1
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Soueid DM, Garner AL. Adaptation of RiPCA for the Live-Cell Detection of mRNA-Protein Interactions. Biochemistry 2023; 62:3323-3336. [PMID: 37963240 DOI: 10.1021/acs.biochem.3c00334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2023]
Abstract
RNA-binding proteins (RBPs) act as essential regulators of cell fate decisions, through their ability to bind and regulate the activity of cellular RNAs. For protein-coding mRNAs, RBPs control the localization, stability, degradation, and ultimately translation of mRNAs to impact gene expression. Disruption of the vast network of mRNA-protein interactions has been implicated in many human diseases, and accordingly, targeting these interactions has surfaced as a new frontier in RNA-targeted drug discovery. To catalyze this new field, methods are needed to enable the detection and subsequent screening of mRNA-RBP interactions, particularly in live cells. Using our laboratory's RNA-interaction with Protein-mediated Complementation Assay (RiPCA) technology, herein we describe its application to mRNA-protein interactions and present a guide for the development of future RiPCA assays for structurally diverse classes of mRNA-protein interactions.
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Affiliation(s)
- Dalia M Soueid
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Amanda L Garner
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109, United States
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2
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Kumar D, Sahoo SS, Chauss D, Kazemian M, Afzali B. Non-coding RNAs in immunoregulation and autoimmunity: Technological advances and critical limitations. J Autoimmun 2023; 134:102982. [PMID: 36592512 PMCID: PMC9908861 DOI: 10.1016/j.jaut.2022.102982] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/11/2022] [Accepted: 12/15/2022] [Indexed: 01/02/2023]
Abstract
Immune cell function is critically dependent on precise control over transcriptional output from the genome. In this respect, integration of environmental signals that regulate gene expression, specifically by transcription factors, enhancer DNA elements, genome topography and non-coding RNAs (ncRNAs), are key components. The first three have been extensively investigated. Even though non-coding RNAs represent the vast majority of cellular RNA species, this class of RNA remains historically understudied. This is partly because of a lag in technological and bioinformatic innovations specifically capable of identifying and accurately measuring their expression. Nevertheless, recent progress in this domain has enabled a profusion of publications identifying novel sub-types of ncRNAs and studies directly addressing the function of ncRNAs in human health and disease. Many ncRNAs, including circular and enhancer RNAs, have now been demonstrated to play key functions in the regulation of immune cells and to show associations with immune-mediated diseases. Some ncRNAs may function as biomarkers of disease, aiding in diagnostics and in estimating response to treatment, while others may play a direct role in the pathogenesis of disease. Importantly, some are relatively stable and are amenable to therapeutic targeting, for example through gene therapy. Here, we provide an overview of ncRNAs and review technological advances that enable their study and hold substantial promise for the future. We provide context-specific examples by examining the associations of ncRNAs with four prototypical human autoimmune diseases, specifically rheumatoid arthritis, psoriasis, inflammatory bowel disease and multiple sclerosis. We anticipate that the utility and mechanistic roles of these ncRNAs in autoimmunity will be further elucidated in the near future.
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Affiliation(s)
- Dhaneshwar Kumar
- Immunoregulation Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), NIH, Bethesda, MD, USA
| | - Subhransu Sekhar Sahoo
- Departments of Biochemistry and Computer Science, Purdue University, West Lafayette, IN, USA
| | - Daniel Chauss
- Immunoregulation Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), NIH, Bethesda, MD, USA
| | - Majid Kazemian
- Departments of Biochemistry and Computer Science, Purdue University, West Lafayette, IN, USA
| | - Behdad Afzali
- Immunoregulation Section, Kidney Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), NIH, Bethesda, MD, USA.
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3
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Neusius D, Kleinknecht L, Teh JT, Ostermeier M, Kelterborn S, Eirich J, Hegemann P, Finkemeier I, Bohne AV, Nickelsen J. Lysine acetylation regulates moonlighting activity of the E2 subunit of the chloroplast pyruvate dehydrogenase complex in Chlamydomonas. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 111:1780-1800. [PMID: 35899410 DOI: 10.1111/tpj.15924] [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: 04/26/2022] [Revised: 07/08/2022] [Accepted: 07/18/2022] [Indexed: 06/15/2023]
Abstract
The dihydrolipoamide acetyltransferase subunit DLA2 of the chloroplast pyruvate dehydrogenase complex (cpPDC) in the green alga Chlamydomonas reinhardtii has previously been shown to possess moonlighting activity in chloroplast gene expression. Under mixotrophic growth conditions, DLA2 forms part of a ribonucleoprotein particle (RNP) with the psbA mRNA that encodes the D1 protein of the photosystem II (PSII) reaction center. Here, we report on the characterization of the molecular switch that regulates shuttling of DLA2 between its functions in carbon metabolism and D1 synthesis. Determination of RNA-binding affinities by microscale thermophoresis demonstrated that the E3-binding domain (E3BD) of DLA2 mediates psbA-specific RNA recognition. Analyses of cpPDC formation and activity, as well as RNP complex formation, showed that acetylation of a single lysine residue (K197) in E3BD induces the release of DLA2 from the cpPDC, and its functional shift towards RNA binding. Moreover, Förster resonance energy transfer microscopy revealed that psbA mRNA/DLA2 complexes localize around the chloroplast's pyrenoid. Pulse labeling and D1 re-accumulation after induced PSII degradation strongly suggest that DLA2 is important for D1 synthesis during de novo PSII biogenesis.
