1
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Young VL, McSweeney AM, Edwards MJ, Ward VK. The Disorderly Nature of Caliciviruses. Viruses 2024; 16:1324. [PMID: 39205298 PMCID: PMC11360831 DOI: 10.3390/v16081324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2024] [Revised: 08/07/2024] [Accepted: 08/17/2024] [Indexed: 09/04/2024] Open
Abstract
An intrinsically disordered protein (IDP) or region (IDR) lacks or has little protein structure but still maintains function. This lack of structure creates flexibility and fluidity, allowing multiple protein conformations and potentially transient interactions with more than one partner. Caliciviruses are positive-sense ssRNA viruses, containing a relatively small genome of 7.6-8.6 kb and have a broad host range. Many viral proteins are known to contain IDRs, which benefit smaller viral genomes by expanding the functional proteome through the multifunctional nature of the IDR. The percentage of intrinsically disordered residues within the total proteome for each calicivirus type species can range between 8 and 23%, and IDRs have been experimentally identified in NS1-2, VPg and RdRP proteins. The IDRs within a protein are not well conserved across the genera, and whether this correlates to different activities or increased tolerance to mutations, driving virus adaptation to new selection pressures, is unknown. The function of norovirus NS1-2 has not yet been fully elucidated but includes involvement in host cell tropism, the promotion of viral spread and the suppression of host interferon-λ responses. These functions and the presence of host cell-like linear motifs that interact with host cell caspases and VAPA/B are all found or affected by the disordered region of norovirus NS1-2. The IDRs of calicivirus VPg are involved in viral transcription and translation, RNA binding, nucleotidylylation and cell cycle arrest, and the N-terminal IDR within the human norovirus RdRP could potentially drive liquid-liquid phase separation. This review identifies and summarises the IDRs of proteins within the Caliciviridae family and their importance during viral replication and subsequent host interactions.
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Affiliation(s)
| | | | | | - Vernon K. Ward
- Department of Microbiology & Immunology, School of Biomedical Sciences, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
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2
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Smertina E, Carroll AJ, Boileau J, Emmott E, Jenckel M, Vohra H, Rolland V, Hands P, Hayashi J, Neave MJ, Liu JW, Hall RN, Strive T, Frese M. Lagovirus Non-structural Protein p23: A Putative Viroporin That Interacts With Heat Shock Proteins and Uses a Disulfide Bond for Dimerization. Front Microbiol 2022; 13:923256. [PMID: 35923397 PMCID: PMC9340658 DOI: 10.3389/fmicb.2022.923256] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 06/16/2022] [Indexed: 12/03/2022] Open
Abstract
The exact function(s) of the lagovirus non-structural protein p23 is unknown as robust cell culture systems for the Rabbit haemorrhagic disease virus (RHDV) and other lagoviruses have not been established. Instead, a range of in vitro and in silico models have been used to study p23, revealing that p23 oligomerizes, accumulates in the cytoplasm, and possesses a conserved C-terminal region with two amphipathic helices. Furthermore, the positional homologs of p23 in other caliciviruses have been shown to possess viroporin activity. Here, we report on the mechanistic details of p23 oligomerization. Site-directed mutagenesis revealed the importance of an N-terminal cysteine for dimerization. Furthermore, we identified cellular interactors of p23 using stable isotope labeling with amino acids in cell culture (SILAC)-based proteomics; heat shock proteins Hsp70 and 110 interact with p23 in transfected cells, suggesting that they ‘chaperone’ p23 proteins before their integration into cellular membranes. We investigated changes to the global transcriptome and proteome that occurred in infected rabbit liver tissue and observed changes to the misfolded protein response, calcium signaling, and the regulation of the endoplasmic reticulum (ER) network. Finally, flow cytometry studies indicate slightly elevated calcium concentrations in the cytoplasm of p23-transfected cells. Taken together, accumulating evidence suggests that p23 is a viroporin that might form calcium-conducting channels in the ER membranes.
