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Liu J, Ito M, Liu L, Nakashima K, Satoh S, Konno A, Suzuki T. Involvement of ribosomal protein L17 and Y-box binding protein 1 in the assembly of hepatitis C virus potentially via their interaction with the 3' untranslated region of the viral genome. J Virol 2024; 98:e0052224. [PMID: 38899899 PMCID: PMC11265288 DOI: 10.1128/jvi.00522-24] [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: 03/19/2024] [Accepted: 05/27/2024] [Indexed: 06/21/2024] Open
Abstract
The 3' untranslated region (3'UTR) of the hepatitis C virus (HCV) RNA genome, which contains a highly conserved 3' region named the 3'X-tail, plays an essential role in RNA replication and promotes viral IRES-dependent translation. Although our previous work has found a cis-acting element for genome encapsidation within 3'X, there is limited information on the involvement of the 3'UTR in particle formation. In this study, proteomic analyses identified host cell proteins that bind to the 3'UTR containing the 3'X region but not to the sequence lacking the 3'X. Further characterization showed that RNA-binding proteins, ribosomal protein L17 (RPL17), and Y-box binding protein 1 (YBX1) facilitate the efficient production of infectious HCV particles in the virus infection cells. Using small interfering RNA (siRNA)-mediated gene silencing in four assays that distinguish between the various stages of the HCV life cycle, RPL17 and YBX1 were found to be most important for particle assembly in the trans-packaging assay with replication-defective subgenomic RNA. In vitro assays showed that RPL17 and YBX1 bind to the 3'UTR RNA and deletion of the 3'X region attenuates their interaction. Knockdown of RPL17 or YBX1 resulted in reducing the amount of HCV RNA co-precipitating with the viral Core protein by RNA immunoprecipitation and increasing the relative distance in space between Core and double-stranded RNA by confocal imaging, suggesting that RPL17 and YBX1 potentially affect HCV RNA-Core interaction, leading to efficient nucleocapsid assembly. These host factors provide new clues to understanding the molecular mechanisms that regulate HCV particle formation. IMPORTANCE Although basic research on the HCV life cycle has progressed significantly over the past two decades, our understanding of the molecular mechanisms that regulate the process of particle formation, in particular encapsidation of the genome or nucleocapsid assembly, has been limited. We present here, for the first time, that two RNA-binding proteins, RPL17 and YBX1, bind to the 3'X in the 3'UTR of the HCV genome, which potentially acts as a packaging signal, and facilitates the viral particle assembly. Our study revealed that RPL17 and YBX1 exert a positive effect on the interaction between HCV RNA and Core protein, suggesting that the presence of both host factors modulate an RNA structure or conformation suitable for packaging the viral genome. These findings help us to elucidate not only the regulatory mechanism of the particle assembly of HCV but also the function of host RNA-binding proteins during viral infection.
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Affiliation(s)
- Jie Liu
- Department of Microbiology and Immunology, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Masahiko Ito
- Department of Microbiology and Immunology, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Liang Liu
- Department of Microbiology and Immunology, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Kenji Nakashima
- Department of Microbiology and Immunology, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Shinya Satoh
- Department of Microbiology and Immunology, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Alu Konno
- Department of Microbiology and Immunology, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Tetsuro Suzuki
- Department of Microbiology and Immunology, Hamamatsu University School of Medicine, Shizuoka, Japan
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Reichel M, Schmidt O, Rettel M, Stein F, Köster T, Butter F, Staiger D. Revealing the Arabidopsis AtGRP7 mRNA binding proteome by specific enhanced RNA interactome capture. BMC PLANT BIOLOGY 2024; 24:552. [PMID: 38877390 PMCID: PMC11177498 DOI: 10.1186/s12870-024-05249-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Accepted: 06/05/2024] [Indexed: 06/16/2024]
Abstract