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Affiliation(s)
- Daniel Neusius
- Molecular Plant Sciences, Faculty of Biology, LMU Munich, Großhaderner Str. 2-4, 82152 Planegg-, Martinsried, Germany
| | - Laura Kleinknecht
- Molecular Plant Sciences, Faculty of Biology, LMU Munich, Großhaderner Str. 2-4, 82152 Planegg-, Martinsried, Germany
| | - Jing Tsong Teh
- Molecular Plant Sciences, Faculty of Biology, LMU Munich, Großhaderner Str. 2-4, 82152 Planegg-, Martinsried, Germany
| | - Matthias Ostermeier
- Molecular Plant Sciences, Faculty of Biology, LMU Munich, Großhaderner Str. 2-4, 82152 Planegg-, Martinsried, Germany
| | - Simon Kelterborn
- Experimental Biophysics, Institute of Biology, Humboldt University of Berlin, Invalidenstr. 42, 10115, Berlin, Germany
| | - Jürgen Eirich
- Institute of Plant Biology and Biotechnology, University of Muenster, Schlossplatz 7, 48149, Münster, Germany
| | - Peter Hegemann
- Experimental Biophysics, Institute of Biology, Humboldt University of Berlin, Invalidenstr. 42, 10115, Berlin, Germany
| | - Iris Finkemeier
- Institute of Plant Biology and Biotechnology, University of Muenster, Schlossplatz 7, 48149, Münster, Germany
| | - Alexandra-Viola Bohne
- Molecular Plant Sciences, Faculty of Biology, LMU Munich, Großhaderner Str. 2-4, 82152 Planegg-, Martinsried, Germany
| | - Jörg Nickelsen
- Molecular Plant Sciences, Faculty of Biology, LMU Munich, Großhaderner Str. 2-4, 82152 Planegg-, Martinsried, Germany
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4
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Fluorescent Platforms for RNA Chemical Biology Research. Genes (Basel) 2022; 13:genes13081348. [PMID: 36011259 PMCID: PMC9407474 DOI: 10.3390/genes13081348] [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: 06/30/2022] [Revised: 07/21/2022] [Accepted: 07/22/2022] [Indexed: 12/03/2022] Open
Abstract
Efficient detection and observation of dynamic RNA changes remain a tremendous challenge. However, the continuous development of fluorescence applications in recent years enhances the efficacy of RNA imaging. Here we summarize some of these developments from different aspects. For example, single-molecule fluorescence in situ hybridization (smFISH) can detect low abundance RNA at the subcellular level. A relatively new aptamer, Mango, is widely applied to label and track RNA activities in living cells. Molecular beacons (MBs) are valid for quantifying both endogenous and exogenous mRNA and microRNA (miRNA). Covalent binding enzyme labeling fluorescent group with RNA of interest (ROI) partially overcomes the RNA length limitation associated with oligonucleotide synthesis. Forced intercalation (FIT) probes are resistant to nuclease degradation upon binding to target RNA and are used to visualize mRNA and messenger ribonucleoprotein (mRNP) activities. We also summarize the importance of some fluorescence spectroscopic techniques in exploring the function and movement of RNA. Single-molecule fluorescence resonance energy transfer (smFRET) has been employed to investigate the dynamic changes of biomolecules by covalently linking biotin to RNA, and a focus on dye selection increases FRET efficiency. Furthermore, the applications of fluorescence assays in drug discovery and drug delivery have been discussed. Fluorescence imaging can also combine with RNA nanotechnology to target tumors. The invention of novel antibacterial drugs targeting non-coding RNAs (ncRNAs) is also possible with steady-state fluorescence-monitored ligand-binding assay and the T-box riboswitch fluorescence anisotropy assay. More recently, COVID-19 tests using fluorescent clustered regularly interspaced short palindromic repeat (CRISPR) technology have been demonstrated to be efficient and clinically useful. In summary, fluorescence assays have significant applications in both fundamental and clinical research and will facilitate the process of RNA-targeted new drug discovery, therefore deserving further development and updating.
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5
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Rosenblum SL, Garner AL. RiPCA: An Assay for the Detection of RNA-Protein Interactions in Live Cells. Curr Protoc 2022; 2:e358. [PMID: 35113480 PMCID: PMC8852372 DOI: 10.1002/cpz1.358] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Increasing interest in studying and modulating the interactions between RNAs and their RNA-binding proteins has indicated the need for enabling technologies. Existing means of detecting RNA-protein interactions (RPIs) are often limited to biochemical or post-lysis methods or cell-based methods that require the addition of an RNA-based affinity tag, such as the MS2 hairpin, precluding them from use in detecting small or highly processed RNAs. Taking advantage of bioorthogonal chemistry- and split-luciferase-based technologies, we developed an assay for the detection of RPIs in live cells. This article details the protocol and design considerations for RiPCA, or RNA interaction with Protein-mediated Complementation Assay. © 2022 Wiley Periodicals LLC.
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Affiliation(s)
| | - Amanda L. Garner
- Program in Chemical Biology, University of Michigan, Ann Arbor, MI,Department of Medicinal Chemistry, College of Pharmacy, University of Michigan, Ann Arbor, MI
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6
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Chen M, Li S, Li W, Zhang ZP, Zhang X, Zhang XE, Ge F, Cui Z. Nanoscale Imaging of RNA-Protein Interactions with a Photoactivatable Trimolecular Fluorescence Complementation System. ACS Chem Biol 2021; 16:1003-1010. [PMID: 34009928 DOI: 10.1021/acschembio.0c00945] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Imaging RNA-protein interaction in the cellular space with single molecule sensitivity is attractive for studying gene expression and regulation, but remains a challenge. In this study, we reported a photoactivatable trimolecular fluorescence complementation (TriFC) system based on fluorescent protein, mIrisFP, to identify and visualize RNA-protein interactions in living mammalian cells. We also combined this TriFC system with photoactivated localization microscopy (PALM), named the TriFC-PALM technique, which allowed us to image the RNA-protein interactions with single molecule sensitivity. Using this TriFC-PALM technique, we identified the actin-bundling protein, FSCN1, specifically interacting with the HOX Transcript Antisense RNA (HOTAIR). The TriFC-PALM imaging acquired a higher resolution compared with the traditional method of total internal reflection (TIRF) imaging. The TriFC-PALM thus provides a useful tool for imaging and identifying the RNA-protein interactions inside cells at the nanometer scale.
