1
|
Xavier CAD, Tyson C, Kerner LM, Whitfield AE. RNAi-mediated knockdown of exportin 1 negatively affected ovary development, survival and maize mosaic virus accumulation in its insect vector Peregrinus maidis. INSECT MOLECULAR BIOLOGY 2024; 33:295-311. [PMID: 38551144 DOI: 10.1111/imb.12910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Accepted: 03/13/2024] [Indexed: 07/10/2024]
Abstract
Exportin 1 (XPO1) is the major karyopherin-β nuclear receptor mediating the nuclear export of hundreds of proteins and some classes of RNA and regulates several critical processes in the cell, including cell-cycle progression, transcription and translation. Viruses have co-opted XPO1 to promote nucleocytoplasmic transport of viral proteins and RNA. Maize mosaic virus (MMV) is a plant-infecting rhabdovirus transmitted in a circulative propagative manner by the corn planthopper, Peregrinus maidis. MMV replicates in the nucleus of plant and insect hosts, and it remains unknown whether MMV co-opts P. maidis XPO1 (PmXPO1) to complete its life cycle. Because XPO1 plays multiple regulatory roles in cell functions and virus infection, we hypothesized that RNAi-mediated silencing of XPO1 would negatively affect MMV accumulation and insect physiology. Although PmXPO1 expression was not modulated during MMV infection, PmXPO1 knockdown negatively affected MMV accumulation in P. maidis at 12 and 15 days after microinjection. Likewise, PmXPO1 knockdown negatively affected P. maidis survival and reproduction. PmXPO1 exhibited tissue-specific expression patterns with higher expression in the ovaries compared with the guts of adult females. Survival rate was significantly lower for PmXPO1 knockdown females, compared with controls, but no effect was observed for males. PmXPO1 knockdown experiments revealed a role for PmXPO1 in ovary function and egg production. Oviposition and egg hatch on plants were dramatically reduced in females treated with dsRNA PmXPO1. These results suggest that PmXPO1 is a positive regulator of P. maidis reproduction and that it plays a proviral role in the insect vector supporting MMV infection.
Collapse
Affiliation(s)
- Cesar A D Xavier
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina, USA
| | - Clara Tyson
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina, USA
| | - Leo M Kerner
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina, USA
| | - Anna E Whitfield
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina, USA
| |
Collapse
|
2
|
Chang YK, Lin YJ, Cheng CY, Tsai PC, Wang CY, Nielsen BL, Liu HJ. Nucleocytoplasmic shuttling of BEFV M protein-modulated by lamin A/C and chromosome maintenance region 1 through a transcription-, carrier- and energy-dependent pathway. Vet Microbiol 2024; 291:110026. [PMID: 38364467 DOI: 10.1016/j.vetmic.2024.110026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 01/30/2024] [Accepted: 02/07/2024] [Indexed: 02/18/2024]
Abstract
This study demonstrates for the first time that the matrix (M) protein of BEFV is a nuclear targeting protein that shuttles between the nucleus and the cytoplasm in a transcription-, carrier-, and energy-dependent manner. Experiments performed in both intact cells and digitonin-permeabilized cells revealed that M protein targets the nucleolus and requires carrier, cytosolic factors or energy input. By employing sequence and mutagenesis analyses, we have determined both nuclear localization signal (NLS) 6KKGKSK11 and nuclear export signal (NES) 98LIITSYL TI106 of M protein that are important for the nucleocytoplasmic shuttling of M protein. Furthermore, we found that both lamin A/C and chromosome maintenance region 1 (CRM-1) proteins could be coimmunoprecipitated and colocalized with the BEFV M protein. Knockdown of lamin A/C by shRNA and inhibition of CRM-1 by leptomycin B significantly reduced virus yield. Collectively, this study provides novel insights into nucleocytoplasmic shuttling of the BEFV M protein modulated by lamin A/C and CRM-1 and by a transcription- and carrier- and energy-dependent pathway.
Collapse
Affiliation(s)
- Yu-Kang Chang
- Department of Medical Research, Tungs' Taichung MetroHarbor Hospital, Taichung, Taiwan, ROC; Depertment of Post-Baccalaureate Medicine, National Chung Hsing University, Taichung, Taiwan, ROC
| | - Yi-Jyum Lin
- Institute of Molecular Biology, National Chung Hsing University, Taichung 402, Taiwan, ROC
| | - Ching-Yuan Cheng
- Institute of Molecular Biology, National Chung Hsing University, Taichung 402, Taiwan, ROC
| | - Pei-Chien Tsai
- Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan, ROC
| | - Chi-Young Wang
- Department of Veterinary Medicine, National Chung Hsing University, Taichung 402, Taiwan, ROC; The iEGG and Animal Biotechnology Center, National Chung Hsing University, Taichung, Taiwan, ROC
| | - Brent L Nielsen
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, USA
| | - Hung-Jen Liu
- Institute of Molecular Biology, National Chung Hsing University, Taichung 402, Taiwan, ROC; Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan, ROC; The iEGG and Animal Biotechnology Center, National Chung Hsing University, Taichung, Taiwan, ROC; Ph.D Program in Translational Medicine, National Chung Hsing University, Taichung, Taiwan, ROC; Rong Hsing Research Center for Translational Medicine, National Chung Hsing, Taiwan, ROC.
| |
Collapse
|
3
|
Rawlinson SM, Zhao T, Ardipradja K, Zhang Y, Veugelers PF, Harper JA, David CT, Sundaramoorthy V, Moseley GW. Henipaviruses and lyssaviruses target nucleolar treacle protein and regulate ribosomal RNA synthesis. Traffic 2023; 24:146-157. [PMID: 36479968 PMCID: PMC10947316 DOI: 10.1111/tra.12877] [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: 04/21/2022] [Revised: 11/24/2022] [Accepted: 11/28/2022] [Indexed: 12/14/2022]
Abstract
The nucleolus is a common target of viruses and viral proteins, but for many viruses the functional outcomes and significance of this targeting remains unresolved. Recently, the first intranucleolar function of a protein of a cytoplasmically-replicating negative-sense RNA virus (NSV) was identified, with the finding that the matrix (M) protein of Hendra virus (HeV) (genus Henipavirus, family Paramyxoviridae) interacts with Treacle protein within nucleolar subcompartments and mimics a cellular mechanism of the nucleolar DNA-damage response (DDR) to suppress ribosomal RNA (rRNA) synthesis. Whether other viruses utilise this mechanism has not been examined. We report that sub-nucleolar Treacle targeting and modulation is conserved between M proteins of multiple Henipaviruses, including Nipah virus and other potentially zoonotic viruses. Furthermore, this function is also evident for P3 protein of rabies virus, the prototype virus of a different RNA virus family (Rhabdoviridae), with Treacle depletion in cells also found to impact virus production. These data indicate that unrelated proteins of viruses from different families have independently developed nucleolar/Treacle targeting function, but that modulation of Treacle has distinct effects on infection. Thus, subversion of Treacle may be an important process in infection by diverse NSVs, and so could provide novel targets for antiviral approaches with broad specificity.
Collapse
Affiliation(s)
- Stephen M. Rawlinson
- Department of Microbiology, Biomedicine Discovery InstituteMonash UniversityMelbourneVictoriaAustralia
| | - Tianyue Zhao
- Department of Microbiology, Biomedicine Discovery InstituteMonash UniversityMelbourneVictoriaAustralia
| | - Katie Ardipradja
- Commonwealth Scientific and Industrial Research Organisation (CSIRO)Australian Centre for Disease Preparedness (ACDP)East GeelongVictoriaAustralia
| | - Yilin Zhang
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology InstituteThe University of MelbourneMelbourneAustralia
| | - Patrick F. Veugelers
- Department of Microbiology, Biomedicine Discovery InstituteMonash UniversityMelbourneVictoriaAustralia
| | - Jennifer A. Harper
- Commonwealth Scientific and Industrial Research Organisation (CSIRO)Australian Centre for Disease Preparedness (ACDP)East GeelongVictoriaAustralia
| | - Cassandra T. David
- Department of Microbiology, Biomedicine Discovery InstituteMonash UniversityMelbourneVictoriaAustralia
| | - Vinod Sundaramoorthy
- Commonwealth Scientific and Industrial Research Organisation (CSIRO)Australian Centre for Disease Preparedness (ACDP)East GeelongVictoriaAustralia
- School of MedicineDeakin UniversityGeelongVictoriaAustralia
| | - Gregory W. Moseley
- Department of Microbiology, Biomedicine Discovery InstituteMonash UniversityMelbourneVictoriaAustralia
| |
Collapse
|
4
|
Lyssavirus P Protein Isoforms Diverge Significantly in Subcellular Interactions Underlying Mechanisms of Interferon Antagonism. J Virol 2022; 96:e0139622. [PMID: 36222519 PMCID: PMC9599249 DOI: 10.1128/jvi.01396-22] [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: 11/20/2022] Open
Abstract
Viral hijacking of microtubule (MT)-dependent transport is well understood, but several viruses also express discrete MT-associated proteins (vMAPs), potentially to modulate MT-dependent processes in the host cell. Specific roles for vMAP-MT interactions include subversion of antiviral responses by P3, an isoform of the P protein of rabies virus (RABV; genus Lyssavirus), which mediates MT-dependent antagonism of interferon (IFN)-dependent signal transducers and activators of transcription 1 (STAT1) signaling. P3 also undergoes nucleocytoplasmic trafficking and inhibits STAT1-DNA binding, indicative of intranuclear roles in a multipronged antagonistic strategy. MT association/STAT1 antagonist functions of P3 correlate with pathogenesis, indicating potential as therapeutic targets. However, key questions remain, including whether other P protein isoforms interact with MTs, the relationship of these interactions with pathogenesis, and the extent of conservation of P3-MT interactions between diverse pathogenic lyssaviruses. Using super-resolution microscopy, live-cell imaging, and immune signaling analyses, we find that multiple P protein isoforms associate with MTs and that association correlates with pathogenesis. Furthermore, P3 proteins from different lyssaviruses exhibit variation in intracellular localization phenotypes that are associated with STAT1 antagonist function, whereby P3-MT association is conserved among lyssaviruses of phylogroup I but not phylogroup II, while nucleocytoplasmic localization varies between P3 proteins of the same phylogroup within both phylogroup I and II. Nevertheless, the divergent P3 proteins retain significant IFN antagonist function, indicative of adaptation to favor different inhibitory mechanisms, with MT interaction important to phylogroup I viruses. IMPORTANCE Lyssaviruses, including rabies virus, cause rabies, a progressive encephalomyelitis that is almost invariably fatal. There are no effective antivirals for symptomatic infection, and effective application of current vaccines is limited in areas of endemicity, such that rabies causes ~59,000 deaths per year. Viral subversion of host cell functions, including antiviral immunity, is critical to disease, and isoforms of the lyssavirus P protein are central to the virus-host interface underpinning immune evasion. Here, we show that specific cellular interactions of P protein isoforms involved in immune evasion vary significantly between different lyssaviruses, indicative of distinct strategies to evade immune responses. These findings highlight the diversity of the virus-host interface, an important consideration in the development of pan-lyssavirus therapeutic approaches.
Collapse
|
5
|
Zhang H, Huang J, Song Y, Liu X, Qian M, Huang P, Li Y, Zhao L, Wang H. Regulation of innate immune responses by rabies virus. Animal Model Exp Med 2022; 5:418-429. [PMID: 36138548 DOI: 10.1002/ame2.12273] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 08/31/2022] [Indexed: 11/10/2022] Open
Abstract
Rabies virus (RABV) is an infectious and neurotropic pathogen that causes rabies and infects humans and almost all warm-blooded animals, posing a great threat to people and public safety. It is well known that innate immunity is the critical first line of host defense against viral infection. It monitors the invading pathogens by recognizing the pathogen-associated molecular patterns and danger-associated molecular patterns through pattern-recognition receptors, leading to the production of type I interferons (IFNα/β), inflammatory cytokines, and chemokines, or the activation of autophagy or apoptosis to inhibit virus replication. In the case of RABV, the innate immune response is usually triggered when the skin or muscle is bitten or scratched. However, RABV has evolved many ways to escape or even hijack innate immune response to complete its own replication and eventually invades the central nervous system (CNS). Once RABV reaches the CNS, it cannot be wiped out by the immune system or any drugs. Therefore, a better understanding of the interplay between RABV and innate immunity is necessary to develop effective strategies to combat its infection. Here, we review the innate immune responses induced by RABV and illustrate the antagonism mechanisms of RABV to provide new insights for the control of rabies.