BACKGROUND The interaction of proteins with RNA in the cell is crucial to orchestrate all steps of RNA processing. RNA interactome capture (RIC) techniques have been implemented to catalogue RNA- binding proteins in the cell. In RIC, RNA-protein complexes are stabilized by UV crosslinking in vivo. Polyadenylated RNAs and associated proteins are pulled down from cell lysates using oligo(dT) beads and the RNA-binding proteome is identified by quantitative mass spectrometry. However, insights into the RNA-binding proteome of a single RNA that would yield mechanistic information on how RNA expression patterns are orchestrated, are scarce. RESULTS Here, we explored RIC in Arabidopsis to identify proteins interacting with a single mRNA, using the circadian clock-regulated Arabidopsis thaliana GLYCINE-RICH RNA-BINDING PROTEIN 7 (AtGRP7) transcript, one of the most abundant transcripts in Arabidopsis, as a showcase. Seedlings were treated with UV light to covalently crosslink RNA and proteins. The AtGRP7 transcript was captured from cell lysates with antisense oligonucleotides directed against the 5'untranslated region (UTR). The efficiency of RNA capture was greatly improved by using locked nucleic acid (LNA)/DNA oligonucleotides, as done in the enhanced RIC protocol. Furthermore, performing a tandem capture with two rounds of pulldown with the 5'UTR oligonucleotide increased the yield. In total, we identified 356 proteins enriched relative to a pulldown from atgrp7 mutant plants. These were benchmarked against proteins pulled down from nuclear lysates by AtGRP7 in vitro transcripts immobilized on beads. Among the proteins validated by in vitro interaction we found the family of Acetylation Lowers Binding Affinity (ALBA) proteins. Interaction of ALBA4 with the AtGRP7 RNA was independently validated via individual-nucleotide resolution crosslinking and immunoprecipitation (iCLIP). The expression of the AtGRP7 transcript in an alba loss-of-function mutant was slightly changed compared to wild-type, demonstrating the functional relevance of the interaction. CONCLUSION We adapted specific RNA interactome capture with LNA/DNA oligonucleotides for use in plants using AtGRP7 as a showcase. We anticipate that with further optimization and up scaling the protocol should be applicable for less abundant transcripts.
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Affiliation(s)
- Marlene Reichel
- RNA Biology and Molecular Physiology, Faculty of Biology, Bielefeld University, 33615, Bielefeld, Germany.
- Department of Biology, University of Copenhagen, København N, 2200, Denmark.
| | - Olga Schmidt
- RNA Biology and Molecular Physiology, Faculty of Biology, Bielefeld University, 33615, Bielefeld, Germany
| | - Mandy Rettel
- Proteomics Core Facility, EMBL, 69117, Heidelberg, Germany
| | - Frank Stein
- Proteomics Core Facility, EMBL, 69117, Heidelberg, Germany
| | - Tino Köster
- RNA Biology and Molecular Physiology, Faculty of Biology, Bielefeld University, 33615, Bielefeld, Germany
| | - Falk Butter
- Institute of Molecular Biology (IMB), Ackermannweg 4, 55128, Mainz, Germany
| | - Dorothee Staiger
- RNA Biology and Molecular Physiology, Faculty of Biology, Bielefeld University, 33615, Bielefeld, Germany.
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Balzarini S, Van Ende R, Voet A, Geuten K. A widely applicable and cost-effective method for specific RNA-protein complex isolation. Sci Rep 2023; 13:6898. [PMID: 37106019 PMCID: PMC10140378 DOI: 10.1038/s41598-023-34157-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 04/24/2023] [Indexed: 04/29/2023] Open
Abstract
Although methodological advances have been made over the past years, a widely applicable, easily scalable and cost-effective procedure that can be routinely used to isolate specific ribonucleoprotein complexes (RNPs) remains elusive. We describe the "Silica-based Acidic Phase Separation (SAPS)-capture" workflow. This versatile method combines previously described techniques in a cost-effective, optimal and widely applicable protocol. The specific RNP isolation procedure is performed on a pre-purified RNP sample instead of cell lysate. This combination of protocols results in an increased RNP/bead ratio and by consequence a reduced experimental cost. To validate the method, the 18S rRNP of S. cerevisiae was captured and to illustrate its applicability we isolated the complete repertoire of RNPs in A. thaliana. The procedure we describe can provide the community with a powerful tool to advance the study of the ribonome of a specific RNA molecule in any organism or tissue type.
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Affiliation(s)
- Sam Balzarini
- Molecular Biotechnology of Plants and Micro-organisms, KU Leuven, 3001, Leuven, Belgium
| | - Roosje Van Ende
- Molecular Biotechnology of Plants and Micro-organisms, KU Leuven, 3001, Leuven, Belgium
| | - Arnout Voet
- Lab of biomolecular modelling and design, KU Leuven, 3001, Leuven, Belgium
| | - Koen Geuten
- Molecular Biotechnology of Plants and Micro-organisms, KU Leuven, 3001, Leuven, Belgium.