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Affiliation(s)
- Minghai Chen
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China
- CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Siting Li
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Wei Li
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Zhi-Ping Zhang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Xiaowei Zhang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China
| | - Xian-En Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Feng Ge
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Zongqiang Cui
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430071, China
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7
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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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8
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Rosenblum SL, Lorenz DA, Garner AL. A live-cell assay for the detection of pre-microRNA-protein interactions. RSC Chem Biol 2021; 2:241-247. [PMID: 33817642 PMCID: PMC8006716 DOI: 10.1039/d0cb00055h] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 11/26/2020] [Indexed: 12/12/2022] Open
Abstract
Recent efforts in genome-wide sequencing and proteomics have revealed the fundamental roles that RNA-binding proteins (RBPs) play in the life cycle and function of coding and non-coding RNAs. While these methodologies provide a systems-level view of the networking of RNA and proteins, approaches to enable the cellular validation of discovered interactions are lacking. Leveraging the power of bioorthogonal chemistry- and split-luciferase-based assay technologies, we have devised a conceptually new assay for the live-cell detection of RNA-protein interactions (RPIs), RNA interaction with Protein-mediated Complementation Assay, or RiPCA. As proof-of-concept, we utilized the interaction of the pre-microRNA, pre-let-7, with its binding partner, Lin28. Using this system, we have demonstrated the selective detection of the pre-let-7-Lin28 RPI in both the cytoplasm and nucleus. Furthermore, we determined that this technology can be used to discern relative affinities for specific sequences as well as of individual RNA binding domains. Thus, RiPCA has the potential to serve as a useful tool in supporting the investigation of cellular RPIs.
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Affiliation(s)
- Sydney L Rosenblum
- Program in Chemical Biology , University of Michigan , 210 Washtenaw Avenue , Ann Arbor , Michigan 48109 , USA .
| | - Daniel A Lorenz
- Program in Chemical Biology , University of Michigan , 210 Washtenaw Avenue , Ann Arbor , Michigan 48109 , USA .
| | - Amanda L Garner
- Program in Chemical Biology , University of Michigan , 210 Washtenaw Avenue , Ann Arbor , Michigan 48109 , USA .
- Department of Medicinal Chemistry , College of Pharmacy , University of Michigan , 428 Church Street , Ann Arbor , Michigan 48109 , USA
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9
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Yu S, Li F, Huang X, Dong C, Ren J. In Situ Study of Interactions between Endogenous c-myc mRNA with CRDBP in a Single Living Cell by Combining Fluorescence Cross-Correlation Spectroscopy with Molecular Beacons. Anal Chem 2020; 92:2988-2996. [DOI: 10.1021/acs.analchem.9b03934] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Shengrong Yu
- School of Chemistry & Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, P. R. China
| | - Fucai Li
- School of Chemistry & Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, P. R. China
| | - Xiangyi Huang
- School of Chemistry & Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, P. R. China
| | - Chaoqing Dong
- School of Chemistry & Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, P. R. China
| | - Jicun Ren
- School of Chemistry & Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, P. R. China
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10
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Baroux C, Schubert V. Technical Review: Microscopy and Image Processing Tools to Analyze Plant Chromatin: Practical Considerations. Methods Mol Biol 2018; 1675:537-589. [PMID: 29052212 DOI: 10.1007/978-1-4939-7318-7_31] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2023]
Abstract
In situ nucleus and chromatin analyses rely on microscopy imaging that benefits from versatile, efficient fluorescent probes and proteins for static or live imaging. Yet the broad choice in imaging instruments offered to the user poses orientation problems. Which imaging instrument should be used for which purpose? What are the main caveats and what are the considerations to best exploit each instrument's ability to obtain informative and high-quality images? How to infer quantitative information on chromatin or nuclear organization from microscopy images? In this review, we present an overview of common, fluorescence-based microscopy systems and discuss recently developed super-resolution microscopy systems, which are able to bridge the resolution gap between common fluorescence microscopy and electron microscopy. We briefly present their basic principles and discuss their possible applications in the field, while providing experience-based recommendations to guide the user toward best-possible imaging. In addition to raw data acquisition methods, we discuss commercial and noncommercial processing tools required for optimal image presentation and signal evaluation in two and three dimensions.
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Affiliation(s)
- Célia Baroux
- Department of Plant and Microbial Biology, Zürich-Basel Plant Science Center, University of Zürich, Zollikerstrasse 107, 8008, Zürich, Switzerland.
| | - Veit Schubert
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, 06466, Seeland, Germany
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11
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van Gijtenbeek LA, Kok J. Illuminating Messengers: An Update and Outlook on RNA Visualization in Bacteria. Front Microbiol 2017; 8:1161. [PMID: 28690601 PMCID: PMC5479882 DOI: 10.3389/fmicb.2017.01161] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 06/07/2017] [Indexed: 01/04/2023] Open
Abstract
To be able to visualize the abundance and spatiotemporal features of RNAs in bacterial cells would permit obtaining a pivotal understanding of many mechanisms underlying bacterial cell biology. The first methods that allowed observing single mRNA molecules in individual cells were introduced by Bertrand et al. (1998) and Femino et al. (1998). Since then, a plethora of techniques to image RNA molecules with the aid of fluorescence microscopy has emerged. Many of these approaches are useful for the large eukaryotic cells but their adaptation to study RNA, specifically mRNA molecules, in bacterial cells progressed relatively slow. Here, an overview will be given of fluorescent techniques that can be used to reveal specific RNA molecules inside fixed and living single bacterial cells. It includes a critical evaluation of their caveats as well as potential solutions.
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Affiliation(s)
- Lieke A van Gijtenbeek
- Department of Molecular Genetics, Faculty of Science and Engineering, University of GroningenGroningen, Netherlands
| | - Jan Kok
- Department of Molecular Genetics, Faculty of Science and Engineering, University of GroningenGroningen, Netherlands
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12
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Integrated structural biology to unravel molecular mechanisms of protein-RNA recognition. Methods 2017; 118-119:119-136. [PMID: 28315749 DOI: 10.1016/j.ymeth.2017.03.015] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 02/19/2017] [Accepted: 03/13/2017] [Indexed: 12/20/2022] Open
Abstract
Recent advances in RNA sequencing technologies have greatly expanded our knowledge of the RNA landscape in cells, often with spatiotemporal resolution. These techniques identified many new (often non-coding) RNA molecules. Large-scale studies have also discovered novel RNA binding proteins (RBPs), which exhibit single or multiple RNA binding domains (RBDs) for recognition of specific sequence or structured motifs in RNA. Starting from these large-scale approaches it is crucial to unravel the molecular principles of protein-RNA recognition in ribonucleoprotein complexes (RNPs) to understand the underlying mechanisms of gene regulation. Structural biology and biophysical studies at highest possible resolution are key to elucidate molecular mechanisms of RNA recognition by RBPs and how conformational dynamics, weak interactions and cooperative binding contribute to the formation of specific, context-dependent RNPs. While large compact RNPs can be well studied by X-ray crystallography and cryo-EM, analysis of dynamics and weak interaction necessitates the use of solution methods to capture these properties. Here, we illustrate methods to study the structure and conformational dynamics of protein-RNA complexes in solution starting from the identification of interaction partners in a given RNP. Biophysical and biochemical techniques support the characterization of a protein-RNA complex and identify regions relevant in structural analysis. Nuclear magnetic resonance (NMR) is a powerful tool to gain information on folding, stability and dynamics of RNAs and characterize RNPs in solution. It provides crucial information that is complementary to the static pictures derived from other techniques. NMR can be readily combined with other solution techniques, such as small angle X-ray and/or neutron scattering (SAXS/SANS), electron paramagnetic resonance (EPR), and Förster resonance energy transfer (FRET), which provide information about overall shapes, internal domain arrangements and dynamics. Principles of protein-RNA recognition and current approaches are reviewed and illustrated with recent studies.
