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Semenova MG, Petina AN, Fedorova EE. Autophagy and Symbiosis: Membranes, ER, and Speculations. Int J Mol Sci 2024; 25:2918. [PMID: 38474164 DOI: 10.3390/ijms25052918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 02/19/2024] [Accepted: 02/26/2024] [Indexed: 03/14/2024] Open
Abstract
The interaction of plants and soil bacteria rhizobia leads to the formation of root nodule symbiosis. The intracellular form of rhizobia, the symbiosomes, are able to perform the nitrogen fixation by converting atmospheric dinitrogen into ammonia, which is available for plants. The symbiosis involves the resource sharing between two partners, but this exchange does not include equivalence, which can lead to resource scarcity and stress responses of one of the partners. In this review, we analyze the possible involvement of the autophagy pathway in the process of the maintenance of the nitrogen-fixing bacteria intracellular colony and the changes in the endomembrane system of the host cell. According to in silico expression analysis, ATG genes of all groups were expressed in the root nodule, and the expression was developmental zone dependent. The analysis of expression of genes involved in the response to carbon or nitrogen deficiency has shown a suboptimal access to sugars and nitrogen in the nodule tissue. The upregulation of several ER stress genes was also detected. Hence, the root nodule cells are under heavy bacterial infection, carbon deprivation, and insufficient nitrogen supply, making nodule cells prone to autophagy. We speculate that the membrane formation around the intracellular rhizobia may be quite similar to the phagophore formation, and the induction of autophagy and ER stress are essential to the success of this process.
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Affiliation(s)
- Maria G Semenova
- Timiryazev Institute of Plant Physiology, Russian Academy of Science, 127276 Moscow, Russia
| | - Alekandra N Petina
- Timiryazev Institute of Plant Physiology, Russian Academy of Science, 127276 Moscow, Russia
| | - Elena E Fedorova
- Timiryazev Institute of Plant Physiology, Russian Academy of Science, 127276 Moscow, Russia
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2
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Sathanantham P, Zhao W, He G, Murray A, Fenech E, Diaz A, Schuldiner M, Wang X. A conserved viral amphipathic helix governs the replication site-specific membrane association. PLoS Pathog 2022; 18:e1010752. [PMID: 36048900 PMCID: PMC9473614 DOI: 10.1371/journal.ppat.1010752] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 09/14/2022] [Accepted: 07/19/2022] [Indexed: 11/18/2022] Open
Abstract
Positive-strand RNA viruses assemble their viral replication complexes (VRCs) on specific host organelle membranes, yet it is unclear how viral replication proteins recognize and what motifs or domains in viral replication proteins determine their destinations. We show here that an amphipathic helix, helix B in replication protein 1a of brome mosaic virus (BMV), is necessary for 1a’s localization to the nuclear endoplasmic reticulum (ER) membrane where BMV assembles its VRCs. Helix B is also sufficient to target soluble proteins to the nuclear ER membrane in yeast and plant cells. We further show that an equivalent helix in several plant- and human-infecting viruses of the Alsuviricetes class targets fluorescent proteins to the organelle membranes where they form their VRCs, including ER, vacuole, and Golgi membranes. Our work reveals a conserved helix that governs the localization of VRCs among a group of viruses and points to a possible target for developing broad-spectrum antiviral strategies. Positive-strand RNA viruses [(+)RNA viruses] are the largest viral class that include numerous pathogens causing important diseases in humans, animals, and plants. During their infections, (+)RNA viruses assemble their viral replication complexes (VRCs), where they multiply themselves, at specific organelle membranes. An initial step to form VRCs is to target viral replication proteins to the designated organelle membranes. For brome mosaic virus (BMV), its replication protein 1a is responsible for the VRC formation at the nuclear endoplasmic reticulum (ER) membrane. We show that an amphipathic alpha-helix, helix B, in BMV 1a is necessary for the association of BMV 1a with the nuclear ER membrane and for BMV genome amplification. In addition, Helix B is sufficient to target several soluble proteins to the nuclear ER membrane in yeast and plant cells. BMV belongs to the Alsuviricetes class that includes viruses infecting humans, animals, and plants. We further show that the helix B across members of the Alsuviricetes class is sufficient to target fluorescence proteins to the designated organelle membranes. Our results reveal a conserved feature among a group of viruses in governing the associations with replication site-specific organelle membranes and point to a target to develop broad-spectrum antivirals.
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Affiliation(s)
- Preethi Sathanantham
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Wenhao Zhao
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Key Lab of Food Quality and Safety of Jiangsu Province-State Key Laboratory Breeding Base, Nanjing, China
| | - Guijuan He
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Austin Murray
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Emma Fenech
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Arturo Diaz
- Department of Biology, La Sierra University, Riverside, California, United States of America
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Xiaofeng Wang
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
- * E-mail:
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3
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Zhu J, Li W, Zhou Y, Pei L, Liu J, Xia X, Che R, Li H. Molecular characterization, expression and functional analysis of acyl-CoA-binding protein gene family in maize (Zea mays). BMC PLANT BIOLOGY 2021; 21:94. [PMID: 33588749 PMCID: PMC7883581 DOI: 10.1186/s12870-021-02863-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 02/01/2021] [Indexed: 05/08/2023]
Abstract
BACKGROUND Acyl-CoA-binding proteins (ACBPs) possess a conserved acyl-CoA-binding (ACB) domain that facilitates binding to acyl-CoA esters and trafficking in eukaryotic cells. Although the various functions of ACBP have been characterized in several plant species, their structure, molecular evolution, expression profile, and function have not been fully elucidated in Zea mays L. RESULTS Genome-wide analysis identified nine ZmACBP genes in Z. mays, which could be divided into four distinct classes (class I, class II, class III, and class IV) via construction of a phylogenetic tree that included 48 ACBP genes from six different plant species. Transient expression of a ZmACBP-GFP fusion protein in tobacco (Nicotiana tabacum) epidermal cells revealed that ZmACBPs localized to multiple different locations. Analyses of expression profiles revealed that ZmACBPs exhibited temporal and spatial expression changes during abiotic and biotic stresses. Eight of the nine ZmACBP genes were also found to have significant association with agronomic traits in a panel of 500 maize inbred lines. The heterologous constitutive expression of ZmACBP1 and ZmACBP3 in Arabidopsis enhanced the resistance of these plants to salinity and drought stress, possibly through alterations in the level of lipid metabolic and stress-responsive genes. CONCLUSION The ACBP gene family was highly conserved across different plant species. ZmACBP genes had clear tissue and organ expression specificity and were responsive to both biotic and abiotic stresses, suggesting their roles in plant growth and stress resistance.
