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Compendium of Methods to Uncover RNA-Protein Interactions In Vivo. Methods Protoc 2021; 4:mps4010022. [PMID: 33808611 PMCID: PMC8006020 DOI: 10.3390/mps4010022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 03/11/2021] [Accepted: 03/17/2021] [Indexed: 01/01/2023] Open
Abstract
Control of gene expression is critical in shaping the pro-and eukaryotic organisms’ genotype and phenotype. The gene expression regulatory pathways solely rely on protein–protein and protein–nucleic acid interactions, which determine the fate of the nucleic acids. RNA–protein interactions play a significant role in co- and post-transcriptional regulation to control gene expression. RNA-binding proteins (RBPs) are a diverse group of macromolecules that bind to RNA and play an essential role in RNA biology by regulating pre-mRNA processing, maturation, nuclear transport, stability, and translation. Hence, the studies aimed at investigating RNA–protein interactions are essential to advance our knowledge in gene expression patterns associated with health and disease. Here we discuss the long-established and current technologies that are widely used to study RNA–protein interactions in vivo. We also present the advantages and disadvantages of each method discussed in the review.
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2
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Jazurek M, Ciesiolka A, Starega-Roslan J, Bilinska K, Krzyzosiak WJ. Identifying proteins that bind to specific RNAs - focus on simple repeat expansion diseases. Nucleic Acids Res 2016; 44:9050-9070. [PMID: 27625393 PMCID: PMC5100574 DOI: 10.1093/nar/gkw803] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 09/01/2016] [Indexed: 12/11/2022] Open
Abstract
RNA–protein complexes play a central role in the regulation of fundamental cellular processes, such as mRNA splicing, localization, translation and degradation. The misregulation of these interactions can cause a variety of human diseases, including cancer and neurodegenerative disorders. Recently, many strategies have been developed to comprehensively analyze these complex and highly dynamic RNA–protein networks. Extensive efforts have been made to purify in vivo-assembled RNA–protein complexes. In this review, we focused on commonly used RNA-centric approaches that involve mass spectrometry, which are powerful tools for identifying proteins bound to a given RNA. We present various RNA capture strategies that primarily depend on whether the RNA of interest is modified. Moreover, we briefly discuss the advantages and limitations of in vitro and in vivo approaches. Furthermore, we describe recent advances in quantitative proteomics as well as the methods that are most commonly used to validate robust mass spectrometry data. Finally, we present approaches that have successfully identified expanded repeat-binding proteins, which present abnormal RNA–protein interactions that result in the development of many neurological diseases.
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Affiliation(s)
- Magdalena Jazurek
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Adam Ciesiolka
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Julia Starega-Roslan
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Katarzyna Bilinska
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Wlodzimierz J Krzyzosiak
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
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3
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van Nues RW, Castro-Roa D, Yuzenkova Y, Zenkin N. Ribonucleoprotein particles of bacterial small non-coding RNA IsrA (IS61 or McaS) and its interaction with RNA polymerase core may link transcription to mRNA fate. Nucleic Acids Res 2015; 44:2577-92. [PMID: 26609136 PMCID: PMC4824073 DOI: 10.1093/nar/gkv1302] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 11/08/2015] [Indexed: 11/23/2022] Open
Abstract
Coupled transcription and translation in bacteria are tightly regulated. Some small RNAs (sRNAs) control aspects of this coupling by modifying ribosome access or inducing degradation of the message. Here, we show that sRNA IsrA (IS61 or McaS) specifically associates with core enzyme of RNAP in vivo and in vitro, independently of σ factor and away from the main nucleic-acids-binding channel of RNAP. We also show that, in the cells, IsrA exists as ribonucleoprotein particles (sRNPs), which involve a defined set of proteins including Hfq, S1, CsrA, ProQ and PNPase. Our findings suggest that IsrA might be directly involved in transcription or can participate in regulation of gene expression by delivering proteins associated with it to target mRNAs through its interactions with transcribing RNAP and through regions of sequence-complementarity with the target. In this eukaryotic-like model only in the context of a complex with its target, IsrA and its associated proteins become active. In this manner, in the form of sRNPs, bacterial sRNAs could regulate a number of targets with various outcomes, depending on the set of associated proteins.