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13
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A Novel Method to Quantify RNA-Protein Interactions In Situ Using FMTRIP and Proximity Ligation. Methods Mol Biol 2017; 1468:155-70. [PMID: 27662876 DOI: 10.1007/978-1-4939-4035-6_12] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
RNA binding proteins (RBP) and small RNAs regulate the editing, localization, stabilization, translation, and degradation of ribonucleic acids (RNAs) through their interactions with specific cis-acting elements within target RNAs. Here, we describe a novel method to detect protein-mRNA interactions, which combines FLAG-peptide modified, multiply-labeled tetravalent RNA imaging probes (FMTRIPs) with proximity ligation (PLA), and rolling circle amplification (RCA). This assay detects native RNA in a sequence specific and single RNA sensitive manner, and PLA allows for the quantification and localization of protein-mRNA interactions with single-interaction sensitivity.
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14
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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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15
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Zurla C, Jung J, Santangelo PJ. Can we observe changes in mRNA "state"? Overview of methods to study mRNA interactions with regulatory proteins relevant in cancer related processes. Analyst 2016; 141:548-62. [PMID: 26605378 PMCID: PMC4701657 DOI: 10.1039/c5an01959a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
RNA binding proteins (RBP) regulate the editing, localization, stabilization, translation, and degradation of ribonucleic acids (RNA) through their interactions with specific cis-acting elements within target RNAs. Post-transcriptional regulatory mechanisms are directly involved in the control of the immune response and stress response and their alterations play a crucial role in cancer related processes. In this review, we discuss mRNAs and RNA binding proteins relevant to tumorigenesis, current methodologies for detecting RNA interactions, and last, we describe a novel method to detect such interactions, which combines peptide modified, RNA imaging probes (FMTRIPs) with proximity ligation (PLA) and rolling circle amplification (RCA). This assay detects native RNA in a sequence specific and single RNA sensitive manner, and PLA allows for the quantification and localization of protein-mRNA interactions with single-interaction sensitivity in situ.
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Affiliation(s)
- C Zurla
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, UA Whitaker Blgd, Atlanta, GA 30332, USA.
| | - J Jung
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, UA Whitaker Blgd, Atlanta, GA 30332, USA.
| | - P J Santangelo
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, UA Whitaker Blgd, Atlanta, GA 30332, USA.
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16
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New insights into functional roles of the polypyrimidine tract-binding protein. Int J Mol Sci 2013; 14:22906-32. [PMID: 24264039 PMCID: PMC3856098 DOI: 10.3390/ijms141122906] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2013] [Revised: 11/13/2013] [Accepted: 11/13/2013] [Indexed: 12/20/2022] Open
Abstract
Polypyrimidine Tract Binding Protein (PTB) is an intensely studied RNA binding protein involved in several post-transcriptional regulatory events of gene expression. Initially described as a pre-mRNA splicing regulator, PTB is now widely accepted as a multifunctional protein shuttling between nucleus and cytoplasm. Accordingly, PTB can interact with selected RNA targets, structural elements and proteins. There is increasing evidence that PTB and its paralog PTBP2 play a major role as repressors of alternatively spliced exons, whose transcription is tissue-regulated. In addition to alternative splicing, PTB is involved in almost all steps of mRNA metabolism, including polyadenylation, mRNA stability and initiation of protein translation. Furthermore, it is well established that PTB recruitment in internal ribosome entry site (IRES) activates the translation of picornaviral and cellular proteins. Detailed studies of the structural properties of PTB have contributed to our understanding of the mechanism of RNA binding by RNA Recognition Motif (RRM) domains. In the present review, we will describe the structural properties of PTB, its paralogs and co-factors, the role in post-transcriptional regulation and actions in cell differentiation and pathogenesis. Defining the multifunctional roles of PTB will contribute to the understanding of key regulatory events in gene expression.
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17
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Yin J, Zhu D, Zhang Z, Wang W, Fan J, Men D, Deng J, Wei H, Zhang XE, Cui Z. Imaging of mRNA-protein interactions in live cells using novel mCherry trimolecular fluorescence complementation systems. PLoS One 2013; 8:e80851. [PMID: 24260494 PMCID: PMC3829953 DOI: 10.1371/journal.pone.0080851] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Accepted: 10/15/2013] [Indexed: 11/18/2022] Open
Abstract
Live cell imaging of mRNA-protein interactions makes it possible to study posttranscriptional processes of cellular and viral gene expression under physiological conditions. In this study, red color mCherry-based trimolecular fluorescence complementation (TriFC) systems were constructed as new tools for visualizing mRNA-protein interaction in living cells using split mCherry fragments and HIV REV-RRE and TAT-TAR peptide-RNA interaction pairs. The new mCherry TriFC systems were successfully used to image RNA-protein interactions such as that between influenza viral protein NS1 and the 5' UTR of influenza viral mRNAs NS, M, and NP. Upon combination of an mCherry TriFC system with a Venus TriFC system, multiple mRNA-protein interactions could be detected simultaneously in the same cells. Then, the new mCherry TriFC system was used for imaging of interactions between influenza A virus mRNAs and some of adapter proteins in cellular TAP nuclear export pathway in live cells. Adapter proteins Aly and UAP56 were found to associate with three kinds of viral mRNAs. Another adapter protein, splicing factor 9G8, only interacted with intron-containing spliced M2 mRNA. Co-immunoprecipitation assays with influenza A virus-infected cells confirmed these interactions. This study provides long-wavelength-spectrum TriFC systems as new tools for visualizing RNA-protein interactions in live cells and help to understand the nuclear export mechanism of influenza A viral mRNAs.
