. Three epitopes common for both B-cell and T-cell were identified, i.e., YQPTELTRS, YKAHDKEET, and ILGTGTPKF merged with a specific linker peptide to construct an active vaccine component. The low atomic contact energy value of docking complex between human TLR4 (TLR4/MD2 complex) and vaccine construct confirms the elevated protein–protein binding interaction. Molecular dynamic simulation and normal mode analysis illustrate the docking complex’s stability, especially by the higher Eigenvalue. In silico cloning of the vaccine construct was applied to amplify the desired vaccine component. Structural allocation of both the vaccine and epitopes also show the efficacy of the developed vaccine. Hence, the computational research design outcomes support that the peptide-based vaccine construction is a crucial drive target to limit the infection of Bunyamwera orthobunyavirus to an extent.
Collapse
Affiliation(s)
- Pratik Ghosh
- Department of Zoology, Vidyasagar University, Midnapore, West Bengal 721102 India
| | - Manojit Bhattacharya
- Department of Zoology, Fakir Mohan University, Vyasa Vihar, Balasore, Odisha 756020 India
| | - Prasanta Patra
- Department of Zoology, Vidyasagar University, Midnapore, West Bengal 721102 India
| | - Garima Sharma
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chuncheon-si, Republic of Korea
| | - Bidhan Chandra Patra
- Department of Zoology, Vidyasagar University, Midnapore, West Bengal 721102 India
| | - Sang-Soo Lee
- Institute for Skeletal Aging & Orthopedic Surgery, Hallym University-Chuncheon Sacred Heart Hospital, Chuncheon-si, 24252 Gangwon-do Republic of Korea
| | - Ashish Ranjan Sharma
- Institute for Skeletal Aging & Orthopedic Surgery, Hallym University-Chuncheon Sacred Heart Hospital, Chuncheon-si, 24252 Gangwon-do Republic of Korea
| | - Chiranjib Chakraborty
- Department of Biotechnology, School of Life Science and Biotechnology, Adamas University, Barasat-Barrackpore Rd, Kolkata, West Bengal 700126 India
| |
Collapse
|
8
|
Hepatitis C virus modulates signal peptide peptidase to alter host protein processing. Proc Natl Acad Sci U S A 2021; 118:2026184118. [PMID: 34035171 PMCID: PMC8179148 DOI: 10.1073/pnas.2026184118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The mechanism by which hepatitis C virus (HCV) evades immune surveillance and causes chronic infection is unclear. We demonstrate here that HCV core protein interferes with the maturation of major histocompatibility complex (MHC) class I catalyzed by signal peptide peptidase (SPP) and induces degradation via HMG-CoA reductase degradation 1 homolog. In addition, we found that the core protein transmembrane domain is homologous to the human cytomegalovirus US2 protein, whose transmembrane region also targets SPP to impair MHC class I molecule expression in a similar manner. Therefore, our data suggest that SPP represents a potential target for the impairment of MHC class I molecules by DNA and RNA viruses. Immunoevasins are viral proteins that prevent antigen presentation on major histocompatibility complex (MHC) class I, thus evading host immune recognition. Hepatitis C virus (HCV) evades immune surveillance to induce chronic infection; however, how HCV-infected hepatocytes affect immune cells and evade immune recognition remains unclear. Herein, we demonstrate that HCV core protein functions as an immunoevasin. Its expression interfered with the maturation of MHC class I molecules catalyzed by the signal peptide peptidase (SPP) and induced their degradation via HMG-CoA reductase degradation 1 homolog, thereby impairing antigen presentation to CD8+ T cells. The expression of MHC class I in the livers of HCV core transgenic mice and chronic hepatitis C patients was impaired but was restored in patients achieving sustained virological response. Finally, we show that the human cytomegalovirus US2 protein, possessing a transmembrane region structurally similar to the HCV core protein, targets SPP to impair MHC class I molecule expression. Thus, SPP represents a potential target for the impairment of MHC class I molecules by DNA and RNA viruses.
Collapse
|
9
|
Orthobunyaviruses: From Virus Binding to Penetration into Mammalian Host Cells. Viruses 2021; 13:v13050872. [PMID: 34068494 PMCID: PMC8151349 DOI: 10.3390/v13050872] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2021] [Revised: 05/05/2021] [Accepted: 05/07/2021] [Indexed: 12/04/2022] Open
Abstract
With over 80 members worldwide, Orthobunyavirus is the largest genus in the Peribunyaviridae family. Orthobunyaviruses (OBVs) are arthropod-borne viruses that are structurally simple, with a trisegmented, negative-sense RNA genome and only four structural proteins. OBVs are potential agents of emerging and re-emerging diseases and overall represent a global threat to both public and veterinary health. The focus of this review is on the very first steps of OBV infection in mammalian hosts, from virus binding to penetration and release of the viral genome into the cytosol. Here, we address the most current knowledge and advances regarding OBV receptors, endocytosis, and fusion.
Collapse
|
10
|
Hulswit RJG, Paesen GC, Bowden TA, Shi X. Recent Advances in Bunyavirus Glycoprotein Research: Precursor Processing, Receptor Binding and Structure. Viruses 2021; 13:353. [PMID: 33672327 PMCID: PMC7926653 DOI: 10.3390/v13020353] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/13/2021] [Accepted: 02/15/2021] [Indexed: 01/04/2023] Open
Abstract
The Bunyavirales order accommodates related viruses (bunyaviruses) with segmented, linear, single-stranded, negative- or ambi-sense RNA genomes. Their glycoproteins form capsomeric projections or spikes on the virion surface and play a crucial role in virus entry, assembly, morphogenesis. Bunyavirus glycoproteins are encoded by a single RNA segment as a polyprotein precursor that is co- and post-translationally cleaved by host cell enzymes to yield two mature glycoproteins, Gn and Gc (or GP1 and GP2 in arenaviruses). These glycoproteins undergo extensive N-linked glycosylation and despite their cleavage, remain associated to the virion to form an integral transmembrane glycoprotein complex. This review summarizes recent advances in our understanding of the molecular biology of bunyavirus glycoproteins, including their processing, structure, and known interactions with host factors that facilitate cell entry.
Collapse
Affiliation(s)
- Ruben J. G. Hulswit
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK; (R.J.G.H.); (G.C.P.)
| | - Guido C. Paesen
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK; (R.J.G.H.); (G.C.P.)
| | - Thomas A. Bowden
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK; (R.J.G.H.); (G.C.P.)
| | - Xiaohong Shi
- MRC-University of Glasgow Centre for Virus Research, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow G61 1QH, UK
| |
Collapse
|
11
|
A Look into Bunyavirales Genomes: Functions of Non-Structural (NS) Proteins. Viruses 2021; 13:v13020314. [PMID: 33670641 PMCID: PMC7922539 DOI: 10.3390/v13020314] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 02/12/2021] [Accepted: 02/16/2021] [Indexed: 12/13/2022] Open
Abstract
In 2016, the Bunyavirales order was established by the International Committee on Taxonomy of Viruses (ICTV) to incorporate the increasing number of related viruses across 13 viral families. While diverse, four of the families (Peribunyaviridae, Nairoviridae, Hantaviridae, and Phenuiviridae) contain known human pathogens and share a similar tri-segmented, negative-sense RNA genomic organization. In addition to the nucleoprotein and envelope glycoproteins encoded by the small and medium segments, respectively, many of the viruses in these families also encode for non-structural (NS) NSs and NSm proteins. The NSs of Phenuiviridae is the most extensively studied as a host interferon antagonist, functioning through a variety of mechanisms seen throughout the other three families. In addition, functions impacting cellular apoptosis, chromatin organization, and transcriptional activities, to name a few, are possessed by NSs across the families. Peribunyaviridae, Nairoviridae, and Phenuiviridae also encode an NSm, although less extensively studied than NSs, that has roles in antagonizing immune responses, promoting viral assembly and infectivity, and even maintenance of infection in host mosquito vectors. Overall, the similar and divergent roles of NS proteins of these human pathogenic Bunyavirales are of particular interest in understanding disease progression, viral pathogenesis, and developing strategies for interventions and treatments.