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Affiliation(s)
- Jiantang Zhu
- School of Biological Science and Technology, University of Jinan, Jinan, 250022 China
| | - Weijun Li
- School of Biological Science and Technology, University of Jinan, Jinan, 250022 China
| | - Yuanyuan Zhou
- School of Biological Science and Technology, University of Jinan, Jinan, 250022 China
| | - Laming Pei
- School of Biological Science and Technology, University of Jinan, Jinan, 250022 China
| | - Jiajia Liu
- School of Biological Science and Technology, University of Jinan, Jinan, 250022 China
| | - Xinyao Xia
- School of Biological Science and Technology, University of Jinan, Jinan, 250022 China
| | - Ronghui Che
- School of Biological Science and Technology, University of Jinan, Jinan, 250022 China
| | - Hui Li
- School of Biological Science and Technology, University of Jinan, Jinan, 250022 China
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4
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Abstract
Viruses manipulate cellular lipids and membranes at each stage of their life cycle. This includes lipid-receptor interactions, the fusion of viral envelopes with cellular membranes during endocytosis, the reorganization of cellular membranes to form replication compartments, and the envelopment and egress of virions. In addition to the physical interactions with cellular membranes, viruses have evolved to manipulate lipid signaling and metabolism to benefit their replication. This review summarizes the strategies that viruses use to manipulate lipids and membranes at each stage in the viral life cycle.
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Affiliation(s)
- Ellen Ketter
- Department of Microbiology, The University of Chicago, Chicago, Illinois 60637, USA;
| | - Glenn Randall
- Department of Microbiology, The University of Chicago, Chicago, Illinois 60637, USA;
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5
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He G, Zhang Z, Sathanantham P, Zhang X, Wu Z, Xie L, Wang X. An engineered mutant of a host phospholipid synthesis gene inhibits viral replication without compromising host fitness. J Biol Chem 2019; 294:13973-13982. [PMID: 31362985 DOI: 10.1074/jbc.ra118.007051] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 07/16/2019] [Indexed: 12/24/2022] Open
Abstract
Viral infections universally rely on numerous hijacked host factors to be successful. It is therefore possible to control viral infections by manipulating host factors that are critical for viral replication. Given that host genes may play essential roles in certain cellular processes, any successful manipulations for virus control should cause no or mild effects on host fitness. We previously showed that a group of positive-strand RNA viruses enrich phosphatidylcholine (PC) at the sites of viral replication. Specifically, brome mosaic virus (BMV) replication protein 1a interacts with and recruits a PC synthesis enzyme, phosphatidylethanolamine methyltransferase, Cho2p, to the viral replication sites that are assembled on the perinuclear endoplasmic reticulum (ER) membrane. Deletion of the CHO2 gene inhibited BMV replication by 5-fold; however, it slowed down host cell growth as well. Here, we show that an engineered Cho2p mutant supports general PC synthesis and normal cell growth but blocks BMV replication. This mutant interacts and colocalizes with BMV 1a but prevents BMV 1a from localizing to the perinuclear ER membrane. The mislocalized BMV 1a fails to induce the formation of viral replication complexes. Our study demonstrates an effective antiviral strategy in which a host lipid synthesis gene is engineered to control viral replication without comprising host growth.
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Affiliation(s)
- Guijuan He
- Fujian Province Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China.,School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, Virginia 24061
| | - Zhenlu Zhang
- Fujian Province Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China.,School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, Virginia 24061.,National Key Laboratory of Crop Biology, National Research Center for Apple Engineering and Technology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong 271018, China
| | - Preethi Sathanantham
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, Virginia 24061
| | - Xin Zhang
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, Virginia 24061
| | - Zujian Wu
- Fujian Province Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Lianhui Xie
- Fujian Province Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Xiaofeng Wang
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, Virginia 24061
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6
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Zhang Z, He G, Filipowicz NA, Randall G, Belov GA, Kopek BG, Wang X. Host Lipids in Positive-Strand RNA Virus Genome Replication. Front Microbiol 2019; 10:286. [PMID: 30863375 PMCID: PMC6399474 DOI: 10.3389/fmicb.2019.00286] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 02/04/2019] [Indexed: 12/19/2022] Open
Abstract
Membrane association is a hallmark of the genome replication of positive-strand RNA viruses [(+)RNA viruses]. All well-studied (+)RNA viruses remodel host membranes and lipid metabolism through orchestrated virus-host interactions to create a suitable microenvironment to survive and thrive in host cells. Recent research has shown that host lipids, as major components of cellular membranes, play key roles in the replication of multiple (+)RNA viruses. This review focuses on how (+)RNA viruses manipulate host lipid synthesis and metabolism to facilitate their genomic RNA replication, and how interference with the cellular lipid metabolism affects viral replication.