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Affiliation(s)
- Juan Yin
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
- Graduate University of Chinese Academy of Sciences, Beijing, China
| | - Duanhao Zhu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
- Graduate University of Chinese Academy of Sciences, Beijing, China
| | - Zhiping Zhang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Wei Wang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Jinyu Fan
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Dong Men
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Jiaoyu Deng
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Hongping Wei
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Xian-En Zhang
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
| | - Zongqiang Cui
- State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China
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18
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Gooding C, Edge C, Lorenz M, Coelho MB, Winters M, Kaminski CF, Cherny D, Eperon IC, Smith CWJ. MBNL1 and PTB cooperate to repress splicing of Tpm1 exon 3. Nucleic Acids Res 2013; 41:4765-82. [PMID: 23511971 PMCID: PMC3643581 DOI: 10.1093/nar/gkt168] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Exon 3 of the rat α-tropomyosin (Tpm1) gene is repressed in smooth muscle cells, allowing inclusion of the mutually exclusive partner exon 2. Two key types of elements affect repression of exon 3 splicing: binding sites for polypyrimidine tract-binding protein (PTB) and additional negative regulatory elements consisting of clusters of UGC or CUG motifs. Here, we show that the UGC clusters are bound by muscleblind-like proteins (MBNL), which act as repressors of Tpm1 exon 3. We show that the N-terminal region of MBNL1, containing its four CCCH zinc-finger domains, is sufficient to mediate repression. The same region of MBNL1 can make a direct protein-to-protein interaction with PTB, and RNA binding by MBNL promotes this interaction, apparently by inducing a conformational change in MBNL. Moreover, single molecule analysis showed that MBNL-binding sites increase the binding of PTB to its own sites. Our data suggest that the smooth muscle splicing of Tpm1 is mediated by allosteric assembly of an RNA–protein complex minimally comprising PTB, MBNL and their cognate RNA-binding sites.
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Affiliation(s)
- Clare Gooding
- Department of Biochemistry, University of Cambridge, CB2 1QW, UK
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19
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Ruggero D. Translational control in cancer etiology. Cold Spring Harb Perspect Biol 2013; 5:cshperspect.a012336. [PMID: 22767671 DOI: 10.1101/cshperspect.a012336] [Citation(s) in RCA: 221] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The link between perturbations in translational control and cancer etiology is becoming a primary focus in cancer research. It has now been established that genetic alterations in several components of the translational apparatus underlie spontaneous cancers as well as an entire class of inherited syndromes known as "ribosomopathies" associated with increased cancer susceptibility. These discoveries have illuminated the importance of deregulations in translational control to very specific cellular processes that contribute to cancer etiology. In addition, a growing body of evidence supports the view that deregulation of translational control is a common mechanism by which diverse oncogenic pathways promote cellular transformation and tumor development. Indeed, activation of these key oncogenic pathways induces rapid and dramatic translational reprogramming both by increasing overall protein synthesis and by modulating specific mRNA networks. These translational changes promote cellular transformation, impacting almost every phase of tumor development. This paradigm represents a new frontier in the multihit model of cancer formation and offers significant promise for innovative cancer therapies. Current research, in conjunction with cutting edge technologies, will further enable us to explore novel mechanisms of translational control, functionally identify translationally controlled mRNA groups, and unravel their impact on cellular transformation and tumorigenesis.
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Affiliation(s)
- Davide Ruggero
- Helen Diller Cancer Center, School of Medicine, University of California, San Francisco, CA 94158, USA.
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20
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Single-stranded nucleic acids promote SAMHD1 complex formation. J Mol Med (Berl) 2013; 91:759-70. [PMID: 23371319 DOI: 10.1007/s00109-013-0995-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Revised: 12/03/2012] [Accepted: 01/02/2013] [Indexed: 10/27/2022]
Abstract
SAM domain and HD domain-containing protein 1 (SAMHD1) is a dGTP-dependent triphosphohydrolase that degrades deoxyribonucleoside triphosphates (dNTPs) thereby limiting the intracellular dNTP pool. Mutations in SAMHD1 cause Aicardi-Goutières syndrome (AGS), an inflammatory encephalopathy that mimics congenital viral infection and that phenotypically overlaps with the autoimmune disease systemic lupus erythematosus. Both disorders are characterized by activation of the antiviral cytokine interferon-α initiated by immune recognition of self nucleic acids. Here we provide first direct evidence that SAMHD1 associates with endogenous nucleic acids in situ. Using fluorescence cross-correlation spectroscopy, we demonstrate that SAMHD1 specifically interacts with ssRNA and ssDNA and establish that nucleic acid-binding and formation of SAMHD1 complexes are mutually dependent. Interaction with nucleic acids and complex formation do not require the SAM domain, but are dependent on the HD domain and the C-terminal region of SAMHD1. We finally demonstrate that mutations associated with AGS exhibit both impaired nucleic acid-binding and complex formation implicating that interaction with nucleic acids is an integral aspect of SAMHD1 function.
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21
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DNA-dependent Oct4-Sox2 interaction and diffusion properties characteristic of the pluripotent cell state revealed by fluorescence spectroscopy. Biochem J 2013; 448:21-33. [PMID: 22909387 DOI: 10.1042/bj20120725] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Oct4 and Sox2 are two essential transcription factors that co-regulate target genes for the maintenance of pluripotency. However, it is unclear whether they interact prior to DNA binding or how the target sites are accessed in the nucleus. By generating fluorescent protein fusions of Oct4 and Sox2 that are functionally capable of producing iPSCs (induced pluripotent stem cells), we show that their interaction is dependent on the presence of cognate DNA-binding elements, based on diffusion time, complex formation and lifetime measurements. Through fluorescence correlation spectroscopy, the levels of Oct4 and Sox2 in the iPSCs were quantified in live cells and two diffusion coefficients, corresponding to free and loosely bound forms of the protein, were distinguished. Notably, the fraction of slow-diffusing molecules in the iPSCs was found to be elevated, similar to the profile in embryonic stem cells, probably due to a change in the nuclear milieu during reprogramming. Taken together, these findings have defined quantitatively the amount of proteins pertinent to the pluripotent state and revealed increased accessibility to the underlying DNA as a mechanism for Oct4 and Sox2 to find their target binding sites and interact, without prior formation of heterodimer complexes.