Collapse
|
12
|
Mentrup T, Cabrera-Cabrera F, Fluhrer R, Schröder B. Physiological functions of SPP/SPPL intramembrane proteases. Cell Mol Life Sci 2020; 77:2959-2979. [PMID: 32052089 PMCID: PMC7366577 DOI: 10.1007/s00018-020-03470-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 01/09/2020] [Accepted: 01/22/2020] [Indexed: 01/07/2023]
Abstract
Intramembrane proteolysis describes the cleavage of substrate proteins within their hydrophobic transmembrane segments. Several families of intramembrane proteases have been identified including the aspartyl proteases Signal peptide peptidase (SPP) and its homologues, the SPP-like (SPPL) proteases SPPL2a, SPPL2b, SPPL2c and SPPL3. As presenilin homologues, they employ a similar catalytic mechanism as the well-studied γ-secretase. However, SPP/SPPL proteases cleave transmembrane proteins with a type II topology. The characterisation of SPP/SPPL-deficient mouse models has highlighted a still growing spectrum of biological functions and also promoted the substrate discovery of these proteases. In this review, we will summarise the current hypotheses how phenotypes of these mouse models are linked to the molecular function of the enzymes. At the cellular level, SPP/SPPL-mediated cleavage events rather provide specific regulatory switches than unspecific bulk proteolysis. By this means, a plethora of different cell biological pathways is influenced including signal transduction, membrane trafficking and protein glycosylation.
Collapse
Affiliation(s)
- Torben Mentrup
- Institute for Physiological Chemistry, Medizinisch-Theoretisches Zentrum MTZ, Technische Universität Dresden, Fiedlerstraße 42, 01307, Dresden, Germany
| | - Florencia Cabrera-Cabrera
- Institute for Physiological Chemistry, Medizinisch-Theoretisches Zentrum MTZ, Technische Universität Dresden, Fiedlerstraße 42, 01307, Dresden, Germany
| | - Regina Fluhrer
- Biochemistry and Molecular Biology, Faculty of Medicine, University of Augsburg, Universitätsstraße 2, 86135, Augsburg, Germany
- Biomedizinisches Centrum (BMC), Ludwig Maximilians University of Munich, Feodor-Lynen-Strasse 17, 81377, Munich, Germany
- DZNE-German Center for Neurodegenerative Diseases, Munich, Feodor-Lynen-Strasse 17, 81377, Munich, Germany
| | - Bernd Schröder
- Institute for Physiological Chemistry, Medizinisch-Theoretisches Zentrum MTZ, Technische Universität Dresden, Fiedlerstraße 42, 01307, Dresden, Germany.
| |
Collapse
|
13
|
The Crimean-Congo Hemorrhagic Fever Virus NSm Protein is Dispensable for Growth In Vitro and Disease in Ifnar -/- Mice. Microorganisms 2020; 8:microorganisms8050775. [PMID: 32455700 PMCID: PMC7285326 DOI: 10.3390/microorganisms8050775] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 05/13/2020] [Accepted: 05/18/2020] [Indexed: 02/06/2023] Open
Abstract
Crimean-Congo hemorrhagic fever virus (CCHFV) is a tri-segmented, tick-borne nairovirus that causes disease of ranging severity in humans. The CCHFV M segment encodes a complex glycoprotein precursor (GPC) that undergoes extensive endoproteolytic cleavage, giving rise to two structural proteins (Gn and Gc) required for virus attachment and entry, and to multiple non-structural proteins (NSm, GP160, GP85, and GP38). The functions of these non-structural proteins remain largely unclear. Here, we investigate the role of NSm during infection by generating a recombinant CCHFV lacking the complete NSm domain (10200∆NSm) and observing CCHFV ∆NSm replication in cell lines and pathogenicity in Ifnar-/- mice. Our data demonstrate that the NSm domain is dispensable for viral replication in vitro, and, despite the delayed onset of clinical signs, CCHFV lacking this domain caused severe or lethal disease in infected mice.
Collapse
|
14
|
Elongin C Contributes to RNA Polymerase II Degradation by the Interferon Antagonist NSs of La Crosse Orthobunyavirus. J Virol 2020; 94:JVI.02134-19. [PMID: 31941775 PMCID: PMC7081911 DOI: 10.1128/jvi.02134-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 12/26/2019] [Indexed: 12/21/2022] Open
Abstract
The mosquito-borne La Crosse virus (LACV; genus Orthobunyavirus, family Peribunyaviridae, order Bunyavirales) is prevalent in the United States and can cause severe childhood meningoencephalitis. Its main virulence factor, the nonstructural protein NSs, is a strong inhibitor of the antiviral type I interferon (IFN) system. NSs acts by imposing a global host mRNA synthesis shutoff, mediated by NSs-driven proteasomal degradation of the RPB1 subunit of RNA polymerase II. Here, we show that RPB1 degradation commences as early as 1 h postinfection, and identify the E3 ubiquitin ligase subunit Elongin C (and its binding partners Elongins A and B) as an NSs cofactor involved in RPB1 degradation and in suppression of global as well as IFN-related mRNA synthesis. Mosquito-borne La Crosse virus (LACV; genus Orthobunyavirus, family Peribunyaviridae, order Bunyavirales) causes up to 100 annual cases of severe meningoencephalitis in children and young adults in the United States. A major virulence factor of LACV is the nonstructural protein NSs, which inhibits host cell mRNA synthesis to prevent the induction of antiviral type I interferons (IFN-α/β). To achieve this host transcriptional shutoff, LACV NSs drives the proteasomal degradation of RPB1, the large subunit of mammalian RNA polymerase II. Here, we show that NSs acts in a surprisingly rapid manner, as RPB1 degradation was commencing already at 1 h postinfection. The RPB1 degradation was partially dependent on the cellular E3 ubiquitin ligase subunit Elongin C. Consequently, removal of Elongin C, but also of the subunits Elongin A or B by siRNA transfection partially rescued general RNAP II transcription and IFN-beta mRNA synthesis from the blockade by NSs. In line with these results, LACV NSs was found to trigger the redistribution of Elongin C out of nucleolar speckles, which, however, is an epiphenomenon rather than part of the NSs mechanism. Our study also shows that the molecular phenotype of LACV NSs is different from RNA polymerase II inhibitors like α-amanitin or Rift Valley fever virus NSs, indicating that LACV is unique in involving the Elongin complex to shut off host transcription and IFN response. IMPORTANCE The mosquito-borne La Crosse virus (LACV; genus Orthobunyavirus, family Peribunyaviridae, order Bunyavirales) is prevalent in the United States and can cause severe childhood meningoencephalitis. Its main virulence factor, the nonstructural protein NSs, is a strong inhibitor of the antiviral type I interferon (IFN) system. NSs acts by imposing a global host mRNA synthesis shutoff, mediated by NSs-driven proteasomal degradation of the RPB1 subunit of RNA polymerase II. Here, we show that RPB1 degradation commences as early as 1 h postinfection, and identify the E3 ubiquitin ligase subunit Elongin C (and its binding partners Elongins A and B) as an NSs cofactor involved in RPB1 degradation and in suppression of global as well as IFN-related mRNA synthesis.