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Affiliation(s)
- Zhenlu Zhang
- National Key Laboratory of Crop Biology, National Research Center for Apple Engineering and Technology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai'an, China
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, United States
| | - Guijuan He
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, United States
- Fujian Province Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, China
| | | | - Glenn Randall
- Department of Microbiology, The University of Chicago, Chicago, IL, United States
| | - George A. Belov
- Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, MD, United States
| | | | - Xiaofeng Wang
- School of Plant and Environmental Sciences, Virginia Tech, Blacksburg, VA, United States
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7
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Garcia-Ruiz H. Susceptibility Genes to Plant Viruses. Viruses 2018; 10:E484. [PMID: 30201857 PMCID: PMC6164914 DOI: 10.3390/v10090484] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 08/28/2018] [Accepted: 09/07/2018] [Indexed: 12/26/2022] Open
Abstract
Plant viruses use cellular factors and resources to replicate and move. Plants respond to viral infection by several mechanisms, including innate immunity, autophagy, and gene silencing, that viruses must evade or suppress. Thus, the establishment of infection is genetically determined by the availability of host factors necessary for virus replication and movement and by the balance between plant defense and viral suppression of defense responses. Host factors may have antiviral or proviral activities. Proviral factors condition susceptibility to viruses by participating in processes essential to the virus. Here, we review current advances in the identification and characterization of host factors that condition susceptibility to plant viruses. Host factors with proviral activity have been identified for all parts of the virus infection cycle: viral RNA translation, viral replication complex formation, accumulation or activity of virus replication proteins, virus movement, and virion assembly. These factors could be targets of gene editing to engineer resistance to plant viruses.
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Affiliation(s)
- Hernan Garcia-Ruiz
- Nebraska Center for Virology, Department of Plant Pathology, University of Nebraska-Lincoln, Lincoln, NE 68503, USA.
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8
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Zhang Z, He G, Han GS, Zhang J, Catanzaro N, Diaz A, Wu Z, Carman GM, Xie L, Wang X. Host Pah1p phosphatidate phosphatase limits viral replication by regulating phospholipid synthesis. PLoS Pathog 2018; 14:e1006988. [PMID: 29649282 PMCID: PMC5916857 DOI: 10.1371/journal.ppat.1006988] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 04/24/2018] [Accepted: 03/24/2018] [Indexed: 11/20/2022] Open
Abstract
Replication of positive-strand RNA viruses [(+)RNA viruses] takes place in membrane-bound viral replication complexes (VRCs). Formation of VRCs requires virus-mediated manipulation of cellular lipid synthesis. Here, we report significantly enhanced brome mosaic virus (BMV) replication and much improved cell growth in yeast cells lacking PAH1 (pah1Δ), the sole yeast ortholog of human LIPIN genes. PAH1 encodes Pah1p (phosphatidic acid phosphohydrolase), which converts phosphatidate (PA) to diacylglycerol that is subsequently used for the synthesis of the storage lipid triacylglycerol. Inactivation of Pah1p leads to altered lipid composition, including high levels of PA, total phospholipids, ergosterol ester, and free fatty acids, as well as expansion of the nuclear membrane. In pah1Δ cells, BMV replication protein 1a and double-stranded RNA localized to the extended nuclear membrane, there was a significant increase in the number of VRCs formed, and BMV genomic replication increased by 2-fold compared to wild-type cells. In another yeast mutant that lacks both PAH1 and DGK1 (encodes diacylglycerol kinase converting diacylglycerol to PA), which has a normal nuclear membrane but maintains similar lipid compositional changes as in pah1Δ cells, BMV replicated as efficiently as in pah1Δ cells, suggesting that the altered lipid composition was responsible for the enhanced BMV replication. We further showed that increased levels of total phospholipids play an important role because the enhanced BMV replication required active synthesis of phosphatidylcholine, the major membrane phospholipid. Moreover, overexpression of a phosphatidylcholine synthesis gene (CHO2) promoted BMV replication. Conversely, overexpression of PAH1 or plant PAH1 orthologs inhibited BMV replication in yeast or Nicotiana benthamiana plants. Competing with its host for limited resources, BMV inhibited host growth, which was markedly alleviated in pah1Δ cells. Our work suggests that Pah1p promotes storage lipid synthesis and thus represses phospholipid synthesis, which in turn restricts both viral replication and cell growth during viral infection.
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Affiliation(s)
- Zhenlu Zhang
- Fujian Province Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, P. R. China
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA, United States of America
| | - Guijuan He
- Fujian Province Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, P. R. China
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA, United States of America
| | - Gil-Soo Han
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ, United States of America
| | - Jiantao Zhang
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA, United States of America
| | - Nicholas Catanzaro
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, United States of America
| | - Arturo Diaz
- Department of Biology, La Sierra University, Riverside, VA, United States of America
| | - Zujian Wu
- Fujian Province Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, P. R. China
| | - George M. Carman
- Department of Food Science and the Rutgers Center for Lipid Research, New Jersey Institute for Food, Nutrition, and Health, Rutgers University, New Brunswick, NJ, United States of America
| | - Lianhui Xie
- Fujian Province Key Laboratory of Plant Virology, Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou, Fujian, P. R. China
| | - Xiaofeng Wang
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA, United States of America
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Jin X, Cao X, Wang X, Jiang J, Wan J, Laliberté JF, Zhang Y. Three-Dimensional Architecture and Biogenesis of Membrane Structures Associated with Plant Virus Replication. FRONTIERS IN PLANT SCIENCE 2018; 9:57. [PMID: 29441085 PMCID: PMC5797596 DOI: 10.3389/fpls.2018.00057] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 01/11/2018] [Indexed: 05/20/2023]
Abstract
Positive-sense (+) RNA viruses represent the most abundant group of viruses and are dependent on the host cell machinery to replicate. One remarkable feature that occurs after (+) RNA virus entry into cells is the remodeling of host endomembranes, leading to the formation of viral replication factories. Recently, rapid progress in three-dimensional (3D) imaging technologies, such as electron tomography (ET) and focused ion beam-scanning electron microscopy (FIB-SEM), has enabled researchers to visualize the novel membrane structures induced by viruses at high resolution. These 3D imaging technologies provide new mechanistic insights into the viral infection cycle. In this review, we summarize the latest reports on the cellular remodeling that occurs during plant virus infection; in particular, we focus on studies that provide 3D architectural information on viral replication factories. We also outline the mechanisms underlying the formation of these membranous structures and discuss possible future research directions.