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22
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Šimková E, Staněk D. Probing nucleic acid interactions and pre-mRNA splicing by Förster Resonance Energy Transfer (FRET) microscopy. Int J Mol Sci 2012; 13:14929-45. [PMID: 23203103 PMCID: PMC3509619 DOI: 10.3390/ijms131114929] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 10/31/2012] [Accepted: 10/31/2012] [Indexed: 01/11/2023] Open
Abstract
Förster resonance energy transfer (FRET) microscopy is a powerful technique routinely used to monitor interactions between biomolecules. Here, we focus on the techniques that are used for investigating the structure and interactions of nucleic acids (NAs). We present a brief overview of the most commonly used FRET microscopy techniques, their advantages and drawbacks. We list experimental approaches recently used for either in vitro or in vivo studies. Next, we summarize how FRET contributed to the understanding of pre-mRNA splicing and spliceosome assembly.
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Affiliation(s)
- Eva Šimková
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20 Prague, Czech Republic; E-Mail:
| | - David Staněk
- Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20 Prague, Czech Republic; E-Mail:
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23
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Janas MM, Wang B, Harris AS, Aguiar M, Shaffer JM, Subrahmanyam YV, Behlke MA, Wucherpfennig KW, Gygi SP, Gagnon E, Novina CD. Alternative RISC assembly: binding and repression of microRNA-mRNA duplexes by human Ago proteins. RNA (NEW YORK, N.Y.) 2012; 18:2041-55. [PMID: 23019594 PMCID: PMC3479394 DOI: 10.1261/rna.035675.112] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
MicroRNAs (miRNAs) are small noncoding RNAs that post-transcriptionally regulate protein output from the majority of human mRNAs. In contrast to the consensus view that all miRNAs are associated with Argonaute (Ago) proteins, we determine that miRNAs are expressed in a 13-fold excess relative to Agos in HeLa cells and that miRNAs are bound to mRNAs in a sevenfold excess relative to Agos, implying the existence of miRNA-mRNA duplexes not stoichiometrically bound by Agos. We show that all four human Agos can repress miRNA-mRNA duplexes, but only Ago2 can cleave small interfering RNA-mRNA duplexes in vitro. We visualize direct Ago binding to miRNA-mRNA duplexes in live cells using fluorescence lifetime imaging microscopy. In contrast to the consensus view that Agos bind miRNA duplexes, these data demonstrate that Agos can bind and repress miRNA-mRNA duplexes and support a model of catalytic Ago function in translational repression.
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Affiliation(s)
- Maja M. Janas
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts 02115, USA
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02141, USA
| | - Bingbing Wang
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts 02115, USA
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02141, USA
| | | | - Mike Aguiar
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | | | | | - Mark A. Behlke
- Integrated DNA Technologies, Coralville, Iowa 52241, USA
| | - Kai W. Wucherpfennig
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Steven P. Gygi
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Etienne Gagnon
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
- Corresponding authorsE-mail E-mail
| | - Carl D. Novina
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts 02115, USA
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02141, USA
- Corresponding authorsE-mail E-mail
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24
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Jung J, Lifland AW, Zurla C, Alonas EJ, Santangelo PJ. Quantifying RNA-protein interactions in situ using modified-MTRIPs and proximity ligation. Nucleic Acids Res 2012; 41:e12. [PMID: 22952158 PMCID: PMC3592441 DOI: 10.1093/nar/gks837] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The stabilization, translation and degradation of RNA are regulated by interactions between trans-acting factors, such as microRNA and RNA-binding proteins (RBP). In order to investigate the relationships between these events and their significance, a method that detects the localization of these interactions within a single cell, as well as their variability across a cell population, is needed. To visualize and quantify RNA–protein interactions in situ, we developed a proximity ligation assay (PLA) that combined peptide-modified, multiply-labelled tetravalent RNA imaging probes (MTRIPs), targeted to sequences near RBP binding sites, with proximity ligation and rolling circle amplification (RCA). Using this method, we detected and quantified, with single-interaction sensitivity, the localization and frequency of interactions of the human respiratory syncytial virus (hRSV) nucleocapsid protein (N) with viral genomic RNA (gRNA). We also described the effects of actinomycin D (actD) on the interactions of HuR with β-actin mRNA and with poly(A)+ mRNA at both native and increased HuR expression levels.
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Affiliation(s)
- Jeenah Jung
- Wallace H Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, UA Whitaker Bldg, Atlanta, GA 30332, USA
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25
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David Gerecht PS, Taylor MA, Port JD. Intracellular localization and interaction of mRNA binding proteins as detected by FRET. BMC Cell Biol 2010; 11:69. [PMID: 20843363 PMCID: PMC2949623 DOI: 10.1186/1471-2121-11-69] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2010] [Accepted: 09/15/2010] [Indexed: 02/10/2023] Open
Abstract
Background A number of RNA binding proteins (BPs) bind to A+U rich elements (AREs), commonly present within 3'UTRs of highly regulated RNAs. Individual RNA-BPs proteins can modulate RNA stability, RNA localization, and/or translational efficiency. Although biochemical studies have demonstrated selectivity of ARE-BPs for individual RNAs, less certain is the in vivo composition of RNA-BP multiprotein complexes and how their composition is affected by signaling events and intracellular localization. Using FRET, we previously demonstrated that two ARE-BPs, HuR and AUF1, form stable homomeric and heteromeric associations in the nucleus and cytoplasm. In the current study, we use immuno-FRET of endogenous proteins to examine the intracellular localization and interactions of HuR and AUF1 as well as KSRP, TIA-1, and Hedls. These results were compared to those obtained with their exogenously expressed, fluorescently labeled counterparts. Results All ARE-BPs examined were found to colocalize and to form stable associations with selected other RNA-BPs in one or more cellular locations variably including the nucleus, cytoplasm (in general), or in stress granules or P bodies. Interestingly, FRET based interaction of the translational suppressor, TIA-1, and the decapping protein, Hedls, was found to occur at the interface of stress granules and P bodies, dynamic sites of intracellular RNA storage and/or turnover. To explore the physical interactions of RNA-BPs with ARE containing RNAs, in vitro transcribed Cy3-labeled RNA was transfected into cells. Interestingly, Cy3-RNA was found to coalesce in P body like punctate structures and, by FRET, was found to interact with the RNA decapping proteins, Hedls and Dcp1. Conclusions Biochemical methodologies, such as co-immunoprecipitation, and cell biological approaches such as standard confocal microscopy are useful in demonstrating the possibility of proteins and/or proteins and RNAs interacting. However, as demonstrated herein, colocalization of proteins and proteins and RNA is not always indicative of interaction. To this point, using FRET and immuno-FRET, we have demonstrated that RNA-BPs can visually colocalize without producing a FRET signal. In contrast, proteins that appear to be delimited to one or another intracellular compartment can be shown to interact when those compartments are juxtaposed.
