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Deng S, Tian X, Belshaw R, Zhou J, Zhang S, Yang Y, Huang C, Chen W, Qiu H, Choo SW. An RNA-Seq analysis of coronavirus in the skin of the Pangolin. Sci Rep 2024; 14:910. [PMID: 38195813 PMCID: PMC10776870 DOI: 10.1038/s41598-024-51261-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 01/02/2024] [Indexed: 01/11/2024] Open
Abstract
Protection of the Critically Endangered East Asian Pangolin species is hampered by the vulnerability of captive individuals to infection. Studies have previously shown the pangolin to have a unique pseudogenisation of many immunity genes (including IFNE, IFIH1, cGAS, STING, TLR5, and TLR11), and we suspected that these losses could account for this vulnerability. Here we used RNA-Seq data to show the effect of these gene losses on the transcriptional response to a viral skin infection in a deceased pangolin. This virus is very closely related to the one causing the current COVID-19 pandemic in the human population (SARS-CoV2), and we found the most upregulated pathway was the same one previously identified in the lungs of SARS-CoV2-infected humans. As predicted, we found that the pathways downstream of the lost genes were not upregulated. For example, the pseudogenised interferon epsilon (IFNE) is known to be particularly important in epithelial immunity, and we show that interferon-related responses were not upregulated in the infected pangolin skin. We suggest that the pangolin's innate gene pseudogenisation is indeed likely to be responsible for the animal's vulnerability to infection.
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Affiliation(s)
- Siwei Deng
- Department of Biology, College of Science, Mathematics and Technology, Wenzhou-Kean University, 88 Daxue Road, Ouhai, Wenzhou, Zhejiang, 325060, China
| | - Xuechen Tian
- Department of Biology, College of Science, Mathematics and Technology, Wenzhou-Kean University, 88 Daxue Road, Ouhai, Wenzhou, Zhejiang, 325060, China
- Zhejiang Bioinformatics International Science and Technology Cooperation Centre, Wenzhou-Kean University, 88 Daxue Road, Ouhai, Wenzhou, Zhejiang, 325060, China
- Wenzhou Municipal Key Laboratory for Applied Biomedical and Biopharmaceutical Informatics, 88 Daxue Road, Ouhai, Wenzhou, Zhejiang, 325060, China
| | - Robert Belshaw
- Department of Biology, College of Science, Mathematics and Technology, Wenzhou-Kean University, 88 Daxue Road, Ouhai, Wenzhou, Zhejiang, 325060, China
| | - Jinfeng Zhou
- China Biodiversity Conservation and Green Development Foundation (CBCGDF), Empark International Apartment, No. 69, Banding Road, Haidian District, Beijing, China
| | - Siyuan Zhang
- China Biodiversity Conservation and Green Development Foundation (CBCGDF), Empark International Apartment, No. 69, Banding Road, Haidian District, Beijing, China
| | - Yixin Yang
- Department of Biology, College of Science, Mathematics and Technology, Wenzhou-Kean University, 88 Daxue Road, Ouhai, Wenzhou, Zhejiang, 325060, China
- Zhejiang Bioinformatics International Science and Technology Cooperation Centre, Wenzhou-Kean University, 88 Daxue Road, Ouhai, Wenzhou, Zhejiang, 325060, China
- Wenzhou Municipal Key Laboratory for Applied Biomedical and Biopharmaceutical Informatics, 88 Daxue Road, Ouhai, Wenzhou, Zhejiang, 325060, China
- Dorothy and George Hennings College of Science, Mathematics and Technology, Kean University, 1000 Morris Ave, Union, NJ, 07083, USA
| | - Chang Huang
- Department of Biology, College of Science, Mathematics and Technology, Wenzhou-Kean University, 88 Daxue Road, Ouhai, Wenzhou, Zhejiang, 325060, China
| | - Weikang Chen
- Department of Biology, College of Science, Mathematics and Technology, Wenzhou-Kean University, 88 Daxue Road, Ouhai, Wenzhou, Zhejiang, 325060, China
| | - Hailu Qiu
- Department of Biology, College of Science, Mathematics and Technology, Wenzhou-Kean University, 88 Daxue Road, Ouhai, Wenzhou, Zhejiang, 325060, China
| | - Siew Woh Choo
- Department of Biology, College of Science, Mathematics and Technology, Wenzhou-Kean University, 88 Daxue Road, Ouhai, Wenzhou, Zhejiang, 325060, China.
- Zhejiang Bioinformatics International Science and Technology Cooperation Centre, Wenzhou-Kean University, 88 Daxue Road, Ouhai, Wenzhou, Zhejiang, 325060, China.
- Wenzhou Municipal Key Laboratory for Applied Biomedical and Biopharmaceutical Informatics, 88 Daxue Road, Ouhai, Wenzhou, Zhejiang, 325060, China.
- Dorothy and George Hennings College of Science, Mathematics and Technology, Kean University, 1000 Morris Ave, Union, NJ, 07083, USA.
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2
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Duan Z, Zhang Q, Liu M, Hu Z. Multifunctionality of matrix protein in the replication and pathogenesis of Newcastle disease virus: A review. Int J Biol Macromol 2023; 249:126089. [PMID: 37532184 DOI: 10.1016/j.ijbiomac.2023.126089] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 07/28/2023] [Accepted: 07/30/2023] [Indexed: 08/04/2023]
Abstract
As an important structural protein in virion morphogenesis, the matrix (M) protein of Newcastle disease virus (NDV) is demonstrated to be a nuclear-cytoplasmic trafficking protein and plays essential roles in viral assembly and budding. In recent years, increasing lines of evidence have indicated that the M protein has obvious influence on the pathotypes of NDV, and the interaction of M protein with cellular proteins is also closely associated with the replication and pathogenicity of NDV. Although substantial progress has been made in the past 40 years towards understanding the structure and function of NDV M protein, the available information is scattered. Therefore, this review article summarizes and updates the research progress on the structural feature, virulence and pathotype correlation, and nucleocytoplasmic transport mechanism of NDV M protein, as well as the functions of M protein and cellular protein interactions in M's intracellular localization, viral RNA synthesis and transcription, viral protein synthesis, viral immune evasion, and viral budding and release, which will provide an in-depth understanding of the biological functions of M protein in the replication and pathogenesis of NDV, and also contribute to the development of effective antiviral strategies aiming at blocking the early or late steps of NDV lifecycles.
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Affiliation(s)
- Zhiqiang Duan
- Key Laboratory of Animal Genetics, Breeding and Reproduction in The Plateau Mountainous Region, Ministry of Education, Guizhou University, Guiyang, China; College of Animal Science, Guizhou University, Guiyang, China.
| | - Qianyong Zhang
- Key Laboratory of Animal Genetics, Breeding and Reproduction in The Plateau Mountainous Region, Ministry of Education, Guizhou University, Guiyang, China; College of Animal Science, Guizhou University, Guiyang, China
| | - Menglan Liu
- Key Laboratory of Animal Genetics, Breeding and Reproduction in The Plateau Mountainous Region, Ministry of Education, Guizhou University, Guiyang, China; College of Animal Science, Guizhou University, Guiyang, China
| | - Zenglei Hu
- Joint International Research Laboratory of Agriculture and Agri-Product Safety, Ministry of Education, Yangzhou University, Yangzhou, China
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3
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Hoffmann G, López-González S, Mahboubi A, Hanson J, Hafrén A. Cauliflower mosaic virus protein P6 is a multivalent node for RNA granule proteins and interferes with stress granule responses during plant infection. THE PLANT CELL 2023; 35:3363-3382. [PMID: 37040611 PMCID: PMC10473198 DOI: 10.1093/plcell/koad101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 03/06/2023] [Accepted: 03/22/2023] [Indexed: 06/19/2023]
Abstract
Biomolecular condensation is a multipurpose cellular process that viruses use ubiquitously during their multiplication. Cauliflower mosaic virus replication complexes are condensates that differ from those of most viruses, as they are nonmembranous assemblies that consist of RNA and protein, mainly the viral protein P6. Although these viral factories (VFs) were described half a century ago, with many observations that followed since, functional details of the condensation process and the properties and relevance of VFs have remained enigmatic. Here, we studied these issues in Arabidopsis thaliana and Nicotiana benthamiana. We observed a large dynamic mobility range of host proteins within VFs, while the viral matrix protein P6 is immobile, as it represents the central node of these condensates. We identified the stress granule (SG) nucleating factors G3BP7 and UBP1 family members as components of VFs. Similarly, as SG components localize to VFs during infection, ectopic P6 localizes to SGs and reduces their assembly after stress. Intriguingly, it appears that soluble rather than condensed P6 suppresses SG formation and mediates other essential P6 functions, suggesting that the increased condensation over the infection time-course may accompany a progressive shift in selected P6 functions. Together, this study highlights VFs as dynamic condensates and P6 as a complex modulator of SG responses.
