1
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Tongsri P, Cheng G, Huang Z, Wang Z, Dong F, Wu Z, Kong W, Yu Y, Xu Z. Mucosal immunity and microbiota change in the rainbow trout (Oncorhynchus mykiss) gills after being challenged with infectious hematopoietic necrosis virus. FISH & SHELLFISH IMMUNOLOGY 2023; 142:109166. [PMID: 37844853 DOI: 10.1016/j.fsi.2023.109166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 09/19/2023] [Accepted: 10/14/2023] [Indexed: 10/18/2023]
Abstract
Respiratory structures are crucial for vertebrate survival, as they serve not only to perform gas-exchange processes but also as entry points for opportunistic pathogens. Previous studies have demonstrated that fish contain gill mucosal-associated lymphoid tissue, and harbor a large number of commensal bacteria on their surface and contribute to maintaining fish health. However, by far, very limited information is known regarding the effects of viral infection on gill mucosal immunity and microbiota homeostasis. In this study, we conducted an infection model by bath with infectious hematopoietic necrosis virus (IHNV) and revealed a 27 % mortality rate among rainbow trout in the first two weeks after infection. Moreover, we found that diseased fish with the highest IHNV loads in gills exhibiting severe damage, as well as increased goblet cell counts in both primary lamellae (PL) and secondary lamellae (SL). Additionally, RT-qPCR and RNA-seq analyses revealed that IHNV infection induced a strong innate and adaptive antiviral immune responses. Interestingly, an antibacterial immune response was also observed, suggesting that a secondary bacterial infection occurred in trout gills after viral infection. Furthermore, 16S rRNA analysis of trout gills revealed a profound dysbiosis marked by a loss of beneficial taxa and expansion of pathobionts following IHNV infection. Overall, our finding demonstrates that IHNV infection induces significant changes of the microbial community in the fish respiratory surface, thus triggering local antiviral and bacterial mucosal immunity.
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Affiliation(s)
- Pajongjit Tongsri
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Gaofeng Cheng
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Zhenyu Huang
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Zixuan Wang
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Fen Dong
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Zhengben Wu
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Weiguang Kong
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Yongyao Yu
- Department of Aquatic Animal Medicine, College of Fisheries, Huazhong Agricultural University, Wuhan, Hubei, 430070, China
| | - Zhen Xu
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.
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2
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Martinez R, Fernández-Trujillo MA, Hernández L, Page A, Béjar J, Estrada MP. Growth hormone secretagogue peptide A233 upregulates Mx expression in teleost fish in vitro and in vivo. Arch Virol 2022; 167:2041-2047. [DOI: 10.1007/s00705-022-05504-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Accepted: 05/05/2022] [Indexed: 11/27/2022]
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3
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Kalia R, Frost A. Open and cut: allosteric motion and membrane fission by dynamin superfamily proteins. Mol Biol Cell 2020; 30:2097-2104. [PMID: 31365329 PMCID: PMC6743466 DOI: 10.1091/mbc.e16-10-0709] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Cells have evolved diverse protein-based machinery to reshape, cut, or fuse their membrane-delimited compartments. Dynamin superfamily proteins are principal components of this machinery and use their ability to hydrolyze GTP and to polymerize into helices and rings to achieve these goals. Nucleotide-binding, hydrolysis, and exchange reactions drive significant conformational changes across the dynamin family, and these changes alter the shape and stability of supramolecular dynamin oligomers, as well as the ability of dynamins to bind receptors and membranes. Mutations that interfere with the conformational repertoire of these enzymes, and hence with membrane fission, exist in several inherited human diseases. Here, we discuss insights from new x-ray crystal structures and cryo-EM reconstructions that have enabled us to infer some of the allosteric dynamics for these proteins. Together, these studies help us to understand how dynamins perform mechanical work, as well as how specific mutants of dynamin family proteins exhibit pathogenic properties.
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Affiliation(s)
- Raghav Kalia
- Department of Physiology, University of California, San Francisco, San Francisco, CA 94158.,Department of Biochemistry, University of Utah, Salt Lake City, UT 84132
| | - Adam Frost
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA 94158.,Department of Biochemistry, University of Utah, Salt Lake City, UT 84132.,Chan-Zuckerberg Biohub, San Francisco, CA 94158
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4
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Vo TTM, Lai YY, Lin CH. The influence of a GT repeat polymorphism on poly(I:C) induction of the grouper MxII gene promoter in GK cells. FISH & SHELLFISH IMMUNOLOGY 2020; 101:99-105. [PMID: 32224278 DOI: 10.1016/j.fsi.2020.03.052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 03/19/2020] [Accepted: 03/24/2020] [Indexed: 06/10/2023]
Abstract
Interferons play an important role in the fish innate immune system against viral infection by inducing the interferon stimulated genes, such as Mx gene. We cloned the MxII gene promoter from orange-spotted grouper and found three MxII gene promoters. All of them contained two interferon stimulated response elements (ISREs), and three dinucleotide repeat sequences located at 5' end of ISREs. Interestingly, there is a polymorphic GT repeat element located upstream of these ISREs. The three MxII gene promoters respectively contained 27, 29, and 31 GT repeats, namely EcMx_27, EcMx_29, and EcMx_31. To determine whether GT repeat element influence the MxII gene expression, the MxII gene promoters were subcloned into promoterless reporter plasmid and transfected into grouper kidney (GK) cells. The results showed that a significant induction by poly(I:C) was detected in GK cells transfected with pEcMx_31 (2.65 folds) whereas there was no induction in GK cells transfected with pEcMx_27 and pEcMx_29. However, the significant induction by nervous necrosis virus (NNV) infection was found in GK cells separately transfected with three reporter plasmids. These results suggest that the GT repeat element plays an important role in modulation of MxII gene expression and the induction by poly(I:C) and NNV may be mediated through different signal transduction pathways.