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Affiliation(s)
- Rob W van Nues
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, NE2 4AX, UK
| | - Daniel Castro-Roa
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, NE2 4AX, UK
| | - Yulia Yuzenkova
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, NE2 4AX, UK
| | - Nikolay Zenkin
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, NE2 4AX, UK
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4
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Nicholson BL, Zaslaver O, Mayberry LK, Browning KS, White KA. Tombusvirus Y-shaped translational enhancer forms a complex with eIF4F and can be functionally replaced by heterologous translational enhancers. J Virol 2013; 87:1872-83. [PMID: 23192876 PMCID: PMC3554133 DOI: 10.1128/jvi.02711-12] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 11/21/2012] [Indexed: 01/03/2023] Open
Abstract
Certain plus-strand RNA plant viruses that are uncapped and nonpolyadenylated rely on RNA elements in their 3' untranslated region, termed 3'-cap-independent translational enhancers (3'CITEs), for efficient translation of their proteins. Here, we have investigated the properties of the Y-shaped class of 3'CITE present in the tombusvirus Carnation Italian ringspot virus (CIRV). While some types of 3'CITE have been found to function through recruitment of translation initiation factors to the viral genome, no trans-acting translation-related factors have yet been identified for the Y-shaped 3'CITE. Our results indicate that the CIRV 3'CITE complexes with eIF4F and eIFiso4F, with the former mediating translation more efficiently than the latter. In nature, some classes of 3'CITE are present in several different viral genera, suggesting that these elements hold a high degree of modularity. Here, we test this concept by engineering chimeric viruses containing heterologous 3'CITEs and show that the Y-shaped class of 3'CITE in CIRV can be replaced by two alternative types of 3'CITE, i.e., a Panicum mosaic virus-like 3'CITE or an I-shaped 3'CITE, without any major loss in in vitro translation or replication efficiency in protoplasts. The heterologous 3'CITEs also mediated whole-plant infections of Nicotiana benthamiana, where distinct symptoms were observed for each of the alternative 3'CITEs and 3'CITE evolution occurred during serial passaging. Our results supply new information on Y-shaped 3'CITE function and provide insights into 3'CITE virus-host compatibilities.
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Affiliation(s)
| | - Olga Zaslaver
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Laura K. Mayberry
- Department of Chemistry and Biochemistry and the Institute for Cellular and Molecular Biology, University of Texas, Austin, Texas, USA
| | - Karen S. Browning
- Department of Chemistry and Biochemistry and the Institute for Cellular and Molecular Biology, University of Texas, Austin, Texas, USA
| | - K. Andrew White
- Department of Biology, York University, Toronto, Ontario, Canada
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5
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Mine A, Hyodo K, Tajima Y, Kusumanegara K, Taniguchi T, Kaido M, Mise K, Taniguchi H, Okuno T. Differential roles of Hsp70 and Hsp90 in the assembly of the replicase complex of a positive-strand RNA plant virus. J Virol 2012; 86:12091-104. [PMID: 22933272 PMCID: PMC3486462 DOI: 10.1128/jvi.01659-12] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 08/21/2012] [Indexed: 02/06/2023] Open
Abstract
Assembly of viral replicase complexes of eukaryotic positive-strand RNA viruses is a regulated process: multiple viral and host components must be assembled on intracellular membranes and ordered into quaternary complexes capable of synthesizing viral RNAs. However, the molecular mechanisms underlying this process are poorly understood. In this study, we used a model virus, Red clover necrotic mosaic virus (RCNMV), whose replicase complex can be detected readily as the 480-kDa functional protein complex. We found that host heat shock proteins Hsp70 and Hsp90 are required for RCNMV RNA replication and that they interact with p27, a virus-encoded component of the 480-kDa replicase complex, on the endoplasmic reticulum membrane. Using a cell-free viral translation/replication system in combination with specific inhibitors of Hsp70 and Hsp90, we found that inhibition of p27-Hsp70 interaction inhibits the formation of the 480-kDa complex but instead induces the accumulation of large complexes that are nonfunctional in viral RNA synthesis. In contrast, inhibition of p27-Hsp90 interaction did not induce such large complexes but rendered p27 incapable of binding to a specific viral RNA element, which is a critical step for the assembly of the 480-kDa replicase complex and viral RNA replication. Together, our results suggest that Hsp70 and Hsp90 regulate different steps in the assembly of the RCNMV replicase complex.