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Affiliation(s)
- Gesa Hoffmann
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, 75007 Uppsala, Sweden
- Linnean Center for Plant Biology, 75007 Uppsala, Sweden
| | - Silvia López-González
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, 75007 Uppsala, Sweden
- Linnean Center for Plant Biology, 75007 Uppsala, Sweden
| | - Amir Mahboubi
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, 90736 Umeå, Sweden
| | - Johannes Hanson
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, 90736 Umeå, Sweden
| | - Anders Hafrén
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, 75007 Uppsala, Sweden
- Linnean Center for Plant Biology, 75007 Uppsala, Sweden
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4
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Bakshi A, Moin M, Gayatri MB, Reddy ABM, Datla R, Madhav MS, Kirti PB. Involvement of Target of Rapamycin (TOR) Signaling in the Regulation of Crosstalk between Ribosomal Protein Small Subunit 6 Kinase-1 (RPS6K-1) and Ribosomal Proteins. PLANTS (BASEL, SWITZERLAND) 2023; 12:176. [PMID: 36616305 PMCID: PMC9824793 DOI: 10.3390/plants12010176] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 12/26/2022] [Accepted: 12/27/2022] [Indexed: 06/17/2023]
Abstract
The target of rapamycin (TOR) protein phosphorylates its downstream effector p70kDa ribosomal protein S6 kinases (S6K1) for ribosome biogenesis and translation initiation in eukaryotes. However, the molecular mechanism of TOR-S6K1-ribosomal protein (RP) signaling is not well understood in plants. In the present study, we report the transcriptional upregulation of ribosomal protein large and small subunit (RPL and RPS) genes in the previously established TOR overexpressing transgenic lines of rice (in Oryza sativa ssp. indica, variety BPT-5204, TR-2.24 and TR-15.1) and of Arabidopsis thaliana (in Col 0 ecotype, ATR-1.4.27 and ATR-3.7.32). The mRNA levels of RP genes from this study were compared with those previously available in transcriptomic datasets on the expression of RPs in relation to TOR inhibitor and in the TOR-RNAi lines of Arabidopsis thaliana. We further analyzed TOR activity, i.e., S6K1 phosphorylation in SALK lines of Arabidopsis with mutation in rpl6, rpl18, rpl23, rpl24 and rps28C, where the rpl18 mutant showed inactivation of S6K1 phosphorylation. We also predicted similar putative Ser/Thr phosphorylation sites for ribosomal S6 kinases (RSKs) in the RPs of Oryza sativa ssp. indica and Arabidopsis thaliana. The findings of this study indicate that the TOR pathway is possibly interlinked in a cyclic manner via the phosphorylation of S6K1 as a modulatory step for the regulation of RP function to switch 'on'/'off' the translational regulation for balanced plant growth.
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Affiliation(s)
- Achala Bakshi
- Indian Institute of Rice Research, Rajendranagar, Hyderabad 500030, Telangana, India
- Global Institute for Food Security, Saskatoon, SK S7N 0W9, Canada
| | - Mazahar Moin
- Indian Institute of Rice Research, Rajendranagar, Hyderabad 500030, Telangana, India
- Agri Biotech Foundation, PJTS Agricultural University Campus, Rajendranagar, Hyderabad 500030, Telangana, India
| | - Meher B. Gayatri
- Department of Animal Biology, University of Hyderabad, Hyderabad 500046, Telangana, India
| | - Aramati B. M. Reddy
- Department of Animal Biology, University of Hyderabad, Hyderabad 500046, Telangana, India
| | - Raju Datla
- Global Institute for Food Security, Saskatoon, SK S7N 0W9, Canada
| | - Maganti S. Madhav
- Indian Institute of Rice Research, Rajendranagar, Hyderabad 500030, Telangana, India
- Central Tobacco Research Institute, Rajahmundry 533105, Andhra Pradesh, India
| | - Pulugurtha B. Kirti
- Agri Biotech Foundation, PJTS Agricultural University Campus, Rajendranagar, Hyderabad 500030, Telangana, India
- Department of Plant Sciences, University of Hyderabad, Hyderabad 500046, Telangana, India
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5
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Xu J, Cao Z, Ji C, Zhou L, Yan X, Sun Y, Ma J. Analysis of Interaction Network Between Host Protein and M Protein of Swine Acute Diarrhea Syndrome Coronavirus. Front Microbiol 2022; 13:858460. [PMID: 35464981 PMCID: PMC9024367 DOI: 10.3389/fmicb.2022.858460] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 03/14/2022] [Indexed: 11/15/2022] Open
Abstract
Swine acute diarrhea syndrome coronavirus (SADS-CoV) is an enterovirus that can cause acute diarrhea and death in piglets and cause serious economic losses to the pig industry. SADS-CoV membrane (M) protein mainly plays a key role in biological processes, such as virus assembly, budding, and host innate immune regulation. Understanding the interaction between M protein and host proteins is very important to define the molecular mechanism of cells at the protein level and to understand specific cellular physiological pathways. In this study, 289 host proteins interacting with M protein were identified by glutathione-S-transferase (GST) pull-down combined with liquid chromatography-mass spectrometry (LC-MS/MS), and the protein-protein interaction (PPI) network was established by Gene Ontology (GO) terms and Kyoto Encyclopedia of Gene and Genomes (KEGG) pathways analysis. Results showed that SADS-CoV M protein was mainly associated with the host metabolism, signal transduction, and innate immunity. The Co-Immunoprecipitation (CO-IP) validation results of six randomly selected proteins, namely, Rab11b, voltage-dependent anion-selective channel 1 (VDAC1), Ribosomal Protein L18 (RPL18), RALY, Ras Homolog Family Member A (RHOA), and Annexin A2 (ANXA2), were consistent with LC-MS results. In addition, overexpression of RPL18 and PHOA significantly promoted SADS-CoV replication, while overexpression of RALY antagonized viral replication. This work will help to clarify the function of SADS-CoV M protein in the life cycle of SADS-CoV.
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Affiliation(s)
- Jingya Xu
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Ze Cao
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Chihai Ji
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Ling Zhou
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Xiaoling Yan
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Yuan Sun
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
- Yuan Sun
| | - Jingyun Ma
- Guangdong Provincial Key Lab of Agro-Animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou, China
- Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
- *Correspondence: Jingyun Ma
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6
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Zhang L, Lin J, Weng M, Wen Y, Zhang Y, Deng W. RPLP1, an NS4B-interacting protein, enhances production of CSFV through promoting translation of viral genome. Virulence 2022; 13:370-386. [PMID: 35129423 PMCID: PMC8824197 DOI: 10.1080/21505594.2022.2033500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Classical swine fever virus (CSFV), the etiological agent of classical swine fever (CSF), causes serious financial losses to the pig industry. Using yeast two-hybrid screening, we have previously identified ribosomal protein RPLP1 as a potential binding partner of CSFV NS4B. In this study, the interaction between host RPLP1 and CSFV NS4B was further characterized by co-immunoprecipitation (co-IP), glutathione S-transferase (GST) pulldown, and confocal microscopy. In addition, lentivirus-mediated shRNA knockdown of RPLP1 drastically attenuated CSFV growth, while stable overexpression of RPLP1 markedly enhanced CSFV production. Moreover, cellular RPLP1 expression was found to be significantly up-regulated along with CSFV infection. Dual-luciferase reporter assay showed that depletion of RPLP1 had no effects on the activity of CSFV internal ribosome entry site (IRES). In the first life cycle of CSFV, further studies revealed that RPLP1 depletion did not influence the intracellular viral RNA abundance but diminished the intracellular and extracellular progeny virus titers as well as the viral E2 protein expression, which indicates that RPLP1 is crucial for CSFV genome translation. In summary, this study demonstrated that RPLP1 interacts with CSFV NS4B and enhances virus production via promoting translation of viral genome.
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Affiliation(s)
- Longxiang Zhang
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
| | - Jihui Lin
- School of Nursing, Southwest Medical University, Luzhou, Sichuan, China
| | - Maoyang Weng
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
| | - Ying Wen
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
| | - Yanming Zhang
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
| | - Wen Deng
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, China
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7
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Duan Z, Tang H, Wang Y, Zhao C, Zhou L, Han Y. The association of ribosomal protein L18 with Newcastle disease virus matrix protein enhances viral translation and replication. Avian Pathol 2021; 51:129-140. [PMID: 34859725 DOI: 10.1080/03079457.2021.2013435] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
ABSTRACTNumerous studies have shown that viruses can utilize or manipulate ribosomal proteins to achieve viral protein biosynthesis and replication. In our recent studies using proteomics analysis of virus-infected cells, we found that ribosomal protein L18 (RPL18) was the highest up-regulated differentially expressed protein, which was along with the increasingly expressed viral proteins later in Newcastle disease virus (NDV) infection. However, the association of RPL18 with viral protein biosynthesis and NDV replication remains unclear. In this study, we found that the expression and transcription levels of RPL18 was reduced early in NDV infection but increased later in NDV infection. In addition, the presence of cytoplasmic NDV matrix (M) protein was responsible for the increased expression of RPL18 in both virus-infected cells and plasmid-transfected cells. Moreover, cytoplasmic M protein increased RPL18 expression in a dose-dependent manner, even though they did not interact with each other. Furthermore, siRNA-mediated knockdown of RPL18 or overexpression of RPL18 dramatically reduced or enhanced NDV replication by decreasing or increasing viral protein translation rather than viral RNA synthesis and transcription. Taken together, these results suggested that the increased expression of RPL18 might be associated with the physical clumping together of the M protein, which in turn promoted viral protein biosynthesis and NDV replication, thus revealing for the first time the association of RPL18 with NDV M protein was important for viral translation and replication.
