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Hedaya OM, Venkata Subbaiah KC, Jiang F, Xie LH, Wu J, Khor ES, Zhu M, Mathews DH, Proschel C, Yao P. Secondary structures that regulate mRNA translation provide insights for ASO-mediated modulation of cardiac hypertrophy. Nat Commun 2023; 14:6166. [PMID: 37789015 PMCID: PMC10547706 DOI: 10.1038/s41467-023-41799-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 09/19/2023] [Indexed: 10/05/2023] Open
Abstract
Translation of upstream open reading frames (uORFs) typically abrogates translation of main (m)ORFs. The molecular mechanism of uORF regulation in cells is not well understood. Here, we data-mined human and mouse heart ribosome profiling analyses and identified a double-stranded RNA (dsRNA) structure within the GATA4 uORF that cooperates with the start codon to augment uORF translation and inhibits mORF translation. A trans-acting RNA helicase DDX3X inhibits the GATA4 uORF-dsRNA activity and modulates the translational balance of uORF and mORF. Antisense oligonucleotides (ASOs) that disrupt this dsRNA structure promote mORF translation, while ASOs that base-pair immediately downstream (i.e., forming a bimolecular double-stranded region) of either the uORF or mORF start codon enhance uORF or mORF translation, respectively. Human cardiomyocytes and mice treated with a uORF-enhancing ASO showed reduced cardiac GATA4 protein levels and increased resistance to cardiomyocyte hypertrophy. We further show the broad utility of uORF-dsRNA- or mORF-targeting ASO to regulate mORF translation for other mRNAs. This work demonstrates that the uORF-dsRNA element regulates the translation of multiple mRNAs as a generalizable translational control mechanism. Moreover, we develop a valuable strategy to alter protein expression and cellular phenotypes by targeting or generating dsRNA downstream of a uORF or mORF start codon.
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Affiliation(s)
- Omar M Hedaya
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine & Dentistry, Rochester, NY, 14642, USA
- Department of Biochemistry & Biophysics, University of Rochester School of Medicine & Dentistry, Rochester, NY, 14642, USA
| | - Kadiam C Venkata Subbaiah
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine & Dentistry, Rochester, NY, 14642, USA
| | - Feng Jiang
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine & Dentistry, Rochester, NY, 14642, USA
- Department of Biochemistry & Biophysics, University of Rochester School of Medicine & Dentistry, Rochester, NY, 14642, USA
| | - Li Huitong Xie
- Department of Biomedical Genetics, University of Rochester School of Medicine & Dentistry, Rochester, NY, 14642, USA
| | - Jiangbin Wu
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine & Dentistry, Rochester, NY, 14642, USA
| | - Eng-Soon Khor
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine & Dentistry, Rochester, NY, 14642, USA
| | - Mingyi Zhu
- Department of Biochemistry & Biophysics, University of Rochester School of Medicine & Dentistry, Rochester, NY, 14642, USA
- The Center for RNA Biology, University of Rochester School of Medicine & Dentistry, Rochester, NY, 14642, USA
| | - David H Mathews
- Department of Biochemistry & Biophysics, University of Rochester School of Medicine & Dentistry, Rochester, NY, 14642, USA
- The Center for RNA Biology, University of Rochester School of Medicine & Dentistry, Rochester, NY, 14642, USA
- The Center for Biomedical Informatics, University of Rochester School of Medicine & Dentistry, Rochester, NY, 14642, USA
| | - Chris Proschel
- Department of Biomedical Genetics, University of Rochester School of Medicine & Dentistry, Rochester, NY, 14642, USA
| | - Peng Yao
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine & Dentistry, Rochester, NY, 14642, USA.
- Department of Biochemistry & Biophysics, University of Rochester School of Medicine & Dentistry, Rochester, NY, 14642, USA.
- The Center for RNA Biology, University of Rochester School of Medicine & Dentistry, Rochester, NY, 14642, USA.
- The Center for Biomedical Informatics, University of Rochester School of Medicine & Dentistry, Rochester, NY, 14642, USA.
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Meyer MO, Yamagami R, Choi S, Keating CD, Bevilacqua PC. RNA folding studies inside peptide-rich droplets reveal roles of modified nucleosides at the origin of life. SCIENCE ADVANCES 2023; 9:eadh5152. [PMID: 37729412 PMCID: PMC10511188 DOI: 10.1126/sciadv.adh5152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 08/16/2023] [Indexed: 09/22/2023]
Abstract
Compartmentalization of RNA in biopolymer-rich membraneless organelles is now understood to be pervasive and critical for the function of extant biology and has been proposed as a prebiotically plausible way to accumulate RNA. However, compartment-RNA interactions that drive encapsulation have the potential to influence RNA structure and function in compartment- and RNA sequence-dependent ways. Here, we detail next-generation sequencing (NGS) experiments performed in membraneless compartments called complex coacervates to characterize the fold of many different transfer RNAs (tRNAs) simultaneously under the potentially denaturing conditions of these compartments. Notably, we find that natural modifications favor the native fold of tRNAs in these compartments. This suggests that covalent RNA modifications could have played a critical role in metabolic processes at the origin of life.