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Affiliation(s)
- Elena Smertina
- Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation, Canberra, ACT, Australia
- Faculty of Science and Technology, University of Canberra, Canberra, ACT, Australia
- Centre for Invasive Species Solutions, Canberra, ACT, Australia
| | - Adam J. Carroll
- RSB/RSC Joint Mass Spectrometry Facility, Research School of Chemistry, Australian National University, Acton, ACT, Australia
| | - Joseph Boileau
- RSB/RSC Joint Mass Spectrometry Facility, Research School of Chemistry, Australian National University, Acton, ACT, Australia
| | - Edward Emmott
- Centre for Proteome Research, Department of Biochemistry & Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Maria Jenckel
- Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation, Canberra, ACT, Australia
| | - Harpreet Vohra
- Imaging and Cytometry Facility, John Curtin School of Medical Research, Acton, ACT, Australia
| | - Vivien Rolland
- Agriculture and Food, Commonwealth Scientific and Industrial Research Organisation, Canberra, ACT, Australia
| | - Philip Hands
- Agriculture and Food, Commonwealth Scientific and Industrial Research Organisation, Canberra, ACT, Australia
| | - Junna Hayashi
- Research School of Chemistry, Australian National University, Acton, ACT, Australia
| | - Matthew J. Neave
- Australian Centre for Disease Preparedness, Commonwealth Scientific and Industrial Research Organisation, Geelong, VIC, Australia
| | - Jian-Wei Liu
- Land and Water, Commonwealth Scientific and Industrial Research Organisation, Canberra, ACT, Australia
| | - Robyn N. Hall
- Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation, Canberra, ACT, Australia
- Centre for Invasive Species Solutions, Canberra, ACT, Australia
| | - Tanja Strive
- Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation, Canberra, ACT, Australia
- Centre for Invasive Species Solutions, Canberra, ACT, Australia
| | - Michael Frese
- Health and Biosecurity, Commonwealth Scientific and Industrial Research Organisation, Canberra, ACT, Australia
- Faculty of Science and Technology, University of Canberra, Canberra, ACT, Australia
- *Correspondence: Michael Frese,
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3
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Xia X, Cheng A, Wang M, Ou X, Sun D, Mao S, Huang J, Yang Q, Wu Y, Chen S, Zhang S, Zhu D, Jia R, Liu M, Zhao XX, Gao Q, Tian B. Functions of Viroporins in the Viral Life Cycle and Their Regulation of Host Cell Responses. Front Immunol 2022; 13:890549. [PMID: 35720341 PMCID: PMC9202500 DOI: 10.3389/fimmu.2022.890549] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 05/10/2022] [Indexed: 11/13/2022] Open
Abstract
Viroporins are virally encoded transmembrane proteins that are essential for viral pathogenicity and can participate in various stages of the viral life cycle, thereby promoting viral proliferation. Viroporins have multifaceted effects on host cell biological functions, including altering cell membrane permeability, triggering inflammasome formation, inducing apoptosis and autophagy, and evading immune responses, thereby ensuring that the virus completes its life cycle. Viroporins are also virulence factors, and their complete or partial deletion often reduces virion release and reduces viral pathogenicity, highlighting the important role of these proteins in the viral life cycle. Thus, viroporins represent a common drug-protein target for inhibiting drugs and the development of antiviral therapies. This article reviews current studies on the functions of viroporins in the viral life cycle and their regulation of host cell responses, with the aim of improving the understanding of this growing family of viral proteins.
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Affiliation(s)
- Xiaoyan Xia
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu City, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China
| | - Anchun Cheng
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu City, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China
| | - Mingshu Wang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu City, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China
| | - Xumin Ou
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu City, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China
| | - Di Sun
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu City, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China
| | - Sai Mao
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu City, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China
| | - Juan Huang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu City, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China
| | - Qiao Yang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu City, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China
| | - Ying Wu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu City, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China
| | - Shun Chen
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu City, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China
| | - Shaqiu Zhang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu City, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China
| | - Dekang Zhu
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu City, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China
| | - Renyong Jia
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu City, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China
| | - Mafeng Liu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu City, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China
| | - Xin-Xin Zhao
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu City, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China
| | - Qun Gao
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China.,Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu City, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China
| | - Bin Tian
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China.,Avian Disease Research Center, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu City, China
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4
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Akt plays differential roles during the life cycles of acute and persistent murine norovirus strains in macrophages. J Virol 2021; 96:e0192321. [PMID: 34787460 DOI: 10.1128/jvi.01923-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Akt (Protein kinase B) is a key signaling protein in eukaryotic cells that controls many cellular processes such as glucose metabolism and cell proliferation for survival. As obligate intracellular pathogens, viruses modulate host cellular processes, including Akt signaling, for optimal replication. The mechanisms by which viruses modulate Akt and the resulting effects on the infectious cycle differ widely depending on the virus. In this study, we explored the effect of Akt serine 473 phosphorylation (p-Akt) during murine norovirus (MNV) infection. p-Akt increased during infection of murine macrophages with acute MNV-1 and persistent CR3 and CR6 strains. Inhibition of Akt with MK2206, an inhibitor of all three isoforms of Akt (Akt1/2/3), reduced infectious virus progeny of all three virus strains. This reduction was due to decreased viral genome replication (CR3), defective virus assembly (MNV-1), or diminished cellular egress (CR3 and CR6) in a virus strain-dependent manner. Collectively, our data demonstrate that Akt activation increases in macrophages during the later stages of the MNV infectious cycle, which may enhance viral infection in unique ways for different virus strains. The data, for the first time, indicate a role for Akt signaling in viral assembly and highlight additional phenotypic differences between closely related MNV strains. Importance Human noroviruses (HNoV) are a leading cause of viral gastroenteritis, resulting in high annual economic burden and morbidity; yet there are no small animal models supporting productive HNoV infection, or robust culture systems producing cell culture-derived virus stocks. As a result, research on drug discovery and vaccine development against norovirus infection has been challenging, and no targeted antivirals or vaccines against HNoV are approved. On the other hand, murine norovirus (MNV) replicates to high titers in cell culture and is a convenient and widespread model in norovirus research. Our data demonstrate the importance of Akt signaling during the late stage of the MNV life cycle. Notably, the effect of Akt signaling on genome replication, virus assembly and cellular egress is virus strain specific, highlighting the diversity of biological phenotypes despite small genetic variability among norovirus strains. This study is the first to demonstrate a role for Akt in viral assembly.