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Affiliation(s)
- Xuejiao Jin
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Xiuling Cao
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Xueting Wang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Jun Jiang
- Institut National de la Recherche Scientifique—Institut Armand-Frappier, Laval, QC, Canada
| | - Juan Wan
- Institut National de la Recherche Scientifique—Institut Armand-Frappier, Laval, QC, Canada
| | - Jean-François Laliberté
- Institut National de la Recherche Scientifique—Institut Armand-Frappier, Laval, QC, Canada
- *Correspondence: Jean-François Laliberté
| | - Yongliang Zhang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China
- Yongliang Zhang
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10
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Li J, Fuchs S, Zhang J, Wellford S, Schuldiner M, Wang X. An unrecognized function for COPII components in recruiting the viral replication protein BMV 1a to the perinuclear ER. J Cell Sci 2016; 129:3597-3608. [PMID: 27539921 DOI: 10.1242/jcs.190082] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 08/13/2016] [Indexed: 01/05/2023] Open
Abstract
Positive-strand RNA viruses invariably assemble their viral replication complexes (VRCs) by remodeling host intracellular membranes. How viral replication proteins are targeted to specific organelle membranes to initiate VRC assembly remains elusive. Brome mosaic virus (BMV), whose replication can be recapitulated in Saccharomyces cerevisiae, assembles its VRCs by invaginating the outer perinuclear endoplasmic reticulum (ER) membrane. Remarkably, BMV replication protein 1a (BMV 1a) is the only viral protein required for such membrane remodeling. We show that ER-vesicle protein of 14 kD (Erv14), a cargo receptor of coat protein complex II (COPII), interacts with BMV 1a. Moreover, the perinuclear ER localization of BMV 1a is disrupted in cells lacking ERV14 or expressing dysfunctional COPII coat components (Sec13, Sec24 or Sec31). The requirement of Erv14 for the localization of BMV 1a is bypassed by addition of a Sec24-recognizable sorting signal to BMV 1a or by overexpressing Sec24, suggesting a coordinated effort by both Erv14 and Sec24 for the proper localization of BMV 1a. The COPII pathway is well known for being involved in protein secretion; our data suggest that a subset of COPII coat proteins have an unrecognized role in targeting proteins to the perinuclear ER membrane.
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Affiliation(s)
- Jianhui Li
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA 24061, USA
| | - Shai Fuchs
- Department of Molecular Genetics, Weizmann Institute of Sciences, Rehovot 7610001, Israel
| | - Jiantao Zhang
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA 24061, USA
| | - Sebastian Wellford
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA 24061, USA
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Sciences, Rehovot 7610001, Israel
| | - Xiaofeng Wang
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA 24061, USA
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11
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Plant acyl-CoA-binding proteins: An emerging family involved in plant development and stress responses. Prog Lipid Res 2016; 63:165-81. [DOI: 10.1016/j.plipres.2016.06.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 06/25/2016] [Accepted: 06/26/2016] [Indexed: 01/22/2023]
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12
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Hyodo K, Okuno T. Pathogenesis mediated by proviral host factors involved in translation and replication of plant positive-strand RNA viruses. Curr Opin Virol 2016; 17:11-18. [DOI: 10.1016/j.coviro.2015.11.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 11/05/2015] [Accepted: 11/11/2015] [Indexed: 01/04/2023]
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13
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Nagy PD, Pogany J, Xu K. Cell-Free and Cell-Based Approaches to Explore the Roles of Host Membranes and Lipids in the Formation of Viral Replication Compartment Induced by Tombusviruses. Viruses 2016; 8:68. [PMID: 26950140 PMCID: PMC4810258 DOI: 10.3390/v8030068] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 02/18/2016] [Accepted: 02/22/2016] [Indexed: 01/14/2023] Open
Abstract
Plant positive strand RNA viruses are intracellular infectious agents that take advantage of cellular lipids and membranes to support replication and protect viral RNA from degradation by host antiviral responses. In this review, we discuss how Tomato bushy stunt virus (TBSV) co-opts lipid transfer proteins and modulates lipid metabolism and transport to facilitate the assembly of the membrane-bound viral replicase complexes within intricate replication compartments. Identification and characterization of the proviral roles of specific lipids and proteins involved in lipid metabolism based on results from yeast (Saccharomyces cerevisiae) model host and cell-free approaches are discussed. The review also highlights the advantage of using liposomes with chemically defined composition to identify specific lipids required for TBSV replication. Remarkably, all the known steps in TBSV replication are dependent on cellular lipids and co-opted membranes.
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Affiliation(s)
- Peter D Nagy
- Department of Plant Pathology, University of Kentucky, Lexington, KY 40546, USA.
| | - Judit Pogany
- Department of Plant Pathology, University of Kentucky, Lexington, KY 40546, USA.
| | - Kai Xu
- Department of Plant Pathology, University of Kentucky, Lexington, KY 40546, USA.
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14
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Positive-strand RNA viruses stimulate host phosphatidylcholine synthesis at viral replication sites. Proc Natl Acad Sci U S A 2016; 113:E1064-73. [PMID: 26858414 DOI: 10.1073/pnas.1519730113] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
All positive-strand RNA viruses reorganize host intracellular membranes to assemble their viral replication complexes (VRCs); however, how these viruses modulate host lipid metabolism to accommodate such membrane proliferation and rearrangements is not well defined. We show that a significantly increased phosphatidylcholine (PC) content is associated with brome mosaic virus (BMV) replication in both natural host barley and alternate host yeast based on a lipidomic analysis. Enhanced PC levels are primarily associated with the perinuclear ER membrane, where BMV replication takes place. More specifically, BMV replication protein 1a interacts with and recruits Cho2p (choline requiring 2), a host enzyme involved in PC synthesis, to the site of viral replication. These results suggest that PC synthesized at the site of VRC assembly, not the transport of existing PC, is responsible for the enhanced accumulation. Blocking PC synthesis by deleting the CHO2 gene resulted in VRCs with wider diameters than those in wild-type cells; however, BMV replication was significantly inhibited, highlighting the critical role of PC in VRC formation and viral replication. We further show that enhanced PC levels also accumulate at the replication sites of hepatitis C virus and poliovirus, revealing a conserved feature among a group of positive-strand RNA viruses. Our work also highlights a potential broad-spectrum antiviral strategy that would disrupt PC synthesis at the sites of viral replication but would not alter cellular processes.