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Affiliation(s)
- Zhiqiang Duan
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountainous Region, Ministry of Education, Guizhou University, Guiyang, China.,College of Animal Science, Guizhou University, Guiyang, China
| | - Hong Tang
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountainous Region, Ministry of Education, Guizhou University, Guiyang, China.,College of Animal Science, Guizhou University, Guiyang, China
| | - Yanbi Wang
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountainous Region, Ministry of Education, Guizhou University, Guiyang, China.,College of Animal Science, Guizhou University, Guiyang, China
| | - Caiqin Zhao
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountainous Region, Ministry of Education, Guizhou University, Guiyang, China.,College of Animal Science, Guizhou University, Guiyang, China
| | - Lei Zhou
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountainous Region, Ministry of Education, Guizhou University, Guiyang, China.,College of Animal Science, Guizhou University, Guiyang, China
| | - Yifan Han
- Key Laboratory of Animal Genetics, Breeding and Reproduction in the Plateau Mountainous Region, Ministry of Education, Guizhou University, Guiyang, China.,College of Animal Science, Guizhou University, Guiyang, China
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8
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Almutairi ZM. Molecular characterization and expression analysis of ribosomal L18/L5e gene in Pennisetum glaucum (L.) R. Br. Saudi J Biol Sci 2021; 28:3585-3593. [PMID: 34121902 PMCID: PMC8176002 DOI: 10.1016/j.sjbs.2021.03.035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 03/08/2021] [Accepted: 03/09/2021] [Indexed: 11/21/2022] Open
Abstract
Ribosomal L18/L5e (RL18/L5e) is a member of the ribosomal L18/L5e protein family, which has an essential function in translation of mRNA into protein in the large ribosomal subunit. In this study, RL18/L5e was isolated and sequenced from local Pennisetum glaucum (L.) R. Br. cultivar which is known to adapt to environmental stress. The obtained cDNA for PgRL18/L5e was 699 bp in length, with an open reading frame of 564 bp. The deduced protein sequence contained 187 amino acids and comprised an RL18/L5e domain, which shared high sequence identity with orthologous proteins from Viridiplantae. The obtained PgRL18/L5e cDNA contained two exons of 154 and 545 bp, respectively, and an intron of 1398 bp. Secondary and 3D structures of the deduced PgRL18/L5e protein were predicted using in silico tools. Phylogenetic analysis showed close relationships between the PgRL18/L5e protein and its orthologs from monocot species. Multiple sequence alignment showed high identity in the RL18/L5e domain sequence in all orthologous proteins in Viridiplantae. Moreover, all orthologous RL18/L5e proteins shared the same domain architecture and were nearly equal in length. Quantitative real-time PCR indicated a higher transcript abundance of PgRL18/L5e in shoots than in roots of 3-day-old seedlings. Moreover, the expression of PgRL18/L5e in seedlings under cold and drought stress was substantially lower than that in untreated seedlings, whereas the highest expression was shown under heat stress. This study provides insights into the structure and function of the RL18/L5e gene in tolerant crops, which could facilitate the understanding of the role of the various plant ribosomal proteins in adaptation to extreme environments.
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Affiliation(s)
- Zainab M. Almutairi
- Biology Department, College of Science and Humanities, Prince Sattam bin Abdulaziz University, P.O. Box: 83, Al-kharj 11942, Saudi Arabia
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9
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Alers-Velazquez R, Jacques S, Muller C, Boldt J, Schoelz J, Leisner S. Cauliflower mosaic virus P6 inclusion body formation: A dynamic and intricate process. Virology 2021; 553:9-22. [PMID: 33197754 DOI: 10.1016/j.virol.2020.10.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/13/2020] [Accepted: 10/18/2020] [Indexed: 11/17/2022]
Abstract
During an infection, Cauliflower mosaic virus (CaMV) forms inclusion bodies (IBs) mainly composed of viral protein P6, where viral activities occur. Because viral processes occur in IBs, understanding the mechanisms by which they are formed is crucial. FL-P6 expressed in N. benthamiana leaves formed IBs of a variety of shapes and sizes. Small IBs were dynamic, undergoing fusion/dissociation events. Co-expression of actin-binding polypeptides with FL-P6 altered IB size distribution and inhibited movement. This suggests that IB movement is required for fusion and growth. A P6 deletion mutant was discovered that formed a single large IB per cell, which suggests it exhibited altered fusion/dissociation dynamics. Myosin-inhibiting drugs did not affect small IB movement, while those inhibiting actin polymerization did. Large IBs colocalized with components of the aggresome pathway, while small ones generally did not. This suggests a possible involvement of the aggresome pathway in large IB formation.
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Affiliation(s)
- Roberto Alers-Velazquez
- Department of Biological Sciences, University of Toledo, 2801 West Bancroft Street, Mail Stop 601, Toledo, OH, 43606, USA
| | - Sarah Jacques
- Department of Biological Sciences, University of Toledo, 2801 West Bancroft Street, Mail Stop 601, Toledo, OH, 43606, USA
| | - Clare Muller
- Department of Biological Sciences, University of Toledo, 2801 West Bancroft Street, Mail Stop 601, Toledo, OH, 43606, USA
| | - Jennifer Boldt
- USDA-Agricultural Research Service, Application Technology Research Unit, 2801 West Bancroft Street, Mail Stop 604, Toledo, OH, 43606, USA
| | - James Schoelz
- Division of Plant Sciences, University of Missouri, Columbia, MO, 65211, USA
| | - Scott Leisner
- Department of Biological Sciences, University of Toledo, 2801 West Bancroft Street, Mail Stop 601, Toledo, OH, 43606, USA.
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10
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Miller CM, Selvam S, Fuchs G. Fatal attraction: The roles of ribosomal proteins in the viral life cycle. WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 12:e1613. [PMID: 32657002 DOI: 10.1002/wrna.1613] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 05/20/2020] [Accepted: 05/26/2020] [Indexed: 12/30/2022]
Abstract
Upon viral infection of a host cell, each virus starts a program to generate many progeny viruses. Although viruses interact with the host cell in numerous ways, one critical step in the virus life cycle is the expression of viral proteins, which are synthesized by the host ribosomes in conjunction with host translation factors. Here we review different mechanisms viruses have evolved to effectively seize host cell ribosomes, the roles of specific ribosomal proteins and their posttranslational modifications on viral RNA translation, or the cellular response to infection. We further highlight ribosomal proteins with extra-ribosomal function during viral infection and put the knowledge of ribosomal proteins during viral infection into the larger context of ribosome-related diseases, known as ribosomopathies. This article is categorized under: Translation > Translation Mechanisms Translation > Translation Regulation.
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Affiliation(s)
- Clare M Miller
- Department of Biological Sciences, University at Albany, Albany, New York, USA
| | - Sangeetha Selvam
- Department of Biological Sciences, University at Albany, Albany, New York, USA
| | - Gabriele Fuchs
- Department of Biological Sciences, University at Albany, Albany, New York, USA.,The RNA Institute, University at Albany, Albany, New York, USA
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11
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Li S. Regulation of Ribosomal Proteins on Viral Infection. Cells 2019; 8:E508. [PMID: 31137833 PMCID: PMC6562653 DOI: 10.3390/cells8050508] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 05/17/2019] [Accepted: 05/21/2019] [Indexed: 12/20/2022] Open
Abstract
Ribosomal proteins (RPs), in conjunction with rRNA, are major components of ribosomes involved in the cellular process of protein biosynthesis, known as "translation". The viruses, as the small infectious pathogens with limited genomes, must recruit a variety of host factors to survive and propagate, including RPs. At present, more and more information is available on the functional relationship between RPs and virus infection. This review focuses on advancements in my own understanding of critical roles of RPs in the life cycle of viruses. Various RPs interact with viral mRNA and proteins to participate in viral protein biosynthesis and regulate the replication and infection of virus in host cells. Most interactions are essential for viral translation and replication, which promote viral infection and accumulation, whereas the minority represents the defense signaling of host cells by activating immune pathway against virus. RPs provide a new platform for antiviral therapy development, however, at present, antiviral therapeutics with RPs involving in virus infection as targets is limited, and exploring antiviral strategy based on RPs will be the guides for further study.
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Affiliation(s)
- Shuo Li
- Institute of Plant Protection, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China.
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12
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Li S, Hu Y, Jiang L, Rui P, Zhao Q, Feng J, Zuo D, Zhou X, Jiang T. Strawberry Vein Banding Virus P6 Protein Is a Translation Trans-Activator and Its Activity Can be Suppressed by FveIF3g. Viruses 2018; 10:E717. [PMID: 30558257 PMCID: PMC6316418 DOI: 10.3390/v10120717] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 12/06/2018] [Accepted: 12/13/2018] [Indexed: 01/25/2023] Open
Abstract
The strawberry vein banding virus (SVBV) open reading frame (ORF) VI encodes a P6 protein known as the RNA silencing suppressor. This protein is known to form inclusion like granules of various sizes and accumulate in both the nuclei and the cytoplasm of SVBV-infected plant cells. In this study, we have determined that the P6 protein is the only trans-activator (TAV) encoded by SVBV, and can efficiently trans-activate the translation of downstream gfp mRNA in a bicistron derived from the SVBV. Furthermore, the P6 protein can trans-activate the expression of different bicistrons expressed by different caulimovirus promoters. The P6 protein encoded by SVBV from an infectious clone can also trans-activate the expression of bicistron. Through protein-protein interaction assays, we determined that the P6 protein could interact with the cell translation initiation factor FveIF3g of Fragaria vesca and co-localize with it in the nuclei of Nicotiana benthamiana cells. This interaction reduced the formation of P6 granules in cells and its trans-activation activity on translation.
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Affiliation(s)
- Shuai Li
- School of Plant Protection, Anhui Agricultural University, Hefei 230036, China.
| | - Yahui Hu
- School of Plant Protection, Anhui Agricultural University, Hefei 230036, China.
| | - Lei Jiang
- School of Plant Protection, Anhui Agricultural University, Hefei 230036, China.
| | - Penghuan Rui
- School of Plant Protection, Anhui Agricultural University, Hefei 230036, China.
| | - Qingqing Zhao
- School of Plant Protection, Anhui Agricultural University, Hefei 230036, China.
| | - Jiying Feng
- School of Plant Protection, Anhui Agricultural University, Hefei 230036, China.
| | - Dengpan Zuo
- School of Plant Protection, Anhui Agricultural University, Hefei 230036, China.
| | - Xueping Zhou
- State Key Laboratory for Plant Disease and Insect Pest, Institute of Plant protection, China Academy of Agricultural Sciences, Beijing 100193, China.
| | - Tong Jiang
- School of Plant Protection, Anhui Agricultural University, Hefei 230036, China.