Collapse
Affiliation(s)
- Haili Zhang
- State Key Laboratory for Zoonotic Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, Institute of Zoonosis, and College of Veterinary Medicine, Jilin University, Changchun, China
| | - Jingbo Huang
- State Key Laboratory for Zoonotic Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, Institute of Zoonosis, and College of Veterinary Medicine, Jilin University, Changchun, China
| | - Yumeng Song
- State Key Laboratory for Zoonotic Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, Institute of Zoonosis, and College of Veterinary Medicine, Jilin University, Changchun, China
| | - Xingqi Liu
- State Key Laboratory for Zoonotic Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, Institute of Zoonosis, and College of Veterinary Medicine, Jilin University, Changchun, China
| | - Meichen Qian
- State Key Laboratory for Zoonotic Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, Institute of Zoonosis, and College of Veterinary Medicine, Jilin University, Changchun, China
| | - Pei Huang
- State Key Laboratory for Zoonotic Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, Institute of Zoonosis, and College of Veterinary Medicine, Jilin University, Changchun, China
| | - Yuanyuan Li
- State Key Laboratory for Zoonotic Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, Institute of Zoonosis, and College of Veterinary Medicine, Jilin University, Changchun, China
| | - Ling Zhao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Hualei Wang
- State Key Laboratory for Zoonotic Diseases, Key Laboratory for Zoonosis Research of the Ministry of Education, Institute of Zoonosis, and College of Veterinary Medicine, Jilin University, Changchun, China
| |
Collapse
|
6
|
Abstract
Ebola virus (EBOV) VP30 regulates viral genome transcription and replication by switching its phosphorylation status. However, the importance of VP30 phosphorylation and dephosphorylation in other viral replication processes such as nucleocapsid and virion assembly is unclear. Interestingly, VP30 is predominantly dephosphorylated by cellular phosphatases in viral inclusions, while it is phosphorylated in the released virions. Thus, uncertainties regarding how VP30 phosphorylation in nucleocapsids is achieved and whether VP30 phosphorylation provides any advantages in later steps in viral replication have arisen. In the present study, to characterize the roles of VP30 phosphorylation in nucleocapsid formation, we used electron microscopic analyses and live cell imaging systems. We identified VP30 localized to the surface of protrusions surrounding nucleoprotein (NP)-forming helical structures in the nucleocapsid, suggesting the involvement in assembly and transport of nucleocapsids. Interestingly, VP30 phosphorylation facilitated its association with nucleocapsid-like structures (NCLSs). On the contrary, VP30 phosphorylation does not influence the transport characteristics and NCLS number leaving from and coming back into viral inclusions, indicating that the phosphorylation status of VP30 is not a prerequisite for NCLS departure. Moreover, the phosphorylation status of VP30 did not cause major differences in nucleocapsid transport in authentic EBOV-infected cells. In the following budding step, the association of VP30 and its phosphorylation status did not influence the budding efficiency of virus-like particles. Taken together, it is plausible that EBOV may utilize the phosphorylation of VP30 for its selective association with nucleocapsids, without affecting nucleocapsid transport and virion budding processes. IMPORTANCE Ebola virus (EBOV) causes severe fevers with unusually high case fatality rates. The nucleocapsid provides the template for viral genome transcription and replication. Thus, understanding the regulatory mechanism behind its formation is important for the development of novel therapeutic approaches. Previously, we established a live-cell imaging system based on the ectopic expression of viral fluorescent fusion proteins, allowing the visualization and characterization of intracytoplasmic transport of nucleocapsid-like structures. EBOV VP30 is an essential transcriptional factor for viral genome synthesis, and, although its role in viral genome transcription and replication is well understood, the functional importance of VP30 phosphorylation in assembly of nucleocapsids is still unclear. Our work determines the localization of VP30 at the surface of ruffled nucleocapsids, which differs from the localization of polymerase in EBOV-infected cells. This study sheds light on the novel role of VP30 phosphorylation in nucleocapsid assembly, which is an important prerequisite for virion formation.
Collapse
|
7
|
Manokaran G, Audsley MD, Funakoda H, David CT, Garnham KA, Rawlinson SM, Deffrasnes C, Ito N, Moseley GW. Deactivation of the antiviral state by rabies virus through targeting and accumulation of persistently phosphorylated STAT1. PLoS Pathog 2022; 18:e1010533. [PMID: 35576230 PMCID: PMC9135343 DOI: 10.1371/journal.ppat.1010533] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 05/26/2022] [Accepted: 04/19/2022] [Indexed: 12/25/2022] Open
Abstract
Antagonism of the interferon (IFN)-mediated antiviral state is critical to infection by rabies virus (RABV) and other viruses, and involves interference in the IFN induction and signaling pathways in infected cells, as well as deactivation of the antiviral state in cells previously activated by IFN. The latter is required for viral spread in the host, but the precise mechanisms involved and roles in RABV pathogenesis are poorly defined. Here, we examined the capacity of attenuated and pathogenic strains of RABV that differ only in the IFN-antagonist P protein to overcome an established antiviral state. Importantly, P protein selectively targets IFN-activated phosphorylated STAT1 (pY-STAT1), providing a molecular tool to elucidate specific roles of pY-STAT1. We find that the extended antiviral state is dependent on a low level of pY-STAT1 that appears to persist at a steady state through ongoing phosphorylation/dephosphorylation cycles, following an initial IFN-induced peak. P protein of pathogenic RABV binds and progressively accumulates pY-STAT1 in inactive cytoplasmic complexes, enabling recovery of efficient viral replication over time. Thus, P protein-pY-STAT1 interaction contributes to ‘disarming’ of the antiviral state. P protein of the attenuated RABV is defective in this respect, such that replication remains suppressed over extended periods in cells pre-activated by IFN. These data provide new insights into the nature of the antiviral state, indicating key roles for residual pY-STAT1 signaling. They also elucidate mechanisms of viral deactivation of antiviral responses, including specialized functions of P protein in selective targeting and accumulation of pY-STAT1. Following viral infection, the host activates multiple antiviral defenses. The ability of viruses to overcome these defenses is critical to disease. The earliest antiviral response involves the production of interferon messenger molecules. Interferons act on infected cells to inhibit viral proliferation, as well as on non-infected cells to establish an antiviral state before infection and so limit viral spread through the host organism. Many strategies used by viruses to overcome the former are well understood, but mechanisms important to the latter, and their importance to disease, are less well defined. In this study, we investigated how rabies virus overcomes a pre-established antiviral state in target cells. We found that the capacity to disable the antiviral state correlates with the ability to cause disease, and involves binding of a viral protein to cellular signaling proteins, which our data indicate are responsible for the maintenance of a prolonged antiviral state. This advances our understanding of antiviral responses, and identifies a key step in lethal infection by rabies virus that causes approximately 60,000 human deaths per year. The findings may contribute to new approaches for the development of vaccines or antivirals.
Collapse
Affiliation(s)
- Gayathri Manokaran
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Michelle D. Audsley
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Haruka Funakoda
- Laboratory of Zoonotic Diseases, Joint Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan
| | - Cassandra T. David
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Katherine A. Garnham
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Stephen M. Rawlinson
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Celine Deffrasnes
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
| | - Naoto Ito
- Laboratory of Zoonotic Diseases, Joint Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan
- * E-mail: (NI); (GWM)
| | - Gregory W. Moseley
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Melbourne, Australia
- * E-mail: (NI); (GWM)
| |
Collapse
|
8
|
Molecular Basis of Functional Effects of Phosphorylation of the C-Terminal Domain of the Rabies Virus P Protein. J Virol 2022; 96:e0011122. [DOI: 10.1128/jvi.00111-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Rabies virus P protein is a multifunctional protein with critical roles in replication and manipulation of host-cell processes, including subversion of immunity. This functional diversity involves interactions of several P protein isoforms with the cell nucleus and microtubules.
Collapse
|
9
|
Brice AM, Watts E, Hirst B, Jans DA, Ito N, Moseley GW. Implication of the nuclear trafficking of rabies virus P3 protein in viral pathogenicity. Traffic 2021; 22:482-489. [PMID: 34622522 DOI: 10.1111/tra.12821] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Revised: 09/27/2021] [Accepted: 10/04/2021] [Indexed: 11/27/2022]
Abstract
Although the majority of viruses of the family Mononegvirales replicate exclusively in the host cell cytoplasm, many of these viruses encode proteins that traffic between the nucleus and cytoplasm, which is believed to enable accessory functions in modulating the biology of the infected host cell. Among these, the P3 protein of rabies virus localizes to the nucleus through the activity of several specific nuclear localization and nuclear export signals. The major defined functions of P3 are in evasion of interferon (IFN)-mediated antiviral responses, including through inhibition of DNA-binding by IFN-activated STAT1. P3 also localizes to nucleoli and promyelocytic leukemia (PML) nuclear bodies, and interacts with nucleolin and PML protein, indicative of several intranuclear roles. The relationship of P3 nuclear localization with pathogenicity, however, is unresolved. We report that nucleocytoplasmic localization of P3 proteins from a pathogenic RABV strain, Nishigahara (Ni) and a non-pathogenic Ni-derived strain, Ni-CE, differs significantly, with nuclear accumulation defective for Ni-CE-P3. Molecular mapping indicates that altered localization derives from a coordinated effect, including two residue substitutions that independently disable nuclear localization and augment nuclear export signals, collectively promoting nuclear exclusion. Intriguingly, this appears to relate to effects on protein conformation or regulatory mechanisms, rather than direct modification of defined trafficking signal sequences. These data provide new insights into the role of regulated nuclear trafficking of a viral protein in the pathogenicity of a virus that replicates in the cytoplasm.
Collapse
Affiliation(s)
- Aaron M Brice
- Viral Pathogenesis Laboratory, Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Ericka Watts
- Viral Pathogenesis Laboratory, Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - Bevan Hirst
- Viral Pathogenesis Laboratory, Department of Microbiology, Monash University, Clayton, Victoria, Australia
| | - David A Jans
- Nuclear Signaling Laboratory, Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Naoto Ito
- Laboratory of Zoonotic Diseases, Faculty of Applied Biological Sciences, and United Graduate School of Veterinary Sciences, Gifu University, Gifu, Japan
| | - Gregory W Moseley
- Viral Pathogenesis Laboratory, Department of Microbiology, Monash University, Clayton, Victoria, Australia
| |
Collapse
|
10
|
Definition of the immune evasion-replication interface of rabies virus P protein. PLoS Pathog 2021; 17:e1009729. [PMID: 34237115 PMCID: PMC8291714 DOI: 10.1371/journal.ppat.1009729] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 07/20/2021] [Accepted: 06/18/2021] [Indexed: 12/24/2022] Open
Abstract
Rabies virus phosphoprotein (P protein) is a multifunctional protein that plays key roles in replication as the polymerase cofactor that binds to the complex of viral genomic RNA and the nucleoprotein (N protein), and in evading the innate immune response by binding to STAT transcription factors. These interactions are mediated by the C-terminal domain of P (PCTD). The colocation of these binding sites in the small globular PCTD raises the question of how these interactions underlying replication and immune evasion, central to viral infection, are coordinated and, potentially, coregulated. While direct data on the binding interface of the PCTD for STAT1 is available, the lack of direct structural data on the sites that bind N protein limits our understanding of this interaction hub. The PCTD was proposed to bind via two sites to a flexible loop of N protein (Npep) that is not visible in crystal structures, but no direct analysis of this interaction has been reported. Here we use Nuclear Magnetic Resonance, and molecular modelling to show N protein residues, Leu381, Asp383, Asp384 and phosphor-Ser389, are likely to bind to a ‘positive patch’ of the PCTD formed by Lys211, Lys214 and Arg260. Furthermore, in contrast to previous predictions we identify a single site of interaction on the PCTD by this Npep. Intriguingly, this site is proximal to the defined STAT1 binding site that includes Ile201 to Phe209. However, cell-based assays indicate that STAT1 and N protein do not compete for P protein. Thus, it appears that interactions critical to replication and immune evasion can occur simultaneously with the same molecules of P protein so that the binding of P protein to activated STAT1 can potentially occur without interrupting interactions involved in replication. These data suggest that replication complexes might be directly involved in STAT1 antagonism. For viruses to infect cells and generate progeny, they must be able to mediate replication, while simultaneously evading the innate immune system. Viruses with small genomes often achieve this through multifunctional proteins that have roles in both replication and immune evasion, such as the phosphoprotein (P protein) of rabies virus. P protein is an essential cofactor in genome replication and transcription, dependent on the well-folded C-terminal domain (PCTD), which binds to the nucleoprotein (N protein) when complexed with RNA. The PCTD can also bind and antagonize signal transducers and activators of transcription (STAT) proteins, that are essential for activating antiviral mechanisms. Here we show using Nuclear Magnetic Resonance spectroscopy and cell-based assays, that the STAT1-binding and N-binding interfaces are proximal but, nevertheless, it appears that the same molecule of PCTD can simultaneously bind STAT1 and N protein. These data suggest that P-protein-STAT1 interaction, critical to immune evasion, can occur without interrupting interactions underlying replication, and so replication complexes might be directly involved in STAT1 antagonism.