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Pankovics P, Boros Á, László Z, Szekeres S, Földvári G, Altan E, Delwart E, Reuter G. Genome characterization, prevalence and tissue distribution of astrovirus, hepevirus and norovirus among wild and laboratory rats (Rattus norvegicus) and mice (Mus musculus) in Hungary. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2021; 93:104942. [PMID: 34044191 DOI: 10.1016/j.meegid.2021.104942] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 05/19/2021] [Accepted: 05/21/2021] [Indexed: 12/17/2022]
Abstract
Rodents including rats are reservoir of several pathogens capable of affecting human health. In this study, faecal and different organ specimens from free-living Norway rats (Rattus norvegicus) (N = 18) and faecal samples from laboratory rodents (rats N = 21 and mice N = 20) collected from different geographic areas in Hungary between 2017 and 2020 were investigated by viral metagenomics and conventional RT-PCR methods. The complete genome of three different RNA viruses, rat astrovirus, rat norovirus and rat hepevirus were characterized and analysed in detail. Rat norovirus was detected in faecal (17.6%, 3/17) and kidney (7.1%, 1/14) samples; rat astrovirus in faecal (23.5%, 4/17) and spleen (13.3%, 2/15) samples, and rat hepevirus in 43% to 67% the faecal, liver, kidney, lung, heart, muscle, brain and blood samples from Norway rats, respectively. Rat norovirus was also identifiable in 5% (1/21) of laboratory rats and rat astrovirus in 40% (8/20) of faecal samples from laboratory mice. Co-infections were found in 28% (5/18) wild Norway rats. The highest RNA viral load of astrovirus (1.81 × 108 copy/g) and norovirus (3.49 × 107 copy/g) were measured in faecal samples; while the highest RNA viral load of hepevirus (1.16 × 109 copy/g) was found in liver samples of Norway rats, respectively. This study confirms the wide geographic distribution and high prevalence of astrovirus, norovirus and hepevirus among wild rats in Hungary with confirmation of different organ involvement of as well as the detection of norovirus and astrovirus in laboratory rats and mice, respectively. This finding further strengthens the role of rodents in the spread of viral pathogens especially infecting human.
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Affiliation(s)
- Péter Pankovics
- Department of Medical Microbiology and Immunology, Medical School, University of Pécs, Pécs, Hungary.
| | - Ákos Boros
- Department of Medical Microbiology and Immunology, Medical School, University of Pécs, Pécs, Hungary
| | - Zoltán László
- Department of Medical Microbiology and Immunology, Medical School, University of Pécs, Pécs, Hungary
| | - Sándor Szekeres
- Department of Parasitology and Zoology, University of Veterinary Medicine, Budapest, Hungary
| | - Gábor Földvári
- Institute of Evolution, Centre for Ecological Research, Budapest, Hungary
| | - Eda Altan
- Vitalant Research Institute, San Francisco, CA, USA
| | - Eric Delwart
- Vitalant Research Institute, San Francisco, CA, USA; University of California, San Francisco, CA, USA
| | - Gábor Reuter
- Department of Medical Microbiology and Immunology, Medical School, University of Pécs, Pécs, Hungary
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6
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Smertina E, Hall RN, Urakova N, Strive T, Frese M. Calicivirus Non-structural Proteins: Potential Functions in Replication and Host Cell Manipulation. Front Microbiol 2021; 12:712710. [PMID: 34335548 PMCID: PMC8318036 DOI: 10.3389/fmicb.2021.712710] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Accepted: 06/21/2021] [Indexed: 01/15/2023] Open
Abstract
The Caliciviridae are a family of viruses with a single-stranded, non-segmented RNA genome of positive polarity. The ongoing discovery of caliciviruses has increased the number of genera in this family to 11 (Norovirus, Nebovirus, Sapovirus, Lagovirus, Vesivirus, Nacovirus, Bavovirus, Recovirus, Salovirus, Minovirus, and Valovirus). Caliciviruses infect a wide range of hosts that include fishes, amphibians, reptiles, birds, and marine and land mammals. All caliciviruses have a genome that encodes a major and a minor capsid protein, a genome-linked viral protein, and several non-structural proteins. Of these non-structural proteins, only the helicase, protease, and RNA-dependent RNA polymerase share clear sequence and structural similarities with proteins from other virus families. In addition, all caliciviruses express two or three non-structural proteins for which functions have not been clearly defined. The sequence diversity of these non-structural proteins and a multitude of processing strategies suggest that at least some have evolved independently, possibly to counteract innate and adaptive immune responses in a host-specific manner. Studying these proteins is often difficult as many caliciviruses cannot be grown in cell culture. Nevertheless, the study of recombinant proteins has revealed many of their properties, such as intracellular localization, capacity to oligomerize, and ability to interact with viral and/or cellular proteins; the release of non-structural proteins from transfected cells has also been investigated. Here, we will summarize these findings and discuss recent in silico studies that identified previously overlooked putative functional domains and structural features, including transmembrane domains that suggest the presence of viroporins.