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13
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Leisner SM, Schoelz JE. Joining the Crowd: Integrating Plant Virus Proteins into the Larger World of Pathogen Effectors. ANNUAL REVIEW OF PHYTOPATHOLOGY 2018; 56:89-110. [PMID: 29852091 DOI: 10.1146/annurev-phyto-080417-050151] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The first bacterial and viral avirulence ( avr) genes were cloned in 1984. Although virus and bacterial avr genes were physically isolated in the same year, the questions associated with their characterization after discovery were very different, and these differences had a profound influence on the narrative of host-pathogen interactions for the past 30 years. Bacterial avr proteins were subsequently shown to suppress host defenses, leading to their reclassification as effectors, whereas research on viral avr proteins centered on their role in the viral infection cycle rather than their effect on host defenses. Recent studies that focus on the multifunctional nature of plant virus proteins have shown that some virus proteins are capable of suppression of the same host defenses as bacterial effectors. This is exemplified by the P6 protein of Cauliflower mosaic virus (CaMV), a multifunctional plant virus protein that facilitates several steps in the infection, including modulation of host defenses. This review highlights the modular structure and multifunctional nature of CaMV P6 and illustrates its similarities to other, well-established pathogen effectors.
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Affiliation(s)
- Scott M Leisner
- Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606, USA
| | - James E Schoelz
- Division of Plant Sciences, University of Missouri, Columbia, Missouri 65211, USA;
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14
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Pooggin MM, Ryabova LA. Ribosome Shunting, Polycistronic Translation, and Evasion of Antiviral Defenses in Plant Pararetroviruses and Beyond. Front Microbiol 2018; 9:644. [PMID: 29692761 PMCID: PMC5902531 DOI: 10.3389/fmicb.2018.00644] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 03/19/2018] [Indexed: 12/15/2022] Open
Abstract
Viruses have compact genomes and usually translate more than one protein from polycistronic RNAs using leaky scanning, frameshifting, stop codon suppression or reinitiation mechanisms. Viral (pre-)genomic RNAs often contain long 5′-leader sequences with short upstream open reading frames (uORFs) and secondary structure elements, which control both translation initiation and replication. In plants, viral RNA and DNA are targeted by RNA interference (RNAi) generating small RNAs that silence viral gene expression, while viral proteins are recognized by innate immunity and autophagy that restrict viral infection. In this review we focus on plant pararetroviruses of the family Caulimoviridae and describe the mechanisms of uORF- and secondary structure-driven ribosome shunting, leaky scanning and reinitiation after translation of short and long uORFs. We discuss conservation of these mechanisms in different genera of Caulimoviridae, including host genome-integrated endogenous viral elements, as well as in other viral families, and highlight a multipurpose use of the highly-structured leader sequence of plant pararetroviruses in regulation of translation, splicing, packaging, and reverse transcription of pregenomic RNA (pgRNA), and in evasion of RNAi. Furthermore, we illustrate how targeting of several host factors by a pararetroviral effector protein can lead to transactivation of viral polycistronic translation and concomitant suppression of antiviral defenses. Thus, activation of the plant protein kinase target of rapamycin (TOR) by the Cauliflower mosaic virus transactivator/viroplasmin (TAV) promotes reinitiation of translation after long ORFs on viral pgRNA and blocks antiviral autophagy and innate immunity responses, while interaction of TAV with the plant RNAi machinery interferes with antiviral silencing.
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Affiliation(s)
- Mikhail M Pooggin
- INRA, UMR Biologie et Génétique des Interactions Plante-Parasite, Montpellier, France
| | - Lyubov A Ryabova
- Institut de Biologie Moléculaire des Plantes, Centre National de la Recherche Scientifique, UPR 2357, Université de Strasbourg, Strasbourg, France
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15
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Li S, Li X, Zhou Y. Ribosomal protein L18 is an essential factor that promote rice stripe virus accumulation in small brown planthopper. Virus Res 2018; 247:15-20. [DOI: 10.1016/j.virusres.2018.01.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 01/13/2018] [Accepted: 01/22/2018] [Indexed: 01/10/2023]
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16
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Wang B, Duan X, Fu M, Liu Y, Wang Y, Li X, Cao H, Zheng SJ. The association of ribosomal protein L18 (RPL18) with infectious bursal disease virus viral protein VP3 enhances viral replication. Virus Res 2017; 245:69-79. [PMID: 29273342 DOI: 10.1016/j.virusres.2017.12.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 12/14/2017] [Accepted: 12/18/2017] [Indexed: 11/26/2022]
Abstract
Infectious bursal disease (IBD) is an acute, highly contagious, and immunosuppressive avian disease caused by IBD virus (IBDV). IBDV VP3 is a multifunctional protein playing a key role in virus assembly and pathogenesis. To investigate the role of VP3 in pathogenesis, we transfected DF-1 cells with pRK5-FLAG-vp3 and found that VP3 enhanced type I interferon expression and suppressed IBDV replication. Furthermore we found that VP3 interacted with chicken Ribosomal Protein L18 (chRPL18) in host cells and knockdown of chRPL18 by RNAi significantly promoted Type I interferon expression and inhibited IBDV replication. Moreover, our data show that chicken double-stranded RNA-activated protein kinase (chPKR) interacted with both VP3 and chRPL18. Thus chRPL18 in association with VP3 and chPKR affects viral replication.
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Affiliation(s)
- Bin Wang
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China; Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, China Agricultural University, Beijing 100193, China; College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Xueyan Duan
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China; Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, China Agricultural University, Beijing 100193, China; College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Mengjiao Fu
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China; Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, China Agricultural University, Beijing 100193, China; College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Yanan Liu
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China; Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, China Agricultural University, Beijing 100193, China; College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Yongqiang Wang
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China; Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, China Agricultural University, Beijing 100193, China; College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Xiaoqi Li
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China; Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, China Agricultural University, Beijing 100193, China; College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Hong Cao
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China; Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, China Agricultural University, Beijing 100193, China; College of Veterinary Medicine, China Agricultural University, Beijing 100193, China
| | - Shijun J Zheng
- State Key Laboratory of Agrobiotechnology, China Agricultural University, Beijing 100193, China; Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, China Agricultural University, Beijing 100193, China; College of Veterinary Medicine, China Agricultural University, Beijing 100193, China.
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17
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Schoelz JE, Leisner S. Setting Up Shop: The Formation and Function of the Viral Factories of Cauliflower mosaic virus. FRONTIERS IN PLANT SCIENCE 2017; 8:1832. [PMID: 29163571 PMCID: PMC5670102 DOI: 10.3389/fpls.2017.01832] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 10/10/2017] [Indexed: 05/23/2023]
Abstract
Similar to cells, viruses often compartmentalize specific functions such as genome replication or particle assembly. Viral compartments may contain host organelle membranes or they may be mainly composed of viral proteins. These compartments are often termed: inclusion bodies (IBs), viroplasms or viral factories. The same virus may form more than one type of IB, each with different functions, as illustrated by the plant pararetrovirus, Cauliflower mosaic virus (CaMV). CaMV forms two distinct types of IBs in infected plant cells, those composed mainly of the viral proteins P2 (which are responsible for transmission of CaMV by insect vectors) and P6 (required for viral intra-and inter-cellular infection), respectively. P6 IBs are the major focus of this review. Much of our understanding of the formation and function of P6 IBs comes from the analyses of their major protein component, P6. Over time, the interactions and functions of P6 have been gradually elucidated. Coupled with new technologies, such as fluorescence microscopy with fluorophore-tagged viral proteins, these data complement earlier work and provide a clearer picture of P6 IB formation. As the activities and interactions of the viral proteins have gradually been determined, the functions of P6 IBs have become clearer. This review integrates the current state of knowledge on the formation and function of P6 IBs to produce a coherent model for the activities mediated by these sophisticated virus-manufacturing machines.
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Affiliation(s)
- James E. Schoelz
- Division of Plant Sciences, University of Missouri, Columbia, MO, United States
| | - Scott Leisner
- Department of Biological Sciences, University of Toledo, Toledo, OH, United States
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18
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Schoelz JE, Angel CA, Nelson RS, Leisner SM. A model for intracellular movement of Cauliflower mosaic virus: the concept of the mobile virion factory. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:2039-48. [PMID: 26687180 DOI: 10.1093/jxb/erv520] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The genomes of many plant viruses have a coding capacity limited to <10 proteins, yet it is becoming increasingly clear that individual plant virus proteins may interact with several targets in the host for establishment of infection. As new functions are uncovered for individual viral proteins, virologists have realized that the apparent simplicity of the virus genome is an illusion that belies the true impact that plant viruses have on host physiology. In this review, we discuss our evolving understanding of the function of the P6 protein of Cauliflower mosaic virus (CaMV), a process that was initiated nearly 35 years ago when the CaMV P6 protein was first described as the 'major inclusion body protein' (IB) present in infected plants. P6 is now referred to in most articles as the transactivator (TAV)/viroplasmin protein, because the first viral function to be characterized for the Caulimovirus P6 protein beyond its role as an inclusion body protein (the viroplasmin) was its role in translational transactivation (the TAV function). This review will discuss the currently accepted functions for P6 and then present the evidence for an entirely new function for P6 in intracellular movement.