Collapse
|
15
|
Evolutionary Dynamics of Oropouche Virus in South America. J Virol 2020; 94:JVI.01127-19. [PMID: 31801869 PMCID: PMC7022353 DOI: 10.1128/jvi.01127-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 11/19/2019] [Indexed: 01/09/2023] Open
Abstract
The emergence and reemergence of pathogens such as Zika virus, chikungunya virus, and yellow fever virus have drawn attention toward other cocirculating arboviruses in South America. Oropouche virus (OROV) is a poorly studied pathogen responsible for over a dozen outbreaks since the early 1960s and represents a public health burden to countries such as Brazil, Panama, and Peru. OROV is likely underreported since its symptomatology can be easily confounded with other febrile illnesses (e.g., dengue fever and leptospirosis) and point-of-care testing for the virus is still uncommon. With limited data, there is a need to optimize the information currently available. Analysis of OROV genomes can help us understand how the virus circulates in nature and can reveal the evolutionary forces that shape the genetic diversity of the virus, which has implications for molecular diagnostics and the design of potential vaccines. The Amazon basin is home to numerous arthropod-borne viral pathogens that cause febrile disease in humans. Among these, Oropouche orthobunyavirus (OROV) is a relatively understudied member of the genus Orthobunyavirus, family Peribunyaviridae, that causes periodic outbreaks in human populations in Brazil and other South American countries. Although several studies have described the genetic diversity of the virus, the evolutionary processes that shape the OROV genome remain poorly understood. Here, we present a comprehensive study of the genomic dynamics of OROV that encompasses phylogenetic analysis, evolutionary rate estimates, inference of natural selective pressures, recombination and reassortment, and structural analysis of OROV variants. Our study includes all available published sequences, as well as a set of new OROV genome sequences obtained from patients in Ecuador, representing the first set of genomes from this country. Our results show differing evolutionary processes on the three segments that comprise the viral genome. We infer differing times of the most recent common ancestors of the genome segments and propose that this can be explained by cryptic reassortment. We also present the discovery of previously unobserved putative N-linked glycosylation sites, as well as codons that evolve under positive selection on the viral surface proteins, and discuss the potential role of these features in the evolution of OROV through a combined phylogenetic and structural approach. IMPORTANCE The emergence and reemergence of pathogens such as Zika virus, chikungunya virus, and yellow fever virus have drawn attention toward other cocirculating arboviruses in South America. Oropouche virus (OROV) is a poorly studied pathogen responsible for over a dozen outbreaks since the early 1960s and represents a public health burden to countries such as Brazil, Panama, and Peru. OROV is likely underreported since its symptomatology can be easily confounded with other febrile illnesses (e.g., dengue fever and leptospirosis) and point-of-care testing for the virus is still uncommon. With limited data, there is a need to optimize the information currently available. Analysis of OROV genomes can help us understand how the virus circulates in nature and can reveal the evolutionary forces that shape the genetic diversity of the virus, which has implications for molecular diagnostics and the design of potential vaccines.
Collapse
|
16
|
Kumar G, Dasgupta I. Comprehensive molecular insights into the stress response dynamics of rice (Oryza sativa L.) during rice tungro disease by RNA-seq-based comparative whole transcriptome analysis. J Biosci 2020. [DOI: 10.1007/s12038-020-9996-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
|
17
|
Kumar G, Dasgupta I. Comprehensive molecular insights into the stress response dynamics of rice ( Oryza sativa L.) during rice tungro disease by RNA-seq-based comparative whole transcriptome analysis. J Biosci 2020; 45:27. [PMID: 32020909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Rice tungro is a serious viral disease of rice resulting from infection by two viruses, Rice tungro bacilliform virus and Rice tungro spherical virus. To gain molecular insights into the global gene expression changes in rice during tungro, a comparative whole genome transcriptome study was performed on healthy and tungroaffected rice plants using Illumina Hiseq 2500. About 10 GB of sequenced data comprising about 50 million paired end reads per sample were then aligned on to the rice genome. Gene expression analysis revealed around 959 transcripts, related to various cellular pathways concerning stress response and hormonal homeostasis to be differentially expressed. The data was validated through qRT-PCR. Gene ontology and pathway analyses revealed enrichment of transcripts and processes similar to the differentially expressed genes categories. In short, the present study is a comprehensive coverage of the differential gene expression landscape and provides molecular insights into the infection dynamics of the rice-tungro virus system.
Collapse
Affiliation(s)
- Gaurav Kumar
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi 110 021, India
| | | |
Collapse
|
18
|
Berčič RL, Bányai K, Růžek D, Fehér E, Domán M, Danielová V, Bakonyi T, Nowotny N. Phylogenetic Analysis of Lednice Orthobunyavirus. Microorganisms 2019; 7:microorganisms7100447. [PMID: 31614950 PMCID: PMC6843640 DOI: 10.3390/microorganisms7100447] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 10/08/2019] [Accepted: 10/09/2019] [Indexed: 11/16/2022] Open
Abstract
Lednice virus (LEDV) has been detected in Culex modestus mosquitoes in several European countries within the last six decades. In this study, phylogenetic analyses of the complete genome segments confirm that LEDV belongs to the Turlock orthobunyavirus (Orthobunyavirus, Peribunyaviridae) species and is closely related to Umbre, Turlock, and Kedah viruses.
Collapse
Affiliation(s)
- Rebeka Lucijana Berčič
- Viral Zoonoses, Emerging and Vector-Borne Infections Group, Institute of Virology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210 Vienna, Austria.
- Department of Microbiology and Infectious Diseases, University of Veterinary Medicine, Hungária krt. 23-25, 1143 Budapest, Hungary.
| | - Krisztián Bányai
- Institute for Veterinary Medical Research, Centre for Agricultural Research, Hungarian Academy of Sciences, Hungária krt. 21, 1143 Budapest, Hungary.
| | - Daniel Růžek
- Department of Virology, Veterinary Research Institute, Hudcova 296, 621 00 Brno, Czech Republic.
- Institute of Parasitology, Biology Centre of the Czech Academy of Sciences, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic.
| | - Enikő Fehér
- Institute for Veterinary Medical Research, Centre for Agricultural Research, Hungarian Academy of Sciences, Hungária krt. 21, 1143 Budapest, Hungary.
| | - Marianna Domán
- Institute for Veterinary Medical Research, Centre for Agricultural Research, Hungarian Academy of Sciences, Hungária krt. 21, 1143 Budapest, Hungary.
| | - Vlasta Danielová
- National Institute of Public Health, Centre of Epidemiology and Microbiology, Šrobárova 48, 10042 Prague, Czech Republic.
| | - Tamás Bakonyi
- Viral Zoonoses, Emerging and Vector-Borne Infections Group, Institute of Virology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210 Vienna, Austria.
- Department of Microbiology and Infectious Diseases, University of Veterinary Medicine, Hungária krt. 23-25, 1143 Budapest, Hungary.
| | - Norbert Nowotny
- Viral Zoonoses, Emerging and Vector-Borne Infections Group, Institute of Virology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, 1210 Vienna, Austria.