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Affiliation(s)
- Elena Smertina
- Commonwealth Scientific and Industrial Research Organization, Health and Biosecurity, Canberra, ACT, Australia
- Faculty of Science and Technology, University of Canberra, Canberra, ACT, Australia
| | - Robyn N. Hall
- Commonwealth Scientific and Industrial Research Organization, Health and Biosecurity, Canberra, ACT, Australia
- Centre for Invasive Species Solutions, Canberra, ACT, Australia
| | - Nadya Urakova
- Department of Medical Microbiology, Leiden University Medical Center, Leiden, Netherlands
| | - Tanja Strive
- Commonwealth Scientific and Industrial Research Organization, Health and Biosecurity, Canberra, ACT, Australia
- Centre for Invasive Species Solutions, Canberra, ACT, Australia
| | - Michael Frese
- Commonwealth Scientific and Industrial Research Organization, Health and Biosecurity, Canberra, ACT, Australia
- Faculty of Science and Technology, University of Canberra, Canberra, ACT, Australia
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7
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Mae Y, Nagara K, Miyazaki M, Katsura Y, Enomoto Y, Koga A. Complex intragene deletion leads to oculocutaneous albinism in tanuki (Japanese raccoon dog). Genome 2020; 63:517-523. [PMID: 32783776 DOI: 10.1139/gen-2020-0049] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Tanuki (Nyctereutes procyonoides viverrinus), or Japanese raccoon dog, is a canine native to Japan. Tanuki with complete oculocutaneous albinism are relatively frequent in mountainous areas of mainland Japan. Tyrosinase, which is encoded by the TYR gene, is an enzyme essential for the biosynthesis of melanin pigment. We examined the structure and nucleotide sequence of TYR in an albino tanuki and found that the third exon was removed due to a deletion of approximately 11 kb. In addition, two nonsynonymous nucleotide substitutions were found in the fifth exon. These mutations are possible causes of the albino phenotype; however, the order of occurrence is unclear. Even if the 11-kb deletion was not the first of these mutations, it is considered to cause a total loss of the tyrosinase function because the third exon carries codons for one of the two copper-binding sites of tyrosinase and these sites are essential for the enzyme function. Intriguingly, the deletion was not a simple removal of an 11-kb segment: an internal portion was retained as a segment in the reverse orientation. We propose possible formation processes for this mutation that involve multiple DNA scission events, or an inversion followed by a deletion.