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Affiliation(s)
- Pamela S David Gerecht
- Department of Medicine/Cardiology and Pharmacology, University of Colorado School of Medicine, 12700 East 19th Avenue, Aurora, CO 80045, USA.
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26
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Abstract
Bioimaging contributes significantly to our understanding of plant virus infections. In the present review, we describe technical advances that enable imaging of the infection process at previously unobtainable levels. We highlight how such new advances in subcellular imaging are contributing to a detailed dissection of all stages of the viral infection process. Specifically, we focus on: (i) the increasingly detailed localizations of viral proteins enabled by a diversifying palette of cellular markers; (ii) approaches using fluorescence microscopy for the functional analysis of proteins in vivo; (iii) the imaging of viral RNAs; (iv) methods that bridge the gap between optical and electron microscopy; and (v) methods that are blurring the distinction between imaging and structural biology. We describe the advantages and disadvantages of such techniques and place them in the broader perspective of their utility in analysing plant virus infection.
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27
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A conserved peptide motif in Raver2 mediates its interaction with the polypyrimidine tract-binding protein. Exp Cell Res 2010; 316:966-79. [DOI: 10.1016/j.yexcr.2009.11.023] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2009] [Revised: 11/23/2009] [Accepted: 11/29/2009] [Indexed: 12/29/2022]
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28
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Christensen NM, Oparka KJ, Tilsner J. Advances in imaging RNA in plants. TRENDS IN PLANT SCIENCE 2010; 15:196-203. [PMID: 20153241 DOI: 10.1016/j.tplants.2010.01.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2009] [Revised: 01/07/2010] [Accepted: 01/12/2010] [Indexed: 05/09/2023]
Abstract
Increasing evidence shows that many RNAs are targeted to specific locations within cells, and that RNA-processing pathways occur in association with specific subcellular structures. Compartmentation of mRNA translation and RNA processing helps to assemble large RNA-protein complexes, while RNA targeting allows local protein synthesis and the asymmetric distribution of transcripts during cell polarisation. In plants, intercellular RNA trafficking also plays an additional role in plant development and pathogen defence. Methods that allow the visualisation of RNA sequences within a cellular context, and preferably at subcellular resolution, can help to answer important questions in plant cell and developmental biology. Here, we summarise the approaches currently available for localising RNA in vivo and address the specific limitations inherent with plant systems.
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Affiliation(s)
- Nynne M Christensen
- Biosystems Department, Risø National Laboratory for Sustainable Energy, Technical University of Denmark, 4000 Roskilde, Denmark
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29
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Meades G, Benson BK, Grove A, Waldrop GL. A tale of two functions: enzymatic activity and translational repression by carboxyltransferase. Nucleic Acids Res 2009; 38:1217-27. [PMID: 19965770 PMCID: PMC2831308 DOI: 10.1093/nar/gkp1079] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Acetyl-CoA Carboxylase catalyzes the first committed step in fatty acid synthesis. Escherichia coli acetyl-CoA carboxylase is composed of biotin carboxylase, carboxyltransferase and biotin carboxyl carrier protein functions. The accA and accD genes that code for the α- and β-subunits, respectively, are not in an operon, yet yield an α2β2 carboxyltransferase. Here, we report that carboxyltransferase regulates its own translation by binding the mRNA encoding its subunits. This interaction is mediated by a zinc finger on the β-subunit; mutation of the four cysteines to alanine diminished nucleic acid binding and catalytic activity. Carboxyltransferase binds the coding regions of both subunit mRNAs and inhibits translation, an inhibition that is relieved by the substrate acetyl-CoA. mRNA binding reciprocally inhibits catalytic activity. Preferential binding of carboxyltransferase to RNA in situ was shown using fluorescence resonance energy transfer. We propose an unusual regulatory mechanism by which carboxyltransferase acts as a ‘dimmer switch’ to regulate protein production and catalytic activity, while sensing the metabolic state of the cell through acetyl-CoA concentration.