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Affiliation(s)
- Thi Tuyet Minh Vo
- Department of Aquaculture, National Taiwan Ocean University, No. 2, Pei-Ning Rd., Keelung, 20224, Taiwan
| | - Ying-Yi Lai
- Department of Aquaculture, National Taiwan Ocean University, No. 2, Pei-Ning Rd., Keelung, 20224, Taiwan
| | - Cheng-Hui Lin
- Department of Aquaculture, National Taiwan Ocean University, No. 2, Pei-Ning Rd., Keelung, 20224, Taiwan.
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5
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Samanta M, Satapathy S, Paichha M, Choudhary P. Labeo rohita Mx1 exhibits the critical structural motifs of the family of large GTPases of mammals and is activated by rhabdovirus vaccination and bacterial RNA stimulations. Anim Biotechnol 2020; 33:22-42. [PMID: 32367758 DOI: 10.1080/10495398.2020.1759612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Myxovirus resistance (Mx) proteins belonging to the dynamin superfamily of high molecular weight GTPases exist in various isoforms and play crucial role in innate immunity. In addition to the isoforms, Mx1 also plays important role in exerting its anti-viral actions against a broad range of animal RNA viruses. In rohu (Labeo rohita), mx1 full-length cDNA sequence consists of 2440 nucleotides (nt) encoding 628 amino acids (aa) polypeptide of 71.289 kDa. Structurally, it belongs to the family of large GTPases with one DYNc domain (13-257aa) comprising of dynamin family motifs (LPRGSGIVTR) and the tripartite GTP-binding motifs (GDQSSGKS, DLPG and TKPD) at the N-terminal and one GED domain (537-628aa) at C-terminus. Rohu Mx1 is closely related to zebrafish Mx1 and is widely expressed in gill, liver, kidney, spleen and blood. In response to rhabdovirus vaccinations, poly I:C stimulation and bacterial infections, mx1 gene expression in rohu was significantly (p < 0.05) induced in majority of the tested organs/tissues. Stimulation of rohu gill cell line with bacterial RNA also induced mx1 gene expression. Together these data suggest the important role of Mx1 in innate immunity in rohu against wide spectrum of fish pathogens.
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Affiliation(s)
- Mrinal Samanta
- Fish Health Management Division, Immunology Laboratory, Indian Council of Agricultural Research-Central Institute of Freshwater Aquaculture Kausalyaganga, Bhubaneswar, Odisha, India
| | - Sweta Satapathy
- Fish Health Management Division, Immunology Laboratory, Indian Council of Agricultural Research-Central Institute of Freshwater Aquaculture Kausalyaganga, Bhubaneswar, Odisha, India
| | - Mahismita Paichha
- Fish Health Management Division, Immunology Laboratory, Indian Council of Agricultural Research-Central Institute of Freshwater Aquaculture Kausalyaganga, Bhubaneswar, Odisha, India
| | - Pushpa Choudhary
- Fish Health Management Division, Immunology Laboratory, Indian Council of Agricultural Research-Central Institute of Freshwater Aquaculture Kausalyaganga, Bhubaneswar, Odisha, India
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6
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Liu Y, Li Y, Zhou Y, Jiang N, Fan Y, Zeng L. Characterization, Expression Pattern and Antiviral Activities of Mx Gene in Chinese Giant Salamander, Andrias davidianus. Int J Mol Sci 2020; 21:ijms21062246. [PMID: 32213935 PMCID: PMC7139979 DOI: 10.3390/ijms21062246] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 03/14/2020] [Accepted: 03/23/2020] [Indexed: 12/16/2022] Open
Abstract
Mx, Myxovirus resistance is an important interferon-stimulated protein that mediates antiviral responses. In this study, the expression and activities of Chinese giant salamander, Andrias davidianus Mx gene, AdMx, were investigated. The AdMx cDNA sequence contains an open reading frame (ORF) of 2112 nucleotides, encoding a putative protein of 703 aa. Meanwhile, AdMx possesses the conserved tripartite GTP binding motif and a dynamin family signature. qRT-PCR analysis revealed a broad expression of AdMx in vivo, with the highest expression levels in brain, kidney and spleen. The AdMx expression level in kidney, spleen and muscle significantly increased at 6 h after Chinese giant salamander iridovirus (GSIV) infection and peaked at 48 h, while that in muscle cell line (GSM) was not noticeably up-regulated until 72 h post infection. Additionally, a plasmid expressing AdMx was constructed and transfected into the Chinese giant salamander GSM cells. The virus load and gene copies in AdMx over-expressed cells were significantly reduced compared with those in the control cells. Moreover, compared to the control cells, a lower level of virus major capsid protein (MCP) synthesis in AdMx over-expressed cells was confirmed by Western blot. These results collectively suggest that Mx plays an important antiviral role in the immune responses against GSIV in Chinese giant salamander.
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Affiliation(s)
- Yanan Liu
- National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, China;
- Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China (Y.Z.); (N.J.); (Y.F.)
| | - Yiqun Li
- Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China (Y.Z.); (N.J.); (Y.F.)
| | - Yongze Zhou
- Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China (Y.Z.); (N.J.); (Y.F.)
| | - Nan Jiang
- Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China (Y.Z.); (N.J.); (Y.F.)
| | - Yuding Fan
- Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China (Y.Z.); (N.J.); (Y.F.)
| | - Lingbing Zeng
- National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai 201306, China;
- Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan 430223, China (Y.Z.); (N.J.); (Y.F.)