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Kovalev N, de Castro Martín IF, Pogany J, Barajas D, Pathak K, Risco C, Nagy PD. Role of Viral RNA and Co-opted Cellular ESCRT-I and ESCRT-III Factors in Formation of Tombusvirus Spherules Harboring the Tombusvirus Replicase. J Virol 2016; 90:3611-26. [PMID: 26792735 PMCID: PMC4794697 DOI: 10.1128/jvi.02775-15] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 01/12/2016] [Indexed: 12/21/2022] Open
Abstract
UNLABELLED Plus-stranded RNA viruses induce membrane deformations in infected cells in order to build viral replication complexes (VRCs). Tomato bushy stunt virus (TBSV) co-opts cellular ESCRT (endosomal sorting complexes required for transport) proteins to induce the formation of vesicle (spherule)-like structures in the peroxisomal membrane with tight openings toward the cytosol. In this study, using a yeast (Saccharomyces cerevisiae) vps23Δ bro1Δ double-deletion mutant, we showed that the Vps23p ESCRT-I protein (Tsg101 in mammals) and Bro1p (ALIX) ESCRT-associated protein, both of which bind to the viral p33 replication protein, play partially complementary roles in TBSV replication in cells and in cell extracts. Dual expression of dominant-negative versions of Arabidopsis homologs of Vps23p and Bro1p inhibited tombusvirus replication to greater extent than individual expression in Nicotiana benthamiana leaves. We also demonstrated the critical role of Snf7p (CHMP4), Vps20p, and Vps24p ESCRT-III proteins in tombusvirus replication in yeast and in vitro. Electron microscopic imaging of vps23Δ yeast revealed the lack of tombusvirus-induced spherule-like structures, while crescent-like structures are formed in ESCRT-III deletion yeasts replicating TBSV RNA. In addition, we also showed that the length of the viral RNA affects the sizes of spherules formed in N. benthamiana cells. The 4.8-kb genomic RNA is needed for the formation of spherules 66 nm in diameter, while spherules formed during the replication of the ∼600-nucleotide (nt)-long defective interfering RNA in the presence of p33 and p92 replication proteins are 42 nm. We propose that the viral RNA serves as a "measuring string" during VRC assembly and spherule formation. IMPORTANCE Plant positive-strand RNA viruses, similarly to animal positive-strand RNA viruses, replicate in membrane-bound viral replicase complexes in the cytoplasm of infected cells. Identification of cellular and viral factors affecting the formation of the membrane-bound viral replication complex is a major frontier in current virology research. In this study, we dissected the functions of co-opted cellular ESCRT-I (endosomal sorting complexes required for transport I) and ESCRT-III proteins and the viral RNA in tombusvirus replicase complex formation using in vitro, yeast-based, and plant-based approaches. Electron microscopic imaging revealed the lack of tombusvirus-induced spherule-like structures in ESCRT-I or ESCRT-III deletion yeasts replicating TBSV RNA, demonstrating the requirement for these co-opted cellular factors in tombusvirus replicase formation. The work could be of broad interest in virology and beyond.
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Affiliation(s)
- Nikolay Kovalev
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, USA
| | | | - Judit Pogany
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, USA
| | - Daniel Barajas
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, USA
| | - Kunj Pathak
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, USA
| | - Cristina Risco
- Cell Structure Laboratory, Centro Nacional de Biotecnología, Madrid, Spain
| | - Peter D Nagy
- Department of Plant Pathology, University of Kentucky, Lexington, Kentucky, USA
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Diaz A, Zhang J, Ollwerther A, Wang X, Ahlquist P. Host ESCRT proteins are required for bromovirus RNA replication compartment assembly and function. PLoS Pathog 2015; 11:e1004742. [PMID: 25748299 PMCID: PMC4351987 DOI: 10.1371/journal.ppat.1004742] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 02/10/2015] [Indexed: 11/18/2022] Open
Abstract
Positive-strand RNA viruses genome replication invariably is associated with vesicles or other rearranged cellular membranes. Brome mosaic virus (BMV) RNA replication occurs on perinuclear endoplasmic reticulum (ER) membranes in ~70 nm vesicular invaginations (spherules). BMV RNA replication vesicles show multiple parallels with membrane-enveloped, budding retrovirus virions, whose envelopment and release depend on the host ESCRT (endosomal sorting complexes required for transport) membrane-remodeling machinery. We now find that deleting components of the ESCRT pathway results in at least two distinct BMV phenotypes. One group of genes regulate RNA replication and the frequency of viral replication complex formation, but had no effect on spherule size, while a second group of genes regulate RNA replication in a way or ways independent of spherule formation. In particular, deleting SNF7 inhibits BMV RNA replication > 25-fold and abolishes detectable BMV spherule formation, even though the BMV RNA replication proteins accumulate and localize normally on perinuclear ER membranes. Moreover, BMV ESCRT recruitment and spherule assembly depend on different sets of protein-protein interactions from those used by multivesicular body vesicles, HIV-1 virion budding, or tomato bushy stunt virus (TBSV) spherule formation. These and other data demonstrate that BMV requires cellular ESCRT components for proper formation and function of its vesicular RNA replication compartments. The results highlight growing but diverse interactions of ESCRT factors with many viruses and viral processes, and potential value of the ESCRT pathway as a target for broad-spectrum antiviral resistance. Positive-strand RNA {(+)RNA} viruses cause numerous human, animal, and plant diseases. (+)RNA viruses reorganize host intracellular membranes to assemble their RNA replication compartments, which are mini-organelles featuring the close association of both viral and host components. To further understand the role of host components in forming such RNA replication compartments, we used brome mosaic virus (BMV), a well characterized model virus, to study some common features of (+)RNA virus RNA replication. We show that knocking out several components of the cellular Endosomal Complex Required for Transport (ESCRT) machinery resulted in parallel defects in BMV RNA replication and replication compartment formation, whereas other ESCRT components affected RNA replication independently of replication compartment formation. Deleting a subset of ESCRT proteins altered the frequency of replication compartment formation but had no effect on the size of these compartments, whereas a second subset affected RNA replication independently of replication compartment formation. Moreover, BMV’s interaction with the ESCRT machinery appears to be distinct from that reported for other viruses and from the ESCRT requirements for forming vesicles in cellular multivesicular bodies. These findings further illuminate the remarkable abilities of positive-strand RNA viruses to integrate viral and host protein functions to remodel membranes, and suggest potentially potent new ways to control such viruses.