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Affiliation(s)
- James E Schoelz
- Division of Plant Sciences, University of Missouri, Columbia, MO 65211, USA
| | - Carlos A Angel
- Division of Plant Sciences, University of Missouri, Columbia, MO 65211, USA
| | - Richard S Nelson
- The Division of Plant Biology, The Samuel Roberts Noble Foundation, Ardmore, OK 73401, USA
| | - Scott M Leisner
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606, USA
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19
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Dengue virus NS1 protein interacts with the ribosomal protein RPL18: This interaction is required for viral translation and replication in Huh-7 cells. Virology 2015; 484:113-126. [DOI: 10.1016/j.virol.2015.05.017] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 05/22/2015] [Accepted: 05/24/2015] [Indexed: 01/06/2023]
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20
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Bouton C, Geldreich A, Ramel L, Ryabova LA, Dimitrova M, Keller M. Cauliflower mosaic virus Transcriptome Reveals a Complex Alternative Splicing Pattern. PLoS One 2015; 10:e0132665. [PMID: 26162084 PMCID: PMC4498817 DOI: 10.1371/journal.pone.0132665] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Accepted: 06/18/2015] [Indexed: 12/23/2022] Open
Abstract
The plant pararetrovirus Cauliflower mosaic virus (CaMV) uses alternative splicing to generate several isoforms from its polycistronic pregenomic 35S RNA. This pro-cess has been shown to be essential for infectivity. Previous works have identified four splice donor sites and a single splice acceptor site in the 35S RNA 5' region and suggested that the main role of CaMV splicing is to downregulate expression of open reading frames (ORFs) I and II. In this study, we show that alternative splicing is a conserved process among CaMV isolates. In Cabb B-JI and Cabb-S isolates, splicing frequently leads to different fusion between ORFs, particularly between ORF I and II. The corresponding P1P2 fusion proteins expressed in E. coli interact with viral proteins P2 and P3 in vitro. However, they are detected neither during infection nor upon transient expression in planta, which suggests rapid degradation after synthesis and no important biological role in the CaMV infectious cycle. To gain a better understanding of the functional relevance of 35S RNA alternative splicing in CaMV infectivity, we inactivated the previously described splice sites. All the splicing mutants were as pathogenic as the corresponding wild-type isolate. Through RT-PCR-based analysis we demonstrate that CaMV 35S RNA exhibits a complex splicing pattern, as we identify new splice donor and acceptor sites whose selection leads to more than thirteen 35S RNA isoforms in infected turnip plants. Inactivating splice donor or acceptor sites is not lethal for the virus, since disrupted sites are systematically rescued by the activation of cryptic and/or seldom used splice sites. Taken together, our data depict a conserved, complex and flexible process, involving multiple sites, that ensures splicing of 35S RNA.
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Affiliation(s)
- Clément Bouton
- Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, Strasbourg, France
| | - Angèle Geldreich
- Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, Strasbourg, France
| | - Laëtitia Ramel
- Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, Strasbourg, France
| | - Lyubov A. Ryabova
- Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, Strasbourg, France
| | - Maria Dimitrova
- Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, Strasbourg, France
- * E-mail: (MD); (MK)
| | - Mario Keller
- Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, Strasbourg, France
- * E-mail: (MD); (MK)
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21
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Lutz L, Okenka G, Schoelz J, Leisner S. Mutations within A 35 amino acid region of P6 influence self-association, inclusion body formation, and Caulimovirus infectivity. Virology 2015; 476:26-36. [PMID: 25506670 PMCID: PMC4323857 DOI: 10.1016/j.virol.2014.11.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 11/14/2014] [Accepted: 11/16/2014] [Indexed: 11/19/2022]
Abstract
Cauliflower mosaic virus gene VI product (P6) is an essential protein that forms cytoplasmic, inclusion bodies (IBs). P6 contains four regions involved in self-association, termed D1-D4. D3 binds to D1, along with D4 and contains a spacer region (termed D3b) between two RNA-binding domains. Here we show D3b binds full-length P6 along with D1 and D4. Full-length P6s harboring single amino acid substitutions within D3b showed reduced binding to both D1 and D4. Full-length P6s containing D3b mutations and fused with green fluorescent protein formed inclusion-like bodies (IL-Bs) when expressed in Nicotiana benthamiana leaves. However, mutant P6s with reduced binding to D1 and D4, showed smaller IL-Bs, than wild type. Likewise, viruses containing these mutations showed a decrease in inoculated leaf viral DNA levels and reduced efficiency of systemic infection. These data suggest that mutations influencing P6 self-association alter IB formation and reduce virus infection.
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Affiliation(s)
- Lindy Lutz
- Department of Biological Sciences, The University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606, USA
| | - Genevieve Okenka
- Department of Biological Sciences, The University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606, USA
| | - James Schoelz
- Division of Plant Sciences, University of Missouri, Columbia, MO 65211, USA
| | - Scott Leisner
- Department of Biological Sciences, The University of Toledo, 2801 West Bancroft Street, Toledo, OH 43606, USA.
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22
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Laird J, McInally C, Carr C, Doddiah S, Yates G, Chrysanthou E, Khattab A, Love AJ, Geri C, Sadanandom A, Smith BO, Kobayashi K, Milner JJ. Identification of the domains of cauliflower mosaic virus protein P6 responsible for suppression of RNA silencing and salicylic acid signalling. J Gen Virol 2013; 94:2777-2789. [PMID: 24088344 PMCID: PMC3836500 DOI: 10.1099/vir.0.057729-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cauliflower mosaic virus (CaMV) encodes a 520 aa polypeptide, P6, which participates in several essential activities in the virus life cycle including suppressing RNA silencing and salicylic acid-responsive defence signalling. We infected Arabidopsis with CaMV mutants containing short in-frame deletions within the P6 ORF. A deletion in the distal end of domain D-I (the N-terminal 112 aa) of P6 did not affect virus replication but compromised symptom development and curtailed the ability to restore GFP fluorescence in a GFP-silenced transgenic Arabidopsis line. A deletion in the minimum transactivator domain was defective in virus replication but retained the capacity to suppress RNA silencing locally. Symptom expression in CaMV-infected plants is apparently linked to the ability to suppress RNA silencing. When transiently co-expressed with tomato bushy stunt virus P19, an elicitor of programmed cell death in Nicotiana tabacum, WT P6 suppressed the hypersensitive response, but three mutants, two with deletions within the distal end of domain D-I and one involving the N-terminal nuclear export signal (NES), were unable to do so. Deleting the N-terminal 20 aa also abolished the suppression of pathogen-associated molecular pattern-dependent PR1a expression following agroinfiltration. However, the two other deletions in domain D-I retained this activity, evidence that the mechanisms underlying these functions are not identical. The D-I domain of P6 when expressed alone failed to suppress either cell death or PR1a expression and is therefore necessary but not sufficient for all three defence suppression activities. Consequently, concerns about the biosafety of genetically modified crops carrying truncated ORFVI sequences appear unfounded.
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Affiliation(s)
- Janet Laird
- Plant Science Research Theme, School of Life Sciences and Institute of Molecular Cellular and Systems Biology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Carol McInally
- Plant Science Research Theme, School of Life Sciences and Institute of Molecular Cellular and Systems Biology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Craig Carr
- Plant Science Research Theme, School of Life Sciences and Institute of Molecular Cellular and Systems Biology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Sowjanya Doddiah
- Plant Science Research Theme, School of Life Sciences and Institute of Molecular Cellular and Systems Biology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Gary Yates
- Plant Science Research Theme, School of Life Sciences and Institute of Molecular Cellular and Systems Biology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Elina Chrysanthou
- Plant Science Research Theme, School of Life Sciences and Institute of Molecular Cellular and Systems Biology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Ahmed Khattab
- Plant Science Research Theme, School of Life Sciences and Institute of Molecular Cellular and Systems Biology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Andrew J Love
- Plant Science Research Theme, School of Life Sciences and Institute of Molecular Cellular and Systems Biology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Chiara Geri
- Istituto di Biologia e Biotechnologia Agraria, Consiglio Nazionale Delle Richerche, Pisa, Italy.,Plant Science Research Theme, School of Life Sciences and Institute of Molecular Cellular and Systems Biology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Ari Sadanandom
- School of Biological and Biomedical Sciences, Durham University, Durham DH1 3LE, UK
| | - Brian O Smith
- Institute of Molecular Cellular and Systems Biology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Kappei Kobayashi
- Plant Molecular Biology and Virology, Faculty of Agriculture, Ehime University, Ehime 790-8566, Japan
| | - Joel J Milner
- Plant Science Research Theme, School of Life Sciences and Institute of Molecular Cellular and Systems Biology, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
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23
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de Bossoreille de Ribou S, Douam F, Hamant O, Frohlich MW, Negrutiu I. Plant science and agricultural productivity: why are we hitting the yield ceiling? PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2013; 210:159-76. [PMID: 23849123 DOI: 10.1016/j.plantsci.2013.05.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2013] [Revised: 04/26/2013] [Accepted: 05/16/2013] [Indexed: 05/11/2023]
Abstract
Trends in conventional plant breeding and in biotechnology research are analyzed with a focus on production and productivity of individual organisms. Our growing understanding of the productive/adaptive potential of (crop) plants is a prerequisite to increasing this potential and also its expression under environmental constraints. This review concentrates on growth rate, ribosome activity, and photosynthetic rate to link these key cellular processes to plant productivity. Examples of how they may be integrated in heterosis, organ growth control, and responses to abiotic stresses are presented. The yield components in rice are presented as a model. The ultimate goal of research programs, that concentrate on yield and productivity and integrating the panoply of systems biology tools, is to achieve "low input, high output" agriculture, i.e. shifting from a conventional "productivist" agriculture to an efficient sustainable agriculture. This is of critical, strategic importance, because the extent to which we, both locally and globally, secure and manage the long-term productive potential of plant resources will determine the future of humanity.
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24
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Angel CA, Lutz L, Yang X, Rodriguez A, Adair A, Zhang Y, Leisner SM, Nelson RS, Schoelz JE. The P6 protein of Cauliflower mosaic virus interacts with CHUP1, a plant protein which moves chloroplasts on actin microfilaments. Virology 2013; 443:363-74. [DOI: 10.1016/j.virol.2013.05.028] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 03/11/2013] [Accepted: 05/18/2013] [Indexed: 10/26/2022]
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25
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Rivas S, Genin S. A plethora of virulence strategies hidden behind nuclear targeting of microbial effectors. FRONTIERS IN PLANT SCIENCE 2011; 2:104. [PMID: 22639625 PMCID: PMC3355726 DOI: 10.3389/fpls.2011.00104] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 12/09/2011] [Indexed: 05/24/2023]
Abstract
Plant immune responses depend on the ability to couple rapid recognition of the invading microbe to an efficient response. During evolution, plant pathogens have acquired the ability to deliver effector molecules inside host cells in order to manipulate cellular and molecular processes and establish pathogenicity. Following translocation into plant cells, microbial effectors may be addressed to different subcellular compartments. Intriguingly, a significant number of effector proteins from different pathogenic microorganisms, including viruses, oomycetes, fungi, nematodes, and bacteria, is targeted to the nucleus of host cells. In agreement with this observation, increasing evidence highlights the crucial role played by nuclear dynamics, and nucleocytoplasmic protein trafficking during a great variety of analyzed plant-pathogen interactions. Once in the nucleus, effector proteins are able to manipulate host transcription or directly subvert essential host components to promote virulence. Along these lines, it has been suggested that some effectors may affect histone packing and, thereby, chromatin configuration. In addition, microbial effectors may either directly activate transcription or target host transcription factors to alter their regular molecular functions. Alternatively, nuclear translocation of effectors may affect subcellular localization of their cognate resistance proteins in a process that is essential for resistance protein-mediated plant immunity. Here, we review recent progress in our field on the identification of microbial effectors that are targeted to the nucleus of host plant cells. In addition, we discuss different virulence strategies deployed by microbes, which have been uncovered through examination of the mechanisms that guide nuclear localization of effector proteins.