- Correspondence: ; Tel.: +86-027-81780158
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7
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Abstract
Outbreaks of severe virus infections with the potential to cause global pandemics are increasing. In many instances these outbreaks have been newly emerging (SARS coronavirus), re-emerging (Ebola virus, Zika virus) or zoonotic (avian influenza H5N1) virus infections. In the absence of a targeted vaccine or a pathogen-specific antiviral, broad-spectrum antivirals would function to limit virus spread. Given the direct antiviral effects of type I interferons (IFNs) in inhibiting the replication of both DNA and RNA viruses at different stages of their replicative cycles, and the effects of type I IFNs on activating immune cell populations to clear virus infections, IFNs-α/β present as ideal candidate broad-spectrum antivirals.
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8
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Wang BX, Fish EN. Interactions Between NS1 of Influenza A Viruses and Interferon-α/β: Determinants for Vaccine Development. J Interferon Cytokine Res 2017; 37:331-341. [PMID: 28514196 DOI: 10.1089/jir.2017.0032] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Influenza A viruses (IAVs) cause mild to severe infections in humans with considerable socioeconomic and global health consequences. The host interferon (IFN)-α/β response, critical as the first line of defense against foreign pathogens, is induced upon detection of IAV genomic RNA in infected cells by host innate pattern recognition receptors. IFN-α/β production and subsequent activation of cell signaling result in the expression of antiviral IFN-stimulated genes whose products target various stages of the IAV life cycle to inhibit viral replication and the spread of infection and establish an antiviral state. IAVs, however, encode a multifunctional virulence factor, nonstructural protein 1 (NS1), that directly antagonizes the host IFN-α/β response to support viral replication. In this review, we highlight the mechanisms by which NS1 suppresses IFN-α/β production and subsequent cell signaling, and consider, therefore, the potential for recombinant IAVs lacking NS1 to be used as live-attenuated vaccines.
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Affiliation(s)
- Ben X Wang
- 1 Toronto General Hospital Research Institute, University Health Network , Toronto, Ontario, Canada .,2 Department of Immunology, University of Toronto , Toronto, Ontario, Canada
| | - Eleanor N Fish
- 1 Toronto General Hospital Research Institute, University Health Network , Toronto, Ontario, Canada .,2 Department of Immunology, University of Toronto , Toronto, Ontario, Canada
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9
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Abstract
Myxovirus resistance proteins represent a family of interferon-induced restriction factors of the innate and adaptive immune system. Human MxB acts as a novel restriction factor with antiviral activity against a range of HIV-1 and other retroviruses mainly by inhibiting the uncoating process after reverse transcription but prior to integration. Based on published data and conservation analysis, we propose a novel hypothesis, in which MxB dimers form higher order oligomers that restrict retroviral replication by binding to the viral capsid. Insights into the mechanistic basis of structural and functional characteristics of MxB will greatly advance our understanding of MxB.
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Affiliation(s)
- Jia Kong
- School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.,School of Life Sciences, Tianjin University, Tianjin 300072, China.,State Key Laboratory of Medicinal Chemical Biology, NanKai University, Tianjin 300071, China
| | - Min Ma
- School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.,School of Life Sciences, Tianjin University, Tianjin 300072, China.,State Key Laboratory of Medicinal Chemical Biology, NanKai University, Tianjin 300071, China
| | - Shuangyi He
- School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.,School of Life Sciences, Tianjin University, Tianjin 300072, China.,State Key Laboratory of Medicinal Chemical Biology, NanKai University, Tianjin 300071, China
| | - Xiaohong Qin
- School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.,School of Life Sciences, Tianjin University, Tianjin 300072, China.,State Key Laboratory of Medicinal Chemical Biology, NanKai University, Tianjin 300071, China
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10
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González-Mariscal JA, Fernández-Trujillo MA, Alonso MC, García-Rosado E, Álvarez MC, Béjar J. Gilthead seabream (Sparus aurata) Mx gene promoters respond differentially to IPNV and VHSV infections in RTG-2 cells. Vet Immunol Immunopathol 2016; 171:73-80. [PMID: 26964720 DOI: 10.1016/j.vetimm.2016.02.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 01/25/2016] [Accepted: 02/10/2016] [Indexed: 12/20/2022]
Abstract
The understanding of virus-host interactions relies on the knowledge of the regulatory mechanisms of the type I interferon (IFN I)-stimulated genes (ISGs). Among ISGs, those coding Mx proteins play a main role due to their direct antiviral activity. The study of these genes in gilthead seabream is interesting, since this species displays high natural resistance to viral diseases, being asymptomatic carrier of infectious pancreatic necrosis virus (IPNV) and viral haemorrhagic septicaemia virus (VHSV). Gilthead seabream has three Mx genes (Mx1, Mx2, and Mx3), encoding proteins with a wide spectrum of antiviral activity. The structure of the three promoters (pMx1, pMx2 and pMx3) has been previously disclosed, and their response to poly I:C in RTG-2 cells characterized. To further analyze these promoters, their response to two viral infections has been evaluated in the present study. For that purpose, RTG-2 cells transiently transfected with the luciferase gene under the control of each promoter were inoculated with either IPNV or VHSV at two different doses. The highest and lowest fold induction values were recorded for pMx2 and pMx3, respectively. The promoter induction was always stronger after VHSV inoculation than in IPNV-inoculated cells. In addition, the higher dose of VHSV tested induced higher response of the three promoters, whereas in IPNV-infected cells the highest induction was recorded after inoculation with the lower viral dose. To further study the response of the Mx2 promoter, RTG-2 cells stably transfected with the luciferase gene under the control of pMx2 were stimulated with poly I:C and subsequently infected with IPNV or VHSV. Interestingly, IPNV infection inhibited the induction caused by poly I:C, suggesting an antagonistic activity of IPNV on Mx2 transcription. In contrast, VHSV infection did not alter the response triggered by poly I:C. These results highlight the specific regulation that controls the activity of each promoter, and support the existence of complex interactions between host cells, specific Mx promoters, and viruses, which are responsible for the final outcome of a viral infection.