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Affiliation(s)
- Yuji Mae
- Iida City Zoo, Iida, Nagano 395-0046, Japan
| | | | - Manabu Miyazaki
- Manabu Miyazaki Photography Office, Iijima, Nagano 399-3705, Japan
| | - Yukako Katsura
- Primate Research Institute, Kyoto University, Inuyama, Aichi 484-8506, Japan
| | - Yuki Enomoto
- Primate Research Institute, Kyoto University, Inuyama, Aichi 484-8506, Japan
| | - Akihiko Koga
- Primate Research Institute, Kyoto University, Inuyama, Aichi 484-8506, Japan
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8
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In vitro translation of virally-encoded replication polyproteins to recapitulate polyprotein maturation processes. Protein Expr Purif 2020; 175:105694. [PMID: 32681958 DOI: 10.1016/j.pep.2020.105694] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 06/23/2020] [Accepted: 06/25/2020] [Indexed: 11/21/2022]
Abstract
Single-stranded, positive-sense RNA viruses encode essential replication polyproteins which are composed of several domains. They are usually subjected to finely regulated proteolytic maturation processes to generate cleavage intermediates and end-products. Both polyproteins and maturation products play multiple key roles that ultimately allow synthesis of viral genome progeny. Despite the importance of these proteins in the course of viral replication, their structural properties, including the conformational changes regulating their numerous functions, are poorly described at the structural level. This lack of information is mainly due to the extreme difficulty to express large, membrane-bound, multi-domain proteins with criteria suitable for structural biology methods. To tackle this challenge, we have used a wheat-germ cell-free expression system. We firstly establish that this approach allows to synthesize viral polyproteins encoded by two unrelated positive-sense RNA viruses, a human norovirus and a plant tymovirus. Then, we demonstrate that these polyproteins are fully functional and are spontaneously auto-cleaved by their active protease domain, giving rise to natural maturation products. Moreover, we show that introduction of point mutations in polyproteins allows to inhibit the proteolytic maturation process of each virus. This allowed us to express and partially purify the uncleaved full-length norovirus polyprotein and the tymoviral RNA-dependent RNA polymerase. Thus, this study provides a powerful tool to obtain soluble viral polyproteins and their maturation products in order to conduct challenging structural biology projects and therefore solve unanswered questions.
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9
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Campillay-Véliz CP, Carvajal JJ, Avellaneda AM, Escobar D, Covián C, Kalergis AM, Lay MK. Human Norovirus Proteins: Implications in the Replicative Cycle, Pathogenesis, and the Host Immune Response. Front Immunol 2020; 11:961. [PMID: 32612600 PMCID: PMC7308418 DOI: 10.3389/fimmu.2020.00961] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 04/23/2020] [Indexed: 12/19/2022] Open
Abstract
Human noroviruses (HuNoVs) are the cause of more than 95% of epidemic non-bacterial gastroenteritis worldwide, with some lethal cases. These viral agents affect people of all ages. However, young children and older adults are the highest-risk groups, being affected with the greatest rate of hospitalizations and morbidity cases. HuNoV structural proteins, especially VP1, have been studied extensively. In contrast, the functions of the non-structural proteins of the virus have been undescribed in depth. Studies on HuNoV non-structural proteins have mostly been made by expressing them individually in in vitro cultures, providing insights of their functions and the role that they play in HuNoV replication and pathogenesis. This review examines exhaustively the functions of both HuNoV structural and non-structural proteins and their possible role within the viral replicative cycle and the pathogenesis of the virus. It also highlights recent findings regarding the host's innate and adaptive immune responses against HuNoV, which are of great relevance for diagnostics and vaccine development so as to prevent infections caused by these fastidious viruses.
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Affiliation(s)
- Claudia P Campillay-Véliz
- Departamento de Biotecnología, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Antofagasta, Chile
| | - Jonatan J Carvajal
- Departamento de Biotecnología, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Antofagasta, Chile
| | - Andrea M Avellaneda
- Departamento de Biotecnología, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Antofagasta, Chile
| | - Darling Escobar
- Departamento de Biotecnología, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Antofagasta, Chile
| | - Camila Covián
- Departamento de Biotecnología, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Antofagasta, Chile.,Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Millennium Institute on Immunology and Immunotherapy, Pontificia Universidad de Chile, Santiago, Chile
| | - Alexis M Kalergis
- Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Millennium Institute on Immunology and Immunotherapy, Pontificia Universidad de Chile, Santiago, Chile.,Departamento de Endocrinología, Facultad de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Margarita K Lay
- Departamento de Biotecnología, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Antofagasta, Chile.,Departamento de Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Millennium Institute on Immunology and Immunotherapy, Pontificia Universidad de Chile, Santiago, Chile
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10
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Ludwig-Begall LF, Lu J, Hosmillo M, de Oliveira-Filho EF, Mathijs E, Goodfellow I, Mauroy A, Thiry E. Replicative fitness recuperation of a recombinant murine norovirus - in vitro reciprocity of genetic shift and drift. J Gen Virol 2020; 101:510-522. [PMID: 32242791 DOI: 10.1099/jgv.0.001406] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Noroviruses are recognized as the major cause of non-bacterial gastroenteritis in humans. Molecular mechanisms driving norovirus evolution are the accumulation of point mutations and recombination. Recombination can create considerable changes in a viral genome, potentially eliciting a fitness cost, which must be compensated via the adaptive capacity of a recombinant virus. We previously described replicative fitness reduction of the first in vitro generated WU20-CW1 recombinant murine norovirus, RecMNV. In this follow-up study, RecMNV's capability of replicative fitness recuperation and genetic characteristics of RecMNV progenies at early and late stages of an adaptation experiment were evaluated. Replicative fitness regain of the recombinant was demonstrated via growth kinetics and plaque size differences between viral progenies prior to and post serial in vitro passaging. Point mutations at consensus and sub-consensus population levels of early and late viral progenies were characterized via next-generation sequencing and putatively associated to fitness changes. To investigate the effect of genomic changes separately and in combination in the context of a lab-generated inter-MNV infectious virus, mutations were introduced into a recombinant WU20-CW1 cDNA for subsequent DNA-based reverse genetics recovery. We thus associated fitness loss of RecMNV to a C7245T mutation and functional VP2 (ORF3) truncation and demonstrated individual and cumulative compensatory effects of one synonymous OFR2 and two non-synonymous ORF1 consensus-level mutations acquired during successive rounds of in vitro replication. Our data provide evidence of viral adaptation in a controlled environment via genetic drift after genetic shift induced a fitness cost of an infectious recombinant norovirus.