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Affiliation(s)
- Akira Mine
- Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
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6
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Poly(A)-binding protein facilitates translation of an uncapped/nonpolyadenylated viral RNA by binding to the 3' untranslated region. J Virol 2012; 86:7836-49. [PMID: 22593149 DOI: 10.1128/jvi.00538-12] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Viruses employ an alternative translation mechanism to exploit cellular resources at the expense of host mRNAs and to allow preferential translation. Plant RNA viruses often lack both a 5' cap and a 3' poly(A) tail in their genomic RNAs. Instead, cap-independent translation enhancer elements (CITEs) located in the 3' untranslated region (UTR) mediate their translation. Although eukaryotic translation initiation factors (eIFs) or ribosomes have been shown to bind to the 3'CITEs, our knowledge is still limited for the mechanism, especially for cellular factors. Here, we searched for cellular factors that stimulate the 3'CITE-mediated translation of Red clover necrotic mosaic virus (RCNMV) RNA1 using RNA aptamer-based one-step affinity chromatography, followed by mass spectrometry analysis. We identified the poly(A)-binding protein (PABP) as one of the key players in the 3'CITE-mediated translation of RCNMV RNA1. We found that PABP binds to an A-rich sequence (ARS) in the viral 3' UTR. The ARS is conserved among dianthoviruses. Mutagenesis and a tethering assay revealed that the PABP-ARS interaction stimulates 3'CITE-mediated translation of RCNMV RNA1. We also found that both the ARS and 3'CITE are important for the recruitment of the plant eIF4F and eIFiso4F factors to the 3' UTR and of the 40S ribosomal subunit to the viral mRNA. Our results suggest that dianthoviruses have evolved the ARS and 3'CITE as substitutes for the 3' poly(A) tail and the 5' cap of eukaryotic mRNAs for the efficient recruitment of eIFs, PABP, and ribosomes to the uncapped/nonpolyadenylated viral mRNA.
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7
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Schmidt C, Kramer K, Urlaub H. Investigation of protein-RNA interactions by mass spectrometry--Techniques and applications. J Proteomics 2012; 75:3478-94. [PMID: 22575267 DOI: 10.1016/j.jprot.2012.04.030] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 04/19/2012] [Accepted: 04/22/2012] [Indexed: 12/26/2022]
Abstract
Protein-RNA complexes play many important roles in diverse cellular functions. They are involved in a wide variety of different processes in growth and differentiation at the various stages of the cell cycle. As their function and catalytic activity are directly coupled to the structural arrangement of their components--proteins and ribonucleic acids--the investigation of protein-RNA interactions is of great functional and structural importance. Here we discuss the most prominent examples of protein-RNA complexes and describe some frequently used purification strategies. We present various techniques and applications of mass spectrometry to study protein-RNA complexes. We discuss the analysis of intact complexes as well as proteomics-based and crosslinking-based approaches in which proteins are cleaved into smaller peptides. This article is part of a Special Section entitled: Understanding genome regulation and genetic diversity by mass spectrometry.