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Affiliation(s)
| | | | - M C Alonso
- Universidad de Málaga, Department of Microbiology, Spain
| | | | - M C Álvarez
- Universidad de Málaga, Department of Genetics, Spain
| | - J Béjar
- Universidad de Málaga, Department of Genetics, Spain.
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11
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Carballo C, Garcia-Rosado E, Borrego JJ, Alonso MC. SJNNV down-regulates RGNNV replication in European sea bass by the induction of the type I interferon system. Vet Res 2016; 47:6. [PMID: 26743933 PMCID: PMC4705746 DOI: 10.1186/s13567-015-0304-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Accepted: 04/17/2015] [Indexed: 01/09/2023] Open
Abstract
European sea bass is highly susceptible to the betanodavirus RGNNV genotype, although the SJNNV genotype has also been detected in this fish species. The coexistence of both genotypes may affect the replication of both viruses by viral interaction or by stimulation of the host antiviral defense system in which the IFN I system plays a key role. IFN I triggers the transcription of interferon-stimulated genes, including Mx genes, whose expression has been used as a reporter of IFN I activity. The present study evaluated the effect of a primary exposure to an SJNNV isolate on a subsequent RGNNV infection and analyzed the role of the IFN I system in controlling VNNV infections in sea bass using different in vivo approaches. VNNV infection and Mx transcription were comparatively evaluated after single infections, superinfection (SJ+RG) and co-infection (poly I:C+RG). The single RGNNV infection resulted in a 24% survival rate, whereas the previous SJNNV or poly I:C inoculation increased the survival rate up to 96 and 100%, respectively. RGNNV replication in superinfection was reduced compared with RGNNV replication after a single inoculation. Mx transcription analysis shows differential induction of the IFN I system by both isolates. SJNNV was a potent Mx inducer, whereas RGNNV induced lower Mx transcription and did not interfere with the IFN I system triggered by SJNNV or poly I:C. This study demonstrates that an antiviral state exists after SJNNV and poly I:C injection, suggesting that the IFN I system plays an important role against VNNV infections in sea bass.
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Affiliation(s)
- Carlos Carballo
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, 29071, Málaga, Spain. .,IFAPA centro El Toruño, Junta de Andalucía, El Puerto de Santa María, Cádiz, Spain.
| | - Esther Garcia-Rosado
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, 29071, Málaga, Spain.
| | - Juan J Borrego
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, 29071, Málaga, Spain.
| | - M Carmen Alonso
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, 29071, Málaga, Spain.
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12
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Alvarez-Torres D, Podadera AM, Bejar J, Bandin I, Alonso MC, Garcia-Rosado E. Role of the IFN I system against the VHSV infection in juvenile Senegalese sole (Solea senegalensis). Vet Res 2016; 47:3. [PMID: 26743229 PMCID: PMC4705576 DOI: 10.1186/s13567-015-0299-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 07/12/2015] [Indexed: 01/09/2023] Open
Abstract
Senegalese sole is susceptible to marine VHSV isolates but is not affected by freshwater isolates, which may indicate differences regarding virus-host immune system interaction. IFN I induces an antiviral state in fish, stimulating the expression of genes encoding antiviral proteins (ISG). In this study, the stimulation of the Senegalese sole IFN I by VHSV infections has been evaluated by the relative quantification of the transcription of several ISG (Mx, Isg15 and Pkr) after inoculation with marine (pathogenic) and freshwater (non-pathogenic) VHSV isolates. Compared to marine VHSV, lower levels of RNA of the freshwater VHSV induced transcription of ISG to similar levels, with the Isg15 showing the highest fold induction. The protective role of the IFN I system was evaluated in poly I:C-inoculated animals subsequently challenged with VHSV isolates. The cumulative mortality caused by the marine isolate in the control group was 68%, whereas in the poly I:C-stimulated group was 5%. The freshwater VHSV isolate did not cause any mortality. Furthermore, viral RNA fold change and viral titers were lower in animals from the poly I:C + VHSV groups than in the controls. The implication of the IFN I system in the protection observed was confirmed by the transcription of the ISG in animals from the poly I:C + VHSV groups. However, the marine VHSV isolate exerts a negative effect on the ISG transcription at 3 and 6 h post-inoculation (hpi), which is not observed for the freshwater isolate. This difference might be partly responsible for the virulence shown by the marine isolate.
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Affiliation(s)
- Daniel Alvarez-Torres
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, 29071, Málaga, Spain. .,Departamento de Genética, Facultad de Ciencias, Universidad de Málaga, 29071, Málaga, Spain.
| | - Ana M Podadera
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, 29071, Málaga, Spain. .,Departamento de Bioquímica y Biología Molecular, Universidad de Oviedo, Oviedo, Spain.
| | - Julia Bejar
- Departamento de Genética, Facultad de Ciencias, Universidad de Málaga, 29071, Málaga, Spain.
| | - Isabel Bandin
- Departamento de Microbiología, Instituto de Acuicultura, Universidad de Santiago de Compostela, 15782, Santiago de Compostela, Spain.
| | - M Carmen Alonso
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, 29071, Málaga, Spain.
| | - Esther Garcia-Rosado
- Departamento de Microbiología, Facultad de Ciencias, Universidad de Málaga, 29071, Málaga, Spain.