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Affiliation(s)
- Arturo Diaz
- Institute for Molecular Virology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Jiantao Zhang
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech University, Blacksburg, Virginia, United States of America
| | - Abigail Ollwerther
- Institute for Molecular Virology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Xiaofeng Wang
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech University, Blacksburg, Virginia, United States of America
- * E-mail: (XW); (PA)
| | - Paul Ahlquist
- Institute for Molecular Virology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Howard Hughes Medical Institute, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Morgridge Institute for Research, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail: (XW); (PA)
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Ammer E, Nietzsche S, Rien C, Kühnl A, Mader T, Heller R, Sauerbrei A, Henke A. The anti-obesity drug orlistat reveals anti-viral activity. Med Microbiol Immunol 2015; 204:635-45. [DOI: 10.1007/s00430-015-0391-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 02/06/2015] [Indexed: 12/28/2022]
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18
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Greninger AL. Picornavirus–Host Interactions to Construct Viral Secretory Membranes. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 129:189-212. [DOI: 10.1016/bs.pmbts.2014.10.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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19
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Wang A. Dissecting the molecular network of virus-plant interactions: the complex roles of host factors. ANNUAL REVIEW OF PHYTOPATHOLOGY 2015; 53:45-66. [PMID: 25938276 DOI: 10.1146/annurev-phyto-080614-120001] [Citation(s) in RCA: 222] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
A successful infection by a plant virus results from the complex molecular interplay between the host plant and the invading virus. Thus, dissecting the molecular network of virus-host interactions advances the understanding of the viral infection process and may assist in the development of novel antiviral strategies. In the past decade, molecular identification and functional characterization of host factors in the virus life cycle, particularly single-stranded, positive-sense RNA viruses, have been a research focus in plant virology. As a result, a number of host factors have been identified. These host factors are implicated in all the major steps of the infection process. Some host factors are diverted for the viral genome translation, some are recruited to improvise the viral replicase complexes for genome multiplication, and others are components of transport complexes for cell-to-cell spread via plasmodesmata and systemic movement through the phloem. This review summarizes current knowledge about host factors and discusses future research directions.
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Affiliation(s)
- Aiming Wang
- Southern Crop Protection and Food Research Centre, Agriculture and Agri-Food Canada, London, Ontario, N5V 4T3, Canada;
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20
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Affiliation(s)
- Jean-François Laliberté
- INRS–Institut Armand-Frappier, Institut National de la Recherche Scientifique, Laval, Québec H7V 1B7, Canada;
| | - Huanquan Zheng
- Department of Biology, McGill University, Montréal, Québec H3A 1B1, Canada;
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21
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Tombusviruses upregulate phospholipid biosynthesis via interaction between p33 replication protein and yeast lipid sensor proteins during virus replication in yeast. Virology 2014; 471-473:72-80. [PMID: 25461533 DOI: 10.1016/j.virol.2014.10.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 10/03/2014] [Accepted: 10/05/2014] [Indexed: 01/27/2023]
Abstract
Positive-stranded RNA viruses induce new membranous structures and promote membrane proliferation in infected cells to facilitate viral replication. In this paper, the authors show that a plant-infecting tombusvirus upregulates transcription of phospholipid biosynthesis genes, such as INO1, OPI3 and CHO1, and increases phospholipid levels in yeast model host. This is accomplished by the viral p33 replication protein, which interacts with Opi1p FFAT domain protein and Scs2p VAP protein. Opi1p and Scs2p are phospholipid sensor proteins and they repress the expression of phospholipid genes. Accordingly, deletion of OPI1 transcription repressor in yeast has a stimulatory effect on TBSV RNA accumulation and enhanced tombusvirus replicase activity in an in vitro assay. Altogether, the presented data convincingly demonstrate that de novo lipid biosynthesis is required for optimal TBSV replication. Overall, this work reveals that a (+)RNA virus reprograms the phospholipid biosynthesis pathway in a unique way to facilitate its replication in yeast cells.
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22
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Diaz A, Wang X. Bromovirus-induced remodeling of host membranes during viral RNA replication. Curr Opin Virol 2014; 9:104-10. [PMID: 25462441 DOI: 10.1016/j.coviro.2014.09.018] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 09/09/2014] [Indexed: 11/28/2022]
Abstract
With its high yield, small genome, and ability to replicate in the yeast Saccharomyces cerevisiae, Brome mosaic virus (BMV) has served as a productive model to study the general features of positive-strand RNA virus infection. BMV RNA is replicated in spherules, vesicle-like invaginations of the outer perinuclear endoplasmic reticulum membrane that remain connected to the cytoplasm via a neck-like opening. Each spherule contains the viral replicase proteins as well as genomic RNAs. Recent advances indicate that multiple interactions between the viral proteins with themselves, cellular membranes, and host factors play crucial roles in BMV-mediated spherule formation. These findings are probably applicable to other positive-strand RNA viruses and might potentially provide new targets for antiviral treatments.
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Affiliation(s)
- Arturo Diaz
- Department of Biology, La Sierra University, Riverside, CA 92505, United States.
| | - Xiaofeng Wang
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech University, Blacksburg, VA 24061, United States.