- Department of Basic Medical Sciences, College of Medicine, Mohammed Bin Rashid University of Medicine and Health Sciences, Building 14, Dubai Healthcare, Dubai, UAE.
| |
Collapse
|
19
|
Williams SH, Che X, Oleynik A, Garcia JA, Muller D, Zabka TS, Firth C, Corrigan RM, Briese T, Jain K, Lipkin WI. Discovery of two highly divergent negative-sense RNA viruses associated with the parasitic nematode, Capillaria hepatica, in wild Mus musculus from New York City. J Gen Virol 2019; 100:1350-1362. [PMID: 31513008 PMCID: PMC7363305 DOI: 10.1099/jgv.0.001315] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Recent advances in high-throughput sequencing technology have led to a rapid expansion in the number of viral sequences associated with samples from vertebrates, invertebrates and environmental samples. Accurate host identification can be difficult in assays of complex samples that contain more than one potential host. Using unbiased metagenomic sequencing, we investigated wild house mice (Mus musculus) and brown rats (Rattus norvegicus) from New York City to determine the aetiology of liver disease. Light microscopy was used to characterize liver disease, and fluorescent microscopy with in situ hybridization was employed to identify viral cell tropism. Sequences representing two novel negative-sense RNA viruses were identified in homogenates of wild house mouse liver tissue: Amsterdam virus and Fulton virus. In situ hybridization localized viral RNA to Capillaria hepatica, a parasitic nematode that had infected the mouse liver. RNA from either virus was found within nematode adults and unembryonated eggs. Expanded PCR screening identified brown rats as a second rodent host for C. hepatica as well as both nematode-associated viruses. Our findings indicate that the current diversity of nematode-associated viruses may be underappreciated and that anatomical imaging offers an alternative to computational host assignment approaches.
Collapse
Affiliation(s)
- Simon H Williams
- Center for Infection and Immunity, Columbia University, New York, NY, USA
| | - Xiaoyu Che
- Center for Infection and Immunity, Columbia University, New York, NY, USA
| | - Alexandra Oleynik
- Center for Infection and Immunity, Columbia University, New York, NY, USA
| | - Joel A Garcia
- Center for Infection and Immunity, Columbia University, New York, NY, USA
| | - Dorothy Muller
- Center for Infection and Immunity, Columbia University, New York, NY, USA
| | - Tanja S Zabka
- Development Sciences Safety Assessment, Genentech, Inc., South San Francisco, California
| | - Cadhla Firth
- Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Australia
| | | | - Thomas Briese
- Center for Infection and Immunity, Columbia University, New York, NY, USA
| | - Komal Jain
- Center for Infection and Immunity, Columbia University, New York, NY, USA
| | - W Ian Lipkin
- Center for Infection and Immunity, Columbia University, New York, NY, USA
| |
Collapse
|
20
|
Throw out the Map: Neuropathogenesis of the Globally Expanding California Serogroup of Orthobunyaviruses. Viruses 2019; 11:v11090794. [PMID: 31470541 PMCID: PMC6784171 DOI: 10.3390/v11090794] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 08/23/2019] [Accepted: 08/26/2019] [Indexed: 12/19/2022] Open
Abstract
The California serogroup (CSG) comprises 18 serologically and genetically related mosquito-borne orthobunyaviruses. Of these viruses, at least seven have been shown to cause neurological disease in humans, including the leading cause of pediatric arboviral encephalitis in the USA, La Crosse virus. Despite the disease burden from these viruses, much is still unknown about the CSG viruses. This review summarizes our current knowledge of the CSG viruses, including human disease and the mechanisms of neuropathogenesis.
Collapse
|
21
|
Plegge T, Spiegel M, Krüger N, Nehlmeier I, Winkler M, González Hernández M, Pöhlmann S. Inhibitors of signal peptide peptidase and subtilisin/kexin-isozyme 1 inhibit Ebola virus glycoprotein-driven cell entry by interfering with activity and cellular localization of endosomal cathepsins. PLoS One 2019; 14:e0214968. [PMID: 30973897 PMCID: PMC6459477 DOI: 10.1371/journal.pone.0214968] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 03/24/2019] [Indexed: 11/30/2022] Open
Abstract
Emerging viruses such as severe fever and thrombocytopenia syndrome virus (SFTSV) and Ebola virus (EBOV) are responsible for significant morbidity and mortality. Host cell proteases that process the glycoproteins of these viruses are potential targets for antiviral intervention. The aspartyl protease signal peptide peptidase (SPP) has recently been shown to be required for processing of the glycoprotein precursor, Gn/Gc, of Bunyamwera virus and for viral infectivity. Here, we investigated whether SPP is also required for infectivity of particles bearing SFTSV-Gn/Gc. Entry driven by the EBOV glycoprotein (GP) and the Lassa virus glycoprotein (LASV-GPC) depends on the cysteine proteases cathepsin B and L (CatB/CatL) and the serine protease subtilisin/kexin-isozyme 1 (SKI-1), respectively, and was examined in parallel for control purposes. We found that inhibition of SPP and SKI-1 did not interfere with SFTSV Gn + Gc-driven entry but, unexpectedly, blocked entry mediated by EBOV-GP. The inhibition occurred at the stage of proteolytic activation and the SPP inhibitor was found to block CatL/CatB activity. In contrast, the SKI-1 inhibitor did not interfere with CatB/CatL activity but disrupted CatB localization in endo/lysosomes, the site of EBOV-GP processing. These results underline the potential of protease inhibitors for antiviral therapy but also show that previously characterized compounds might exert broader specificity than initially appreciated and might block viral entry via diverse mechanisms.
Collapse
Affiliation(s)
- Teresa Plegge
- Infection Biology Unit, German Primate Center–Leibniz Institute for Primate Research, Göttingen, Germany
- Faculty of Biology and Psychology, University Göttingen, Göttingen, Germany
| | - Martin Spiegel
- Infection Biology Unit, German Primate Center–Leibniz Institute for Primate Research, Göttingen, Germany
- Institute of Microbiology and Virology, Brandenburg Medical School Theodor Fontane, Senftenberg, Germany
| | - Nadine Krüger
- Institute of Virology, University of Veterinary Medicine Hannover, Hannover, Germany
- Research Center for Emerging Infections and Zoonoses, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Inga Nehlmeier
- Infection Biology Unit, German Primate Center–Leibniz Institute for Primate Research, Göttingen, Germany
| | - Michael Winkler
- Infection Biology Unit, German Primate Center–Leibniz Institute for Primate Research, Göttingen, Germany
| | - Mariana González Hernández
- Infection Biology Unit, German Primate Center–Leibniz Institute for Primate Research, Göttingen, Germany
- Faculty of Biology and Psychology, University Göttingen, Göttingen, Germany
| | - Stefan Pöhlmann
- Infection Biology Unit, German Primate Center–Leibniz Institute for Primate Research, Göttingen, Germany
- Faculty of Biology and Psychology, University Göttingen, Göttingen, Germany
- * E-mail:
| |
Collapse
|
22
|
Hellert J, Aebischer A, Wernike K, Haouz A, Brocchi E, Reiche S, Guardado-Calvo P, Beer M, Rey FA. Orthobunyavirus spike architecture and recognition by neutralizing antibodies. Nat Commun 2019; 10:879. [PMID: 30787296 PMCID: PMC6382863 DOI: 10.1038/s41467-019-08832-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 01/29/2019] [Indexed: 12/29/2022] Open
Abstract
Orthobunyaviruses (OBVs) form a distinct genus of arthropod-borne bunyaviruses that can cause severe disease upon zoonotic transmission to humans. Antigenic drift or genome segment re-assortment have in the past resulted in new pathogenic OBVs, making them potential candidates for causing emerging zoonoses in the future. Low-resolution electron cryo-tomography studies have shown that OBV particles feature prominent trimeric spikes, but their molecular organization remained unknown. Here we report X-ray crystallography studies of four different OBVs showing that the spikes are formed by an N-terminal extension of the fusion glycoprotein Gc. Using Schmallenberg virus, a recently emerged OBV, we also show that the projecting spike is the major target of the neutralizing antibody response, and provide X-ray structures in complex with two protecting antibodies. We further show that immunization of mice with the spike domains elicits virtually sterilizing immunity, providing fundamental knowledge essential in the preparation for potential newly emerging OBV zoonoses. Orthobunyaviruses (OBVs) cause severe disease in humans and farm animals, but the molecular basis for infection is not fully understood. Here, the authors present crystal structures of free and antibody-bound OBV envelope glycoproteins and show that their domains enable efficient immunization in a mouse model.