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13
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Fernández-Trujillo MA, García-Rosado E, Alonso MC, Álvarez MC, Béjar J. Synergistic effects in the antiviral activity of the three Mx proteins from gilthead seabream (Sparus aurata). Vet Immunol Immunopathol 2015; 168:83-90. [PMID: 26319936 DOI: 10.1016/j.vetimm.2015.08.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Revised: 07/13/2015] [Accepted: 08/14/2015] [Indexed: 01/23/2023]
Abstract
Due to their direct antiviral activity, Mx proteins play a main role in the response mediated by type I interferon against viral infections. The study on gilthead seabream Mx proteins is especially interesting, since this species is unusually resistant to viral diseases, being asymptomatic carrier of several viruses pathogenic to other fish species. Gilthead seabream has three Mx proteins (Mx1, Mx2 and Mx3) that, separately, display antiviral activity against a wide range of viruses, showing interesting differences in their antiviral specificities. In this work, the possible synergy between the three Mx isoforms has been studied using in vitro systems consisting of CHSE-214 cells stably expressing two or the three gilthead seabream Mx proteins. The antiviral activity of these Mx combinations has been tested against the Infectious Pancreatic Necrosis Virus (IPNV), the Viral Haemorrhagic Septicaemia Virus (VHSV), the European Sheatfish Virus (ESV) and the Lymphocystis Disease Virus (LCDV). A synergistic effect of the Mx proteins was only detected against ESV, no synergy was observed against LCDV, and a negative interference was detected against the two RNA viruses tested, IPNV and VHSV, as viral replication was higher in cells expressing certain Mx combinations than in cells expressing these proteins separately. These results suggest a functional interaction between gilthead seabream Mx isoforms, which results in a higher or lower antiviral activity depending on the virus tested, thus supporting the idea of complex virus-host interactions and finely tuned mechanisms controlling the antiviral activity of Mx proteins.
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Affiliation(s)
- M A Fernández-Trujillo
- Universidad de Málaga, Departamento de Microbiología, Facultad de Ciencias, 29071 Málaga, Spain
| | - E García-Rosado
- Universidad de Málaga, Departamento de Genética, Facultad de Ciencias, 29071 Málaga, Spain
| | - M C Alonso
- Universidad de Málaga, Departamento de Genética, Facultad de Ciencias, 29071 Málaga, Spain
| | - M C Álvarez
- Universidad de Málaga, Departamento de Microbiología, Facultad de Ciencias, 29071 Málaga, Spain
| | - J Béjar
- Universidad de Málaga, Departamento de Microbiología, Facultad de Ciencias, 29071 Málaga, Spain.
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14
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Daumke O, Gao S, von der Malsburg A, Haller O, Kochs G. Structure of the MxA stalk elucidates the assembly of ring-like units of an antiviral module. Small GTPases 2014; 1:62-64. [PMID: 21686120 DOI: 10.4161/sgtp.1.1.12989] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Revised: 07/02/2010] [Accepted: 07/12/2010] [Indexed: 12/11/2022] Open
Abstract
The dynamin-like MxA GTP ase (Myxovirus resistance protein 1) mediates cellular resistance against a wide range of viruses. MxA is composed of an amino-terminal G domain, a middle domain and a carboxy-terminal GTPase effector domain. We recently determined the structure of the middle domain and GTPase effector domain of MxA constituting an elongated helical stalk, and elucidated the mechanism how the stalk mediates formation of ring-like MxA oligomers. Here, we shortly review our work and discuss the MxA rings as functional units of a cellular module orchestrating and executing the antiviral response.
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Affiliation(s)
- Oliver Daumke
- Max-Delbrück-Centrum for Molecular Medicine; Crystallography; Berlin, Germany
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15
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González-Mariscal JA, Gallardo-Gálvez JB, Méndez T, Álvarez MC, Béjar J. Cloning and characterization of the Mx1, Mx2 and Mx3 promoters from gilthead seabream (Sparus aurata). FISH & SHELLFISH IMMUNOLOGY 2014; 38:311-317. [PMID: 24704419 DOI: 10.1016/j.fsi.2014.03.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 03/06/2014] [Accepted: 03/26/2014] [Indexed: 06/03/2023]
Abstract
Mx proteins are main effectors of the antiviral innate immune response mediated by type I interferon (IFN I). Actually, diverse Mx proteins from fish proved highly active against fish viruses, standing out among them the Mx1, Mx2 and Mx3 from gilthead seabream (Sparus aurata), a species exhibiting a natural resistance to viral diseases. In this study, the structure and functional activity of their corresponding promoters (pMx1, pMx2 and pMx3) have been assessed. The three promoters present an identical 3' region of 157 bp, exhibiting a single canonical interferon-stimulated response element (ISRE), which is indispensible for the poli:IC induction of pMx1 and pMx3, while not for that of pMx2. In the remaining part of the three promoters other regulatory motifs were identified, as gamma IFN activated sites in variable number (1, 4 and 2 in pMx1, pMx2 and pMx3, respectively), as well as several independent GAAA elements or ISRE core sequences (13, 15 and 12 in pMx1, pMx2 and pMx3, respectively). The structural dissimilarities shown by the three promoters parallels with the differences observed in their response profiles, in terms of the time course of the induction, and basal and induced expression levels of each promoter. Altogether, these findings indicate that the expression of Mx1, Mx2 and Mx3 genes from the gilthead seabream might be specifically regulated, in accordance with the functional role of each Mx protein in the successful antiviral response shown by this species.
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Affiliation(s)
| | | | - T Méndez
- Department of Genetics, University of Málaga, Spain
| | - M C Álvarez
- Department of Genetics, University of Málaga, Spain
| | - J Béjar
- Department of Genetics, University of Málaga, Spain.