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Affiliation(s)
- Carla Schmidt
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
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8
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Identification of amino acids in auxiliary replicase protein p27 critical for its RNA-binding activity and the assembly of the replicase complex in Red clover necrotic mosaic virus. Virology 2011; 413:300-9. [PMID: 21440279 DOI: 10.1016/j.virol.2011.02.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Revised: 02/04/2011] [Accepted: 02/20/2011] [Indexed: 01/17/2023]
Abstract
The specific recognition of genomic RNAs by viral replicase proteins is a key regulatory step during the early replication process in positive-strand RNA viruses. In this study, we characterized the RNA-binding activity of the auxiliary replicase protein p27 of Red clover necrotic mosaic virus (RCNMV), which has a bipartite genome consisting of RNA1 and RNA2. Aptamer pull-down assays identified the amino acid residues of p27 involved in its specific interaction with RNA2. The RNA-binding activity of p27 correlated with its activity in recruiting RNA2 to membranes. We also identified the amino acids required for the formation of the 480-kDa replicase complex, a key player of RCNMV RNA replication. These amino acids are not involved in the functions of p27 that bind viral RNA or replicase proteins, suggesting an additional role for p27 in the assembly of the replicase complex. Our results demonstrate that p27 has multiple functions in RCNMV replication.
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Slobodin B, Gerst JE. RaPID: an aptamer-based mRNA affinity purification technique for the identification of RNA and protein factors present in ribonucleoprotein complexes. Methods Mol Biol 2011; 714:387-406. [PMID: 21431754 DOI: 10.1007/978-1-61779-005-8_24] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
RNA metabolism involves regulatory processes, such as transcription, splicing, nuclear export, transport and localization, association with sites of RNA modification, silencing and decay, and necessitates a wide variety of diverse RNA-interacting proteins. These interactions can be direct via RNA-binding proteins (RBPs) or indirect via other proteins and RNAs that form ribonucleoprotein complexes that together control RNA fate. While pull-down methods for the isolation of known RBPs are commonly used, strategies have also been described for the direct isolation of messenger RNAs (mRNAs) and their associated factors. The latter techniques allow for the identification of interacting proteins and RNAs, but most suffer from problems of low sensitivity and high background. Here we describe a simple and highly effective method for RNA purification and identification (RaPID) that allows for the isolation of specific mRNAs of interest from yeast and mammalian cells, and subsequent analysis of the associated proteins and RNAs using mass spectrometry and reverse transcription-PCR, respectively. This method employs the MS2 coat RBP fused to both GFP and streptavidin-binding protein to precipitate MS2 aptamer-tagged RNAs using immobilized streptavidin.
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Affiliation(s)
- Boris Slobodin
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
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10
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Iwakawa HO, Mine A, Hyodo K, An M, Kaido M, Mise K, Okuno T. Template recognition mechanisms by replicase proteins differ between bipartite positive-strand genomic RNAs of a plant virus. J Virol 2011; 85:497-509. [PMID: 20980498 PMCID: PMC3014169 DOI: 10.1128/jvi.01754-10] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Accepted: 10/21/2010] [Indexed: 01/14/2023] Open
Abstract
Recognition of RNA templates by viral replicase proteins is one of the key steps in the replication process of all RNA viruses. However, the mechanisms underlying this phenomenon, including primary RNA elements that are recognized by the viral replicase proteins, are not well understood. Here, we used aptamer pulldown assays with membrane fractionation and protein-RNA coimmunoprecipitation in a cell-free viral translation/replication system to investigate how viral replicase proteins recognize the bipartite genomic RNAs of the Red clover necrotic mosaic virus (RCNMV). RCNMV replicase proteins bound specifically to a Y-shaped RNA element (YRE) located in the 3' untranslated region (UTR) of RNA2, which also interacted with the 480-kDa replicase complexes that contain viral and host proteins. The replicase-YRE interaction recruited RNA2 to the membrane fraction. Conversely, RNA1 fragments failed to interact with the replicase proteins supplied in trans. The results of protein-RNA coimmunoprecipitation assays suggest that RNA1 interacts with the replicase proteins coupled with their translation. Thus, the initial template recognition mechanisms employed by the replicase differ between RCNMV bipartite genomic RNAs and RNA elements are primary determinants of the differential replication mechanism.