Collapse
Affiliation(s)
- Jan Hellert
- Structural Virology Unit, Virology Department, Institut Pasteur, CNRS UMR 3569, 25-28 rue du Dr. Roux, 75015, Paris, France
| | - Andrea Aebischer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Kerstin Wernike
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Ahmed Haouz
- Crystallography Platform, Department of Structural Biology and Chemistry, Institut Pasteur, CNRS UMR 3528, 25-28 rue du Dr. Roux, 75015, Paris, France
| | - Emiliana Brocchi
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, Via Bianchi 7, 25125, Brescia, Italy
| | - Sven Reiche
- Department of Experimental Animal Facilities and Biorisk Management, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany
| | - Pablo Guardado-Calvo
- Structural Virology Unit, Virology Department, Institut Pasteur, CNRS UMR 3569, 25-28 rue du Dr. Roux, 75015, Paris, France
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493, Greifswald, Insel Riems, Germany.
| | - Félix A Rey
- Structural Virology Unit, Virology Department, Institut Pasteur, CNRS UMR 3569, 25-28 rue du Dr. Roux, 75015, Paris, France.
| |
Collapse
|
23
|
Hsu FF, Chou YT, Chiang MT, Li FA, Yeh CT, Lee WH, Chau LY. Signal peptide peptidase promotes tumor progression via facilitating FKBP8 degradation. Oncogene 2018; 38:1688-1701. [PMID: 30348988 DOI: 10.1038/s41388-018-0539-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 08/28/2018] [Accepted: 09/21/2018] [Indexed: 11/09/2022]
Abstract
Signal peptide peptidase (SPP) is an endoplasmic reticulum (ER)-resident aspartyl protease mediating intramembrane cleavage of type II transmembrane proteins. Increasing evidence has supported the role of SPP in ER-associated protein degradation. In the present study, we show that SPP expression is highly induced in human lung and breast cancers and correlated with disease outcome. Stable depletion of SPP expression in lung and breast cancer cell lines significantly reduced cell growth and migration/invasion abilities. Quantitative analysis of the proteomic changes of microsomal proteins in lung cancer cells by the stable isotope labeling with amino acids in cell culture (SILAC) approach revealed that the level of FKBP8, an endogenous inhibitor of mTOR, was significantly increased following SPP depletion. Co-immunoprecipitation assay and confocal immunofluorescence demonstrated that SPP interacted and colocalized with FKBP8 in ER, supporting that FKBP8 is a protein substrate of SPP. Cycloheximide chase and proteasome inhibition experiments revealed that SPP-mediated proteolysis facilitated FKBP8 protein degradation in cytosol. Further experiment demonstrated that the levels of phosphorylation in mTOR and its downstream effectors, S6K and 4E-BP1, were significantly lower in SPP-depleted cells. The reduced mTOR signaling and decreases of growth and migration/invasion abilities induced by SPP depletion in cancer cells could be reversed by FKBP8 downregulation. The implication of FKBP8 in SPP-mediated tumorigenicity was also observed in the xenograft model. Together, these findings disclose that SPP promotes tumor progression, at least in part, via facilitating the degradation of FKBP8 to enhance mTOR signaling.
Collapse
Affiliation(s)
- Fu-Fei Hsu
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yi-Tai Chou
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Ming-Tsai Chiang
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Fu-An Li
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Chi-Tai Yeh
- Cancer Center, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan
| | - Wei-Hwa Lee
- Cancer Center, Shuang Ho Hospital, Taipei Medical University, Taipei, Taiwan
| | - Lee-Young Chau
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
| |
Collapse
|
24
|
Interferon-Stimulated Gene (ISG)-Expression Screening Reveals the Specific Antibunyaviral Activity of ISG20. J Virol 2018; 92:JVI.02140-17. [PMID: 29695422 PMCID: PMC6002717 DOI: 10.1128/jvi.02140-17] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 04/14/2018] [Indexed: 11/20/2022] Open
Abstract
Bunyaviruses pose a significant threat to human health, prosperity, and food security. In response to viral infections, interferons (IFNs) upregulate the expression of hundreds of interferon-stimulated genes (ISGs), whose cumulative action can potently inhibit the replication of bunyaviruses. We used a flow cytometry-based method to screen the ability of ∼500 unique ISGs from humans and rhesus macaques to inhibit the replication of Bunyamwera orthobunyavirus (BUNV), the prototype of both the Peribunyaviridae family and the Bunyavirales order. Candidates possessing antibunyaviral activity were further examined using a panel of divergent bunyaviruses. Interestingly, one candidate, ISG20, exhibited potent antibunyaviral activity against most viruses examined from the Peribunyaviridae, Hantaviridae, and Nairoviridae families, whereas phleboviruses (Phenuiviridae) largely escaped inhibition. Similar to the case against other viruses known to be targeted by ISG20, the antibunyaviral activity of ISG20 is dependent upon its functional RNase activity. Through use of an infectious virus-like particle (VLP) assay (based on the BUNV minigenome system), we confirmed that gene expression from all 3 viral segments is strongly inhibited by ISG20. Using in vitro evolution, we generated a substantially ISG20-resistant BUNV and mapped the determinants of ISG20 sensitivity/resistance. Taking all the data together, we report that ISG20 is a broad and potent antibunyaviral factor but that some bunyaviruses are remarkably ISG20 resistant. Thus, ISG20 sensitivity/resistance may influence the pathogenesis of bunyaviruses, many of which are emerging viruses of clinical or veterinary significance. IMPORTANCE There are hundreds of bunyaviruses, many of which cause life-threatening acute diseases in humans and livestock. The interferon (IFN) system is a key component of innate immunity, and type I IFNs limit bunyaviral propagation both in vitro and in vivo. Type I IFN signaling results in the upregulation of hundreds of IFN-stimulated genes (ISGs), whose concerted action generates an “antiviral state.” Although IFNs are critical in limiting bunyaviral replication and pathogenesis, much is still unknown about which ISGs inhibit bunyaviruses. Using ISG-expression screening, we examined the ability of ∼500 unique ISGs to inhibit Bunyamwera orthobunyavirus (BUNV), the prototypical bunyavirus. Using this approach, we identified ISG20, an interferon-stimulated exonuclease, as a potent inhibitor of BUNV. Interestingly, ISG20 possesses highly selective antibunyaviral activity, with multiple bunyaviruses being potently inhibited while some largely escape inhibition. We speculate that the ability of some bunyaviruses to escape ISG20 may influence their pathogenesis.
