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Gori Savellini G, Bini L, Gagliardi A, Anichini G, Gandolfo C, Prathyumnan S, Cusi MG. Ubiquitin and Not Only Unfolded Domains Drives Toscana Virus Non-Structural NSs Protein Degradation. Viruses 2020; 12:E1153. [PMID: 33053780 PMCID: PMC7601456 DOI: 10.3390/v12101153] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 10/05/2020] [Accepted: 10/09/2020] [Indexed: 01/09/2023] Open
Abstract
The non-structural protein NSs of the Phenuiviridae family members appears to have a role in the host immunity escape. The stability of Toscana virus (TOSV) NSs protein was tested by a cycloheximide (CHX) chase approach on cells transfected with NSs deleted versions fused to a reporter gene. The presence of intrinsically disordered regions (IDRs) both at the C- and N-terminus appeared to affect the protein stability. Indeed, the NSsΔC and NSsΔN proteins were more stable than the wild-type NSs counterpart. Since TOSV NSs exerts its inhibitory function by triggering RIG-I for proteasomal degradation, the interaction of the ubiquitin system and TOSV NSs was further examined. Chase experiments with CHX and the proteasome inhibitor MG-132 demonstrated the involvement of the ubiquitin-proteasome system in controlling NSs protein amount expressed in the cells. The analysis of TOSV NSs by mass spectrometry allowed the direct identification of K104, K109, K154, K180, K244, K294, and K298 residues targeted for ubiquitination. Analysis of NSs K-mutants confirmed the presence and the important role of lysine residues located in the central and the C-terminal parts of the protein in controlling the NSs cellular level. Therefore, we directly demonstrated a new cellular pathway involved in controlling TOSV NSs fate and activity, and this opens the way to new investigations among more pathogenic viruses of the Phenuiviridae family.
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Affiliation(s)
- Gianni Gori Savellini
- Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy; (G.A.); (C.G.); (S.P.); (M.G.C.)
| | - Luca Bini
- Department of Life Sciences, University of Siena, 53100 Siena, Italy;
| | - Assunta Gagliardi
- Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Laboratory of Synthetic and Structural Vaccinology, 38122 Trento, Italy;
| | - Gabriele Anichini
- Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy; (G.A.); (C.G.); (S.P.); (M.G.C.)
| | - Claudia Gandolfo
- Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy; (G.A.); (C.G.); (S.P.); (M.G.C.)
- S. Maria delle Scotte Hospital, V.le Bracci, 1, 53100 Siena, Italy
| | - Shibily Prathyumnan
- Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy; (G.A.); (C.G.); (S.P.); (M.G.C.)
| | - Maria Grazia Cusi
- Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy; (G.A.); (C.G.); (S.P.); (M.G.C.)
- S. Maria delle Scotte Hospital, V.le Bracci, 1, 53100 Siena, Italy
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2
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Development of a Reverse Genetics System for Toscana Virus (Lineage A). Viruses 2020; 12:v12040411. [PMID: 32272808 PMCID: PMC7232365 DOI: 10.3390/v12040411] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 03/30/2020] [Accepted: 04/03/2020] [Indexed: 12/14/2022] Open
Abstract
Toscana virus (TOSV) is a Phlebovirus in the Phenuiviridae family, order Bunyavirales, found in the countries surrounding the Mediterranean. TOSV is an important cause of seasonal acute meningitis and encephalitis within its range. Here, we determined the full sequence of the TOSV strain 1500590, a lineage A virus obtained from an infected patient (Marseille, 2007) and used this in combination with other sequence information to construct functional cDNA plasmids encoding the viral L, M, and S antigenomic sequences under the control of the T7 RNA promoter to recover recombinant viruses. Importantly, resequencing identified two single nucleotide changes to a TOSV reference genome, which, when corrected, restored functionality to the polymerase L and made it possible to recover infectious recombinant TOSV (rTOSV) from cDNA, as well as establish a minigenome system. Using reverse genetics, we produced an NSs-deletant rTOSV and also obtained viruses expressing reporter genes instead of NSs. The availability of such a system assists investigating questions that require genetic manipulation of the viral genome, such as investigations into replication and tropism, and beyond these fundamental aspects, also the development of novel vaccine design strategies.