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Mokhtari J, Nourisefat M, Zamiri B, Fotouhi L, Zarnani AH, Moosavi-Movahedi AA, Karimian K. Novel Method for the Isolation of Proteins and Small Target Molecules from Biological and Aqueous Media by Salt-Assisted Phase Transformation of Their PEGylated Recognition Counterparts. ACS OMEGA 2021; 6:7585-7597. [PMID: 33778269 PMCID: PMC7992175 DOI: 10.1021/acsomega.0c06149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 03/01/2021] [Indexed: 06/12/2023]
Abstract
An efficient and simple method for the application of PEGylated affinity ligands in precipitative isolation of protein target molecules (TMs) from a biological fluid such as blood serum or small target molecules from an aqueous medium is presented for the first time. This approach is based on the high binding specificity of PEGylated recognition molecules (PEG-RMs) to their TMs and the unique physicochemical properties of PEG that result in their salt-assisted phase transformation. Addition of PEG-RM to blood serum results in the formation of an RM-specific macromolecular complex (PEG-RM + TM → PEG-RM.TM) that undergoes facile salt-assisted phase transformation to a separable semisolid with ammonium sulfate. PEG-RM.TM is then dissociated into its components by pH reduction or an increase of ionic strength (PEG-RM.TM → PEG-RM + TM). PEG-RM is salted out to afford pure TM in solution. The same phenomenon is observed when RM or TM are small molecules. The general applicability of the method was validated by PEGylation of two proteins (protein A, sheep antihuman IgG) and a small molecule (salicylic acid) used as model RMs for the isolation of Igs, IgG, and serum albumin from blood serum. The isolated protein TMs were shown to be pure and aggregate-free by gel electrophoresis and dynamic light scattering (DLS). IgG isolated by this method was further characterized by peptide mass fingerprinting. PEGylated protein A was used to demonstrate the recyclability and scale-up potential of PEG-RM. IgG isolated by this method from blood serum of a hepatitis C-vaccinated individual was tested for its binding to sheep antihuman IgG by UV spectroscopy, and its bioactivity was ascertained by comparison of its enzyme-linked immunosorbent assay (ELISA) result to that of a blood sample from the same individual. Reciprocity of RM and TM was ascertained using PEGylated salicylic acid to obtain pure serum albumin, and PEGylated serum albumin was utilized for near-exclusive isolation of one drug from an aqueous equimolar mixture of three drugs (salicylic acid, 91%; capecitabine, 6%; and deferiprone, 3%). Advantages of this approach, including target specificity and general applicability and celerity, over other affinity methods for the isolation of proteins are discussed at a molecular level.
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Affiliation(s)
- Javad Mokhtari
- Arasto Pharmaceutical Chemicals Inc., Yousefabad, Jahanarar Avenue, 23rd St. No. 8, Tehran 1438933741, Iran
- Departments of Chemistry, Science and Research Branch, Azad University, Tehran 1477893855, Iran
| | - Maryam Nourisefat
- Institute of Biochemistry and Biophysics, University of Tehran, Tehran 1417466191 Iran
| | - Bita Zamiri
- Institute of Biochemistry and Biophysics, University of Tehran, Tehran 1417466191 Iran
| | - Leila Fotouhi
- Institute of Biochemistry and Biophysics, University of Tehran, Tehran 1417466191 Iran
| | - Amir-Hassan Zarnani
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran 1417466191, Iran
- Reproductive Immunology Research Center, Avicenna Research Institute, ACECR, Tehran 1936773493, Iran
| | | | - Khashayar Karimian
- Arasto Pharmaceutical Chemicals Inc., Yousefabad, Jahanarar Avenue, 23rd St. No. 8, Tehran 1438933741, Iran
- Institute of Biochemistry and Biophysics, University of Tehran, Tehran 1417466191 Iran
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Gerber AP. RNA-Centric Approaches to Profile the RNA-Protein Interaction Landscape on Selected RNAs. Noncoding RNA 2021; 7:ncrna7010011. [PMID: 33671874 PMCID: PMC7930960 DOI: 10.3390/ncrna7010011] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 02/05/2021] [Accepted: 02/10/2021] [Indexed: 12/11/2022] Open
Abstract
RNA–protein interactions frame post-transcriptional regulatory networks and modulate transcription and epigenetics. While the technological advances in RNA sequencing have significantly expanded the repertoire of RNAs, recently developed biochemical approaches combined with sensitive mass-spectrometry have revealed hundreds of previously unrecognized and potentially novel RNA-binding proteins. Nevertheless, a major challenge remains to understand how the thousands of RNA molecules and their interacting proteins assemble and control the fate of each individual RNA in a cell. Here, I review recent methodological advances to approach this problem through systematic identification of proteins that interact with particular RNAs in living cells. Thereby, a specific focus is given to in vivo approaches that involve crosslinking of RNA–protein interactions through ultraviolet irradiation or treatment of cells with chemicals, followed by capture of the RNA under study with antisense-oligonucleotides and identification of bound proteins with mass-spectrometry. Several recent studies defining interactomes of long non-coding RNAs, viral RNAs, as well as mRNAs are highlighted, and short reference is given to recent in-cell protein labeling techniques. These recent experimental improvements could open the door for broader applications and to study the remodeling of RNA–protein complexes upon different environmental cues and in disease.