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16
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Fernández-Trujillo M, García-Rosado E, Alonso M, Castro D, Álvarez M, Béjar J. Mx1, Mx2 and Mx3 proteins from the gilthead seabream (Sparus aurata) show in vitro antiviral activity against RNA and DNA viruses. Mol Immunol 2013; 56:630-6. [DOI: 10.1016/j.molimm.2013.06.018] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 06/17/2013] [Accepted: 06/27/2013] [Indexed: 10/26/2022]
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17
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Novel P, Fernández-Trujillo M, Gallardo-Gálvez J, Cano I, Manchado M, Buonocore F, Randelli E, Scapigliati G, Álvarez M, Béjar J. Two Mx genes identified in European sea bass (Dicentrarchus labrax) respond differently to VNNV infection. Vet Immunol Immunopathol 2013; 153:240-8. [DOI: 10.1016/j.vetimm.2013.03.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 03/05/2013] [Accepted: 03/07/2013] [Indexed: 11/30/2022]
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18
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Alvarez-Torres D, Garcia-Rosado E, Fernandez-Trujillo MA, Bejar J, Alvarez MC, Borrego JJ, Alonso MC. Antiviral specificity of the Solea senegalensis Mx protein constitutively expressed in CHSE-214 cells. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2013; 15:125-132. [PMID: 22886190 DOI: 10.1007/s10126-012-9478-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Accepted: 07/14/2012] [Indexed: 06/01/2023]
Abstract
Interferons play a key role in fish resistance to viral infections by inducing the expression of antiviral proteins, such as Mx. The aim of the present study was to test the antiviral activity of the Senegalese sole Mx protein (SsMx) against RNA and DNA viruses pathogenic to fish, i.e. the infectious pancreatic necrosis virus (IPNV, dsRNA), the viral haemorrhagic septicaemia virus (VHSV, ssRNA), and the European sheatfish virus (ESV, dsDNA), using a CHSE-214 cell clone expressing this antiviral protein. A strong inhibition of IPNV and VHSV replication was recorded in SsMx-expressing cells, as has been shown by the virus yield reduction and the decrease in the synthesis of the viral RNA encoding the polyprotein (for IPNV) and the nucleoprotein (for VHSV). The titres of these viruses replicating on SsMx-expressing cells were 100 times lower than those recorded on non-transfected cells. In contrast, SsMx did not inhibit ESV replication since no significant differences were observed regarding the virus yield or the major capsid protein gene transcription in transfected and non-transfected cells.
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Affiliation(s)
- Daniel Alvarez-Torres
- Department of Microbiology, Faculty of Sciences, University of Malaga, Campus Teatinos, 29071 Malaga, Spain
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19
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Abstract
Cache Valley virus (CVV)-induced malformations have been previously reproduced in ovine fetuses. To evaluate the development of the antiviral response by the early, infected fetus, before the development of immunocompetency, ovine fetuses at 35 days of gestation were inoculated in utero with CVV and euthanized at 7, 10, 14, 21, and 28 days postinfection. The antiviral immune response in immature fetuses infected with CVV was evaluated. Gene expression associated with an innate, immune response was quantified by real-time quantitative PCR. The upregulated genes in infected fetuses included ISG15, Mx1, Mx2, IL-1, IL-6, TNF-α, TLR-7, and TLR-8. The amount of Mx1 protein, an interferon-stimulated GTPase capable of restricting growth of bunyaviruses, was elevated in the allantoic and amniotic fluid in infected fetuses. ISG15 protein expression was significantly increased in target tissues of infected animals. B lymphocytes and immunoglobulin-positive cells were detected in lymphoid tissues and in the meninges of infected animals. These results demonstrated that the infected ovine fetus is able to initiate an innate and adaptive immune response much earlier than previously known, which presumably contributes to viral clearance in infected animals.
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20
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Differential antiviral activity of Mx1, Mx2 and Mx3 proteins from gilthead seabream (Sparus aurata) against Infectious Pancreatic Necrosis Virus (IPNV). Mol Immunol 2011; 49:107-14. [DOI: 10.1016/j.molimm.2011.07.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 07/29/2011] [Accepted: 07/30/2011] [Indexed: 12/13/2022]
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21
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Wang L, Su J, Peng L, Heng J, Chen L. Genomic structure of grass carp Mx2 and the association of its polymorphisms with susceptibility/resistance to grass carp reovirus. Mol Immunol 2011; 49:359-66. [DOI: 10.1016/j.molimm.2011.09.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 09/09/2011] [Accepted: 09/12/2011] [Indexed: 12/26/2022]
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22
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Faelber K, Posor Y, Gao S, Held M, Roske Y, Schulze D, Haucke V, Noé F, Daumke O. Crystal structure of nucleotide-free dynamin. Nature 2011; 477:556-60. [PMID: 21927000 DOI: 10.1038/nature10369] [Citation(s) in RCA: 242] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Accepted: 07/17/2011] [Indexed: 12/18/2022]
Abstract
Dynamin is a mechanochemical GTPase that oligomerizes around the neck of clathrin-coated pits and catalyses vesicle scission in a GTP-hydrolysis-dependent manner. The molecular details of oligomerization and the mechanism of the mechanochemical coupling are currently unknown. Here we present the crystal structure of human dynamin 1 in the nucleotide-free state with a four-domain architecture comprising the GTPase domain, the bundle signalling element, the stalk and the pleckstrin homology domain. Dynamin 1 oligomerized in the crystals via the stalks, which assemble in a criss-cross fashion. The stalks further interact via conserved surfaces with the pleckstrin homology domain and the bundle signalling element of the neighbouring dynamin molecule. This intricate domain interaction rationalizes a number of disease-related mutations in dynamin 2 and suggests a structural model for the mechanochemical coupling that reconciles previous models of dynamin function.
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Affiliation(s)
- Katja Faelber
- Crystallography, Max-Delbrück-Centrum for Molecular Medicine, Robert-Rössle-Strasse 10, 13125 Berlin, Germany.