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Woelfl F, Léger P, Oreshkova N, Pahmeier F, Windhaber S, Koch J, Stanifer M, Roman Sosa G, Uckeley ZM, Rey FA, Boulant S, Kortekaas J, Wichgers Schreur PJ, Lozach PY. Novel Toscana Virus Reverse Genetics System Establishes NSs as an Antagonist of Type I Interferon Responses. Viruses 2020; 12:v12040400. [PMID: 32260371 PMCID: PMC7232479 DOI: 10.3390/v12040400] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 03/30/2020] [Accepted: 04/03/2020] [Indexed: 12/13/2022] Open
Abstract
The sand fly-borne Toscana virus (TOSV) is the major cause of human meningoencephalitis in the Mediterranean basin during the summer season. In this work, we have developed a T7 RNA polymerase-driven reverse genetics system to recover infectious particles of a lineage B strain of TOSV. The viral protein pattern and growth properties of the rescued virus (rTOSV) were found to be similar to those of the corresponding wild-type (wt) virus. Using this system, we genetically engineered a TOSV mutant lacking expression of the non-structural protein NSs (rTOSVɸNSs). Unlike rTOSV and the wt virus, rTOSVɸNSs was unable to (i) suppress interferon (IFN)-b messenger RNA induction; and (ii) grow efficiently in cells producing IFN-b. Together, our results highlight the importance of NSs for TOSV in evading the IFN response and provide a comprehensive toolbox to investigate the TOSV life cycle in mammalian and insect host cells, including several novel polyclonal antibodies.
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Affiliation(s)
- Franziska Woelfl
- CellNetworks Cluster of Excellence, University Hospital Heidelberg, 69120 Heidelberg, Germany; (F.W.); (P.L.); (F.P.); (S.W.); (J.K.); (Z.M.U.)
- Center for Integrative Infectious Diseases Research (CIID), Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany;
| | - Psylvia Léger
- CellNetworks Cluster of Excellence, University Hospital Heidelberg, 69120 Heidelberg, Germany; (F.W.); (P.L.); (F.P.); (S.W.); (J.K.); (Z.M.U.)
- Center for Integrative Infectious Diseases Research (CIID), Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany;
| | - Nadia Oreshkova
- Wageningen Bioveterinary Research, Department of Virology, 8221 RA Lelystad, The Netherlands; (N.O.); (J.K.)
| | - Felix Pahmeier
- CellNetworks Cluster of Excellence, University Hospital Heidelberg, 69120 Heidelberg, Germany; (F.W.); (P.L.); (F.P.); (S.W.); (J.K.); (Z.M.U.)
- Center for Integrative Infectious Diseases Research (CIID), Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany;
| | - Stefan Windhaber
- CellNetworks Cluster of Excellence, University Hospital Heidelberg, 69120 Heidelberg, Germany; (F.W.); (P.L.); (F.P.); (S.W.); (J.K.); (Z.M.U.)
- Center for Integrative Infectious Diseases Research (CIID), Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany;
| | - Jana Koch
- CellNetworks Cluster of Excellence, University Hospital Heidelberg, 69120 Heidelberg, Germany; (F.W.); (P.L.); (F.P.); (S.W.); (J.K.); (Z.M.U.)
- Center for Integrative Infectious Diseases Research (CIID), Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany;
| | - Megan Stanifer
- Center for Integrative Infectious Diseases Research (CIID), Molecular Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany;
| | - Gleyder Roman Sosa
- Structural Virology Unit, Pasteur Institute, 75015 Paris, France; (G.R.S.); (F.A.R.)
| | - Zina M. Uckeley
- CellNetworks Cluster of Excellence, University Hospital Heidelberg, 69120 Heidelberg, Germany; (F.W.); (P.L.); (F.P.); (S.W.); (J.K.); (Z.M.U.)
- Center for Integrative Infectious Diseases Research (CIID), Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany;
| | - Felix A. Rey
- Structural Virology Unit, Pasteur Institute, 75015 Paris, France; (G.R.S.); (F.A.R.)
| | - Steeve Boulant
- Center for Integrative Infectious Diseases Research (CIID), Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany;
| | - Jeroen Kortekaas
- Wageningen Bioveterinary Research, Department of Virology, 8221 RA Lelystad, The Netherlands; (N.O.); (J.K.)
- Laboratory of Virology, Wageningen University, 6708 PB Wageningen, The Netherlands
| | - Paul J. Wichgers Schreur
- Wageningen Bioveterinary Research, Department of Virology, 8221 RA Lelystad, The Netherlands; (N.O.); (J.K.)
- Correspondence: (P.J.W.S.); (P.-Y.L.)
| | - Pierre-Yves Lozach
- CellNetworks Cluster of Excellence, University Hospital Heidelberg, 69120 Heidelberg, Germany; (F.W.); (P.L.); (F.P.); (S.W.); (J.K.); (Z.M.U.)
- Center for Integrative Infectious Diseases Research (CIID), Virology, University Hospital Heidelberg, 69120 Heidelberg, Germany;
- INRAE, EPHE, Viral Infections and Comparative Pathology (IVPC), University Claude Bernard Lyon1, University of Lyon, UMR754, 69007 Lyon, France
- Correspondence: (P.J.W.S.); (P.-Y.L.)