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Affiliation(s)
- Hiro-oki Iwakawa
- Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Akira Mine
- Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Kiwamu Hyodo
- Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Mengnan An
- Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Masanori Kaido
- Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Kazuyuki Mise
- Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Tetsuro Okuno
- Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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11
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Nicholson BL, Wu B, Chevtchenko I, White KA. Tombusvirus recruitment of host translational machinery via the 3' UTR. RNA (NEW YORK, N.Y.) 2010; 16:1402-19. [PMID: 20507975 PMCID: PMC2885689 DOI: 10.1261/rna.2135210] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
RNA viruses recruit the host translational machinery by different mechanisms that depend partly on the structure of their genomes. In this regard, the plus-strand RNA genomes of several different pathogenic plant viruses do not contain traditional translation-stimulating elements, i.e., a 5'-cap structure and a 3'-poly(A) tail, and instead rely on a 3'-cap-independent translational enhancer (3'CITE) located in their 3' untranslated regions (UTRs) for efficient synthesis of viral proteins. We investigated the structure and function of the I-shaped class of 3'CITE in tombusviruses--also present in aureusviruses and carmoviruses--using biochemical and molecular approaches and we determined that it adopts a complex higher-order RNA structure that facilitates translation by binding simultaneously to both eukaryotic initiation factor (eIF) 4F and the 5' UTR of the viral genome. The specificity of 3'CITE binding to eIF4F is mediated, at least in part, through a direct interaction with its eIF4E subunit, whereas its association with the viral 5' UTR relies on complementary RNA-RNA base-pairing. We show for the first time that this tripartite 5' UTR/3'CITE/eIF4F complex forms in vitro in a translationally relevant environment and is required for recruitment of ribosomes to the 5' end of the viral RNA genome by a mechanism that shares some fundamental features with cap-dependent translation. Notably, our results demonstrate that the 3'CITE facilitates the initiation step of translation and validate a molecular model that has been proposed to explain how several different classes of 3'CITE function. Moreover, the virus-host interplay defined in this study provides insights into natural host resistance mechanisms that have been linked to 3'CITE activity.
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Affiliation(s)
- Beth L Nicholson
- Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada
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12
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Unterberger A, Torrisani J, Szyf M. A method for purification, identification and validation of DNMT1 mRNA binding proteins. Biol Proced Online 2008; 10:47-57. [PMID: 19048127 PMCID: PMC2591025 DOI: 10.1251/bpo142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2007] [Revised: 01/28/2008] [Accepted: 01/31/2008] [Indexed: 11/30/2022] Open
Abstract
DNA methyltransferase 1 (DNMT1) is the enzyme responsible for the maintenance of DNA methylation patterns during cell division. DNMT1 expression is tightly regulated within the cell cycle. Our previous study showed that the binding of a protein with an apparent size of ~40 kDa on DNMT1 3’-UTR triggered the destabilization of DNMT1 mRNA transcript during Go/G1 phase. Using RNA affinity capture with the 3’-UTR of DNMT1 mRNA and matrix-assisted laser desorption-time of flight tandem mass spectrometry (MALDI-TOF-MS-MS) analysis, we isolated and identified AUF 1 (AU-rich element ARE:poly-(U)-binding/degradation factor) as the binding protein. We then validated the role of this protein in the destabilization of DNMT1 mRNA. In this report, we detail the different approaches used for the isolation, the identification of a RNA binding protein and the validation of its role.