Collapse
|
11
|
Beilstein F, Abou Hamdan A, Raux H, Belot L, Ouldali M, Albertini AA, Gaudin Y. Identification of a pH-Sensitive Switch in VSV-G and a Crystal Structure of the G Pre-fusion State Highlight the VSV-G Structural Transition Pathway. Cell Rep 2021; 32:108042. [PMID: 32814045 DOI: 10.1016/j.celrep.2020.108042] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 07/12/2020] [Accepted: 07/24/2020] [Indexed: 10/23/2022] Open
Abstract
VSV fusion machinery, like that of many other enveloped viruses, is triggered at low pH in endosomes after virion endocytosis. It was suggested that some histidines could play the role of pH-sensitive switches. By mutating histidine residues H22, H60, H132, H162, H389, H397, H407, and H409, we demonstrate that residues H389 and D280, facing each other in the six-helix bundle of the post-fusion state, and more prominently H407, located at the interface between the C-terminal part of the ectodomain and the fusion domain, are crucial for fusion. Passages of recombinant viruses bearing mutant G resulted in the selection of compensatory mutations. Thus, the H407A mutation in G resulted in two independent compensatory mutants, L396I and S422I. Together with a crystal structure of G, presented here, which extends our knowledge of G pre-fusion structure, this indicates that the conformational transition is initiated by refolding of the C-terminal part of the G ectodomain.
Collapse
Affiliation(s)
- Frauke Beilstein
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Abbas Abou Hamdan
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Hélène Raux
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Laura Belot
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Malika Ouldali
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Aurélie A Albertini
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France.
| | - Yves Gaudin
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France.
| |
Collapse
|
12
|
Phenotypic Divergence of P Proteins of Australian Bat Lyssavirus Lineages Circulating in Microbats and Flying Foxes. Viruses 2021; 13:v13050831. [PMID: 34064444 PMCID: PMC8147779 DOI: 10.3390/v13050831] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 04/12/2021] [Accepted: 04/18/2021] [Indexed: 12/13/2022] Open
Abstract
Bats are reservoirs of many pathogenic viruses, including the lyssaviruses rabies virus (RABV) and Australian bat lyssavirus (ABLV). Lyssavirus strains are closely associated with particular host reservoir species, with evidence of specific adaptation. Associated phenotypic changes remain poorly understood but are likely to involve phosphoprotein (P protein), a key mediator of the intracellular virus-host interface. Here, we examine the phenotype of P protein of ABLV, which circulates as two defined lineages associated with frugivorous and insectivorous bats, providing the opportunity to compare proteins of viruses adapted to divergent bat species. We report that key functions of P protein in the antagonism of interferon/signal transducers and activators of transcription 1 (STAT1) signaling and the capacity of P protein to undergo nuclear trafficking differ between lineages. Molecular mapping indicates that these differences are functionally distinct and appear to involve modulatory effects on regulatory regions or structural impact rather than changes to defined interaction sequences. This results in partial but significant phenotypic divergence, consistent with "fine-tuning" to host biology, and with potentially distinct properties in the virus-host interface between bat families that represent key zoonotic reservoirs.
Collapse
|
13
|
Liao Y, Ke X, Deng T, Qin Q. The Second-Generation XPO1 Inhibitor Eltanexor Inhibits Human Cytomegalovirus (HCMV) Replication and Promotes Type I Interferon Response. Front Microbiol 2021; 12:675112. [PMID: 34012430 PMCID: PMC8126617 DOI: 10.3389/fmicb.2021.675112] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 04/12/2021] [Indexed: 02/05/2023] Open
Abstract
Human cytomegalovirus (HCMV) is a ubiquitous opportunistic pathogen and can be life-threatening for immunocompromised individuals. There is currently no available vaccine for the prevention of HCMV- associated diseases and most of the available antiviral drugs that target viral DNA synthesis become ineffective in treating HCMV mutants that arise after long-term use in immunocompromised patients. Here, we examined the effects of Eltanexor, a second-generation selective inhibitor of nuclear export (SINE), on HCMV replication. Eltanexor effectively inhibits HCMV replication in human foreskin fibroblasts in a dose-dependent manner. Eltanexor does not significantly inhibit viral entry and nuclear import of viral genomic DNA, but rather suppress the transcript and protein levels of viral immediate-early (IE), early (E) and late (L) genes, and abolishes the production of infectious virions. We further found Eltanexor treatment promotes proteasome-mediated degradation of XPO1, which contributes to the nuclear retention of interferon regulatory factor 3 (IRF-3), resulting in increased expression of type I interferon as well as interferon stimulating genes ISG15 and ISG54. This study reveals a novel antiviral mechanism of Eltanexor which suggests it has potential to inhibit a broad spectrum of viral pathogens.
Collapse
Affiliation(s)
- Yueyan Liao
- Laboratory of Human Virology and Oncology, Shantou University Medical College, Shantou, China
| | - Xiangyu Ke
- Laboratory of Human Virology and Oncology, Shantou University Medical College, Shantou, China
| | - Tianyi Deng
- Laboratory of Human Virology and Oncology, Shantou University Medical College, Shantou, China
| | - Qingsong Qin
- Laboratory of Human Virology and Oncology, Shantou University Medical College, Shantou, China
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou, China
- Guangdong Provincial Key Laboratory for Diagnosis and Treatment of Breast Cancer, Shantou, China
- *Correspondence: Qingsong Qin,
| |
Collapse
|
14
|
Liu J, Liao M, Yan Y, Yang H, Wang H, Zhou J. Rabies virus phosphoprotein P5 binding to BECN1 regulates self-replication by BECN1-mediated autophagy signaling pathway. Cell Commun Signal 2020; 18:153. [PMID: 32948206 PMCID: PMC7499888 DOI: 10.1186/s12964-020-00644-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 08/10/2020] [Indexed: 12/25/2022] Open
Abstract
Background Rabies virus (RABV) is reported to encode five phosphoproteins (P), which are involved in viral genomic replication, axonal transport, oxidative stress, interferon antagonism, and autophagy induction. However, the functions of the different P proteins are poorly understood. Methods Immunofluorescence staining and western blot were performed to detect the autophagy activity, the form of ring-like structure, and the colocalization of BECN1 and P. Co-immunoprecipitation was performed to detect the interaction between P and BECN1. QRT-PCR and TCID50 assay were performed to detect the replication level of RABV. Small interfering RNA was used to detect the autophagy signaling pathway. Results We found that P5 attaches to N-terminal residues 1–139 of BECN1 (beclin1) on the BECN1 ring-like structure through amino acid residues 173–222 of P5. Subsequently, we found that P5-induced autophagosomes did not fuse with lysosomes. Becn1 silencing did not recover P5 overexpression-induced promotion of RABV replication. Mechanistically, RABV protein PΔN82 (P5) induced incomplete autophagy via the BECN1-mediated signaling pathway. Conclusions Our data indicate that P5 binding to the BECN1 ring benefits RABV replication by inducing BECN1 signaling pathway-dependent incomplete autophagy, which provides a potential target for antiviral drugs against RABV. Video abstract
Graphical abstract ![]()
Collapse
Affiliation(s)
- Juan Liu
- MOA Key Laboratory of Animal Virology, Center for Veterinary Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang, 310058, PR China
| | - Min Liao
- MOA Key Laboratory of Animal Virology, Center for Veterinary Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang, 310058, PR China.
| | - Yan Yan
- MOA Key Laboratory of Animal Virology, Center for Veterinary Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang, 310058, PR China
| | - Hui Yang
- MOA Key Laboratory of Animal Virology, Center for Veterinary Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang, 310058, PR China
| | - Hailong Wang
- MOA Key Laboratory of Animal Virology, Center for Veterinary Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang, 310058, PR China
| | - Jiyong Zhou
- MOA Key Laboratory of Animal Virology, Center for Veterinary Sciences, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang, 310058, PR China.,Collaborative innovation center and State Key laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University, Hangzhou, 310058, PR China
| |
Collapse
|
15
|
Harrison AR, Lieu KG, Larrous F, Ito N, Bourhy H, Moseley GW. Lyssavirus P-protein selectively targets STAT3-STAT1 heterodimers to modulate cytokine signalling. PLoS Pathog 2020; 16:e1008767. [PMID: 32903273 PMCID: PMC7480851 DOI: 10.1371/journal.ppat.1008767] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 07/01/2020] [Indexed: 12/24/2022] Open
Abstract
Many viruses target signal transducer and activator of transcription (STAT) 1 to antagonise antiviral interferon signalling, but targeting of STAT3, a pleiotropic molecule that mediates signalling by diverse cytokines, is poorly understood. Here, using lyssavirus infection, quantitative live cell imaging, innate immune signalling and protein interaction assays, and complementation/depletion of STAT expression, we show that STAT3 antagonism is conserved among P-proteins of diverse pathogenic lyssaviruses and correlates with pathogenesis. Importantly, P-protein targeting of STAT3 involves a highly selective mechanism whereby P-protein antagonises cytokine-activated STAT3-STAT1 heterodimers, but not STAT3 homodimers. RT-qPCR and reporter gene assays indicate that this results in specific modulation of interleukin-6-dependent pathways, effecting differential antagonism of target genes. These data provide novel insights into mechanisms by which viruses can modulate cellular function to support infection through discriminatory targeting of immune signalling complexes. The findings also highlight the potential application of selective interferon-antagonists as tools to delineate signalling by particular STAT complexes, significant not only to pathogen-host interactions but also cell physiology, development and cancer.
Collapse
Affiliation(s)
- Angela R. Harrison
- Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Kim G. Lieu
- Department of Biochemistry and Molecular Biology, Bio21 Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Florence Larrous
- Lyssavirus Epidemiology and Neuropathology Unit, Institut Pasteur, Paris, France
| | - Naoto Ito
- Laboratory of Zoonotic Diseases, Joint Department of Veterinary Medicine, Faculty of Applied Biological Sciences, Gifu University, Gifu, Japan
| | - Hervé Bourhy
- Lyssavirus Epidemiology and Neuropathology Unit, Institut Pasteur, Paris, France
| | - Gregory W. Moseley
- Department of Microbiology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| |
Collapse
|
16
|
Sugiyama A, Nomai T, Jiang X, Minami M, Yao M, Maenaka K, Ito N, Gooley PR, Moseley GW, Ose T. Structural comparison of the C-terminal domain of functionally divergent lyssavirus P proteins. Biochem Biophys Res Commun 2020; 529:507-512. [PMID: 32703459 DOI: 10.1016/j.bbrc.2020.05.195] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 05/26/2020] [Indexed: 12/22/2022]
Abstract
Lyssavirus P protein is a multifunctional protein that interacts with numerous host-cell proteins. The C-terminal domain (CTD) of P is important for inhibition of JAK-STAT signaling enabling the virus to evade host immunity. Several regions on the surface of rabies virus P are reported to interact with host factors. Among them, an extended, discrete hydrophobic patch of P CTD is notable. Although structures of P CTD of two strains of rabies virus, and of mokola virus have been solved, the structure of P CTD for Duvenhage virus, which is functionally divergent from these species for immune evasion function, is not known. Here, we analyze the structures of P CTD of Duvenhage and of a distinct rabies virus strain to gain further insight on the nature and potential function of the hydrophobic surface. Molecular contacts in crystals suggest that the hydrophobic patch is important to intermolecular interactions with other proteins, which differ between the lyssavirus species.