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Affiliation(s)
- André P Gerber
- Department of Microbial Sciences, School of Biosciences and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, UK
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Single and Combined Methods to Specifically or Bulk-Purify RNA-Protein Complexes. Biomolecules 2020; 10:biom10081160. [PMID: 32784769 PMCID: PMC7464009 DOI: 10.3390/biom10081160] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/31/2020] [Accepted: 08/06/2020] [Indexed: 12/12/2022] Open
Abstract
The ribonome interconnects the proteome and the transcriptome. Specific biology is situated at this interface, which can be studied in bulk using omics approaches or specifically by targeting an individual protein or RNA species. In this review, we focus on both RNA- and ribonucleoprotein-(RNP) centric methods. These methods can be used to study the dynamics of the ribonome in response to a stimulus or to identify the proteins that interact with a specific RNA species. The purpose of this review is to provide and discuss an overview of strategies to cross-link RNA to proteins and the currently available RNA- and RNP-centric approaches to study RNPs. We elaborate on some major challenges common to most methods, involving RNP yield, purity and experimental cost. We identify the origin of these difficulties and propose to combine existing approaches to overcome these challenges. The solutions provided build on the recently developed organic phase separation protocols, such as Cross-Linked RNA eXtraction (XRNAX), orthogonal organic phase separation (OOPS) and Phenol-Toluol extraction (PTex).
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Theil K, Imami K, Rajewsky N. Identification of proteins and miRNAs that specifically bind an mRNA in vivo. Nat Commun 2019; 10:4205. [PMID: 31527589 PMCID: PMC6746756 DOI: 10.1038/s41467-019-12050-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 08/19/2019] [Indexed: 12/26/2022] Open
Abstract
Understanding regulation of an mRNA requires knowledge of its regulators. However, methods for reliable de-novo identification of proteins binding to a particular RNA are scarce and were thus far only successfully applied to abundant noncoding RNAs in cell culture. Here, we present vIPR, an RNA-protein crosslink, RNA pulldown, and shotgun proteomics approach to identify proteins bound to selected mRNAs in C. elegans. Applying vIPR to the germline-specific transcript gld-1 led to enrichment of known and novel interactors. By comparing enrichment upon gld-1 and lin-41 pulldown, we demonstrate that vIPR recovers both common and specific RNA-binding proteins, and we validate DAZ-1 as a specific gld-1 regulator. Finally, combining vIPR with small RNA sequencing, we recover known and biologically important transcript-specific miRNA interactions, and we identify miR-84 as a specific interactor of the gld-1 transcript. We envision that vIPR will provide a platform for investigating RNA in vivo regulation in diverse biological systems.
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Affiliation(s)
- Kathrin Theil
- Systems Biology of Gene Regulatory Elements, Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125, Berlin, Germany.
| | - Koshi Imami
- Proteome Dynamics, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125, Berlin, Germany
- Laboratory of Molecular and Cellular BioAnalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501, Japan
| | - Nikolaus Rajewsky
- Systems Biology of Gene Regulatory Elements, Berlin Institute for Medical Systems Biology (BIMSB), Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125, Berlin, Germany.