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Affiliation(s)
- Susana Rivas
- Institut National de la Recherche Agronomique, Laboratoire des Interactions Plantes-MicroorganismesUMR 441, Castanet-Tolosan, France
- Centre National de la Recherche Scientifique, Laboratoire des Interactions Plantes-MicroorganismesUMR 2594, Castanet-Tolosan, France
| | - Stéphane Genin
- Institut National de la Recherche Agronomique, Laboratoire des Interactions Plantes-MicroorganismesUMR 441, Castanet-Tolosan, France
- Centre National de la Recherche Scientifique, Laboratoire des Interactions Plantes-MicroorganismesUMR 2594, Castanet-Tolosan, France
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Viral factor TAV recruits TOR/S6K1 signalling to activate reinitiation after long ORF translation. EMBO J 2011; 30:1343-56. [PMID: 21343906 DOI: 10.1038/emboj.2011.39] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Accepted: 01/26/2011] [Indexed: 11/08/2022] Open
Abstract
The protein kinase TOR (target-of-rapamycin) upregulates translation initiation in eukaryotes, but initiation restart after long ORF translation is restricted by largely unknown pathways. The plant viral reinitiation factor transactivator-viroplasmin (TAV) exceptionally promotes reinitiation through a mechanism involving retention on 80S and reuse of eIF3 and the host factor reinitiation-supporting protein (RISP) to regenerate reinitiation-competent ribosomal complexes. Here, we show that TAV function in reinitiation depends on physical association with TOR, with TAV-TOR binding being critical for both translation reinitiation and viral fitness. Consistently, TOR-deficient plants are resistant to viral infection. TAV triggers TOR hyperactivation and S6K1 phosphorylation in planta. When activated, TOR binds polyribosomes concomitantly with polysomal accumulation of eIF3 and RISP--a novel and specific target of TOR/S6K1--in a TAV-dependent manner, with RISP being phosphorylated. TAV mutants defective in TOR binding fail to recruit TOR, thereby abolishing RISP phosphorylation in polysomes and reinitiation. Thus, activation of reinitiation after long ORF translation is more complex than previously appreciated, with TOR/S6K1 upregulation being the key event in the formation of reinitiation-competent ribosomal complexes.
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27
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Spurgers KB, Alefantis T, Peyser BD, Ruthel GT, Bergeron AA, Costantino JA, Enterlein S, Kota KP, Boltz RCD, Aman MJ, Delvecchio VG, Bavari S. Identification of essential filovirion-associated host factors by serial proteomic analysis and RNAi screen. Mol Cell Proteomics 2010; 9:2690-703. [PMID: 20702783 DOI: 10.1074/mcp.m110.003418] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
An assessment of the total protein composition of filovirus (ebolavirus and marburgvirus) virions is currently lacking. In this study, liquid chromatography-linked tandem mass spectrometry of purified ebola and marburg virions was performed to identify associated cellular proteins. Host proteins involved in cell adhesion, cytoskeleton, cell signaling, intracellular trafficking, membrane organization, and chaperones were identified. Significant overlap exists between this data set and proteomic studies of disparate viruses, including HIV-1 and influenza A, generated in multiple cell types. However, the great majority of proteins identified here have not been previously described to be incorporated within filovirus particles. Host proteins identified by liquid chromatography-linked tandem mass spectrometry could lack biological relevance because they represent protein contaminants in the virus preparation, or because they are incorporated within virions by chance. These issues were addressed using siRNA library-mediated gene knockdown (targeting each identified virion-associated host protein), followed by filovirus infection. Knockdown of several host proteins (e.g. HSPA5 and RPL18) significantly interfered with ebolavirus and marburgvirus infection, suggesting specific and relevant virion incorporation. Notably, select siRNAs inhibited ebolavirus, but enhanced marburgvirus infection, suggesting important differences between the two viruses. The proteomic analysis presented here contributes to a greater understanding of filovirus biology and potentially identifies host factors that can be targeted for antiviral drug development.
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Affiliation(s)
- Kevin B Spurgers
- The United States Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD 21702, USA
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28
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Taliansky ME, Brown JWS, Rajamäki ML, Valkonen JPT, Kalinina NO. Involvement of the plant nucleolus in virus and viroid infections: parallels with animal pathosystems. Adv Virus Res 2010; 77:119-58. [PMID: 20951872 PMCID: PMC7149663 DOI: 10.1016/b978-0-12-385034-8.00005-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The nucleolus is a dynamic subnuclear body with roles in ribosome subunit biogenesis, mediation of cell-stress responses, and regulation of cell growth. An increasing number of reports reveal that similar to the proteins of animal viruses, many plant virus proteins localize in the nucleolus to divert host nucleolar proteins from their natural functions in order to exert novel role(s) in the virus infection cycle. This chapter will highlight studies showing how plant viruses recruit nucleolar functions to facilitate virus translation and replication, virus movement and assembly of virus-specific ribonucleoprotein (RNP) particles, and to counteract plant host defense responses. Plant viruses also provide a valuable tool to gain new insights into novel nucleolar functions and processes. Investigating the interactions between plant viruses and the nucleolus will facilitate the design of novel strategies to control plant virus infections.
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Affiliation(s)
- M E Taliansky
- Scottish Crop Research Institute, Invergowrie, Dundee, United Kingdom
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29
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Abstract
Regulation of protein synthesis by viruses occurs at all levels of translation. Even prior to protein synthesis itself, the accessibility of the various open reading frames contained in the viral genome is precisely controlled. Eukaryotic viruses resort to a vast array of strategies to divert the translation machinery in their favor, in particular, at initiation of translation. These strategies are not only designed to circumvent strategies common to cell protein synthesis in eukaryotes, but as revealed more recently, they also aim at modifying or damaging cell factors, the virus having the capacity to multiply in the absence of these factors. In addition to unraveling mechanisms that may constitute new targets in view of controlling virus diseases, viruses constitute incomparably useful tools to gain in-depth knowledge on a multitude of cell pathways.
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30
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Thiébeauld O, Schepetilnikov M, Park HS, Geldreich A, Kobayashi K, Keller M, Hohn T, Ryabova LA. A new plant protein interacts with eIF3 and 60S to enhance virus-activated translation re-initiation. EMBO J 2009; 28:3171-84. [PMID: 19745810 DOI: 10.1038/emboj.2009.256] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Accepted: 08/06/2009] [Indexed: 12/31/2022] Open
Abstract
The plant viral re-initiation factor transactivator viroplasmin (TAV) activates translation of polycistronic mRNA by a re-initiation mechanism involving translation initiation factor 3 (eIF3) and the 60S ribosomal subunit (60S). QJ;Here, we report a new plant factor-re-initiation supporting protein (RISP)-that enhances TAV function in re-initiation. RISP interacts physically with TAV in vitro and in vivo. Mutants defective in interaction are less active, or inactive, in transactivation and viral amplification. RISP alone can serve as a scaffold protein, which is able to interact with eIF3 subunits a/c and 60S, apparently through the C-terminus of ribosomal protein L24. RISP pre-bound to eIF3 binds 40S, suggesting that RISP enters the translational machinery at the 43S formation step. RISP, TAV and 60S co-localize in epidermal cells of infected plants, and eIF3-TAV-RISP-L24 complex formation can be shown in vitro. These results suggest that RISP and TAV bridge interactions between eIF3-bound 40S and L24 of 60S after translation termination to ensure 60S recruitment during repetitive initiation events on polycistronic mRNA; RISP can thus be considered as a new component of the cell translation machinery.
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Affiliation(s)
- Odon Thiébeauld
- Institut de Biologie Moléculaire des Plantes du CNRS, Université de Strasbourg, Strasbourg Cedex, France
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31
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Harries PA, Palanichelvam K, Yu W, Schoelz JE, Nelson RS. The cauliflower mosaic virus protein P6 forms motile inclusions that traffic along actin microfilaments and stabilize microtubules. PLANT PHYSIOLOGY 2009; 4:454-6. [PMID: 19028879 PMCID: PMC2633818 DOI: 10.1104/pp.108.131755] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Accepted: 11/19/2008] [Indexed: 05/19/2023]
Abstract
The gene VI product (P6) of Cauliflower mosaic virus (CaMV) is a multifunctional protein known to be a major component of cytoplasmic inclusion bodies formed during CaMV infection. Although these inclusions are known to contain virions and are thought to be sites of translation from the CaMV 35S polycistronic RNA intermediate, the precise role of these bodies in the CaMV infection cycle remains unclear. Here, we examine the functionality and intracellular location of a fusion between P6 and GFP (P6-GFP). We initially show that the ability of P6-GFP to transactivate translation is comparable to unmodified P6. Consequently, our work has direct application for the large body of literature in which P6 has been expressed ectopically and its functions characterized. We subsequently found that P6-GFP forms highly motile cytoplasmic inclusion bodies and revealed through fluorescence colocalization studies that these P6-GFP bodies associate with the actin/endoplasmic reticulum network as well as microtubules. We demonstrate that while P6-GFP inclusions traffic along microfilaments, those associated with microtubules appear stationary. Additionally, inhibitor studies reveal that the intracellular movement of P6-GFP inclusions is sensitive to the actin inhibitor, latrunculin B, which also inhibits the formation of local lesions by CaMV in Nicotiana edwardsonii leaves. The motility of P6 along microfilaments represents an entirely new property for this protein, and these results imply a role for P6 in intracellular and cell-to-cell movement of CaMV.