Collapse
|
25
|
Nunes MRT, de Souza WM, Acrani GO, Cardoso JF, da Silva SP, Badra SJ, Figueiredo LTM, Vasconcelos PFDC. Revalidation and genetic characterization of new members of Group C (Orthobunyavirus genus, Peribunyaviridae family) isolated in the Americas. PLoS One 2018; 13:e0197294. [PMID: 29795585 PMCID: PMC5967719 DOI: 10.1371/journal.pone.0197294] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 04/30/2018] [Indexed: 01/06/2023] Open
Abstract
Group C serogroup includes members of the Orthobunyavirus genus (family Peribunyaviridae) and comprises 15 arboviruses that can be associated with febrile illness in humans. Although previous studies described the genome characterization of Group C orthobunyavirus, there is a gap in genomic information about the other viruses in this group. Therefore, in this study, complete genomes of members of Group C serogroup were sequenced or re-sequenced and used for genetic characterization, as well as to understand their phylogenetic and evolutionary aspects. Thus, our study reported the genomes of three new members in Group C virus (Apeu strain BeAn848, Itaqui strain BeAn12797 and Nepuyo strain BeAn10709), as well as re-sequencing of original strains of five members: Caraparu (strain BeAn3994), Madrid (strain BT4075), Murucutu (strain BeAn974), Oriboca (strain BeAn17), and Marituba (strain BeAn15). These viruses presented a typical genomic organization related to members of the Orthobunyavirus genus. Interestingly, all viruses of this serogroup showed an open reading frame (ORF) that encodes the putative nonstructural NSs protein that precedes the nucleoprotein ORF, an unprecedented fact in Group C virus. Also, we confirmed the presence of natural reassortment events. This study expands the genomic information of Group C viruses, as well as revalidates the genomic organization of viruses that were previously reported.
Collapse
Affiliation(s)
- Márcio Roberto Teixeira Nunes
- Center for Technological Innovation, Evandro Chagas Institute, Ministry of Health, Ananindeua, Pará, Brazil
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas, United States of America
- * E-mail: (MRT); (PFCV)
| | - William Marciel de Souza
- Virology Research Center, School of Medicine of Ribeirão Preto of University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | | | - Jedson Ferreira Cardoso
- Center for Technological Innovation, Evandro Chagas Institute, Ministry of Health, Ananindeua, Pará, Brazil
| | - Sandro Patroca da Silva
- Center for Technological Innovation, Evandro Chagas Institute, Ministry of Health, Ananindeua, Pará, Brazil
| | - Soraya Jabur Badra
- Virology Research Center, School of Medicine of Ribeirão Preto of University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Luiz Tadeu Moraes Figueiredo
- Virology Research Center, School of Medicine of Ribeirão Preto of University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Pedro Fernando da Costa Vasconcelos
- Department of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute, Ministry of Health, Ananindeua, Pará, Brazil
- * E-mail: (MRT); (PFCV)
| |
Collapse
|
26
|
Rodamilans B, Shan H, Pasin F, García JA. Plant Viral Proteases: Beyond the Role of Peptide Cutters. FRONTIERS IN PLANT SCIENCE 2018; 9:666. [PMID: 29868107 PMCID: PMC5967125 DOI: 10.3389/fpls.2018.00666] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 04/30/2018] [Indexed: 05/23/2023]
Abstract
Almost half of known plant viral species rely on proteolytic cleavages as key co- and post-translational modifications throughout their infection cycle. Most of these viruses encode their own endopeptidases, proteases with high substrate specificity that internally cleave large polyprotein precursors for the release of functional sub-units. Processing of the polyprotein, however, is not an all-or-nothing process in which endopeptidases act as simple peptide cutters. On the contrary, spatial-temporal modulation of these polyprotein cleavage events is crucial for a successful viral infection. In this way, the processing of the polyprotein coordinates viral replication, assembly and movement, and has significant impact on pathogen fitness and virulence. In this mini-review, we give an overview of plant viral proteases emphasizing their importance during viral infections and the varied functionalities that result from their proteolytic activities.
Collapse
Affiliation(s)
- Bernardo Rodamilans
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain
| | - Hongying Shan
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain
| | - Fabio Pasin
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan
| | - Juan Antonio García
- Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain
| |
Collapse
|
27
|
Kraatz F, Wernike K, Reiche S, Aebischer A, Reimann I, Beer M. Schmallenberg virus non-structural protein NSm: Intracellular distribution and role of non-hydrophobic domains. Virology 2018; 516:46-54. [PMID: 29329078 DOI: 10.1016/j.virol.2017.12.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2017] [Revised: 12/20/2017] [Accepted: 12/28/2017] [Indexed: 12/20/2022]
Abstract
Schmallenberg virus (SBV) induces fetal malformation, abortions and stillbirth in ruminants. While the non-structural protein NSs is a major virulence factor, the biological function of NSm, the second non-structural protein which consists of three hydrophobic transmembrane (I, III, V) and two non-hydrophobic regions (II, IV), is still unknown. Here, a series of NSm mutants displaying deletions of nearly the entire NSm or of the non-hydrophobic domains was generated and the intracellular distribution of NSm was assessed. SBV-NSm is dispensable for the generation of infectious virus and mutants lacking domains II - V showed growth properties similar to the wild-type virus. In addition, a comparable intracellular distribution of SBV-NSm was observed in mammalian cells infected with domain II mutants or wild-type virus. In both cases, NSm co-localized with the glycoprotein Gc in the Golgi compartment. However, domain IV-deletion mutants showed an altered distribution pattern and no co-localization of NSm and Gc.
Collapse
Affiliation(s)
- Franziska Kraatz
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald, Insel Riems, Germany
| | - Kerstin Wernike
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald, Insel Riems, Germany
| | - Sven Reiche
- Department of Experimental Animal Facilities and Biorisk Management, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald, Insel Riems, Germany
| | - Andrea Aebischer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald, Insel Riems, Germany
| | - Ilona Reimann
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald, Insel Riems, Germany
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Südufer 10, 17493 Greifswald, Insel Riems, Germany.
| |
Collapse
|
28
|
Hirano J, Okamoto T, Sugiyama Y, Suzuki T, Kusakabe S, Tokunaga M, Fukuhara T, Sasai M, Tougan T, Matsunaga Y, Yamashita K, Sakai Y, Yamamoto M, Horii T, Standley DM, Moriishi K, Moriya K, Koike K, Matsuura Y. Characterization of SPP inhibitors suppressing propagation of HCV and protozoa. Proc Natl Acad Sci U S A 2017; 114:E10782-E10791. [PMID: 29187532 PMCID: PMC5740650 DOI: 10.1073/pnas.1712484114] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Signal peptide peptidase (SPP) is an intramembrane aspartic protease involved in the maturation of the core protein of hepatitis C virus (HCV). The processing of HCV core protein by SPP has been reported to be critical for the propagation and pathogenesis of HCV. Here we examined the inhibitory activity of inhibitors for γ-secretase, another intramembrane cleaving protease, against SPP, and our findings revealed that the dibenzoazepine-type structure in the γ-secretase inhibitors is critical for the inhibition of SPP. The spatial distribution showed that the γ-secretase inhibitor compound YO-01027 with the dibenzoazepine structure exhibits potent inhibiting activity against SPP in vitro and in vivo through the interaction of Val223 in SPP. Treatment with this SPP inhibitor suppressed the maturation of core proteins of all HCV genotypes without the emergence of drug-resistant viruses, in contrast to the treatment with direct-acting antivirals. YO-01027 also efficiently inhibited the propagation of protozoa such as Plasmodium falciparum and Toxoplasma gondii These data suggest that SPP is an ideal target for the development of therapeutics not only against chronic hepatitis C but also against protozoiasis.