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8
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Bradrick SS, Garcia-Blanco MA. RNA-based methods in virology. Methods 2016; 91:1-2. [PMID: 26678321 DOI: 10.1016/j.ymeth.2015.11.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Affiliation(s)
- Shelton S Bradrick
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, TX 77550, United States.
| | - Mariano A Garcia-Blanco
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, TX 77550, United States; Program in Emerging Infectious Diseases, Duke-NUS Graduate Medical School, Singapore 169857, Singapore.
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Viktorovskaya OV, Greco TM, Cristea IM, Thompson SR. Identification of RNA Binding Proteins Associated with Dengue Virus RNA in Infected Cells Reveals Temporally Distinct Host Factor Requirements. PLoS Negl Trop Dis 2016; 10:e0004921. [PMID: 27556644 PMCID: PMC4996428 DOI: 10.1371/journal.pntd.0004921] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 07/22/2016] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND There are currently no vaccines or antivirals available for dengue virus infection, which can cause dengue hemorrhagic fever and death. A better understanding of the host pathogen interaction is required to develop effective therapies to treat DENV. In particular, very little is known about how cellular RNA binding proteins interact with viral RNAs. RNAs within cells are not naked; rather they are coated with proteins that affect localization, stability, translation and (for viruses) replication. METHODOLOGY/PRINCIPAL FINDINGS Seventy-nine novel RNA binding proteins for dengue virus (DENV) were identified by cross-linking proteins to dengue viral RNA during a live infection in human cells. These cellular proteins were specific and distinct from those previously identified for poliovirus, suggesting a specialized role for these factors in DENV amplification. Knockdown of these proteins demonstrated their function as viral host factors, with evidence for some factors acting early, while others late in infection. Their requirement by DENV for efficient amplification is likely specific, since protein knockdown did not impair the cell fitness for viral amplification of an unrelated virus. The protein abundances of these host factors were not significantly altered during DENV infection, suggesting their interaction with DENV RNA was due to specific recruitment mechanisms. However, at the global proteome level, DENV altered the abundances of proteins in particular classes, including transporter proteins, which were down regulated, and proteins in the ubiquitin proteasome pathway, which were up regulated. CONCLUSIONS/SIGNIFICANCE The method for identification of host factors described here is robust and broadly applicable to all RNA viruses, providing an avenue to determine the conserved or distinct mechanisms through which diverse viruses manage the viral RNA within cells. This study significantly increases the number of cellular factors known to interact with DENV and reveals how DENV modulates and usurps cellular proteins for efficient amplification.
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Affiliation(s)
- Olga V. Viktorovskaya
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Todd M. Greco
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Ileana M. Cristea
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States of America
| | - Sunnie R. Thompson
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
- * E-mail:
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Identification of Proteins Bound to Dengue Viral RNA In Vivo Reveals New Host Proteins Important for Virus Replication. mBio 2016; 7:e01865-15. [PMID: 26733069 PMCID: PMC4725007 DOI: 10.1128/mbio.01865-15] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Dengue virus is the most prevalent cause of arthropod-borne infection worldwide. Due to the limited coding capacity of the viral genome and the complexity of the viral life cycle, host cell proteins play essential roles throughout the course of viral infection. Host RNA-binding proteins mediate various aspects of virus replication through their physical interactions with viral RNA. Here we describe a technique designed to identify such interactions in the context of infected cells using UV cross-linking followed by antisense-mediated affinity purification and mass spectrometry. Using this approach, we identified interactions, several of them novel, between host proteins and dengue viral RNA in infected Huh7 cells. Most of these interactions were subsequently validated using RNA immunoprecipitation. Using small interfering RNA (siRNA)-mediated gene silencing, we showed that more than half of these host proteins are likely involved in regulating virus replication, demonstrating the utility of this method in identifying biologically relevant interactions that may not be identified using traditional in vitro approaches. Dengue virus is the most prevalent cause of arthropod-borne infection worldwide. Viral RNA molecules physically interact with cellular RNA-binding proteins (RBPs) throughout the course of infection; the identification of such interactions will lead to the elucidation of the molecular mechanisms of virus replication. Until now, the identification of host proteins bound to dengue viral RNA has been accomplished using in vitro strategies. Here, we used a method for the specific purification of dengue viral ribonucleoprotein (RNP) complexes from infected cells and subsequently identified the associated proteins by mass spectrometry. We then validated a functional role for the majority of these proteins in mediating efficient virus replication. This approach has broad relevance to virology and RNA biology, as it could theoretically be used to purify any viral RNP complex of interest.
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