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23
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Chasman D, Gancarz B, Hao L, Ferris M, Ahlquist P, Craven M. Inferring host gene subnetworks involved in viral replication. PLoS Comput Biol 2014; 10:e1003626. [PMID: 24874113 PMCID: PMC4038467 DOI: 10.1371/journal.pcbi.1003626] [Citation(s) in RCA: 5] [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: 04/15/2013] [Accepted: 02/06/2014] [Indexed: 12/16/2022] Open
Abstract
Systematic, genome-wide loss-of-function experiments can be used to identify host factors that directly or indirectly facilitate or inhibit the replication of a virus in a host cell. We present an approach that combines an integer linear program and a diffusion kernel method to infer the pathways through which those host factors modulate viral replication. The inputs to the method are a set of viral phenotypes observed in single-host-gene mutants and a background network consisting of a variety of host intracellular interactions. The output is an ensemble of subnetworks that provides a consistent explanation for the measured phenotypes, predicts which unassayed host factors modulate the virus, and predicts which host factors are the most direct interfaces with the virus. We infer host-virus interaction subnetworks using data from experiments screening the yeast genome for genes modulating the replication of two RNA viruses. Because a gold-standard network is unavailable, we assess the predicted subnetworks using both computational and qualitative analyses. We conduct a cross-validation experiment in which we predict whether held-aside test genes have an effect on viral replication. Our approach is able to make high-confidence predictions more accurately than several baselines, and about as well as the best baseline, which does not infer mechanistic pathways. We also examine two kinds of predictions made by our method: which host factors are nearest to a direct interaction with a viral component, and which unassayed host genes are likely to be involved in viral replication. Multiple predictions are supported by recent independent experimental data, or are components or functional partners of confirmed relevant complexes or pathways. Integer program code, background network data, and inferred host-virus subnetworks are available at http://www.biostat.wisc.edu/~craven/chasman_host_virus/.
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Affiliation(s)
- Deborah Chasman
- Department of Computer Sciences, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
- Department of Biostatistics and Medical Informatics, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
| | - Brandi Gancarz
- Luminex Corporation, Madison, Wisconsin, United States of America
- Institute for Molecular Virology, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
| | - Linhui Hao
- Institute for Molecular Virology, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
- Howard Hughes Medical Institute, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
| | - Michael Ferris
- Department of Computer Sciences, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
| | - Paul Ahlquist
- Institute for Molecular Virology, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
- Howard Hughes Medical Institute, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
- Morgridge Institute for Research, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
| | - Mark Craven
- Department of Computer Sciences, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
- Department of Biostatistics and Medical Informatics, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
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24
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Palukaitis P, Groen SC, Carr JP. The Rumsfeld paradox: some of the things we know that we don't know about plant virus infection. CURRENT OPINION IN PLANT BIOLOGY 2013; 16:513-9. [PMID: 23820310 DOI: 10.1016/j.pbi.2013.06.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 06/06/2013] [Accepted: 06/07/2013] [Indexed: 05/06/2023]
Abstract
Plant-infecting viruses cause significant crop losses around the world and the majority of emerging threats to crop production have a viral etiology. Significant progress has been made and continues to be made in understanding how viruses induce disease and overcome some forms of resistance-particularly resistance based on RNA silencing. However, it is still not clear how other antiviral mechanisms work, how viruses manage to exploit their hosts so successfully, or how viruses affect the interactions of susceptible plants with other organisms and if this is advantageous to the virus, the host, or both. In this article we explore these questions.
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Affiliation(s)
- Peter Palukaitis
- Division of Environmental and Life Sciences, Seoul Women's University, Seoul 139-774, Republic of Korea
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25
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Template RNA length determines the size of replication complex spherules for Semliki Forest virus. J Virol 2013; 87:9125-34. [PMID: 23760239 DOI: 10.1128/jvi.00660-13] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The replication complexes of positive-strand RNA viruses are always associated with cellular membranes. The morphology of the replication-associated membranes is altered in different ways in different viral systems, but many viruses induce small membrane invaginations known as spherules as their replication sites. We show here that for Semliki Forest virus (SFV), an alphavirus, the size of the spherules is tightly connected with the length of the replicating RNA template. Cells with different model templates, expressed in trans and copied by the viral replicase, were analyzed with correlative light and electron microscopy. It was demonstrated that the viral-genome-sized template of 11.5 kb induced spherules that were ∼58 nm in diameter, whereas a template of 6 kb yielded ∼39-nm spherules. Different sizes of viral templates were replicated efficiently in trans, as assessed by radioactive labeling and Northern blotting. The replication of two different templates, in cis and trans, yielded two size classes of spherules in the same cell. These results indicate that RNA plays a crucial determining role in spherule assembly for SFV, in direct contrast with results from other positive-strand RNA viruses, in which either the presence of viral RNA or the RNA size do not contribute to spherule formation.