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Affiliation(s)
- Phillip A Harries
- Plant Biology Division, Samuel Roberts Noble Foundation, Ardmore, Oklahoma 73401, USA
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32
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Nuclear import of CaMV P6 is required for infection and suppression of the RNA silencing factor DRB4. EMBO J 2008; 27:2102-12. [PMID: 18615098 DOI: 10.1038/emboj.2008.129] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2008] [Accepted: 06/06/2008] [Indexed: 01/02/2023] Open
Abstract
Replication of Cauliflower mosaic virus (CaMV), a plant double-stranded DNA virus, requires the viral translational transactivator protein P6. Although P6 is known to form cytoplasmic inclusion bodies (viroplasms) so far considered essential for virus biology, a fraction of the protein is also present in the nucleus. Here, we report that monomeric P6 is imported into the nucleus through two importin-alpha-dependent nuclear localization signals, and show that this process is mandatory for CaMV infectivity and is independent of translational transactivation and viroplasm formation. One nuclear function of P6 is to suppress RNA silencing, a gene regulation mechanism with antiviral roles, commonly counteracted by dedicated viral suppressor proteins (viral silencing suppressors; VSRs). Transgenic P6 expression in Arabidopsis is genetically equivalent to inactivating the nuclear protein DRB4 that facilitates the activity of the major plant antiviral silencing factor DCL4. We further show that a fraction of P6 immunoprecipitates with DRB4 in CaMV-infected cells. This study identifies both genetic and physical interactions between a VSR to a host RNA silencing component, and highlights the importance of subcellular compartmentalization in VSR function.
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33
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Ghorbel S, Sinha-Datta U, Dundr M, Brown M, Franchini G, Nicot C. Human T-cell leukemia virus type I p30 nuclear/nucleolar retention is mediated through interactions with RNA and a constituent of the 60 S ribosomal subunit. J Biol Chem 2006; 281:37150-8. [PMID: 17008317 DOI: 10.1074/jbc.m603981200] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Human T-cell leukemia virus type I is the etiological agent of adult T-cell leukemia/lymphoma, an aggressive and fatal lymphoproliferative malignancy. The virus has evolved strategies to escape immune clearance by remaining latent in most infected cells in vivo. We demonstrated previously that virally encoded p30 protein is a potent post-transcriptional inhibitor of virus replication (Nicot, C., Dundr, M., Johnson, J. M., Fullen, J. R., Alonzo, N., Fukumoto, R., Princler, G. L., Derse, D., Misteli, T., and Franchini, G. (2004) Nat. Med. 10, 197-201). p30 is unable to shuttle out of the nucleus in heterokaryon assays, suggesting the existence of specific retention signals. Because suppression of virus replication relies on nuclear retention of the tax/rex mRNA by p30, determining the retention features of p30 will offer hints to break latency in infected cells and insights into new therapeutic approaches. In this study, we used live cell imaging technologies to study the kinetics of p30 and to delineate its retention signals and their function in virus replication. Notably, this is the first study to identify p30 nucleolar retention domains. Using mutants of p30 that localized in different cellular compartments, we show that post-transcriptional control of virus replication by p30 occurs in the nucleoplasm. We further demonstrate that p30 nuclear/nucleolar retention is dependent upon de novo RNA transcripts and interactions with components of the ribosomal machinery.
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Affiliation(s)
- Sofiane Ghorbel
- Department of Microbiology, Molecular Genetics, and Immunology, University of Kansas Medical Center, Kansas City, Kansas 66160-7420, USA
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34
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Dhar D, Mapa K, Pudi R, Srinivasan P, Bodhinathan K, Das S. Human ribosomal protein L18a interacts with hepatitis C virus internal ribosome entry site. Arch Virol 2005; 151:509-24. [PMID: 16195786 DOI: 10.1007/s00705-005-0642-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2005] [Accepted: 08/15/2005] [Indexed: 02/05/2023]
Abstract
Translation initiation of hepatitis C virus RNA occurs via ribosome binding to an 'internal ribosome entry site (IRES)' located in the 5'untranslated region of the viral RNA. The principle interaction between the 40S ribosomal subunit and the HCV IRES has been shown to be largely factor independent, which is followed by the joining of the 60S ribosomal subunit to form functional 80S complex. However several additional cellular proteins have been reported to bind to HCV IRES and enhance the initiation of translation. In order to identify novel factors involved in the ribosome assembly during internal initiation of HCV RNA, northwestern screening of a HeLa cDNA expression library was performed, using HCV IRES RNA as probe. We demonstrate here, that human ribosomal protein L18a, a constituent of 60S subunit, interacts with HCV IRES RNA. This interaction was further confirmed by using a recombinant protein similar to L18a (sL18a), cloned from human blood. Interestingly, addition of increasing concentration of the purified recombinant sL18a protein, showed moderate stimulation of HCV IRES activity in the in vitro translation assay. These observations suggest that the human L18a might influence the HCV IRES mediated translation.
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Affiliation(s)
- D Dhar
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India
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35
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Haas M, Geldreich A, Bureau M, Dupuis L, Leh V, Vetter G, Kobayashi K, Hohn T, Ryabova L, Yot P, Keller M. The open reading frame VI product of Cauliflower mosaic virus is a nucleocytoplasmic protein: its N terminus mediates its nuclear export and formation of electron-dense viroplasms. THE PLANT CELL 2005; 17:927-43. [PMID: 15746075 PMCID: PMC1069709 DOI: 10.1105/tpc.104.029017] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2004] [Accepted: 12/09/2004] [Indexed: 05/20/2023]
Abstract
The Cauliflower mosaic virus (CaMV) open reading frame VI product (P6) is essential for the viral infection cycle. It controls translation reinitiation of the viral polycistronic RNAs and forms cytoplasmic inclusion bodies (viroplasms) where virus replication and assembly occur. In this study, the mechanism involved in viroplasm formation was investigated by in vitro and in vivo experiments. Far protein gel blot assays using a collection of P6 deletion mutants demonstrated that the N-terminal alpha-helix of P6 mediates interaction between P6 molecules. Transient expression in tobacco (Nicotiana tabacum) BY-2 cells of full-length P6 and P6 mutants fused to enhanced green fluorescent protein revealed that viroplasms are formed at the periphery of the nucleus and that the N-terminal domain of P6 is an important determinant in this process. Finally, this study led to the unexpected finding that P6 is a nucleocytoplasmic shuttle protein and that its nuclear export is mediated by a Leu-rich sequence that is part of the alpha-helix domain implicated in viroplasm formation. The discovery that P6 can localize to the nucleus opens new prospects for understanding yet unknown roles of this viral protein in the course of the CaMV infection cycle.
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Affiliation(s)
- Muriel Haas
- Institut de Biologie Moléculaire des Plantes, Unité Propre de Recherche, Centre National de la Recherche Scientifique 2357, Université Louis Pasteur, 67084 Strasbourg Cedex, France
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36
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Bureau M, Leh V, Haas M, Geldreich A, Ryabova L, Yot P, Keller M. P6 protein of Cauliflower mosaic virus, a translation reinitiator, interacts with ribosomal protein L13 from Arabidopsis thaliana. J Gen Virol 2004; 85:3765-3775. [PMID: 15557250 DOI: 10.1099/vir.0.80242-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The P6 protein of Cauliflower mosaic virus (CaMV) transactivates translation of the CaMV 35S polycistronic pregenomic RNA and its spliced versions, and thus allows synthesis of a complete set of viral proteins. Previous studies have shown that P6 interacts with plant L18 and L24 ribosomal proteins and initiation factor eIF3, and it has been proposed that these interactions are involved in the reinitiation of translation of polycistronic viral RNAs. This study characterizes a novel cellular partner of P6, the ribosomal protein L13 from Arabidopsis thaliana. Far-Western assays performed with several P6 deletion mutants have shown that L13 interacts with the miniTAV of P6, which represents the minimal domain for transactivation, suggesting that the P6-L13 interaction might also be involved in this process. L13 and L18 were found to bind to the same region within the miniTAV. Competition assays between L18 and L13 for binding to miniTAV suggest that interactions between P6 and these ribosomal proteins involve separate P6 molecules, and/or occur at different stages of translation or in the context of another function also mediated by P6.