Collapse
Affiliation(s)
- Junki Hirano
- Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Toru Okamoto
- Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan;
| | - Yukari Sugiyama
- Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Tatsuya Suzuki
- Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Shinji Kusakabe
- Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Makoto Tokunaga
- Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Takasuke Fukuhara
- Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Miwa Sasai
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Takahiro Tougan
- Department of Molecular Protozoology, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Yasue Matsunaga
- Planning and Promotion Office for University-Industry Collaboration, Osaka University, Osaka 565-0871, Japan
| | | | - Yusuke Sakai
- Department of Veterinary Pathology, Yamaguchi University, Yamaguchi 753-0841, Japan
| | - Masahiro Yamamoto
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Toshihiro Horii
- Department of Molecular Protozoology, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Daron M Standley
- Department of Genome Informatics, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Kohji Moriishi
- Department of Microbiology, Faculty of Medicine, University of Yamanashi, Yamanashi 400-8510, Japan
| | - Kyoji Moriya
- Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-8654, Japan
| | - Kazuhiko Koike
- Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo 113-8654, Japan
| | - Yoshiharu Matsuura
- Department of Molecular Virology, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan;
| |
Collapse
|
29
|
Kumar S, Subbarao BL, Hallan V. Molecular characterization of emaraviruses associated with Pigeonpea sterility mosaic disease. Sci Rep 2017; 7:11831. [PMID: 28928453 PMCID: PMC5605523 DOI: 10.1038/s41598-017-11958-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 08/23/2017] [Indexed: 12/20/2022] Open
Abstract
Sterility Mosaic Disease (SMD) of pigeonpea (Cajanus cajan (L.) Millspaugh) is a complex disease due to various factors including the presence of a mixed infection. Comparison of dsRNA profile and small RNA (sRNA) deep sequencing analysis of samples from three locations revealed the presence of Pigeonpea sterility mosaic virus-I and II (PPSMV-I and II) from Chevella and only PPSMV-II from Bengaluru and Coimbatore. PPSMV-I genome consisted of four while PPSMV-II encompassed six RNAs. The two viruses have modest sequence homology between their corresponding RNA 1-4 encoding RdRp, glycoprotein precursor, nucleocapsid and movement proteins and the corresponding orthologs of other emaraviruses. However, PPSMV-II is more related to Fig mosaic virus (FMV) than to PPSMV-I. ELISA based detection methodology was standardized to identify these two viruses, uniquely. Mite inoculation of sub-isolate Chevella sometimes resulted in few- to- many pigeonpea plants containing PPSMV-I alone. The study shows that (i) the N-terminal region of RdRp (SRD-1) of both the viruses contain "cap-snatching" endonuclease domain and a 13 AA cap binding site at the C-terminal, essential for viral cap-dependent transcription similar to the members of Bunyaviridae family and (ii) P4 is the movement protein and may belong to '30 K superfamily' of MPs.
Collapse
Affiliation(s)
- Surender Kumar
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Institute of Himalayan Bioresource Technology (CSIR-IHBT) Campus, Palampur, 176061, India
- Plant Virology Lab, Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, HP, 176061, India
| | - B L Subbarao
- House # B-88, 3rd Ave, 6th Cross, Sainikpuri, Secunderabad, 500 094, Telangana, India
| | - Vipin Hallan
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Institute of Himalayan Bioresource Technology (CSIR-IHBT) Campus, Palampur, 176061, India.
- Plant Virology Lab, Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, HP, 176061, India.
| |
Collapse
|
30
|
Mentrup T, Fluhrer R, Schröder B. Latest emerging functions of SPP/SPPL intramembrane proteases. Eur J Cell Biol 2017; 96:372-382. [DOI: 10.1016/j.ejcb.2017.03.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 02/28/2017] [Accepted: 03/02/2017] [Indexed: 10/20/2022] Open
|
31
|
Roman-Sosa G, Karger A, Kraatz F, Aebischer A, Wernike K, Maksimov P, Lillig CH, Reimann I, Brocchi E, Keller M, Beer M. The amino terminal subdomain of glycoprotein Gc of Schmallenberg virus: disulfide bonding and structural determinants of neutralization. J Gen Virol 2017. [PMID: 28640745 DOI: 10.1099/jgv.0.000810] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Orthobunyaviruses are enveloped viruses that can cause human and animal diseases. A novel and major member is the Schmallenberg virus (SBV), the etiological agent of an emerging disease of ruminants that has been spreading all over Europe since 2011. The glycoproteins Gn and Gc of orthobunyaviruses mediate the viral entry, and specifically Gc is a major target for the humoral immune response. For example, the N terminal subdomain of the SBV glycoprotein Gc is targeted by neutralizing monoclonal antibodies that recognize conformational epitopes. Here, we determined the structural features of the N terminus of Gc, and analysed its interaction with monoclonal antibodies. We were able to demonstrate that one of two N-glycosylation sites is essential for secretion and interaction with a subset of Gc-specific monoclonal antibodies. Furthermore, four disulfide bonds (S-S) were identified and the deletion of the third S-S blocked reactivity with another subset of mAbs with virus-neutralizing and non-neutralizing activity. The mutagenesis of the N-glycosylation sites and the disulfide bonds strongly indicated the independent folding of two subdomains within the SBV Gc N terminus. Further, the epitopes recognized by a panel of mAbs could be grouped into two clusters, as revealed by fine mapping using chimeric proteins. Combining the disulfide bonding and epitope mapping allowed us to generate a structural model of the SBV Gc N-terminus. This novel information about the role and structure of the amino terminal region of SBV Gc is of general relevance for the design of antivirals and vaccines against this virus.
Collapse
Affiliation(s)
- Gleyder Roman-Sosa
- Present address: Unité de Virologie Structurale, Institut Pasteur, France.,Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Axel Karger
- Institute of Molecular Virology and Cell Biology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Franziska Kraatz
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Andrea Aebischer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Kerstin Wernike
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Pavlo Maksimov
- Institute of Epidemiology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Christopher H Lillig
- Institute for Medical Biochemistry and Molecular Biology, Ernst Moritz Arndt University, Greifswald, Germany
| | - Ilona Reimann
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Emiliana Brocchi
- Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, Brescia, Italy
| | - Markus Keller
- Institute for Novel and Emerging Infectious Diseases, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| | - Martin Beer
- Institute of Diagnostic Virology, Friedrich-Loeffler-Institut, Greifswald-Insel Riems, Germany
| |
Collapse
|
32
|
Signal peptide peptidase and SPP-like proteases - Possible therapeutic targets? BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2017. [PMID: 28624439 DOI: 10.1016/j.bbamcr.2017.06.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Signal peptide peptidase (SPP) and the four homologous SPP-like proteases SPPL2a, SPPL2b, SPPL2c and SPPL3 are GxGD-type intramembrane-cleaving proteases (I-CLIPs). In addition to divergent subcellular localisations, distinct differences in the mechanistic properties and substrate requirements of individual family members have been unravelled. SPP/SPPL proteases employ a catalytic mechanism related to that of the γ-secretase complex. Nevertheless, differential targeting of SPP/SPPL proteases and γ-secretase by inhibitors has been demonstrated. Furthermore, also within the SPP/SPPL family significant differences in the sensitivity to currently available inhibitory compounds have been reported. Though far from complete, our knowledge on pathophysiological functions of SPP/SPPL proteases, in particular based on studies in mice, has been significantly increased over the last years. Based on this, inhibition of distinct SPP/SPPL proteases has been proposed as a novel therapeutic concept e.g. for the treatment of autoimmunity and viral or protozoal infections, as we will discuss in this review. This article is part of a Special Issue entitled: Proteolysis as a Regulatory Event in Pathophysiology edited by Stefan Rose-John.