Collapse
Affiliation(s)
- Aoi Sugiyama
- Faculty of Advanced Life Science, Hokkaido University, Kita-10, Nishi-8, Kita-ku, Sapporo, 060-0810, Japan
| | - Tomo Nomai
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo, 060-0812, Japan
| | - Xinxin Jiang
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo, 060-0812, Japan
| | - Miku Minami
- Faculty of Advanced Life Science, Hokkaido University, Kita-10, Nishi-8, Kita-ku, Sapporo, 060-0810, Japan
| | - Min Yao
- Faculty of Advanced Life Science, Hokkaido University, Kita-10, Nishi-8, Kita-ku, Sapporo, 060-0810, Japan
| | - Katsumi Maenaka
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo, 060-0812, Japan
| | - Naoto Ito
- Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu, 501-1193, Japan
| | - Paul R Gooley
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, 3010, Australia
| | - Gregory W Moseley
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton Campus, Victoria, 3800, Australia
| | - Toyoyuki Ose
- Faculty of Advanced Life Science, Hokkaido University, Kita-10, Nishi-8, Kita-ku, Sapporo, 060-0810, Japan; Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo, 060-0812, Japan; PRESTO, Japan Science and Technology Agency, 4-1-8, Honcho Kawaguchi, Saitama, 332-0012, Japan.
| |
Collapse
|
17
|
Økland AL, Nylund A, Øvergård AC, Skoge RH, Kongshaug H. Genomic characterization, phylogenetic position and in situ localization of a novel putative mononegavirus in Lepeophtheirus salmonis. Arch Virol 2019; 164:675-689. [PMID: 30535526 PMCID: PMC6394706 DOI: 10.1007/s00705-018-04119-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Accepted: 11/15/2018] [Indexed: 11/28/2022]
Abstract
The complete genome sequence of a novel mononegavirus, Lepeophtheirus salmonis negative-stranded RNA virus 1 (LsNSRV-1), obtained from a salmonid ectoparasite, Lepeophtheirus salmonis was determined. The viral genome contains five open reading frames encoding three unknown proteins (ORF I, II and III), a putative glycoprotein (G), and a large (L) protein. Phylogenetic analysis placed LsNSRV-1 in the recently established mononegaviral family Artoviridae. LsNSRV-1 showed a prevalence of around 97% and was detected in all L. salmonis developmental stages. Viral genomic and antigenomic RNA was localized to nerve tissue, connective tissue, epithelial cells of the gut, subepidermal tissue, exocrine and cement glands, as well as the testis, vas deferens and spermatophore sac of male L. salmonis and the ovaries and oocytes of females. Viral RNA was detected in both the cytoplasm and the nucleoli of infected cells, and putative nuclear export and localization signals were found within the ORF I, III and L proteins, suggesting nuclear replication of LsNSRV-1. RNA interference (RNAi) was induced twice during development by the introduction of a double-stranded RNA fragment of ORF I, resulting in a transient knockdown of viral RNA. A large variation in the knockdown level was seen in adult males and off springs of knockdown animals, whereas the RNA level was more stable in adult females. Together with the localization of viral RNA within the male spermatophore and female oocytes and the amplification of viral RNA in developing embryos, this suggests that LsNSRV-1 is transmitted both maternally and paternally. Small amounts of viral RNA were detected at the site where chalimi were attached to the skin of Atlantic salmon (Salmo salar). However, as the RNAi-mediated treatment did not result in LsNSRV-1-negative offspring and the virus failed to replicate in the tested fish cell cultures, it is difficult to investigate the influence of secreted LsNSRV-1 on the salmon immune response.
Collapse
Affiliation(s)
- Arnfinn Lodden Økland
- Fish Disease Research Group, Department of Biological Sciences, University of Bergen, Thormøhlensgt. 55, Pb. 7803, 5020, Bergen, Norway.
| | - Are Nylund
- Fish Disease Research Group, Department of Biological Sciences, University of Bergen, Thormøhlensgt. 55, Pb. 7803, 5020, Bergen, Norway
| | - Aina-Cathrine Øvergård
- Sea Lice Research Centre, Department of Biological Sciences, University of Bergen, Thormøhlensgt. 55, Pb. 7803, 5020, Bergen, Norway
| | - Renate Hvidsten Skoge
- Fish Disease Research Group, Department of Biological Sciences, University of Bergen, Thormøhlensgt. 55, Pb. 7803, 5020, Bergen, Norway
| | - Heidi Kongshaug
- Sea Lice Research Centre, Department of Biological Sciences, University of Bergen, Thormøhlensgt. 55, Pb. 7803, 5020, Bergen, Norway
| |
Collapse
|
18
|
Status of antiviral therapeutics against rabies virus and related emerging lyssaviruses. Curr Opin Virol 2019; 35:1-13. [PMID: 30753961 DOI: 10.1016/j.coviro.2018.12.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 12/19/2018] [Accepted: 12/20/2018] [Indexed: 12/19/2022]
Abstract
Rabies virus (RABV) constitutes a major social and economic burden associated with 60 000 deaths annually worldwide. Although pre-exposure and post-exposure treatment options are available, they are efficacious only when initiated before the onset of clinical symptoms. Aggravating the problem, the current RABV vaccine does not cross-protect against the emerging zoonotic phylogroup II lyssaviruses. A requirement for an uninterrupted cold chain and high cost of the immunoglobulin component of rabies prophylaxis generate an unmet need for the development of RABV-specific antivirals. We discuss desirable anti-RABV drug profiles, past efforts to address the problem and inhibitor candidates identified, and examine how the rapidly expanding structural insight into RABV protein organization has illuminated novel druggable target candidates and paved the way to structure-aided drug optimization. Special emphasis is given to the viral RNA-dependent RNA polymerase complex as a promising target for direct-acting broad-spectrum RABV inhibitors.
Collapse
|
19
|
Ohtsuka J, Matsumoto Y, Ohta K, Fukumura M, Tsurudome M, Nosaka T, Nishio M. Nucleocytoplasmic shuttling of the human parainfluenza virus type 2 phosphoprotein. Virology 2018; 528:54-63. [PMID: 30576860 DOI: 10.1016/j.virol.2018.12.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 11/21/2018] [Accepted: 12/05/2018] [Indexed: 02/08/2023]
Abstract
Human parainfluenza virus type 2 phosphoprotein (P) is an essential component of viral polymerase. The P gene encodes both P and accessory V proteins by a specific gene editing mechanism. Therefore, the N-terminal 164 amino acids of P protein are common to V protein. Interestingly, while P protein is located in the cytoplasm, V protein is found mainly in the nucleus. Using deletion mutants, we show the presence of a nuclear localization signal (NLS) in the P/V common domain, and a nuclear export signal (NES) in the C-terminal P specific region. The NLS region makes a complex with importin α5 or 7. In the presence of leptomycin B, P protein is retained in the nucleus, indicating that it contains a CRM1-dependent NES. We identified the NLS (65PVKPRRKK72) and the NES (225IIELLKGLDL234) using β-galactosidase fusion proteins. Moreover, nucleocytoplasmic shuttling of P protein appears to be important for efficient viral polymerase activity.
Collapse
Affiliation(s)
- Junpei Ohtsuka
- Department of Microbiology, Mie University Graduate School of Medicine, Mie, Japan; Biocomo Inc., Mie, Japan
| | - Yusuke Matsumoto
- Department of Microbiology, School of Medicine, Wakayama Medical University, Wakayama, Japan
| | - Keisuke Ohta
- Department of Microbiology, School of Medicine, Wakayama Medical University, Wakayama, Japan
| | - Masayuki Fukumura
- Department of Microbiology, Mie University Graduate School of Medicine, Mie, Japan; Biocomo Inc., Mie, Japan
| | - Masato Tsurudome
- Department of Biomedical Sciences, College of Life and Health Sciences, Chubu University, Aichi, Japan
| | - Tetsuya Nosaka
- Department of Microbiology, Mie University Graduate School of Medicine, Mie, Japan
| | - Machiko Nishio
- Department of Microbiology, School of Medicine, Wakayama Medical University, Wakayama, Japan.
| |
Collapse
|
20
|
Vasilakis N, Tesh RB, Widen SG, Mirchandani D, Walker PJ. Genomic characterisation of Cuiaba and Charleville viruses: arboviruses (family Rhabdoviridae, genus Sripuvirus) infecting reptiles and amphibians. Virus Genes 2018; 55:87-94. [PMID: 30511209 DOI: 10.1007/s11262-018-1620-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 11/23/2018] [Indexed: 11/25/2022]
Abstract
Viruses in the family Rhabdoviridae are ecologically very diverse, infecting mammals, birds, reptiles, fish, plants and a wide range of other terrestrial and aquatic invertebrates. The genus Sripuvirus currently comprises five viruses that appear to circulate in transmission cycles involving reptiles and sandflies. Here, we report an analysis of the complete coding sequences of Cuiaba virus (CUIV), isolated from an amphibian (Bufo marinus) collected in Brazil, and Charleville virus (CHVV), isolated from sandflies (Phlebotomus sp.) and lizards (Gehyra australis), collected in Australia. CUIV and CHVV cluster phylogenetically with the sripuviruses in maximum likelihood trees generated from complete L protein (RdRp) sequences. They also share with sripuviruses unique features in genome organisation, including an additional gene (U1) between the matrix protein (M) gene and glycoprotein (G) gene, and an alternative long open reading frame near the start of the G ORF that encodes a predicted transmembrane protein. In view of their phylogenetic relationships, similar genome organisations and similar ecological characteristics, we propose the assignment of CUIV and CHVV as novel members of the genus Sripuvirus.
Collapse
Affiliation(s)
- Nikos Vasilakis
- Department of Pathology, Center for Biodefence and Emerging Infectious Diseases, The University of Texas Medical Branch, Galveston, TX, USA
- Center for Tropical Diseases, The University of Texas Medical Branch, Galveston, TX, USA
- Institute for Human Infection and Immunity, The University of Texas Medical Branch, Galveston, TX, USA
| | - Robert B Tesh
- Department of Pathology, Center for Biodefence and Emerging Infectious Diseases, The University of Texas Medical Branch, Galveston, TX, USA
- Center for Tropical Diseases, The University of Texas Medical Branch, Galveston, TX, USA
- Institute for Human Infection and Immunity, The University of Texas Medical Branch, Galveston, TX, USA
| | - Steven G Widen
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, TX, USA
| | - Divya Mirchandani
- Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, TX, USA
| | - Peter J Walker
- School of Biological Sciences, The University of Queensland, St Lucia, QLD, Australia.
| |
Collapse
|
21
|
Mathew C, Ghildyal R. CRM1 Inhibitors for Antiviral Therapy. Front Microbiol 2017; 8:1171. [PMID: 28702009 PMCID: PMC5487384 DOI: 10.3389/fmicb.2017.01171] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 06/08/2017] [Indexed: 12/22/2022] Open
Abstract
Infectious diseases are a major global concern and despite major advancements in medical research, still cause significant morbidity and mortality. Progress in antiviral therapy is particularly hindered by appearance of mutants capable of overcoming the effects of drugs targeting viral components. Alternatively, development of drugs targeting host proteins essential for completion of viral lifecycle holds potential as a viable strategy for antiviral therapy. Nucleocytoplasmic trafficking pathways in particular are involved in several pathological conditions including cancer and viral infections, where hijacking or alteration of function of key transporter proteins, such as Chromosome Region Maintenance1 (CRM1) is observed. Overexpression of CRM1-mediated nuclear export is evident in several solid and hematological malignancies. Interestingly, CRM1-mediated nuclear export of viral components is crucial in various stages of the viral lifecycle and assembly. This review summarizes the role of CRM1 in cancer and selected viruses. Leptomycin B (LMB) is the prototypical inhibitor of CRM1 potent against various cancer cell lines overexpressing CRM1 and in limiting viral infections at nanomolar concentrations in vitro. However, the irreversible shutdown of nuclear export results in high cytotoxicity and limited efficacy in vivo. This has prompted search for synthetic and natural CRM1 inhibitors that can potentially be developed as broadly active antivirals, some of which are summarized in this review.