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13
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Stead JA, McDowall KJ. Two-dimensional gel electrophoresis for identifying proteins that bind DNA or RNA. Nat Protoc 2007; 2:1839-48. [PMID: 17703194 DOI: 10.1038/nprot.2007.248] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Electrophoretic mobility shift assays (EMSAs) are commonly used to analyze nucleic acid-protein interactions. When nucleic acid is bound by protein, its mobility during gel electrophoresis is reduced. Similarly, the final position of protein within a complex is shifted when compared to its free state. Here we provide a protocol for a simple approach that uses these mobility differences to identify nucleic acid-binding proteins. Following EMSA, denaturing gel electrophoresis is implemented to provide a second dimension of separation. Protein that binds a specific nucleic acid is identified as a spot(s) whose presence at a particular position(s) is dependent on nucleic acid within the initial binding reaction. The polypeptide in a spot can be subsequently identified by mass spectrometry. As EMSAs can be performed using partially purified or cell extracts, this approach substantially reduces the need for protein purification. It should facilitate the identification of a nucleic acid-binding protein within approximately 4 d.
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Affiliation(s)
- Jonathan A Stead
- Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK
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14
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Windbichler N, Schroeder R. Isolation of specific RNA-binding proteins using the streptomycin-binding RNA aptamer. Nat Protoc 2007; 1:637-40. [PMID: 17406291 DOI: 10.1038/nprot.2006.95] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Here we report a simple and cheap one-step affinity purification protocol for isolating RNAs or proteins that interact with selected functional RNAs. The streptomycin-binding aptamer, termed 'StreptoTag,' is embedded in or fused to either end of any RNA of interest. The resulting hybrid RNA can then be immobilized on a streptomycin affinity matrix. When a complex protein mixture or total cellular lysate is applied to the matrix, subsequent elution with free streptomycin allows efficient recovery of specific ribonucleoprotein or RNA-RNA complexes. The method was successfully used to purify yeast and phage RNA-binding proteins and group II intron, viral and bacterial noncoding RNA (ncRNA)-binding proteins. The selective enrichment of bacterial mRNAs that bind ncRNAs has also been demonstrated. Once the affinity matrix, the RNA construct and the protein extracts have been prepared, the experimental procedure can be performed in 1-2 h.
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Affiliation(s)
- Nikolai Windbichler
- Imperial College London, Department of Biological Sciences, Imperial College Road, London SW7 2AZ, UK
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15
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Hégarat N, Cardoso GM, Rusconi F, François JC, Praseuth D. Analytical biochemistry of DNA--protein assemblies from crude cell extracts. Nucleic Acids Res 2007; 35:e92. [PMID: 17617645 PMCID: PMC1935021 DOI: 10.1093/nar/gkm490] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Purification of specific DNA-protein complexes is a challenging task, as the involved interactions can be both electrostatic/H-bond and hydrophobic. The chromatographic stringency needed to obtain reasonable purifications uses salts and detergents. However, these components elicit the removal of proteins unspecifically bound to the chromatographic support itself, thus contaminating the purification products. In this work, a photocleavable linker connected the target oligonucleotidic sequence to the chromatographic beads so as to allow the irradiation-based release of the purified DNA-protein complexes off the beads. Our bioanalytical conditions were validated by purifying the tetracycline repressor protein onto a specific oligonucleotide. The purification factor was unprecedented, with a single contaminant. The robustness of our method was challenged by applying it to the purification of multiprotein assemblies forming onto DNA damage-mimicking oligonucleotides. The purified components were identified as well-known DNA repair proteins, and were shown to retain their enzymatic activities, as seen by monitoring DNA ligation products. Remarkably, kinase activities, also monitored, were found to be distinct on the beads and on the purified DNA-protein complexes, showing the benefits to uncouple the DNA-protein assemblies from the beads for a proper understanding of biochemical regulatory mechanisms involved in the DNA-protein assemblies.