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Affiliation(s)
- Marina Bureau
- Institut de Biologie Moléculaire des Plantes, UPR CNRS 2357, Université Louis Pasteur, 12 rue du Général Zimmer, 67084 Strasbourg Cedex, France
| | - Véronique Leh
- Institut de Biologie Moléculaire des Plantes, UPR CNRS 2357, Université Louis Pasteur, 12 rue du Général Zimmer, 67084 Strasbourg Cedex, France
| | - Muriel Haas
- Institut de Biologie Moléculaire des Plantes, UPR CNRS 2357, Université Louis Pasteur, 12 rue du Général Zimmer, 67084 Strasbourg Cedex, France
| | - Angèle Geldreich
- Institut de Biologie Moléculaire des Plantes, UPR CNRS 2357, Université Louis Pasteur, 12 rue du Général Zimmer, 67084 Strasbourg Cedex, France
| | - Lyubov Ryabova
- Institut de Biologie Moléculaire des Plantes, UPR CNRS 2357, Université Louis Pasteur, 12 rue du Général Zimmer, 67084 Strasbourg Cedex, France
| | - Pierre Yot
- Institut de Biologie Moléculaire des Plantes, UPR CNRS 2357, Université Louis Pasteur, 12 rue du Général Zimmer, 67084 Strasbourg Cedex, France
| | - Mario Keller
- Institut de Biologie Moléculaire des Plantes, UPR CNRS 2357, Université Louis Pasteur, 12 rue du Général Zimmer, 67084 Strasbourg Cedex, France
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37
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Ryabova L, Park HS, Hohn T. Control of translation reinitiation on the cauliflower mosaic virus (CaMV) polycistronic RNA. Biochem Soc Trans 2004; 32:592-6. [PMID: 15270684 DOI: 10.1042/bst0320592] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Translation of the polycistronic 35S RNA of CaMV (cauliflower mosaic virus) occurs via a reinitiation mechanism, which requires TAV (transactivator/viroplasmin). To allow translation reinitiation of the major open reading frames on the polycistronic RNA, TAV interacts with the host translational machinery via eIF3 (eukaryotic initiation factor 3) and the 60S ribosome. Accumulation of TAV and eIF3 in the polysomal fraction isolated from CaMV-infected cells suggested that TAV prevents loss of eIF3 from the translating ribosomes during the first initiation event. The TAV–eIF3–80S complex could be detected in vitro by sucrose-gradient-sedimentation analysis. The question is whether TAV interacts directly with the 48S preinitiation complex or enters polysomes after the first initiation event. eIF4B, a component of the 48S initiation complex, can preclude formation of the TAV–eIF3 complex via competition with TAV for eIF3 binding; the eIF4B- and TAV-binding sites on eIF3g overlap. eIF4B out-competes TAV for binding to eIF3 and to the eIF3–40S complex. Transient overexpression of eIF4B in plant protoplasts specifically inhibits TAV-mediated transactivation of polycistronic translation. Our results thus indicate that eIF4B precludes TAV–eIF3–40S complex formation during the first initiation event. Consequently, overexpression of TAV in plant protoplasts affects only the second and subsequent initiation events. We propose a model in which TAV enters the host translational machinery at the eIF4B-removal step to stabilize eIF3 within polysomes.
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Affiliation(s)
- L Ryabova
- Institut de Biologie Moléculaire des Plantes, UPR CNRS 2357, Strasbourg, France.
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38
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Park HS, Browning KS, Hohn T, Ryabova LA. Eucaryotic initiation factor 4B controls eIF3-mediated ribosomal entry of viral reinitiation factor. EMBO J 2004; 23:1381-91. [PMID: 14988734 PMCID: PMC381412 DOI: 10.1038/sj.emboj.7600140] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2003] [Accepted: 02/02/2004] [Indexed: 11/09/2022] Open
Abstract
The cauliflower mosaic virus reinitiation factor TAV interacts with host translation initiation factor 3 (eIF3) and the 60S ribosomal subunit to accomplish translation of polycistronic mRNAs. Interaction between TAV and eIF3g is critical for the reinitiation process. Here, we show that eIF4B can preclude formation of the TAV/eIF3 complex via competition with TAV for eIF3g binding; indeed, the eIF4B- and TAV-binding sites on eIF3g overlap. Our data indicate that eIF4B interferes with TAV/eIF3/40S ribosome complex formation during the first initiation event. Consequently, overexpression of TAV in plant protoplasts affects only second initiation events. Transient overexpression of eIF4B in plant protoplasts specifically inhibits TAV-mediated reinitiation of a second ORF. These data suggest that TAV enters the host translation machinery at the eIF4B removal step to stabilize eIF3 on the translating ribosome, thereby allowing translation of polycistronic viral RNA.
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Affiliation(s)
| | - Karen S Browning
- Department of Chemistry and Biochemistry, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX, USA
| | - Thomas Hohn
- Friedrich Miescher-Institute, Basel, Switzerland
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39
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Kobayashi K, Hohn T. Dissection of cauliflower mosaic virus transactivator/viroplasmin reveals distinct essential functions in basic virus replication. J Virol 2003; 77:8577-83. [PMID: 12857928 PMCID: PMC165242 DOI: 10.1128/jvi.77.15.8577-8583.2003] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2003] [Accepted: 05/16/2003] [Indexed: 12/24/2022] Open
Abstract
Cauliflower mosaic virus (CaMV) transactivator/viroplasmin (Tav) is an essential multifunctional viral protein. Dissection of Tav by deletion mutagenesis revealed that the central region is essential for CaMV replication in single cells but that the N- and C-terminal parts are not. Strains with mutations in the central region were defective in the translational transactivator function and could be complemented by coexpressing Gag (capsid protein precursor) and Pol (polyprotein with protease, reverse transcriptase, and RNase H activity) from separate monocistronic plasmids. In contrast, total omission of Tav was only partially complemented by Gag and Pol overexpression from separate plasmids. These results indicate that CaMV basic replication requires both Tav-activated polycistronic translation and some posttranslational function(s) of Tav that is not affected by the deletions in the central region of Tav.
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40
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Haas M, Bureau M, Geldreich A, Yot P, Keller M. Cauliflower mosaic virus: still in the news. MOLECULAR PLANT PATHOLOGY 2002; 3:419-29. [PMID: 20569349 DOI: 10.1046/j.1364-3703.2002.00136.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
SUMMARY Taxonomic relationship: Cauliflower mosaic virus (CaMV) is the type member of the Caulimovirus genus in the Caulimoviridae family, which comprises five other genera. CaMV replicates its DNA genome by reverse transcription of a pregenomic RNA and thus belongs to the pararetrovirus supergroup, which includes the Hepadnaviridae family infecting vertebrates. Physical properties: Virions are non-enveloped isometric particles, 53 nm in diameter (Fig. 1). They are constituted by 420 capsid protein subunits organized following T= 7 icosahedral symmetry (Cheng, R.H., Olson, N.H. and Baker, T.S. (1992) Cauliflower mosaic virus: a 420 subunit (T= 7), multilayer structure. Virology, 16, 655-668). The genome consists of a double-stranded circular DNA of approximately 8000 bp that is embedded in the inner surface of the capsid. Viral proteins: The CaMV genome encodes six proteins, a cell-to-cell movement protein (P1), two aphid transmission factors (P2 and P3), the precursor of the capsid proteins (P4), a polyprotein precursor of proteinase, reverse transcriptase and ribonuclease H (P5) and an inclusion body protein/translation transactivator (P6). Hosts: The host range of CaMV is limited to plants of the Cruciferae family, i.e. Brassicae species and Arabidopsis thaliana, but some viral strains can also infect solanaceous plants. In nature, CaMV is transmitted by aphids in a non-circulative manner.
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Affiliation(s)
- Muriel Haas
- Institut de Biologie Moléculaire des Plantes CNRS, Université Louis Pasteur, 12 rue du Général Zimmer, 67084 Strasbourg Cedex, France
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Maule A, Leh V, Lederer C. The dialogue between viruses and hosts in compatible interactions. CURRENT OPINION IN PLANT BIOLOGY 2002; 5:279-284. [PMID: 12179959 DOI: 10.1016/s1369-5266(02)00272-8] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Understanding the biological principles behind virus-induced symptom expression in plants remains a longstanding challenge. By dissecting the compatible host-virus relationship temporally and genetically, we have begun to map out the relationships of its component parts. The picture that emerges is one in which host gene expression and physiology are under tight temporal control during infection.
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Affiliation(s)
- Andrew Maule
- John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, UK.
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Ryabova LA, Pooggin MM, Hohn T. Viral strategies of translation initiation: ribosomal shunt and reinitiation. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 2002; 72:1-39. [PMID: 12206450 PMCID: PMC7133299 DOI: 10.1016/s0079-6603(02)72066-7] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Due to the compactness of their genomes, viruses are well suited to the study of basic expression mechanisms, including details of transcription, RNA processing, transport, and translation. In fact, most basic principles of these processes were first described in viral systems. Furthermore, viruses seem not to respect basic rules, and cases of "abnormal" expression strategies are quiet common, although such strategies are usually also finally observed in rare cases of cellular gene expression. Concerning translation, viruses most often violate Kozak's original rule that eukaryotic translation starts from a capped monocistronic mRNA and involves linear scanning to find the first suitable start codon. Thus, many viral cases have been described where translation is initiated from noncapped RNA, using an internal ribosome entry site. This review centers on other viral translation strategies, namely shunting and virus-controlled reinitiation as first described in plant pararetroviruses (Caulimoviridae). In shunting, major parts of a complex leader are bypassed and not melted by scanning ribosomes. In the Caulimoviridae, this process is coupled to reinitiation after translation of a small open reading frame; in other cases, it is possibly initiated upon pausing of the scanning ribosome. Most of the Caulimoviridae produce polycistronic mRNAs. Two basic mechanisms are used for their translation. Alternative translation of the downstream open reading frames in the bacilliform Caulimoviridae occurs by a leaky scanning mechanism, and reinitiation of polycistronic translation in many of the icosahedral Caulimoviridae is enabled by the action of a viral transactivator. Both of these processes are discussed here in detail and compared to related processes in other viruses and cells.
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Park HS, Himmelbach A, Browning KS, Hohn T, Ryabova LA. A plant viral "reinitiation" factor interacts with the host translational machinery. Cell 2001; 106:723-33. [PMID: 11572778 DOI: 10.1016/s0092-8674(01)00487-1] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The cauliflower mosaic virus transactivator, TAV, controls translation reinitiation of major open reading frames on polycistronic RNA. We show here that TAV function depends on its association with polysomes and eukaryotic initiation factor eIF3 in vitro and in vivo. TAV physically interacts with eIF3 and the 60S ribosomal subunit. Two proteins mediating these interactions were identified: eIF3g and 60S ribosomal protein L24. Transient expression of eIF3g and L24 in plant protoplasts strongly affects TAV-mediated reinitiation activity. We demonstrate that TAV/eIF3/40S and eIF3/TAV/60S ternary complexes form in vitro, and propose that TAV mediates efficient recruitment of eIF3 to polysomes, allowing translation of polycistronic mRNAs by reinitiation, overcoming the normal cell barriers to this process.
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Affiliation(s)
- H S Park
- Friedrich Miescher-Institute, P.O. Box 2543, CH-4002, Basel, Switzerland
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