Collapse
Affiliation(s)
| | - Reena Ghildyal
- Respiratory Virology Group, Centre for Research in Therapeutic Solutions, Health Research Institute, University of CanberraCanberra, ACT, Australia
| |
Collapse
|
22
|
Scott TP, Nel LH. Subversion of the Immune Response by Rabies Virus. Viruses 2016; 8:v8080231. [PMID: 27548204 PMCID: PMC4997593 DOI: 10.3390/v8080231] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 08/11/2016] [Accepted: 08/12/2016] [Indexed: 12/24/2022] Open
Abstract
Rabies has affected mankind for several centuries and is one of the oldest known zoonoses. It is peculiar how little is known regarding the means by which rabies virus (RABV) evades the immune response and kills its host. This review investigates the complex interplay between RABV and the immune system, including the various means by which RABV evades, or advantageously utilizes, the host immune response in order to ensure successful replication and spread to another host. Different factors that influence immune responses—including age, sex, cerebral lateralization and temperature—are discussed, with specific reference to RABV and the effects on host morbidity and mortality. We also investigate the role of apoptosis and discuss whether it is a detrimental or beneficial mechanism of the host’s response to infection. The various RABV proteins and their roles in immune evasion are examined in depth with reference to important domains and the downstream effects of these interactions. Lastly, an overview of the means by which RABV evades important immune responses is provided. The research discussed in this review will be important in determining the roles of the immune response during RABV infections as well as to highlight important therapeutic target regions and potential strategies for rabies treatment.
Collapse
Affiliation(s)
- Terence P Scott
- Department of Microbiology and Plant Pathology, University of Pretoria, Pretoria 0002, South Africa.
| | - Louis H Nel
- Department of Microbiology and Plant Pathology, University of Pretoria, Pretoria 0002, South Africa.
| |
Collapse
|
23
|
Audsley MD, Jans DA, Moseley GW. Roles of nuclear trafficking in infection by cytoplasmic negative-strand RNA viruses: paramyxoviruses and beyond. J Gen Virol 2016; 97:2463-2481. [PMID: 27498841 DOI: 10.1099/jgv.0.000575] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Genome replication and virion production by most negative-sense RNA viruses (NSVs) occurs exclusively in the cytoplasm, but many NSV-expressed proteins undergo active nucleocytoplasmic trafficking via signals that exploit cellular nuclear transport pathways. Nuclear trafficking has been reported both for NSV accessory proteins (including isoforms of the rabies virus phosphoprotein, and V, W and C proteins of paramyxoviruses) and for structural proteins. Trafficking of the former is thought to enable accessory functions in viral modulation of antiviral responses including the type I IFN system, but the intranuclear roles of structural proteins such as nucleocapsid and matrix proteins, which have critical roles in extranuclear replication and viral assembly, are less clear. Nevertheless, nuclear trafficking of matrix protein has been reported to be critical for efficient production of Nipah virus and Respiratory syncytial virus, and nuclear localization of nucleocapsid protein of several morbilliviruses has been linked to mechanisms of immune evasion. Together, these data point to the nucleus as a significant host interface for viral proteins during infection by NSVs with otherwise cytoplasmic life cycles. Importantly, several lines of evidence now suggest that nuclear trafficking of these proteins may be critical to pathogenesis and thus could provide new targets for vaccine development and antiviral therapies.
Collapse
Affiliation(s)
- Michelle D Audsley
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - David A Jans
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
| | - Gregory W Moseley
- Department of Biochemistry and Molecular Biology, BIO21 Molecular Science and Biotechnology Institute, University of Melbourne, VIC 3000, Australia
| |
Collapse
|
24
|
The co-chaperone Cdc37 regulates the rabies virus phosphoprotein stability by targeting to Hsp90AA1 machinery. Sci Rep 2016; 6:27123. [PMID: 27251758 PMCID: PMC4890047 DOI: 10.1038/srep27123] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 05/12/2016] [Indexed: 12/25/2022] Open
Abstract
Cdc37, as a kinase-specific co-chaperone of the chaperone Hsp90AA1 (Hsp90), actively aids with the maturation, stabilization and activation of the cellular or viral kinase/kinase-like targets. Phosphoprotein (P) of rabies virus (RABV) is a multifunctional, non-kinase protein involved in interferon antagonism, viral transcription and replication. Here, we demonstrated that the RABV non-kinase P is chaperoned by Cdc37 and Hsp90 during infection. We found that Cdc37 and Hsp90 affect the RABV life cycle directly. Activity inhibition and knockdown of Cdc37 and Hsp90 increased the instability of the viral P protein. Overexpression of Cdc37 and Hsp90 maintained P's stability but did not increase the yield of infectious RABV virions. We further demonstrated that the non-enzymatic polymerase cofactor P protein of all the genotypes of lyssaviruses is a target of the Cdc37/Hsp90 complex. Cdc37, phosphorylated or unphosphorylated on Ser13, aids the P protein to load onto the Hsp90 machinery, with or without Cdc37 binding to Hsp90. However, the interaction between Cdc37 and Hsp90 appears to have additional allosteric regulation of the conformational switch of Hsp90. Our study highlighted a novel mechanism in which Cdc37/Hsp90 chaperones a non-kinase target, which has significant implications for designing therapeutic targets against Rabies.
Collapse
|
25
|
Ito N, Moseley GW, Sugiyama M. The importance of immune evasion in the pathogenesis of rabies virus. J Vet Med Sci 2016; 78:1089-98. [PMID: 27041139 PMCID: PMC4976263 DOI: 10.1292/jvms.16-0092] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Rabies is a zoonotic disease caused by the Lyssavirus rabies virus
(RABV) that can infect most mammals, including humans, where it has a case-fatality rate
of almost 100%. Although preventable by vaccination, rabies causes c. 59,000 human
fatalities every year worldwide. Thus, there exists an urgent need to establish an
effective therapy and/or improve dissemination of vaccines for humans and animals. These
outcomes require greater understanding of the mechanisms of RABV pathogenesis to identify
new molecular targets for the development of therapeutics and/or live vaccines with high
levels of safety. Importantly, a number of studies in recent years have indicated that
RABV specifically suppresses host immunity through diverse mechanisms and that this is a
key process in pathogenicity. Here, we review current understanding of immune modulation
by RABV, with an emphasis on its significance to pathogenicity and the potential
exploitation of this knowledge to develop new vaccines and antivirals.
Collapse
Affiliation(s)
- Naoto Ito
- Laboratory of Zoonotic Diseases, Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu, Gifu 501-1193, Japan
| | | | | |
Collapse
|
26
|
Nuclear Trafficking of the Rabies Virus Interferon Antagonist P-Protein Is Regulated by an Importin-Binding Nuclear Localization Sequence in the C-Terminal Domain. PLoS One 2016; 11:e0150477. [PMID: 26939125 PMCID: PMC4777398 DOI: 10.1371/journal.pone.0150477] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 02/14/2016] [Indexed: 12/25/2022] Open
Abstract
Rabies virus P-protein is expressed as five isoforms (P1-P5) which undergo nucleocytoplasmic trafficking important to roles in immune evasion. Although nuclear import of P3 is known to be mediated by an importin (IMP)-recognised nuclear localization sequence in the N-terminal region (N-NLS), the mechanisms underlying nuclear import of other P isoforms in which the N-NLS is inactive or has been deleted have remained unresolved. Based on the previous observation that mutation of basic residues K214/R260 of the P-protein C-terminal domain (P-CTD) can result in nuclear exclusion of P3, we used live cell imaging, protein interaction analysis and in vitro nuclear transport assays to examine in detail the nuclear trafficking properties of this domain. We find that the effect of mutation of K214/R260 on P3 is largely dependent on nuclear export, suggesting that nuclear exclusion of mutated P3 involves the P-CTD-localized nuclear export sequence (C-NES). However, assays using cells in which nuclear export is pharmacologically inhibited indicate that these mutations significantly inhibit P3 nuclear accumulation and, importantly, prevent nuclear accumulation of P1, suggestive of effects on NLS-mediated import activity in these isoforms. Consistent with this, molecular binding and transport assays indicate that the P-CTD mediates IMPα2/IMPβ1-dependent nuclear import by conferring direct binding to the IMPα2/IMPβ1 heterodimer, as well as to a truncated form of IMPα2 lacking the IMPβ-binding autoinhibitory domain (ΔIBB-IMPα2), and IMPβ1 alone. These properties are all dependent on K214 and R260. This provides the first evidence that P-CTD contains a genuine IMP-binding NLS, and establishes the mechanism by which P-protein isoforms other than P3 can be imported to the nucleus. These data underpin a refined model for P-protein trafficking that involves the concerted action of multiple NESs and IMP-binding NLSs, and highlight the intricate regulation of P-protein subcellular localization, consistent with important roles in infection.
Collapse
|
27
|
Li Y, Dong W, Shi Y, Deng F, Chen X, Wan C, Zhou M, Zhao L, Fu ZF, Peng G. Rabies virus phosphoprotein interacts with ribosomal protein L9 and affects rabies virus replication. Virology 2015; 488:216-24. [PMID: 26655239 DOI: 10.1016/j.virol.2015.11.018] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2015] [Revised: 11/09/2015] [Accepted: 11/19/2015] [Indexed: 10/22/2022]
Abstract
Rabies virus is a highly neurotropic virus that can cause fatal infection of the central nervous system in warm-blooded animals. The RABV phosphoprotein (P), an essential cofactor of the virus RNA-dependent RNA polymerase, is required for virus replication. In this study, the ribosomal protein L9, which has functions in protein translation, is identified as P-interacting cellular factor using phage display analysis. Direct binding between the L9 and P was confirmed by protein pull-down and co-immunoprecipitation analyses. It was further demonstrated that L9 translocates from the nucleus to the cytoplasm, where it colocalizes with P in cells infected with RABV or transfected with P gene. RABV replication was reduced with L9 overexpression and enhanced with L9 knockdown. Thus, we propose that during RABV infection, P binds to L9 that translocates from the nucleus to the cytoplasm, inhibiting the initial stage of RABV transcription.
Collapse
Affiliation(s)
- Youwen Li
- The National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China; College of Animal Science, Tarim University, Alar, Xinjiang, China
| | - Wanyu Dong
- The National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Yuejun Shi
- The National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Feng Deng
- The National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Xi Chen
- The National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Chunyun Wan
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Ming Zhou
- The National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Ling Zhao
- The National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Zhen F Fu
- The National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China; Departments of Pathology, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA.
| | - Guiqing Peng
- The National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei 430070, China.
| |
Collapse
|
28
|
Blondel D, Maarifi G, Nisole S, Chelbi-Alix MK. Resistance to Rhabdoviridae Infection and Subversion of Antiviral Responses. Viruses 2015; 7:3675-702. [PMID: 26198243 PMCID: PMC4517123 DOI: 10.3390/v7072794] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 06/29/2015] [Accepted: 07/01/2015] [Indexed: 12/13/2022] Open
Abstract
Interferon (IFN) treatment induces the expression of hundreds of IFN-stimulated genes (ISGs). However, only a selection of their products have been demonstrated to be responsible for the inhibition of rhabdovirus replication in cultured cells; and only a few have been shown to play a role in mediating the antiviral response in vivo using gene knockout mouse models. IFNs inhibit rhabdovirus replication at different stages via the induction of a variety of ISGs. This review will discuss how individual ISG products confer resistance to rhabdoviruses by blocking viral entry, degrading single stranded viral RNA, inhibiting viral translation or preventing release of virions from the cell. Furthermore, this review will highlight how these viruses counteract the host IFN system.