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Affiliation(s)
- Louisa F Ludwig-Begall
- Veterinary Virology and Animal Viral Diseases, Department of Infectious and Parasitic Diseases, FARAH Research Centre, Faculty of Veterinary Medicine, Liège University, Liège, Belgium
| | - Jia Lu
- Present address: The Babraham Institute, Babraham Hall House, Babraham, Cambridge, UK.,Division of Virology, Department of Pathology, University of Cambridge, Cambridge, UK
| | - Myra Hosmillo
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, UK
| | - Edmilson F de Oliveira-Filho
- Institute of Virology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.,Veterinary Virology and Animal Viral Diseases, Department of Infectious and Parasitic Diseases, FARAH Research Centre, Faculty of Veterinary Medicine, Liège University, Liège, Belgium
| | - Elisabeth Mathijs
- Infectious diseases in animals, Sciensano, Ukkel, Belgium.,Veterinary Virology and Animal Viral Diseases, Department of Infectious and Parasitic Diseases, FARAH Research Centre, Faculty of Veterinary Medicine, Liège University, Liège, Belgium
| | - Ian Goodfellow
- Division of Virology, Department of Pathology, University of Cambridge, Cambridge, UK
| | - Axel Mauroy
- Staff direction for risk assessment, Control Policy, FASFC, Brussels, Belgium.,Veterinary Virology and Animal Viral Diseases, Department of Infectious and Parasitic Diseases, FARAH Research Centre, Faculty of Veterinary Medicine, Liège University, Liège, Belgium
| | - Etienne Thiry
- Veterinary Virology and Animal Viral Diseases, Department of Infectious and Parasitic Diseases, FARAH Research Centre, Faculty of Veterinary Medicine, Liège University, Liège, Belgium
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Curto P, Riley SP, Simões I, Martinez JJ. Macrophages Infected by a Pathogen and a Non-pathogen Spotted Fever Group Rickettsia Reveal Differential Reprogramming Signatures Early in Infection. Front Cell Infect Microbiol 2019; 9:97. [PMID: 31024862 PMCID: PMC6467950 DOI: 10.3389/fcimb.2019.00097] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 03/22/2019] [Indexed: 12/22/2022] Open
Abstract
Despite their high degree of genomic similarity, different spotted fever group (SFG) Rickettsia are often associated with very different clinical presentations. For example, Rickettsia conorii causes Mediterranean spotted fever, a life-threatening disease for humans, whereas Rickettsia montanensis is associated with limited or no pathogenicity to humans. However, the molecular basis responsible for the different pathogenicity attributes are still not understood. Although killing microbes is a critical function of macrophages, the ability to survive and/or proliferate within phagocytic cells seems to be a phenotypic feature of several intracellular pathogens. We have previously shown that R. conorii and R. montanensis exhibit different intracellular fates within macrophage-like cells. By evaluating early macrophage responses upon insult with each of these rickettsial species, herein we demonstrate that infection with R. conorii results in a profound reprogramming of host gene expression profiles. Transcriptional programs generated upon infection with this pathogenic bacteria point toward a sophisticated ability to evade innate immune signals, by modulating the expression of several anti-inflammatory molecules. Moreover, R. conorii induce the expression of several pro-survival genes, which may result in the ability to prolong host cell survival, thus protecting its replicative niche. Remarkably, R. conorii-infection promoted a robust modulation of different transcription factors, suggesting that an early manipulation of the host gene expression machinery may be key to R. conorii proliferation in THP-1 macrophages. This work provides new insights into the early molecular processes hijacked by a pathogenic SFG Rickettsia to establish a replicative niche in macrophages, opening several avenues of research in host-rickettsiae interactions.