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23
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von der Malsburg A, Abutbul-Ionita I, Haller O, Kochs G, Danino D. Stalk domain of the dynamin-like MxA GTPase protein mediates membrane binding and liposome tubulation via the unstructured L4 loop. J Biol Chem 2011; 286:37858-65. [PMID: 21900240 DOI: 10.1074/jbc.m111.249037] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The human MxA protein is an interferon-induced large GTPase with antiviral activity against a wide range of viruses, including influenza viruses. Recent structural data demonstrated that MxA oligomerizes into multimeric filamentous or ring-like structures by virtue of its stalk domain. Here, we show that negatively charged lipid membranes support MxA self-assembly. Like dynamin, MxA assembled around spherical liposomes inducing liposome tubulation. Cryo-transmission electron microscopy revealed that MxA oligomers around liposomes have a "T-bar" shape similar to dynamin. Moreover, biochemical assays indicated that the unstructured L4 loop of the MxA stalk serves as the lipid-binding moiety, and mutational analysis of L4 revealed that a stretch of four lysine residues is critical for binding. The orientation of the MxA molecule within the membrane-associated oligomer is in agreement with the proposed topology of MxA oligomers based on crystallographic data. Although oligomerization of wild-type MxA around liposomes led to the creation of helically decorated tubes similar to those formed by dynamin, this lipid interaction did not stimulate GTPase activity, in sharp contrast to the assembly-stimulated nucleotide hydrolysis observed with dynamin. Moreover, MxA readily self-assembles into rings at physiological conditions, as opposed to dynamin which self-assembles only at low salt conditions or onto lipids. Thus, the present results indicate that the oligomeric structures formed by MxA critically differ from those of dynamin.
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24
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Haller O, Gao S, von der Malsburg A, Daumke O, Kochs G. Dynamin-like MxA GTPase: structural insights into oligomerization and implications for antiviral activity. J Biol Chem 2010; 285:28419-24. [PMID: 20538602 DOI: 10.1074/jbc.r110.145839] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The interferon-inducible MxA GTPase is a key mediator of cell-autonomous innate immunity against a broad range of viruses such as influenza and bunyaviruses. MxA shares a similar domain structure with the dynamin superfamily of mechanochemical enzymes, including an N-terminal GTPase domain, a central middle domain, and a C-terminal GTPase effector domain. Recently, crystal structures of a GTPase domain dimer of dynamin 1 and of the oligomerized stalk of MxA (built by the middle and GTPase effector domains) were determined. These data provide exciting insights into the architecture and antiviral function of the MxA oligomer. Moreover, the structural knowledge paves the way for the development of novel antiviral drugs against influenza and other highly pathogenic viruses.
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Affiliation(s)
- Otto Haller
- Department of Virology, Institute for Medical Microbiology and Hygiene, University of Freiburg, Hermann-Herder-Strasse 11, D-79104 Freiburg, Germany.
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25
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Structural basis of oligomerization in the stalk region of dynamin-like MxA. Nature 2010; 465:502-6. [PMID: 20428112 DOI: 10.1038/nature08972] [Citation(s) in RCA: 191] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Accepted: 02/25/2010] [Indexed: 12/11/2022]
Abstract
The interferon-inducible dynamin-like myxovirus resistance protein 1 (MxA; also called MX1) GTPase is a key mediator of cell-autonomous innate immunity against pathogens such as influenza viruses. MxA partially localizes to COPI-positive membranes of the smooth endoplasmic reticulum-Golgi intermediate compartment. At the point of infection, it redistributes to sites of viral replication and promotes missorting of essential viral constituents. It has been proposed that the middle domain and the GTPase effector domain of dynamin-like GTPases constitute a stalk that mediates oligomerization and transmits conformational changes from the G domain to the target structure; however, the molecular architecture of this stalk has remained elusive. Here we report the crystal structure of the stalk of human MxA, which folds into a four-helical bundle. This structure tightly oligomerizes in the crystal in a criss-cross pattern involving three distinct interfaces and one loop. Mutations in each of these interaction sites interfere with native assembly, oligomerization, membrane binding and antiviral activity of MxA. On the basis of these results, we propose a structural model for dynamin oligomerization and stimulated GTP hydrolysis that is consistent with previous structural predictions and has functional implications for all members of the dynamin family.
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26
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Chen YM, Su YL, Shie PS, Huang SL, Yang HL, Chen TY. Grouper Mx confers resistance to nodavirus and interacts with coat protein. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2008; 32:825-836. [PMID: 18222539 DOI: 10.1016/j.dci.2007.12.003] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2007] [Revised: 12/03/2007] [Accepted: 12/06/2007] [Indexed: 05/25/2023]
Abstract
Over-expression of grouper Mx negatively regulated nodavirus activity through direct interaction, likely via the binding and perturbation of the intracellular localization of nodavirus coat protein. Deletion analysis of grouper Mx indicated that the coat protein binds to the effector domain of Mx. The presence of grouper Mx in a poly [I:C] interferon system inhibited nodavirus infection, demonstrating that grouper Mx over-expression has an inhibitory effect on both coat protein and RNA-dependent RNA polymerase of nodavirus antigens, which results in reduced viral yields. We conclude that grouper Mx has a key role in cellular resistance to nodavirus infection.