Collapse
Affiliation(s)
- Danielle Blondel
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS UMR 9198, Université Paris-Sud, Gif-sur-Yvette 91190, France.
| | - Ghizlane Maarifi
- INSERM UMR-S 1124, Université Paris Descartes, Centre Interdisciplinaire Chimie Biologie-Paris (FR 3567, CNRS), 75270 Paris Cedex 6, France.
| | - Sébastien Nisole
- INSERM UMR-S 1124, Université Paris Descartes, Centre Interdisciplinaire Chimie Biologie-Paris (FR 3567, CNRS), 75270 Paris Cedex 6, France.
| | - Mounira K Chelbi-Alix
- INSERM UMR-S 1124, Université Paris Descartes, Centre Interdisciplinaire Chimie Biologie-Paris (FR 3567, CNRS), 75270 Paris Cedex 6, France.
| |
Collapse
|
29
|
Structure of the low pH conformation of Chandipura virus G reveals important features in the evolution of the vesiculovirus glycoprotein. PLoS Pathog 2015; 11:e1004756. [PMID: 25803715 PMCID: PMC4372607 DOI: 10.1371/journal.ppat.1004756] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 02/20/2015] [Indexed: 11/19/2022] Open
Abstract
Chandipura virus (CHAV), a member of the vesiculovirus genus, is an emerging human pathogen. As for other rhabdoviruses, CHAV entry into susceptible cells is mediated by its single envelope glycoprotein G which is both involved in receptor recognition and fusion of viral and cellular membranes. Here, we have characterized the fusion properties of CHAV-G. As for vesicular stomatitis virus (VSV, the prototype of the genus) G, fusion is triggered at low pH below 6.5. We have also analyzed the biochemical properties of a soluble form of CHAV-G ectodomain (CHAV-Gth, generated by thermolysin limited-proteolysis of recombinant VSV particles in which the G gene was replaced by that of CHAV). The overall behavior of CHAV-Gth is similar to that previously reported for VSV-Gth. Particularly, CHAV-Gth pre-fusion trimer is not stable in solution and low-pH-induced membrane association of CHAV-Gth is reversible. Furthermore, CHAV-Gth was crystallized in its low pH post-fusion conformation and its structure was determined at 3.6Å resolution. An overall comparison of this structure with the previously reported VSV-Gth post-fusion conformation, shows a high structural similarity as expected from the comparison of primary structure. Among the three domains of G, the pleckstrin homology domain (PHD) appears to be the most divergent and the largest differences are confined to the secondary structure of the major antigenic site of rhabdoviruses. Finally, local differences indicate that CHAV has evolved alternate structural solutions in hinge regions between PH and fusion domains but also distinct pH sensitive switches. Globally the comparison between the post fusion conformation of CHAV and VSV-G highlights several features essential for the protein's function. It also reveals the remarkable plasticity of G in terms of local structures.
Collapse
|
30
|
Oksayan S, Nikolic J, David CT, Blondel D, Jans DA, Moseley GW. Identification of a role for nucleolin in rabies virus infection. J Virol 2015; 89:1939-43. [PMID: 25428867 PMCID: PMC4300734 DOI: 10.1128/jvi.03320-14] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 11/17/2014] [Indexed: 12/24/2022] Open
Abstract
Rabies virus replicates in the cytoplasm of host cells, but rabies virus phosphoprotein (P-protein) undergoes active nucleocytoplasmic trafficking. Here we show that the largely nuclear P-protein isoform P3 can localize to nucleoli and forms specific interactions with nucleolin. Importantly, depletion of nucleolin expression inhibits viral protein expression and infectious virus production by infected cells. This provides the first evidence that lyssaviruses interact with nucleolin and that nucleolin is important to lyssavirus infection.
Collapse
Affiliation(s)
- S Oksayan
- Viral Pathogenesis Laboratory, Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Australia Nuclear Signalling Laboratory, Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | - J Nikolic
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Université Paris-Sud, Gif-sur-Yvette, France
| | - C T David
- Viral Pathogenesis Laboratory, Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Australia
| | - D Blondel
- Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, CEA, CNRS, Université Paris-Sud, Gif-sur-Yvette, France
| | - D A Jans
- Nuclear Signalling Laboratory, Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia
| | - G W Moseley
- Viral Pathogenesis Laboratory, Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Australia
| |
Collapse
|
31
|
Wongabel rhabdovirus accessory protein U3 targets the SWI/SNF chromatin remodeling complex. J Virol 2014; 89:1377-88. [PMID: 25392228 DOI: 10.1128/jvi.02010-14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
UNLABELLED Wongabel virus (WONV) is an arthropod-borne rhabdovirus that infects birds. It is one of the growing array of rhabdoviruses with complex genomes that encode multiple accessory proteins of unknown function. In addition to the five canonical rhabdovirus structural protein genes (N, P, M, G, and L), the 13.2-kb negative-sense single-stranded RNA (ssRNA) WONV genome contains five uncharacterized accessory genes, one overlapping the N gene (Nx or U4), three located between the P and M genes (U1 to U3), and a fifth one overlapping the G gene (Gx or U5). Here we show that WONV U3 is expressed during infection in insect and mammalian cells and is required for efficient viral replication. A yeast two-hybrid screen against a mosquito cell cDNA library identified that WONV U3 interacts with the 83-amino-acid (aa) C-terminal domain of SNF5, a component of the SWI/SNF chromatin remodeling complex. The interaction was confirmed by affinity chromatography, and nuclear colocalization was established by confocal microscopy. Gene expression studies showed that SNF5 transcripts are upregulated during infection of mosquito cells with WONV, as well as West Nile virus (Flaviviridae) and bovine ephemeral fever virus (Rhabdoviridae), and that SNF5 knockdown results in increased WONV replication. WONV U3 also inhibits SNF5-regulated expression of the cytokine gene CSF1. The data suggest that WONV U3 targets the SWI/SNF complex to block the host response to infection. IMPORTANCE The rhabdoviruses comprise a large family of RNA viruses infecting plants, vertebrates, and invertebrates. In addition to the major structural proteins (N, P, M, G, and L), many rhabdoviruses encode a diverse array of accessory proteins of largely unknown function. Understanding the role of these proteins may reveal much about host-pathogen interactions in infected cells. Here we examine accessory protein U3 of Wongabel virus, an arthropod-borne rhabdovirus that infects birds. We show that U3 enters the nucleus and interacts with SNF5, a component of the chromatin remodeling complex that is upregulated in response to infection and restricts viral replication. We also show that U3 inhibits SNF5-regulated expression of the cytokine colony-stimulating factor 1 (CSF1), suggesting that it targets the chromatin remodeling complex to block the host response to infection. This study appears to provide the first evidence of a virus targeting SNF5 to inhibit host gene expression.
Collapse
|
32
|
Characterization of pH-sensitive molecular switches that trigger the structural transition of vesicular stomatitis virus glycoprotein from the postfusion state toward the prefusion state. J Virol 2014; 88:13396-409. [PMID: 25210175 DOI: 10.1128/jvi.01962-14] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
UNLABELLED Vesicular stomatitis virus (VSV; the prototype rhabdovirus) fusion is triggered at low pH and mediated by glycoprotein G, which undergoes a low-pH-induced structural transition. A unique feature of rhabdovirus G is that its conformational change is reversible. This allows G to recover its native prefusion state at the viral surface after its transport through the acidic Golgi compartments. The crystal structures of G pre- and postfusion states have been elucidated, leading to the identification of several acidic amino acid residues, clustered in the postfusion trimer, as potential pH-sensitive switches controlling the transition back toward the prefusion state. We mutated these residues and produced a panel of single and double mutants whose fusion properties, conformational change characteristics, and ability to pseudotype a virus lacking the glycoprotein gene were assayed. Some of these mutations were also introduced in the genome of recombinant viruses which were further characterized. We show that D268, located in the segment consisting of residues 264 to 273, which refolds into postfusion helix F during G structural transition, is the major pH sensor while D274, D395, and D393 have additional contributions. Furthermore, a single passage of recombinant virus bearing the mutation D268L (which was demonstrated to stabilize the G postfusion state) resulted in a pseudorevertant with a compensatory second mutation, L271P. This revealed that the propensity of the segment of residues 264 to 273 to refold into helix F has to be finely tuned since either an increase (mutation D268L alone) or a decrease (mutation L271P alone) of this propensity is detrimental to the virus. IMPORTANCE Vesicular stomatitis virus enters cells via endocytosis. Endosome acidification induces a structural transition of its unique glycoprotein (G), which mediates fusion between viral and endosomal membranes. G conformational change is reversible upon increases in pH. This allows G to recover its native prefusion state at the viral surface after its transport through the acidic Golgi compartments. We mutated five acidic residues, proposed to be pH-sensitive switches controlling the structural transition back toward the prefusion state. Our results indicate that residue D268 is the major pH sensor, while other acidic residues have additional contributions, and reveal that the propensity of the segment consisting of residues 264 to 273 to adopt a helical conformation is finely regulated. This segment might be a good target for antiviral compounds.
Collapse
|
33
|
Abstract
Membrane envelopment and budding of negative strand RNA viruses (NSVs) is mainly driven by viral matrix proteins (M). In addition, several M proteins are also known to be involved in host cell manipulation. Knowledge about the cellular targets and detailed molecular mechanisms, however, is poor for many M proteins. For instance, Nipah Virus (NiV) M protein trafficking through the nucleus is essential for virus release, but nuclear targets of NiV M remain unknown. To identify cellular interactors of henipavirus M proteins, tagged Hendra Virus (HeV) M proteins were expressed and M-containing protein complexes were isolated and analysed. Presence of acidic leucine-rich nuclear phosphoprotein 32 family member B (ANP32B) in the complex suggested that this protein represents a direct or indirect interactor of the viral matrix protein. Over-expression of ANP32B led to specific nuclear accumulation of HeV M, providing a functional link between ANP32B and M protein. ANP32B-dependent nuclear accumulation was observed after plasmid-driven expression of HeV and NiV matrix proteins and also in NiV infected cells. The latter indicated that an interaction of henipavirus M protein with ANP32B also occurs in the context of virus replication. From these data we conclude that ANP32B is a nuclear target of henipavirus M that may contribute to virus replication. Potential effects of ANP32B on HeV nuclear shuttling and host cell manipulation by HeV M affecting ANP32B functions in host cell survival and gene expression regulation are discussed.
Collapse
|
34
|
Wiltzer L, Okada K, Yamaoka S, Larrous F, Kuusisto HV, Sugiyama M, Blondel D, Bourhy H, Jans DA, Ito N, Moseley GW. Interaction of Rabies Virus P-Protein With STAT Proteins is Critical to Lethal Rabies Disease. J Infect Dis 2013; 209:1744-53. [DOI: 10.1093/infdis/jit829] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
|
35
|
Martinez N, Ribeiro EA, Leyrat C, Tarbouriech N, Ruigrok RWH, Jamin M. Structure of the C-terminal domain of lettuce necrotic yellows virus phosphoprotein. J Virol 2013; 87:9569-78. [PMID: 23785215 PMCID: PMC3754093 DOI: 10.1128/jvi.00999-13] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 06/14/2013] [Indexed: 12/26/2022] Open
Abstract
Lettuce necrotic yellows virus (LNYV) is a prototype of the plant-adapted cytorhabdoviruses. Through a meta-prediction of disorder, we localized a folded C-terminal domain in the amino acid sequence of its phosphoprotein. This domain consists of an autonomous folding unit that is monomeric in solution. Its structure, solved by X-ray crystallography, reveals a lollipop-shaped structure comprising five helices. The structure is different from that of the corresponding domains of other Rhabdoviridae, Filoviridae, and Paramyxovirinae; only the overall topology of the polypeptide chain seems to be conserved, suggesting that this domain evolved under weak selective pressure and varied in size by the acquisition or loss of functional modules.