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Affiliation(s)
- Pedro Curto
- Ph.D. Programme in Experimental Biology and Biomedicine, Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
- CNC-Center for Neuroscience and Cell Biology, Coimbra, Portugal
- Vector Borne Disease Laboratories, Department of Pathobiological Sciences, LSU School of Veterinary Medicine, Baton Rouge, LA, United States
| | - Sean P. Riley
- Vector Borne Disease Laboratories, Department of Pathobiological Sciences, LSU School of Veterinary Medicine, Baton Rouge, LA, United States
| | - Isaura Simões
- CNC-Center for Neuroscience and Cell Biology, Coimbra, Portugal
- Vector Borne Disease Laboratories, Department of Pathobiological Sciences, LSU School of Veterinary Medicine, Baton Rouge, LA, United States
| | - Juan J. Martinez
- Vector Borne Disease Laboratories, Department of Pathobiological Sciences, LSU School of Veterinary Medicine, Baton Rouge, LA, United States
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12
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Abstract
Viruses depend on the host cells they infect to provide the machinery and substrates for replication. Host cells are highly dynamic systems that can alter their intracellular environment and metabolic behavior, which may be helpful or inhibitory for an infecting virus. In this study, we show that macrophages, a target cell of murine norovirus (MNV), increase glycolysis upon viral infection, which is important for early steps in MNV infection. Human noroviruses (hNoV) are a major cause of gastroenteritis globally, causing enormous morbidity and economic burden. Currently, no effective antivirals or vaccines exist for hNoV, mainly due to the lack of high-efficiency in vitro culture models for their study. Thus, insights gained from the MNV model may reveal aspects of host cell metabolism that can be targeted for improving hNoV cell culture systems and for developing effective antiviral therapies. The metabolic pathways of central carbon metabolism, glycolysis and oxidative phosphorylation (OXPHOS), are important host factors that determine the outcome of viral infections and can be manipulated by some viruses to favor infection. However, mechanisms of metabolic modulation and their effects on viral replication vary widely. Herein, we present the first metabolomics and energetic profiling of norovirus-infected cells, which revealed increases in glycolysis, OXPHOS, and the pentose phosphate pathway (PPP) during murine norovirus (MNV) infection. Inhibiting glycolysis with 2-deoxyglucose (2DG) in macrophages revealed that glycolysis is an important factor for optimal MNV infection, while inhibiting the PPP and OXPHOS showed a relatively minor impact of these pathways on MNV infection. 2DG affected an early stage in the viral life cycle after viral uptake and capsid uncoating, leading to decreased viral protein production and viral RNA. The requirement of glycolysis was specific for MNV (but not astrovirus) infection, independent of the type I interferon antiviral response, and unlikely to be due to a lack of host cell nucleotide synthesis. MNV infection increased activation of the protein kinase Akt, but not AMP-activated protein kinase (AMPK), two master regulators of cellular metabolism, implicating Akt signaling in upregulating host metabolism during norovirus infection. In conclusion, our findings suggest that the metabolic state of target cells is an intrinsic host factor that determines the extent of norovirus replication and implicates glycolysis as a virulence determinant. They further point to cellular metabolism as a novel therapeutic target for norovirus infections and improvements in current human norovirus culture systems.
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Genomics Analyses of GIV and GVI Noroviruses Reveal the Distinct Clustering of Human and Animal Viruses. Viruses 2019; 11:v11030204. [PMID: 30823663 PMCID: PMC6466045 DOI: 10.3390/v11030204] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 02/23/2019] [Accepted: 02/25/2019] [Indexed: 01/23/2023] Open
Abstract
Noroviruses are highly diverse viruses that are the major viral cause of acute gastroenteritis in humans. Although these viruses can infect multiple mammalian species, their potential for zoonosis is not well understood, especially within Genogroup IV (GIV), which contains viruses that infect humans, canines, and felines. The study of GIV viruses has been, in part, hindered by the limited number of complete genomes. Here, we developed a full-genome amplicon-based platform that facilitated the sequencing of canine noroviruses circulating in the United States. Eight novel nearly full-length canine norovirus genomes and two nearly complete VP1 sequences, including four GIV.2, three GVI.1, and three GVI.2 viruses, were successfully obtained. Only animal strains exhibited GVI/GIV chimeric viruses, demonstrating restrictions in norovirus recombination. Using genomic, phylogenetic, and structural analyses, we show that differences within the major capsid protein and the non-structural proteins of GIV and GVI noroviruses could potentially limit cross-species transmission between humans, canines, and felines.