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26
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Nchoutmboube JA, Viktorova EG, Scott AJ, Ford LA, Pei Z, Watkins PA, Ernst RK, Belov GA. Increased long chain acyl-Coa synthetase activity and fatty acid import is linked to membrane synthesis for development of picornavirus replication organelles. PLoS Pathog 2013; 9:e1003401. [PMID: 23762027 PMCID: PMC3675155 DOI: 10.1371/journal.ppat.1003401] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 04/19/2013] [Indexed: 12/20/2022] Open
Abstract
All positive strand (+RNA) viruses of eukaryotes replicate their genomes in association with membranes. The mechanisms of membrane remodeling in infected cells represent attractive targets for designing future therapeutics, but our understanding of this process is very limited. Elements of autophagy and/or the secretory pathway were proposed to be hijacked for building of picornavirus replication organelles. However, even closely related viruses differ significantly in their requirements for components of these pathways. We demonstrate here that infection with diverse picornaviruses rapidly activates import of long chain fatty acids. While in non-infected cells the imported fatty acids are channeled to lipid droplets, in infected cells the synthesis of neutral lipids is shut down and the fatty acids are utilized in highly up-regulated phosphatidylcholine synthesis. Thus the replication organelles are likely built from de novo synthesized membrane material, rather than from the remodeled pre-existing membranes. We show that activation of fatty acid import is linked to the up-regulation of cellular long chain acyl-CoA synthetase activity and identify the long chain acyl-CoA syntheatse3 (Acsl3) as a novel host factor required for polio replication. Poliovirus protein 2A is required to trigger the activation of import of fatty acids independent of its protease activity. Shift in fatty acid import preferences by infected cells results in synthesis of phosphatidylcholines different from those in uninfected cells, arguing that the viral replication organelles possess unique properties compared to the pre-existing membranes. Our data show how poliovirus can change the overall cellular membrane homeostasis by targeting one critical process. They explain earlier observations of increased phospholipid synthesis in infected cells and suggest a simple model of the structural development of the membranous scaffold of replication complexes of picorna-like viruses, that may be relevant for other (+)RNA viruses as well. Eukaryotic cells feature astonishing complexity of regulatory networks, yet control over this fine-tuned machinery is easily overrun by viruses with expression of just a handful of proteins. One of the striking examples of such hostile take-over is the rewiring of normal cellular membrane metabolism by (+)RNA viruses towards development of new membranous organelles harboring viral replication machinery. (+)RNA viruses of eukaryotes infect organisms from unicellular algae to humans. Many of them induce diseases resulting in significant economic losses, public health burden, human suffering and sometimes fatal consequences. We show how picornaviruses reorganize cellular lipid metabolism by targeting long chain acyl-CoA synthetase activity. This induces increased import of fatty acids in infected cells and up-regulation of phospholipid synthesis, resulting in formation of replication organelles different from the pre-existing cellular membranes. This mechanism is utilized by diverse viruses and may represent an attractive target for anti-viral interventions.
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Affiliation(s)
- Jules A. Nchoutmboube
- Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland, United States of America
| | - Ekaterina G. Viktorova
- Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland, United States of America
| | - Alison J. Scott
- University of Maryland, School of Dentistry, Baltimore, Maryland, United States of America
| | - Lauren A. Ford
- Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland, United States of America
| | - Zhengtong Pei
- Kennedy Krieger Institute and Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Paul A. Watkins
- Kennedy Krieger Institute and Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Robert K. Ernst
- University of Maryland, School of Dentistry, Baltimore, Maryland, United States of America
| | - George A. Belov
- Virginia-Maryland Regional College of Veterinary Medicine, University of Maryland, College Park, Maryland, United States of America
- * E-mail:
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27
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Mine A, Okuno T. Composition of plant virus RNA replicase complexes. Curr Opin Virol 2012; 2:669-75. [DOI: 10.1016/j.coviro.2012.09.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 09/18/2012] [Accepted: 09/27/2012] [Indexed: 01/26/2023]
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28
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Grangeon R, Jiang J, Laliberté JF. Host endomembrane recruitment for plant RNA virus replication. Curr Opin Virol 2012; 2:683-90. [PMID: 23123078 PMCID: PMC7185485 DOI: 10.1016/j.coviro.2012.10.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Revised: 10/03/2012] [Accepted: 10/04/2012] [Indexed: 01/27/2023]
Abstract
Although there is a significant amount of literature that deals with the identification of plant viral proteins involved in membrane remodeling and vesicle production in infected cells, there are very few investigations that report on the impact that infection has on the overall architecture and dynamics of the early secretory endomembranes. Recent investigations have shown that for some viruses the endoplasmic reticulum, Golgi bodies and other organelles are heavily recruited into virus-induced perinuclear structures. These structures are not isolated organelles and are dynamically connected to the bulk of non-modified endomembranes. They also have a functional link with peripheral motile vesicles involved in virus intracellular movement. The full molecular events that consubstantiate with this endomembrane recruitment in virus-induced structures remain to be elucidated but viral genome replication and virion assembly are probably taking place within these structures.
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Affiliation(s)
- Romain Grangeon
- INRS-Institut Armand Frappier, 531 Boulevard des Prairies, Laval, Québec H7V 1B7, Canada
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29
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Chukkapalli V, Heaton NS, Randall G. Lipids at the interface of virus-host interactions. Curr Opin Microbiol 2012; 15:512-8. [PMID: 22682978 DOI: 10.1016/j.mib.2012.05.013] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Revised: 05/21/2012] [Accepted: 05/22/2012] [Indexed: 01/26/2023]
Abstract
Viruses physically and metabolically remodel the host cell to establish an optimal environment for their replication. Many of these processes involve the manipulation of lipid signaling, synthesis, and metabolism. An emerging theme is that these lipid-modifying pathways are also linked to innate antiviral responses and can be modulated to inhibit viral replication.
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Affiliation(s)
- Vineela Chukkapalli
- Department of Microbiology, The University of Chicago, Chicago, IL 60637, United States
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30
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Diaz A, Ahlquist P. Role of host reticulon proteins in rearranging membranes for positive-strand RNA virus replication. Curr Opin Microbiol 2012; 15:519-24. [PMID: 22621853 PMCID: PMC3670673 DOI: 10.1016/j.mib.2012.04.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 04/25/2012] [Accepted: 04/27/2012] [Indexed: 11/30/2022]
Abstract
Positive-strand RNA [(+)RNA] viruses are responsible for numerous human, animal, and plant diseases. Because of the limiting coding capacity of (+)RNA viruses, their replication requires a complex orchestration of interactions between the viral genome, viral proteins and exploited host factors. To replicate their genomic RNAs, (+)RNA viruses induce membrane rearrangements that create membrane-linked RNA replication compartments. Along with substantial advances on the ultrastructure of the membrane-bound RNA replication compartments, recent results have shed light into the role that host factors play in rearranging these membranes. This review focuses on recent insights that have driven a new understanding of the role that the membrane-shaping host reticulon homology domain proteins (RHPs) play in facilitating the replication of various (+)RNA viruses.
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Affiliation(s)
- Arturo Diaz
- Institute for Molecular Virology, University of Wisconsin-Madison, Madison, WI 53706, United States
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