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Affiliation(s)
- Nadia Hégarat
- INSERM, U565 and MNHN, USM503, Département de ‘Régulations, développement et diversité moléculaire’, Laboratoire des Régulations et dynamique des génomes, CNRS, UMR5153, Acides nucléiques: dynamique, ciblage et fonctions biologiques, 57 rue Cuvier, CP26, Paris Cedex 05, F-75231, France
| | - Gildas Mouta Cardoso
- INSERM, U565 and MNHN, USM503, Département de ‘Régulations, développement et diversité moléculaire’, Laboratoire des Régulations et dynamique des génomes, CNRS, UMR5153, Acides nucléiques: dynamique, ciblage et fonctions biologiques, 57 rue Cuvier, CP26, Paris Cedex 05, F-75231, France
| | - Filippo Rusconi
- INSERM, U565 and MNHN, USM503, Département de ‘Régulations, développement et diversité moléculaire’, Laboratoire des Régulations et dynamique des génomes, CNRS, UMR5153, Acides nucléiques: dynamique, ciblage et fonctions biologiques, 57 rue Cuvier, CP26, Paris Cedex 05, F-75231, France
| | - Jean-Christophe François
- INSERM, U565 and MNHN, USM503, Département de ‘Régulations, développement et diversité moléculaire’, Laboratoire des Régulations et dynamique des génomes, CNRS, UMR5153, Acides nucléiques: dynamique, ciblage et fonctions biologiques, 57 rue Cuvier, CP26, Paris Cedex 05, F-75231, France
| | - Danièle Praseuth
- INSERM, U565 and MNHN, USM503, Département de ‘Régulations, développement et diversité moléculaire’, Laboratoire des Régulations et dynamique des génomes, CNRS, UMR5153, Acides nucléiques: dynamique, ciblage et fonctions biologiques, 57 rue Cuvier, CP26, Paris Cedex 05, F-75231, France
- *To whom correspondence should be addressed. +33 1 40 79 37 10+33 1 40 79 37 05 Correspondence may also be addressed to Dr. Jean-Christophe François, +33 1 40 79 38 01+33 1 40 79 37 05
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16
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Abstract
Aptamers are artificial nucleic acid ligands that can be generated in vitro against a wide range of molecules, including the gene products of viruses. Aptamers are isolated from complex libraries of synthetic nucleic acids by an iterative, cell-free process that involves repetitively reducing the complexity of the library by partitioning on the basis of selective binding to the target molecule, followed by reamplification. For virologists, aptamers have potential uses as tools to help to analyse the molecular biology of virus replication, as a complement to the more familiar monoclonal antibodies. They also have potential applications as diagnostic biosensors and in the development of antiviral agents. In recent years, these two promising avenues have been explored increasingly by virologists; here, the progress that has been made is reviewed.
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Affiliation(s)
- William James
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX2 3RE, UK
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17
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Piekna-Przybylska D, Liu B, Fournier MJ. The U1 snRNA hairpin II as a RNA affinity tag for selecting snoRNP complexes. Methods Enzymol 2007; 425:317-53. [PMID: 17673090 DOI: 10.1016/s0076-6879(07)25014-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
When isolating ribonucleoprotein (RNP) complexes by an affinity selection approach, tagging the RNA component can prove to be strategically important. This is especially true for purifying single types of snoRNPs, because in most cases the snoRNA is thought to be the only unique component. Here, we present a general strategy for selecting specific snoRNPs that features a high-affinity tag in the snoRNA and another in a snoRNP core protein. The RNA tag (called U1hpII) is a small (26 nt) stem-loop domain from human U1 snRNA. This structure binds with high affinity (K(D)=10(-11)M) to the RRM domain of the snRNP protein U1A. In our approach, the U1A protein contains a unique affinity tag and is coexpressed in vivo with the tagged snoRNA to yield snoRNP-U1A complexes with two unique protein tags-one in the bound U1A protein and the other in the snoRNP core protein. This scheme has been used effectively to select C/D and H/ACA snoRNPs, including both processing and modifying snoRNPs, and the snoRNA and core proteins are highly enriched. Depending on selection stringency other proteins are isolated as well, including an RNA helicase involved in snoRNP release from pre-rRNA and additional proteins that function in ribosome biogenesis. Tagging the snoRNA component alone is also effective when U1A is expressed with a myc-Tev-protein A fusion sequence. Combined with reduced stringency, enrichment of the U14 snoRNP with this latter system revealed potential interactions with two other snoRNPs, including one processing snoRNP involved in the same cleavages of pre-rRNA.
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