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14
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Doerflinger SY, Cortese M, Romero-Brey I, Menne Z, Tubiana T, Schenk C, White PA, Bartenschlager R, Bressanelli S, Hansman GS, Lohmann V. Membrane alterations induced by nonstructural proteins of human norovirus. PLoS Pathog 2017; 13:e1006705. [PMID: 29077760 PMCID: PMC5678787 DOI: 10.1371/journal.ppat.1006705] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Revised: 11/08/2017] [Accepted: 10/20/2017] [Indexed: 01/09/2023] Open
Abstract
Human noroviruses (huNoV) are the most frequent cause of non-bacterial acute gastroenteritis worldwide, particularly genogroup II genotype 4 (GII.4) variants. The viral nonstructural (NS) proteins encoded by the ORF1 polyprotein induce vesical clusters harboring the viral replication sites. Little is known so far about the ultrastructure of these replication organelles or the contribution of individual NS proteins to their biogenesis. We compared the ultrastructural changes induced by expression of norovirus ORF1 polyproteins with those induced upon infection with murine norovirus (MNV). Characteristic membrane alterations induced by ORF1 expression resembled those found in MNV infected cells, consisting of vesicle accumulations likely built from the endoplasmic reticulum (ER) which included single membrane vesicles (SMVs), double membrane vesicles (DMVs) and multi membrane vesicles (MMVs). In-depth analysis using electron tomography suggested that MMVs originate through the enwrapping of SMVs with tubular structures similar to mechanisms reported for picornaviruses. Expression of GII.4 NS1-2, NS3 and NS4 fused to GFP revealed distinct membrane alterations when analyzed by correlative light and electron microscopy. Expression of NS1-2 induced proliferation of smooth ER membranes forming long tubular structures that were affected by mutations in the active center of the putative NS1-2 hydrolase domain. NS3 was associated with ER membranes around lipid droplets (LDs) and induced the formation of convoluted membranes, which were even more pronounced in case of NS4. Interestingly, NS4 was the only GII.4 protein capable of inducing SMV and DMV formation when expressed individually. Our work provides the first ultrastructural analysis of norovirus GII.4 induced vesicle clusters and suggests that their morphology and biogenesis is most similar to picornaviruses. We further identified NS4 as a key factor in the formation of membrane alterations of huNoV and provide models of the putative membrane topologies of NS1-2, NS3 and NS4 to guide future studies. Positive-strand RNA viruses induce membrane alterations harboring the viral replication complexes. In the case of human noroviruses (huNoV), the major cause of acute viral gastroenteritis, these are induced by the ORF1 polyprotein, which is post-translationally processed into the functional nonstructural (NS) proteins. Partly due to the lack of efficient cell culture models, little is known so far about membrane alterations induced by huNoV belonging to the most clinically relevant genogroup II, genotype 4 (GII.4), nor about the function of individual NS proteins in their formation. We therefore expressed ORF1 proteins of GII.4 and individual NS proteins in cells to study their contribution to viral replication complex formation. Expression of ORF1 proteins of GII.4 induced vesicular membrane alterations comparable to those found in infected cells and similar to picornaviruses and hepatitis C virus (HCV). GII.4 NS1-2, NS3 and NS4 are contributing to viral membrane alterations. Our work provides new insights into their function in huNoV induced replication complex formation while identifying NS4 as the most important single determinant. This knowledge might provide novel attractive targets for future therapies inhibiting the formation of the membranous viral replication complex, as exemplified by the efficacy of HCV NS5A inhibitors.
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Affiliation(s)
- Sylvie Y. Doerflinger
- Department of Infectious Diseases, Virology, Heidelberg University, Heidelberg, Germany
- Schaller Research Group at the University of Heidelberg and the DKFZ, Heidelberg, Germany
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, Heidelberg, Germany
| | - Mirko Cortese
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, Heidelberg, Germany
| | - Inés Romero-Brey
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, Heidelberg, Germany
| | - Zach Menne
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, Heidelberg, Germany
| | - Thibault Tubiana
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris Sud, Université Paris-Saclay, Gif sur Yvette cedex, France
| | - Christian Schenk
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, Heidelberg, Germany
| | - Peter A. White
- School of Biotechnology and Biomolecular Sciences, Faculty of Science, University of New South Wales, Sydney, Australia
| | - Ralf Bartenschlager
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, Heidelberg, Germany
- German Center for Infection Research (DZIF), Heidelberg University, Heidelberg, Germany
| | - Stéphane Bressanelli
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ Paris Sud, Université Paris-Saclay, Gif sur Yvette cedex, France
| | - Grant S. Hansman
- Department of Infectious Diseases, Virology, Heidelberg University, Heidelberg, Germany
- Schaller Research Group at the University of Heidelberg and the DKFZ, Heidelberg, Germany
| | - Volker Lohmann
- Department of Infectious Diseases, Molecular Virology, Heidelberg University, Im Neuenheimer Feld 345, Heidelberg, Germany
- * E-mail:
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