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Affiliation(s)
- Glen Meades
- Division of Biochemistry and Molecular Biology, Louisiana State University, Baton Rouge, LA 70803, USA
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30
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The nuclear pore complex protein ALADIN is anchored via NDC1 but not via POM121 and GP210 in the nuclear envelope. Biochem Biophys Res Commun 2009; 390:205-10. [DOI: 10.1016/j.bbrc.2009.09.080] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2009] [Accepted: 09/20/2009] [Indexed: 11/19/2022]
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31
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Storr HL, Kind B, Parfitt DA, Chapple JP, Lorenz M, Koehler K, Huebner A, Clark AJL. Deficiency of ferritin heavy-chain nuclear import in triple a syndrome implies nuclear oxidative damage as the primary disease mechanism. Mol Endocrinol 2009; 23:2086-94. [PMID: 19855093 PMCID: PMC5419132 DOI: 10.1210/me.2009-0056] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Accepted: 09/04/2009] [Indexed: 12/17/2022] Open
Abstract
Triple A syndrome is a rare autosomal recessive disorder characterized by ACTH-resistant adrenal failure, alacrima, achalasia, and progressive neurological manifestations. The majority of cases are associated with mutations in the AAAS gene, which encodes a novel, 60-kDa WD-repeat nuclear pore protein, alacrima-achalasia-adrenal insufficiency neurological disorder (ALADIN) of unknown function. Our aim was to elucidate the functional role of ALADIN by determining its interacting protein partners using the bacterial two-hybrid (B2-H) technique. Nonidentical cDNA fragments were identified from both a HeLa S-3 cell and human cerebellar cDNA library that encoded the full-length ferritin heavy chain protein (FTH1). This interaction was confirmed by both co-immunoprecipitation and fluorescence lifetime imaging microscopy-fluorescence resonance energy transfer studies. Immunoblotting showed that fibroblasts from triple A patients (with known AAAS mutations) lack nuclear FTH1, suggesting that the nuclear translocation of FTH1 is defective. Cells transfected with FTH1 and visualized by confocal microscopy had very little nuclear FTH1, but when cotransfected with AAAS, FTH1 is readily visible in the nuclei. Therefore, FTH1 nuclear translocation is enhanced when ALADIN is coexpressed in these cells. In addition to its well known iron storage role, FTH1 has been shown to protect the nucleus from oxidative damage. Apoptosis of neuronal cells induced by hydrogen peroxide was significantly reduced by transfection of AAAS or by FTH1 or maximally by both genes together. Taken together, this work offers a plausible mechanism for the progressive clinical features of triple A syndrome.
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Affiliation(s)
- Helen L Storr
- Centre for Endocrinology, William Harvey Research Institute, Queen Mary University of London, United Kingdom
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32
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Huranová M, Jablonski JA, Benda A, Hof M, Stanek D, Caputi M. In vivo detection of RNA-binding protein interactions with cognate RNA sequences by fluorescence resonance energy transfer. RNA (NEW YORK, N.Y.) 2009; 15:2063-2071. [PMID: 19767419 PMCID: PMC2764471 DOI: 10.1261/rna.1678209] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2009] [Accepted: 08/12/2009] [Indexed: 05/28/2023]
Abstract
Expression of the nascent RNA transcript is regulated by its interaction with a number of proteins. The misregulation of such interactions can often result in impaired cellular functions that can lead to cancer and a number of diseases. Thus, our understanding of RNA-protein interactions within the cellular context is essential for the development of novel diagnostic and therapeutic tools. While there are many in vitro methods that analyze RNA-protein interactions in vivo approaches are scarce. Here we established a method based on fluorescence resonance energy transfer (FRET), which we term RNA-binding mediated FRET (RB-FRET), which determines RNA-protein interaction inside cells and tested it on hnRNP H protein binding to its cognate RNA. Using two different approaches, we provide evidence that RB-FRET is sensitive enough to detect specific RNA-protein interactions in the cell, providing a powerful tool to study spatial and temporal localization of specific RNA-protein complexes.
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Affiliation(s)
- Martina Huranová
- Department of RNA Biology, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, CZ-14220 Prague 4, Czech Republic
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33
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Norton JT, Titus SA, Dexter D, Austin CP, Zheng W, Huang S. Automated high-content screening for compounds that disassemble the perinucleolar compartment. ACTA ACUST UNITED AC 2009; 14:1045-53. [PMID: 19762548 DOI: 10.1177/1087057109343120] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
All solid malignancies share characteristic traits, including unlimited cellular proliferation, evasion of immune regulation, and the propensity to metastasize. The authors have previously described that a subnuclear structure, the perinucleolar compartment (PNC), is associated with the metastatic phenotype in solid tumor cancer cells. The percentage of cancer cells that contain PNCs (PNC prevalence) is indicative of the malignancy of a tumor both in vitro and in vivo, and thus PNC prevalence is a marker that reflects metastatic capability in a population of tumor cells. Although the function of the PNC remains to be determined, the PNC is highly enriched with small RNAs and RNA binding proteins. The initial chemical biology studies using a set of anticancer drugs that disassemble PNCs revealed a direct association of the structure with DNA. Therefore, PNC prevalence reduction as a phenotypic marker can be used to identify compounds that target cellular processes required for PNC maintenance and hence used to elucidate the nature of the PNC function. Here the authors report the development of an automated high-content screening assay that is capable of detecting PNC prevalence in prostate cancer cells (PC-3M) stably expressing a green fluorescent protein (GFP)-fusion protein that localizes to the PNC. The assay was optimized using known PNC-reducing drugs and non-PNC-reducing cytotoxic drugs. After optimization, the fidelity of the assay was probed with a collection of 8284 compounds and was shown to be robust and capable of detecting known and novel PNC-reducing compounds, making it the first reported high-content phenotypic screen for small changes in nuclear structure.
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Affiliation(s)
- John T Norton
- Northwestern University, Feinberg School of Medicine, Cell and Molecular Biology, Chicago, Illinois 60611, USA
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Sapra AK, Ankö ML, Grishina I, Lorenz M, Pabis M, Poser I, Rollins J, Weiland EM, Neugebauer KM. SR protein family members display diverse activities in the formation of nascent and mature mRNPs in vivo. Mol Cell 2009; 34:179-90. [PMID: 19394295 DOI: 10.1016/j.molcel.2009.02.031] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Revised: 12/19/2008] [Accepted: 02/25/2009] [Indexed: 11/30/2022]
Abstract
The SR proteins are a family of pre-mRNA splicing factors with additional roles in gene regulation. To investigate individual family members in vivo, we generated a comprehensive panel of stable cell lines expressing GFP-tagged SR proteins under endogenous promoter control. Recruitment of SR proteins to nascent FOS RNA was transcription dependent and RNase sensitive, with unique patterns of accumulation along the gene specified by the RNA recognition motifs (RRMs). In addition, all SR protein interactions with Pol II were RNA dependent, indicating that SR proteins are not preassembled with Pol II. SR protein interactions with RNA were confirmed in situ by FRET/FLIM. Interestingly, SC35-GFP also exhibited FRET with DNA and failed to associate with cytoplasmic mRNAs, whereas all other SR proteins underwent nucleocytoplasmic shuttling and associated with specific nuclear and cytoplasmic mRNAs. Because different constellations of SR proteins bound nascent, nuclear, and cytoplasmic mRNAs, mRNP remodeling must occur throughout an mRNA's lifetime.
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Affiliation(s)
- Aparna K Sapra
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, Dresden, Germany
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