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Affiliation(s)
- Young-Mao Chen
- Laboratory of Molecular Genetics, Institute of Biotechnology, College of Bioscience and Biotechnology, National Cheng Kung University, Tainan 701, Taiwan
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27
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Affiliation(s)
- Jason A Mears
- Laboratory of Cell Biochemistry and Biology, NIDDK, NIH, Bethesda, Maryland 20892, USA
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28
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Haller O, Stertz S, Kochs G. The Mx GTPase family of interferon-induced antiviral proteins. Microbes Infect 2007; 9:1636-43. [PMID: 18062906 DOI: 10.1016/j.micinf.2007.09.010] [Citation(s) in RCA: 132] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Mx proteins are interferon-induced members of the dynamin superfamily of large GTPases. They inhibit a wide range of viruses by blocking an early stage of the replication cycle. Studies in genetically defined mouse strains highlight their powerful action in early antiviral host defence.
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Affiliation(s)
- Otto Haller
- Abteilung Virologie, Institut für Medizinische Mikrobiologie und Hygiene, Universität Freiburg, Hermann-Herderstrasse 11, D-79008 Freiburg, Germany.
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29
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Haller O, Staeheli P, Kochs G. Interferon-induced Mx proteins in antiviral host defense. Biochimie 2007; 89:812-8. [PMID: 17570575 DOI: 10.1016/j.biochi.2007.04.015] [Citation(s) in RCA: 236] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2007] [Accepted: 04/27/2007] [Indexed: 12/13/2022]
Abstract
Mx proteins are key components of the antiviral state induced by interferons in many species. They belong to the class of dynamin-like large guanosine triphosphatases (GTPases) known to be involved in intracellular vesicle trafficking and organelle homeostasis. Mx GTPases share structural and functional properties with dynamin, such as self-assembly and association with intracellular membranes. A unique property of some Mx GTPases is their antiviral activity against a wide range of RNA viruses, including influenza viruses and members of the bunyavirus family. These viruses are inhibited at an early stage in their life cycle, soon after host cell entry and before genome amplification. The mouse Mx1 GTPase accumulates in the cell nucleus where it associates with components of the PML nuclear bodies and inhibits influenza and Thogoto viruses known to replicate in the nucleus. The human MxA GTPase accumulates in the cytoplasm and is partly associated with a COP-I-positive subcompartment of the endoplasmic reticulum. This membrane compartment seems to provide an interaction platform that facilitates viral target recognition. In the case of bunyaviruses, MxA recognizes the viral nucleocapsid protein and interferes with its role in viral genome replication. In the case of Thogoto virus, MxA recognizes the viral nucleoprotein and prevents the incoming viral nucleocapsids from being transported into the nucleus, the site of viral transcription and replication. In both cases, GTP-binding and carboxy-terminal effector functions of MxA are required for target recognition. In general, Mx GTPases appear to detect viral infection by sensing nucleocapsid-like structures. As a consequence, these viral components are trapped and sorted to locations where they become unavailable for the generation of new virus particles.
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Affiliation(s)
- Otto Haller
- Abteilung Virologie, Institut für Medizinische Mikrobiologie und Hygiene, Universität Freiburg, D-79008 Freiburg, Germany.
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30
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Weinstock-Guttman B, Tamaño-Blanco M, Bhasi K, Zivadinov R, Ramanathan M. Pharmacogenetics of MXA SNPs in interferon-beta treated multiple sclerosis patients. J Neuroimmunol 2006; 182:236-9. [PMID: 17126411 DOI: 10.1016/j.jneuroim.2006.10.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2006] [Revised: 10/12/2006] [Accepted: 10/13/2006] [Indexed: 12/22/2022]
Abstract
The myxovirus resistance A (MXA) mRNA has been extensively investigated for assessing the biologic responses of multiple sclerosis (MS) patients to interferon-beta (IFN-beta) therapy. The objective of this study was to evaluate the associations between two MXA promoter region single nucleotide polymorphisms (rs2071430 and rs17000900) and the gene expression responses, clinical and MRI phenotypes in IFN-beta treated MS patients. The rs2071430 and rs17000900 SNPs, which are located in or near an interferon-stimulated response element (ISRE), were genotyped in 179 relapsing MS patients. Quantitative MRI measurements were available for 101 patients on IFN-beta monotherapy. Gene expression was assessed in 22 anti-interferon-beta neutralizing antibody negative patients. No significant association was found between the MXA genotype at these two SNPs and clinical, MRI and MXA gene expression in MS patients treated with IFN-beta therapy.
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31
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Stertz S, Reichelt M, Krijnse-Locker J, Mackenzie J, Simpson JC, Haller O, Kochs G. Interferon-Induced, Antiviral Human MxA Protein Localizes to a Distinct Subcompartment of the Smooth Endoplasmic Reticulum. J Interferon Cytokine Res 2006; 26:650-60. [PMID: 16978069 DOI: 10.1089/jir.2006.26.650] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Human MxA protein belongs to the superfamily of dynamin-like large GTPases that are involved in intracellular membrane trafficking. MxA is induced by interferons-alpha/beta (IFN-alpha/beta) and is a key component of the antiviral response against RNA viruses. Here, we show that MxA localizes to membranes that are positive for specific markers of the smooth endoplasmic reticulum, such as Syntaxin17, but is excluded from other membrane compartments. Overexpression of MxA leads to a characteristic reorganization of the associated membranes. Interestingly, Hook3, mannose-6-phosphate receptor, and Lamp-1, which normally accumulate in cis- Golgi, endosomes, and lysosomes, respectively, also colocalized with MxA, indicating that these markers were redistributed to the MxA-positive compartment. Functional assays, however, did not show any effect of MxA on endocytosis or the secretory pathway. The present results demonstrate that MxA is an IFN-induced antiviral effector protein that resembles the constitutively expressed large GTPase family members in its capacity to localize to and reorganize intracellular membranes.
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Affiliation(s)
- Silke Stertz
- Abteilung Virologie, Institut für Medizinische Mikrobiologie und Hygiene, Universität Freiburg, D-79008 Freiburg, Germany
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