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Gori Savellini G, Anichini G, Gandolfo C, Prathyumnan S, Cusi MG. Toscana virus non-structural protein NSs acts as E3 ubiquitin ligase promoting RIG-I degradation. PLoS Pathog 2019; 15:e1008186. [PMID: 31815967 PMCID: PMC6901176 DOI: 10.1371/journal.ppat.1008186] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Accepted: 11/04/2019] [Indexed: 01/04/2023] Open
Abstract
It is known that the non-structural protein (NSs) of Toscana virus (TOSV), an emergent sandfly-borne virus causing meningitis or more severe central nervous system injuries in humans, exerts its function triggering RIG-I for degradation in a proteasome-dependent manner, thus breaking off the IFN-β production. The non-structural protein of different members of Bunyavirales has recently appeared as a fundamental protagonist in immunity evasion through ubiquitination-mediated protein degradation targets. We showed that TOSV NSs has an E3 ubiquitin ligase activity, mapping at the carboxy-terminal domain and also involving the amino-terminal of the protein. Indeed, neither the amino- (NSsΔN) nor the carboxy- (NSsΔC) terminal-deleted mutants of TOSV NSs were able to cause ubiquitin-mediated proteasome degradation of RIG-I. Moreover, the addition of the C-terminus of TOSV NSs to the homologous protein of the Sandfly Fever Naples Virus, belonging to the same genus and unable to inhibit IFN-β activity, conferred new properties to this protein, favoring RIG-I ubiquitination and its degradation. NSs lost its antagonistic activity to IFN when one of the terminal residues was missing. Therefore, we showed that NSs could behave as an atypical RING between RING (RBR) E3 ubiquitin ligases. This is the first report which identified the E3 ubiquitin ligase activity in a viral protein among negative strand RNA viruses.
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Affiliation(s)
| | - Gabriele Anichini
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | - Claudia Gandolfo
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
| | | | - Maria Grazia Cusi
- Department of Medical Biotechnologies, University of Siena, Siena, Italy
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Ter Horst S, Conceição-Neto N, Neyts J, Rocha-Pereira J. Structural and functional similarities in bunyaviruses: Perspectives for pan-bunya antivirals. Rev Med Virol 2019; 29:e2039. [PMID: 30746831 PMCID: PMC7169261 DOI: 10.1002/rmv.2039] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 11/29/2018] [Accepted: 01/17/2019] [Indexed: 01/03/2023]
Abstract
The order of Bunyavirales includes numerous (re)emerging viruses that collectively have a major impact on human and animal health worldwide. There are no vaccines for human use or antiviral drugs available to prevent or treat infections with any of these viruses. The development of efficacious and safe drugs and vaccines is a pressing matter. Ideally, such antivirals possess pan‐bunyavirus antiviral activity, allowing the containment of every bunya‐related threat. The fact that many bunyaviruses need to be handled in laboratories with biosafety level 3 or 4, the great variety of species and the frequent emergence of novel species complicate such efforts. We here examined the potential druggable targets of bunyaviruses, together with the level of conservation of their biological functions, structure, and genetic similarity by means of heatmap analysis. In the light of this, we revised the available models and tools currently available, pointing out directions for antiviral drug discovery.
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Affiliation(s)
- Sebastiaan Ter Horst
- Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, KU Leuven, Leuven, Belgium
| | - Nádia Conceição-Neto
- Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Clinical and Epidemiological Virology, KU Leuven, Leuven, Belgium
| | - Johan Neyts
- Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, KU Leuven, Leuven, Belgium
| | - Joana Rocha-Pereira
- Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Virology and Chemotherapy, KU Leuven, Leuven, Belgium
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Ly HJ, Ikegami T. Rift Valley fever virus NSs protein functions and the similarity to other bunyavirus NSs proteins. Virol J 2016; 13:118. [PMID: 27368371 PMCID: PMC4930582 DOI: 10.1186/s12985-016-0573-8] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 06/23/2016] [Indexed: 12/31/2022] Open
Abstract
Rift Valley fever is a mosquito-borne zoonotic disease that affects both ruminants and humans. The nonstructural (NS) protein, which is a major virulence factor for Rift Valley fever virus (RVFV), is encoded on the S-segment. Through the cullin 1-Skp1-Fbox E3 ligase complex, the NSs protein promotes the degradation of at least two host proteins, the TFIIH p62 and the PKR proteins. NSs protein bridges the Fbox protein with subsequent substrates, and facilitates the transfer of ubiquitin. The SAP30-YY1 complex also bridges the NSs protein with chromatin DNA, affecting cohesion and segregation of chromatin DNA as well as the activation of interferon-β promoter. The presence of NSs filaments in the nucleus induces DNA damage responses and causes cell-cycle arrest, p53 activation, and apoptosis. Despite the fact that NSs proteins have poor amino acid similarity among bunyaviruses, the strategy utilized to hijack host cells are similar. This review will provide and summarize an update of recent findings pertaining to the biological functions of the NSs protein of RVFV as well as the differences from those of other bunyaviruses.