Collapse
Affiliation(s)
- Nicolas Martinez
- Université Grenoble Alpes, UVHCI, Grenoble, France
- CNRS, UVHCI, Grenoble, France
- Unit for Virus Host-Cell Interactions, Université Grenoble Alpes-EMBL-CNRS, Grenoble, France
- Institut Laue Langevin, Grenoble, France
| | - Euripedes A. Ribeiro
- Université Grenoble Alpes, UVHCI, Grenoble, France
- CNRS, UVHCI, Grenoble, France
- Unit for Virus Host-Cell Interactions, Université Grenoble Alpes-EMBL-CNRS, Grenoble, France
| | - Cédric Leyrat
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Nicolas Tarbouriech
- Université Grenoble Alpes, UVHCI, Grenoble, France
- CNRS, UVHCI, Grenoble, France
- Unit for Virus Host-Cell Interactions, Université Grenoble Alpes-EMBL-CNRS, Grenoble, France
| | - Rob W. H. Ruigrok
- Université Grenoble Alpes, UVHCI, Grenoble, France
- CNRS, UVHCI, Grenoble, France
- Unit for Virus Host-Cell Interactions, Université Grenoble Alpes-EMBL-CNRS, Grenoble, France
| | - Marc Jamin
- Université Grenoble Alpes, UVHCI, Grenoble, France
- CNRS, UVHCI, Grenoble, France
- Unit for Virus Host-Cell Interactions, Université Grenoble Alpes-EMBL-CNRS, Grenoble, France
| |
Collapse
|
36
|
Lieu KG, Brice A, Wiltzer L, Hirst B, Jans DA, Blondel D, Moseley GW. The rabies virus interferon antagonist P protein interacts with activated STAT3 and inhibits Gp130 receptor signaling. J Virol 2013; 87:8261-5. [PMID: 23698294 PMCID: PMC3700209 DOI: 10.1128/jvi.00989-13] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 05/12/2013] [Indexed: 12/24/2022] Open
Abstract
Immune evasion by rabies virus depends on targeting of the signal transducers and activator of transcription 1 (STAT1) and STAT2 proteins by the viral interferon antagonist P protein, but targeting of other STAT proteins has not been investigated. Here, we find that P protein associates with activated STAT3 and inhibits STAT3 nuclear accumulation and Gp130-dependent signaling. This is the first report of STAT3 targeting by the interferon antagonist of a virus other than a paramyxovirus, indicating that STAT3 antagonism is important to a range of human-pathogenic viruses.
Collapse
Affiliation(s)
- Kim G. Lieu
- Viral Pathogenesis Laboratory
- Nuclear Signalling Laboratory, Department of Biochemistry and Molecular Biology, Monash University, Victoria, Australia
| | | | - Linda Wiltzer
- Viral Pathogenesis Laboratory
- Nuclear Signalling Laboratory, Department of Biochemistry and Molecular Biology, Monash University, Victoria, Australia
| | | | - David A. Jans
- Nuclear Signalling Laboratory, Department of Biochemistry and Molecular Biology, Monash University, Victoria, Australia
| | - Danielle Blondel
- Laboratoire de Virologie Moléculaire et Structurale, CNRS, Gif sur Yvette, France
| | | |
Collapse
|
37
|
Brice A, Moseley GW. Viral interactions with microtubules: orchestrators of host cell biology? Future Virol 2013. [DOI: 10.2217/fvl.12.137] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Viral interaction with the microtubule (MT) cytoskeleton is critical to infection by many viruses. Most data regarding virus–MT interaction indicate key roles in the subcellular transport of virions/viral genomic material to sites of replication, assembly and egress. However, the MT cytoskeleton orchestrates diverse processes in addition to subcellular cargo transport, including regulation of signaling pathways, cell survival and mitosis, suggesting that viruses, expert manipulators of the host cell, may use the virus–MT interface to control multiple aspects of cell biology. Several lines of evidence support this idea, indicating that specific viral proteins can modify MT dynamics and/or structure and regulate processes such as apoptosis and innate immune signaling through MT-dependent mechanisms. Here, the authors review general aspects of virus–MT interactions, with emphasis on viral mechanisms that modify MT dynamics and functions to affect processes beyond virion transport. The emerging importance of discrete viral protein–MT interactions in pathogenic processes indicates that these interfaces may represent new targets for future therapeutics and vaccine development.
Collapse
Affiliation(s)
- Aaron Brice
- Viral Immune Evasion & Pathogenicity Laboratory, Department of Biochemistry & Molecular Biology, Monash University, Victoria 3800, Australia
| | - Gregory W Moseley
- Viral Immune Evasion & Pathogenicity Laboratory, Department of Biochemistry & Molecular Biology, Monash University, Victoria 3800, Australia.
| |
Collapse
|
38
|
Park JS, Kim CK, Kim SY, Ju YR. Molecular characterization of KGH, the first human isolate of rabies virus in Korea. Virus Genes 2012; 46:231-41. [PMID: 23242520 DOI: 10.1007/s11262-012-0850-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Accepted: 11/12/2012] [Indexed: 12/25/2022]
Abstract
The complete genome sequence of the KGH strain of the first human rabies virus, which was isolated from a skin biopsy of a patient with rabies, whose symptoms developed due to bites from a raccoon dog in 2001. The size of the KGH strain genome was determined to be 11,928 nucleotides (nt) with a leader sequence of 58 nt, nucleoprotein gene of 1,353 nt, phosphoprotein gene of 894 nt, matrix protein gene of 609 nt, glycoprotein gene of 1,575 nt, RNA-dependent RNA polymerase gene of 6,384 nt, and trailer region of 69 nt. Sequence similarity was compared with 39 fully sequenced rabies virus genomes currently available, and the result showed 70.6-91.6 % at the nucleotide level, and 82.8-97.9 % at the amino acid level. The deduced amino acids in the viral protein were compared with those of other rabies viruses, and various functional regions were investigated. As a result, we found that the KGH strain only had a unique amino acid substitution that was identified to be associated either with host immune response and pathogenicity in the N protein, or with a related region regulating STAT1 in the P protein, and related to pathogenicity in G protein. Based on phylogenetic analyses using the complete genome of 39 rabies viruses, the KGH strain was determined to be closely related with the NNV-RAB-H strain and transplant rabies virus serotype 1, which are Indian isolates, and was confirmed to belong to the Arctic-like 2 clade. The KGH strain was most closely related to the SKRRD0204HC and SKRRD0205HC strain when compared with Korean animal isolates, which was separated around the same time and place, and belonged to the Gangwon III subgroup.
Collapse
|
39
|
Reply to “Nuclear Export Signal and Immunodominant CD8
+
T Cell Epitope in Influenza A Virus Matrix Protein 1”. J Virol 2012. [DOI: 10.1128/jvi.01245-12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
|
40
|
Oksayan S, Wiltzer L, Rowe CL, Blondel D, Jans DA, Moseley GW. A novel nuclear trafficking module regulates the nucleocytoplasmic localization of the rabies virus interferon antagonist, P protein. J Biol Chem 2012; 287:28112-21. [PMID: 22700958 PMCID: PMC3431689 DOI: 10.1074/jbc.m112.374694] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 06/13/2012] [Indexed: 12/25/2022] Open
Abstract
Regulated nucleocytoplasmic transport of proteins is central to cellular function and dysfunction during processes such as viral infection. Active protein trafficking into and out of the nucleus is dependent on the presence within cargo proteins of intrinsic specific modular signals for nuclear import (nuclear localization signals, NLSs) and export (nuclear export signals, NESs). Rabies virus (RabV) phospho (P) protein, which is largely responsible for antagonising the host anti-viral response, is expressed as five isoforms (P1-P5). The subcellular trafficking of these isoforms is thought to depend on a balance between the activities of a dominant N-terminal NES (N-NES) and a distinct C-terminal NLS (C-NLS). Specifically, the N-NES-containing isoforms P1 and P2 are cytoplasmic, whereas the shorter P3-P5 isoforms, which lack the N-NES, are believed to be nuclear through the activity of the C-NLS. Here, we show for the first time that RabV P contains an additional strong NLS in the N-terminal region (N-NLS), which, intriguingly, overlaps with the N-NES. This arrangement represents a novel nuclear trafficking module where the N-NLS is inactive in P1 but becomes activated in P3, concomitant with truncation of the N-NES, to become the principal targeting signal conferring nuclear accumulation. Understanding this unique switch arrangement of overlapping, co-regulated NES/NLS sequences is vital to delineating the critical role of RabV P protein in viral infection.
Collapse
Affiliation(s)
- Sibil Oksayan
- From the Viral Immune Evasion and Pathogenicity Laboratory and
- Nuclear Signaling Laboratory, Department of Biochemistry and Molecular Biology, Monash University, 3800 Victoria, Australia and
| | - Linda Wiltzer
- From the Viral Immune Evasion and Pathogenicity Laboratory and
- Nuclear Signaling Laboratory, Department of Biochemistry and Molecular Biology, Monash University, 3800 Victoria, Australia and
| | - Caitlin L. Rowe
- From the Viral Immune Evasion and Pathogenicity Laboratory and
- Nuclear Signaling Laboratory, Department of Biochemistry and Molecular Biology, Monash University, 3800 Victoria, Australia and
| | - Danielle Blondel
- the Laboratoire de Virologie Moléculaire et Structurale, Centre de Recherche de Gif, CNRS 91198 Gif-sur-Yvette, France
| | - David A. Jans
- Nuclear Signaling Laboratory, Department of Biochemistry and Molecular Biology, Monash University, 3800 Victoria, Australia and
| | | |
Collapse
|
41
|
Abstract
The evasion of host innate immunity by Rabies virus, the prototype of the genus Lyssavirus, depends on a unique mechanism of selective targeting of interferon-activated STAT proteins by the viral phosphoprotein (P-protein). However, the immune evasion strategies of other lyssaviruses, including several lethal human pathogens, are unresolved. Here, we show that this mechanism is conserved between the most distantly related members of the genus, providing important insights into the pathogenesis and potential therapeutic targeting of lyssaviruses.
Collapse
|
42
|
Abstract
The family Rhabdoviridae has a non-segmented single stranded negative-sense RNA and its genome ranges in size from approximately 11 kb to almost 16 kb. It is one of the most ecologically diverse families of RNA viruses with members infecting a wide range of organisms. The five structural protein genes are arranged in the same linear order (3'-N-P-M-G-L-5') and may be interspersed with one more additional accessory gene. For many years, a full of knowledge of the rhabdoviridae has been established on extensive studies of two kinds of prototype viruses; vesicular stomatitis virus (VSV) and rabies virus (RABV). Among them, the genus Lyssavirus includes RABV and rabies-related viruses naturally infect mammals and chiropterans via bite-exposure by rabid animals and finally cause fatal encephalitis. In this review, we describe the sketch of the various virological features of the Rhabdoviridae, especially focusing on VSV and RABV.
Collapse
|
43
|
Walker PJ, Dietzgen RG, Joubert DA, Blasdell KR. Rhabdovirus accessory genes. Virus Res 2011; 162:110-25. [PMID: 21933691 PMCID: PMC7114375 DOI: 10.1016/j.virusres.2011.09.004] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 09/02/2011] [Accepted: 09/04/2011] [Indexed: 12/16/2022]
Abstract
The Rhabdoviridae is one of the most ecologically diverse families of RNA viruses with members infecting a wide range of organisms including placental mammals, marsupials, birds, reptiles, fish, insects and plants. The availability of complete nucleotide sequences for an increasing number of rhabdoviruses has revealed that their ecological diversity is reflected in the diversity and complexity of their genomes. The five canonical rhabdovirus structural protein genes (N, P, M, G and L) that are shared by all rhabdoviruses are overprinted, overlapped and interspersed with a multitude of novel and diverse accessory genes. Although not essential for replication in cell culture, several of these genes have been shown to have roles associated with pathogenesis and apoptosis in animals, and cell-to-cell movement in plants. Others appear to be secreted or have the characteristics of membrane-anchored glycoproteins or viroporins. However, most encode proteins of unknown function that are unrelated to any other known proteins. Understanding the roles of these accessory genes and the strategies by which rhabdoviruses use them to engage, divert and re-direct cellular processes will not only present opportunities to develop new anti-viral therapies but may also reveal aspects of cellar function that have broader significance in biology, agriculture and medicine.