Collapse
|
33
|
Abstract
The Bunyavirales Order encompasses nine families of enveloped viruses containing a single-stranded negative-sense RNA genome divided into three segments. The small (S) and large (L) segments encode proteins participating in genome replication in the infected cell cytoplasm. The middle (M) segment encodes the viral glycoproteins Gn and Gc, which are derived from a precursor polyprotein by host cell proteases. Entry studies are available only for a few viruses in the Order, and in each case they were shown to enter cells via receptor-mediated endocytosis. The acidic endosomal pH triggers the fusion of the viral envelope with the membrane of an endosome. Structural studies on two members of this Order, the phleboviruses and the hantaviruses, have shown that the membrane fusion protein Gc displays a class II fusion protein fold and is homologous to its counterparts in flaviviruses and alphaviruses, which are positive-sense, single-stranded RNA viruses. We analyze here recent data on the structure and function of the structure of the phlebovirus Gc and hantavirus Gn and Gc glycoproteins, and extrapolate common features identified in the amino acid sequences to understand also the structure and function of their counterparts in other families of the Bunyavirales Order. Our analysis also identified clear structural homology between the hantavirus Gn and alphavirus E2 glycoproteins, which make a heterodimer with the corresponding fusion proteins Gc and E1, respectively, revealing that not only the fusion protein has been conserved across viral families.
Collapse
Affiliation(s)
- Pablo Guardado-Calvo
- Institut Pasteur, Unité de Virologie Structurale, Paris Cedex 15, France; CNRS UMR 3569 Virologie, Paris Cedex 15, France
| | - Félix A Rey
- Institut Pasteur, Unité de Virologie Structurale, Paris Cedex 15, France; CNRS UMR 3569 Virologie, Paris Cedex 15, France.
| |
Collapse
|
34
|
Mouse Mammary Tumor Virus Signal Peptide Uses a Novel p97-Dependent and Derlin-Independent Retrotranslocation Mechanism To Escape Proteasomal Degradation. mBio 2017; 8:mBio.00328-17. [PMID: 28351922 PMCID: PMC5371415 DOI: 10.1128/mbio.00328-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Multiple pathogens, including viruses and bacteria, manipulate endoplasmic reticulum-associated degradation (ERAD) to avoid the host immune response and promote their replication. The betaretrovirus mouse mammary tumor virus (MMTV) encodes Rem, which is a precursor protein that is cleaved into a 98-amino-acid signal peptide (SP) and a C-terminal protein (Rem-CT). SP uses retrotranslocation for ER membrane extraction and yet avoids ERAD by an unknown mechanism to enter the nucleus and function as a Rev-like protein. To determine how SP escapes ERAD, we used a ubiquitin-activated interaction trap (UBAIT) screen to trap and identify transient protein interactions with SP, including the ERAD-associated p97 ATPase, but not E3 ligases or Derlin proteins linked to retrotranslocation, polyubiquitylation, and proteasomal degradation of extracted proteins. A dominant negative p97 ATPase inhibited both Rem and SP function. Immunoprecipitation experiments indicated that Rem, but not SP, is polyubiquitylated. Using both yeast and mammalian expression systems, linkage of a ubiquitin-like domain (UbL) to SP or Rem induced degradation by the proteasome, whereas SP was stable in the absence of the UbL. ERAD-associated Derlin proteins were not required for SP activity. Together, these results suggested that Rem uses a novel p97-dependent, Derlin-independent retrotranslocation mechanism distinct from other pathogens to avoid SP ubiquitylation and proteasomal degradation. Bacterial and viral infections produce pathogen-specific proteins that interfere with host functions, including the immune response. Mouse mammary tumor virus (MMTV) is a model system for studies of human complex retroviruses, such as HIV-1, as well as cancer induction. We have shown that MMTV encodes a regulatory protein, Rem, which is cleaved into an N-terminal signal peptide (SP) and a C-terminal protein (Rem-CT) within the endoplasmic reticulum (ER) membrane. SP function requires ER membrane extraction by retrotranslocation, which is part of a protein quality control system known as ER-associated degradation (ERAD) that is essential to cellular health. Through poorly understood mechanisms, certain pathogen-derived proteins are retrotranslocated but not degraded. We demonstrate here that MMTV SP retrotranslocation from the ER membrane avoids degradation through a unique process involving interaction with cellular p97 ATPase and failure to acquire cellular proteasome-targeting sequences.
Collapse
|
35
|
The Antiviral RNAi Response in Vector and Non-vector Cells against Orthobunyaviruses. PLoS Negl Trop Dis 2017; 11:e0005272. [PMID: 28060823 PMCID: PMC5245901 DOI: 10.1371/journal.pntd.0005272] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 01/19/2017] [Accepted: 12/20/2016] [Indexed: 11/19/2022] Open
Abstract
Background Vector arthropods control arbovirus replication and spread through antiviral innate immune responses including RNA interference (RNAi) pathways. Arbovirus infections have been shown to induce the exogenous small interfering RNA (siRNA) and Piwi-interacting RNA (piRNA) pathways, but direct antiviral activity by these host responses in mosquito cells has only been demonstrated against a limited number of positive-strand RNA arboviruses. For bunyaviruses in general, the relative contribution of small RNA pathways in antiviral defences is unknown. Methodology/Principal Findings The genus Orthobunyavirus in the Bunyaviridae family harbours a diverse range of mosquito-, midge- and tick-borne arboviruses. We hypothesized that differences in the antiviral RNAi response in vector versus non-vector cells may exist and that could influence viral host range. Using Aedes aegypti-derived mosquito cells, mosquito-borne orthobunyaviruses and midge-borne orthobunyaviruses we showed that bunyavirus infection commonly induced the production of small RNAs and the effects of the small RNA pathways on individual viruses differ in specific vector-arbovirus interactions. Conclusions/Significance These findings have important implications for our understanding of antiviral RNAi pathways and orthobunyavirus-vector interactions and tropism. A number of orthobunyaviruses such as Oropouche virus, La Crosse virus and Schmallenberg virus are important global human or animal pathogens transmitted by arthropod vectors. Further understanding of the antiviral control mechanisms in arthropod vectors is key to developing novel prevention strategies based on preventing transmission. Antiviral small RNA pathways such as the exogenous siRNA and piRNA pathways have been shown to mediate antiviral activity against positive-strand RNA arboviruses, but information about their activities against negative-strand RNA arboviruses is critically lacking. Here we show that in Aedes aegypti-derived mosquito cells, the antiviral responses to mosquito-borne orthobunyaviruses is largely mediated by both siRNA and piRNA pathways, whereas the piRNA pathway plays only a minor role in controlling midge-borne orthobunyaviruses. This suggests that vector specificity is in part controlled by antiviral responses that depend on the host species. These findings contribute significantly to our understanding of arbovirus-vector interactions.
Collapse
|
36
|
Okamoto T. [Signal peptide peptidase participates in propagation and pathogenesis of hepatitis C virus]. Uirusu 2017; 67:49-58. [PMID: 29593153 DOI: 10.2222/jsv.67.49] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Hepatitis C virus (HCV) is a blood-borne virus and causes chronic infection leading to development of steatosis, cirrhosis and hepatocellular carcinoma. However, molecular mechanisms of induction of liver diseases by HCV infection are still unclear. This review focuses on thevirological significance of processing of HCV core protein by signal peptide peptidase in propagation and pathogenesis of HCV.
Collapse
Affiliation(s)
- Toru Okamoto
- Department of Molecular Virology, Research Institute for Microbial Diseases
| |
Collapse
|