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Affiliation(s)
- Hoai J Ly
- Department of Pathology, The University of Texas Medical Branch at Galveston, Galveston, TX, USA
| | - Tetsuro Ikegami
- Department of Pathology, The University of Texas Medical Branch at Galveston, Galveston, TX, USA. .,The Sealy Center for Vaccine Development, The University of Texas Medical Branch at Galveston, Galveston, TX, USA. .,The Center for Biodefense and Emerging Infectious Diseases, The University of Texas Medical Branch at Galveston, Galveston, TX, USA.
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Wuerth JD, Weber F. Phleboviruses and the Type I Interferon Response. Viruses 2016; 8:v8060174. [PMID: 27338447 PMCID: PMC4926194 DOI: 10.3390/v8060174] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2016] [Revised: 06/15/2016] [Accepted: 06/20/2016] [Indexed: 12/16/2022] Open
Abstract
The genus Phlebovirus of the family Bunyaviridae contains a number of emerging virus species which pose a threat to both human and animal health. Most prominent members include Rift Valley fever virus (RVFV), sandfly fever Naples virus (SFNV), sandfly fever Sicilian virus (SFSV), Toscana virus (TOSV), Punta Toro virus (PTV), and the two new members severe fever with thrombocytopenia syndrome virus (SFTSV) and Heartland virus (HRTV). The nonstructural protein NSs is well established as the main phleboviral virulence factor in the mammalian host. NSs acts as antagonist of the antiviral type I interferon (IFN) system. Recent progress in the elucidation of the molecular functions of a growing list of NSs proteins highlights the astonishing variety of strategies employed by phleboviruses to evade the IFN system.
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Affiliation(s)
- Jennifer Deborah Wuerth
- Institute for Virology, FB10-Veterinary Medicine, Justus-Liebig University, Giessen 35392, Germany.
| | - Friedemann Weber
- Institute for Virology, FB10-Veterinary Medicine, Justus-Liebig University, Giessen 35392, Germany.
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Meningitis Caused by Toscana Virus Is Associated with Strong Antiviral Response in the CNS and Altered Frequency of Blood Antigen-Presenting Cells. Viruses 2015; 7:5831-43. [PMID: 26569288 PMCID: PMC4664982 DOI: 10.3390/v7112909] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Revised: 10/28/2015] [Accepted: 11/03/2015] [Indexed: 01/31/2023] Open
Abstract
Toscana virus (TOSV) is a Phlebotomus-transmitted RNA virus and a frequent cause of human meningitis and meningoencephalitis in Southern Europe during the summer season. While evidence for TOSV-related central nervous system (CNS) cases is increasing, little is known about the host defenses against TOSV. We evaluated innate immune response to TOSV by analyzing frequency and activation of blood antigen-presenting cells (APCs) and cytokine levels in plasma and cerebrospinal fluid (CSF) from patients with TOSV neuroinvasive infection and controls. An altered frequency of different blood APC subsets was observed in TOSV-infected patients, with signs of monocytic deactivation. Nevertheless, a proper or even increased responsiveness of toll-like receptor 3 and 7/8 was observed in blood APCs of these patients as compared to healthy controls. Systemic levels of cytokines remained low in TOSV-infected patients, while levels of anti-inflammatory and antiviral mediators were significantly higher in CSF from TOSV-infected patients as compared to patients with other infectious and noninfectious neurological diseases. Thus, the early host response to TOSV appears effective for viral clearance, by proper response to TLR3 and TLR7/8 agonists in peripheral blood and by a strong and selective antiviral and anti-inflammatory response in the CNS.
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Non-structural proteins of arthropod-borne bunyaviruses: roles and functions. Viruses 2013; 5:2447-68. [PMID: 24100888 PMCID: PMC3814597 DOI: 10.3390/v5102447] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 09/20/2013] [Accepted: 09/25/2013] [Indexed: 12/24/2022] Open
Abstract
Viruses within the Bunyaviridae family are tri-segmented, negative-stranded RNA viruses. The family includes several emerging and re-emerging viruses of humans, animals and plants, such as Rift Valley fever virus, Crimean-Congo hemorrhagic fever virus, La Crosse virus, Schmallenberg virus and tomato spotted wilt virus. Many bunyaviruses are arthropod-borne, so-called arboviruses. Depending on the genus, bunyaviruses encode, in addition to the RNA-dependent RNA polymerase and the different structural proteins, one or several non-structural proteins. These non-structural proteins are not always essential for virus growth and replication but can play an important role in viral pathogenesis through their interaction with the host innate immune system. In this review, we will summarize current knowledge and understanding of insect-borne bunyavirus non-structural protein function(s) in vertebrate, plant and arthropod.
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