Collapse
Affiliation(s)
- Peter J Walker
- CSIRO Livestock Industries, Australian Animal Health Laboratory, 5 Portarlington Road, Geelong, VIC 3220, Australia.
| | | | | | | |
Collapse
|
44
|
Abstract
Rabies is among the longest known and most dangerous and feared infectious diseases for humans and animals and still is responsible for tenth of thousands of human deaths per year. The rabies virus (RABV) is a rather atypical member of the Rhabdoviridae family as it has completely adapted during evolution to warm-blooded hosts and is directly transmitted between them, whereas most other rhabdoviruses are transmitted by insect vectors. The virus is also unique with respect to its extremely broad host species range and a very narrow host organ range, namely its strict neurotropism. It is becoming increasingly clear that the host innate immune system, particularly the type I interferon system, and the viral counteractions profoundly shape this virus-host relationship. In the past few years, exciting new insight was obtained on how viruses are sensed by innate immune receptors, how the downstream signaling networks for activation of interferon are working, and how viruses can interfere with the system. While RABV 5'-triphosphate RNAs were identified as the major pathogen-associated molecular pattern sensed by cytoplasmic RIG-I-like receptors (RLR), the RABV phosphoprotein (P) has emerged as a potent multifunctional antagonist able to counteract the signaling cascades leading to transcriptional activation of interferon genes as well as interferon signaling pathways, thereby limiting expression of antiviral and immune-stimulatory genes.
Collapse
Affiliation(s)
- Martina Rieder
- Max von Pettenkofer Institute and Gene Center, Ludwig-Maximilians-University Munich, Munich, Germany
| | | |
Collapse
|
45
|
Choi MK, Moon CH, Ko MS, Lee UH, Cho WJ, Cha SJ, Do JW, Heo GJ, Jeong SG, Hahm YS, Harmache A, Bremont M, Kurath G, Park JW. A nuclear localization of the infectious haematopoietic necrosis virus NV protein is necessary for optimal viral growth. PLoS One 2011; 6:e22362. [PMID: 21814578 PMCID: PMC3141031 DOI: 10.1371/journal.pone.0022362] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Accepted: 06/22/2011] [Indexed: 12/14/2022] Open
Abstract
The nonvirion (NV) protein of infectious hematopoietic necrosis virus (IHNV) has been previously reported to be essential for efficient growth and pathogenicity of IHNV. However, little is known about the mechanism by which the NV supports the viral growth. In this study, cellular localization of NV and its role in IHNV growth in host cells was investigated. Through transient transfection in RTG-2 cells of NV fused to green fluorescent protein (GFP), a nuclear localization of NV was demonstrated. Deletion analyses showed that the (32)EGDL(35) residues were essential for nuclear localization of NV protein, and fusion of these 4 amino acids to GFP directed its transport to the nucleus. We generated a recombinant IHNV, rIHNV-NV-ΔEGDL in which the (32)EGDL(35) was deleted from the NV. rIHNVs with wild-type NV (rIHNV-NV) or with the NV gene replaced with GFP (rIHNV-ΔNV-GFP) were used as controls. RTG-2 cells infected with rIHNV-ΔNV-GFP and rIHNV-NV-ΔEGDL yielded 12- and 5-fold less infectious virion, respectively, than wild type rIHNV-infected cells at 48 h post-infection (p.i.). While treatment with poly I∶C at 24 h p.i. did not inhibit replication of wild-type rIHNVs, replication rates of rIHNV-ΔNV-GFP and rIHNV-NV-ΔEGDL were inhibited by poly I∶C. In addition, both rIHNV-ΔNV and rIHNV-NV-ΔEGDL induced higher levels of expressions of both IFN1 and Mx1 than wild-type rIHNV. These data suggest that the IHNV NV may support the growth of IHNV through inhibition of the INF system and the amino acid residues of (32)EGDL(35) responsible for nuclear localization are important for the inhibitory activity of NV.
Collapse
Affiliation(s)
- Myeong Kyu Choi
- Department of Biological Sciences, University of Ulsan, Ulsan, Korea
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
46
|
Abstract
Among members of the order Mononegavirales, RNA splicing events have been found only in the family Bornaviridae. Here, we report that a new rhabdovirus isolated from the mosquito Culex tritaeniorhynchus replicates in the nuclei of infected cells and requires RNA splicing for viral mRNA maturation. The virus, designated Culex tritaeniorhynchus rhabdovirus (CTRV), shares a similar genome organization with other rhabdoviruses, except for the presence of a putative intron in the coding region for the L protein. Molecular phylogenetic studies indicated that CTRV belongs to the family Rhabdoviridae, but it is yet to be assigned a genus. Electron microscopic analysis revealed that the CTRV virion is extremely elongated, unlike virions of rhabdoviruses, which are generally bullet shaped. Northern hybridization confirmed that a large transcript (approximately 6,500 nucleotides [nt]) from the CTRV L gene was present in the infected cells. Strand-specific reverse transcription-PCR (RT-PCR) analyses identified the intron-exon boundaries and the 76-nt intron sequence, which contains the typical motif for eukaryotic spliceosomal intron-splice donor/acceptor sites (GU-AG), a predicted branch point, and a polypyrimidine tract. In situ hybridization exhibited that viral RNAs are primarily localized in the nucleus of infected cells, indicating that CTRV replicates in the nucleus and is allowed to utilize the host's nuclear splicing machinery. This is the first report of RNA splicing among the members of the family Rhabdoviridae.
Collapse
|
47
|
Regulation of nucleocytoplasmic trafficking of viral proteins: an integral role in pathogenesis? BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1813:2176-90. [PMID: 21530593 PMCID: PMC7114211 DOI: 10.1016/j.bbamcr.2011.03.019] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Revised: 03/15/2011] [Accepted: 03/30/2011] [Indexed: 12/24/2022]
Abstract
Signal-dependent targeting of proteins into and out of the nucleus is mediated by members of the importin (IMP) family of transport receptors, which recognise targeting signals within a cargo protein and mediate passage through the nuclear envelope-embedded nuclear pore complexes. Regulation of this process is paramount to processes such as cell division and differentiation, but is also critically important for viral replication and pathogenesis; phosphorylation appears to play a major role in regulating viral protein nucleocytoplasmic trafficking, along with other posttranslational modifications. This review focuses on viral proteins that utilise the host cell IMP machinery in order to traffic into/out of the nucleus, and in particular those where trafficking is critical to viral replication and/or pathogenesis, such as simian virus SV40 large tumour antigen (T-ag), human papilloma virus E1 protein, human cytomegalovirus processivity factor ppUL44, and various gene products from RNA viruses such as Rabies. Understanding of the mechanisms regulating viral protein nucleocytoplasmic trafficking is paramount to the future development of urgently needed specific and effective anti-viral therapeutics. This article was originally intended for the special issue "Regulation of Signaling and Cellular Fate through Modulation of Nuclear Protein Import". The Publisher apologizes for any inconvenience caused.
Collapse
|
48
|
Leyrat C, Ribeiro EA, Gérard FCA, Ivanov I, Ruigrok RWH, Jamin M. Structure, interactions with host cell and functions of rhabdovirus phosphoprotein. Future Virol 2011. [DOI: 10.2217/fvl.11.10] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Rabies is an incurable albeit preventable disease that remains an important human health issue, with the number of deaths exceeding 50,000 people each year. Its causative agent, the rabies virus, is a negative-sense RNA virus, the genome of which encodes five proteins. Three of these proteins, the nucleoprotein, the phosphoprotein (P) and the large protein, are required to synthesize viral RNA in an efficient and regulated manner. P plays multiple roles during the transcription and replication of the RNA genome. It acts as a noncatalytic cofactor of the large protein polymerase and it chaperones nucleoprotein. Recent structural characterizations of rabies virus P revealed that P forms elongated and flexible dimers and uncovered the structural basis of its modular organization, revealing the existence of two independent structured domains and two long intrinsically disordered regions. In addition, recent studies also revealed that P interacts with nucleocytoplasmic trafficking carriers and with the host cell cytoskeleton, probably allowing viral components to be transported within the host cell and blocking the innate immune response by inhibiting different steps of the interferon pathway. With multiple binding sites for different viral and cellular partners located in either its structured or disordered regions, P appears to be a flexible ‘hub’ protein that connects viral or cellular proteins and allows their assembly into multimolecular complexes. These new findings shed light on the mechanism of replication of the virus and on the intimate interactions between the virus and its host cell, and will also help to identify new targets for the development of antiviral treatments.
Collapse
Affiliation(s)
- Cédric Leyrat
- UMI 3265 UJF-EMBL-CNRS, Unit of Virus Host Cell Interactions, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9, France
| | - Euripedes A Ribeiro
- UMI 3265 UJF-EMBL-CNRS, Unit of Virus Host Cell Interactions, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9, France
| | - Francine CA Gérard
- UMI 3265 UJF-EMBL-CNRS, Unit of Virus Host Cell Interactions, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9, France
| | - Ivan Ivanov
- UMI 3265 UJF-EMBL-CNRS, Unit of Virus Host Cell Interactions, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9, France
| | - Rob WH Ruigrok
- UMI 3265 UJF-EMBL-CNRS, Unit of Virus Host Cell Interactions, 6 rue Jules Horowitz, 38042 Grenoble Cedex 9, France
| | | |
Collapse
|
49
|
Marschalek A, Drechsel L, Conzelmann KK. The importance of being short: the role of rabies virus phosphoprotein isoforms assessed by differential IRES translation initiation. Eur J Cell Biol 2011; 91:17-23. [PMID: 21397980 DOI: 10.1016/j.ejcb.2011.01.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2010] [Accepted: 01/23/2011] [Indexed: 10/18/2022] Open
Abstract
The rabies virus (RV) phosphoprotein P is a multifunctional protein involved in viral RNA synthesis and in counteracting host innate immune responses. We have previously shown that RV P gene expression levels can be regulated by using picornavirus internal ribosome entry site (IRES) elements. Here we exploited a particular feature of the foot-and-mouth disease virus (FMDV) IRES, namely, preferential initiation at a downstream initiation codon, to address the role of N-terminally truncated RV phosphoproteins usually generated in RV-infected cells through ribosomal leaky scanning. Recombinant RVs in which P synthesis was directed by the poliovirus or FMDV IRES produced full-length P (P1) or a truncated form (P2), as the dominant product, respectively. While the P2 overexpressing virus showed attenuated growth in interferon-incompetent cells, it was superior to the P1 overexpressing virus in preventing expression of host interferon-stimulated genes. This indicates that in RV infected cells the availability of the truncated P2 protein is critical for viral resistance to interferon.
Collapse
Affiliation(s)
- Adriane Marschalek
- Max von Pettenkofer-Institute & Gene Center, Ludwig-Maximilians-University Munich, Feodor-Lynen-Strasse 25, Munich, Germany
| | | | | |
Collapse
|
50
|
Abstract
Various reports implicate PML and PML nuclear bodies (NBs) in an intrinsic antiviral response targeting diverse cytoplasmic replicating RNA viruses. PML conjugation to the small ubiquitin-like modifier (SUMO) is required for its localization within NBs. PML displays antiviral effects in vivo, as PML deficiency renders mice more susceptible to infection with the rhabdovirus vesicular stomatitis virus (VSV). Cells derived from these mice are also more sensitive to infection with rabies virus, another member of the rhabdovirus family. Alternative splicing from a single gene results in the synthesis of several PML isoforms, and these are classified into seven groups, designated PMLI to -VII. We report here that expression of PMLIV or PMLIVa, which is missing exon 5, inhibited viral mRNA and protein synthesis, leading to a reduction in viral replication. However, the expression of other nuclear isoforms (PMLI to -VI) and cytoplasmic PMLVIIb failed to impair viral production. This antiviral effect required PMLIV SUMOylation, as it was not observed with PMLIV 3KR, in which the lysines involved in SUMO conjugation were mutated. Thus, PMLIV and PMLIVa may exert this isoform-specific function through interaction with specific NB protein partners via their common C-terminal region.
Collapse
|