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Affiliation(s)
- McCauley O. Meyer
- Department of Biochemistry, Microbiology, and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
- Center for RNA Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Ryota Yamagami
- Center for RNA Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Saehyun Choi
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Christine D. Keating
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
| | - Philip C. Bevilacqua
- Department of Biochemistry, Microbiology, and Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
- Center for RNA Molecular Biology, The Pennsylvania State University, University Park, PA 16802, USA
- Department of Chemistry, The Pennsylvania State University, University Park, PA 16802, USA
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3
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Hedaya OM, Subbaiah KCV, Jiang F, Xie LH, Wu J, Khor E, Zhu M, Mathews DH, Proschel C, Yao P. Secondary structures that regulate mRNA translation provide insights for ASO-mediated modulation of cardiac hypertrophy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.15.545153. [PMID: 37397986 PMCID: PMC10312771 DOI: 10.1101/2023.06.15.545153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Translation of upstream open reading frames (uORFs) typically abrogates translation of main (m)ORFs. The molecular mechanism of uORF regulation in cells is not well understood. Here, we identified a double-stranded RNA (dsRNA) structure residing within the GATA4 uORF that augments uORF translation and inhibits mORF translation. Antisense oligonucleotides (ASOs) that disrupt this dsRNA structure promote mORF translation, while ASOs that base-pair immediately downstream (i.e., forming a bimolecular double-stranded region) of either the uORF or mORF start codon enhance uORF or mORF translation, respectively. Human cardiomyocytes and mice treated with a uORF-enhancing ASO showed reduced cardiac GATA4 protein levels and increased resistance to cardiomyocyte hypertrophy. We further show the general utility of uORF-dsRNA- or mORF- targeting ASO to regulate mORF translation for other mRNAs. Our work demonstrates a regulatory paradigm that controls translational efficiency and a useful strategy to alter protein expression and cellular phenotypes by targeting or generating dsRNA downstream of a uORF or mORF start codon. Bullet points for discoveries dsRNA within GATA4 uORF activates uORF translation and inhibits mORF translation. ASOs that target the dsRNA can either inhibit or enhance GATA4 mORF translation. ASOs can be used to impede hypertrophy in human cardiomyocytes and mouse hearts.uORF- and mORF-targeting ASOs can be used to control translation of multiple mRNAs.
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Affiliation(s)
- Omar M. Hedaya
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine & Dentistry, Rochester, New York 14642
- Department of Biochemistry & Biophysics, University of Rochester School of Medicine & Dentistry, Rochester, New York 14642
| | - Kadiam C. Venkata Subbaiah
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine & Dentistry, Rochester, New York 14642
| | - Feng Jiang
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine & Dentistry, Rochester, New York 14642
- Department of Biochemistry & Biophysics, University of Rochester School of Medicine & Dentistry, Rochester, New York 14642
| | - Li Huitong Xie
- Department of Biomedical Genetics, University of Rochester School of Medicine & Dentistry, Rochester, New York 14642
| | - Jiangbin Wu
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine & Dentistry, Rochester, New York 14642
| | - EngSoon Khor
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine & Dentistry, Rochester, New York 14642
| | - Mingyi Zhu
- Department of Biochemistry & Biophysics, University of Rochester School of Medicine & Dentistry, Rochester, New York 14642
- The Center for RNA Biology, University of Rochester School of Medicine & Dentistry, Rochester, New York 14642
| | - David H. Mathews
- Department of Biochemistry & Biophysics, University of Rochester School of Medicine & Dentistry, Rochester, New York 14642
- The Center for RNA Biology, University of Rochester School of Medicine & Dentistry, Rochester, New York 14642
- The Center for Biomedical Informatics, University of Rochester School of Medicine & Dentistry, Rochester, New York 14642
| | - Chris Proschel
- Department of Biomedical Genetics, University of Rochester School of Medicine & Dentistry, Rochester, New York 14642
| | - Peng Yao
- Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester School of Medicine & Dentistry, Rochester, New York 14642
- Department of Biochemistry & Biophysics, University of Rochester School of Medicine & Dentistry, Rochester, New York 14642
- The Center for RNA Biology, University of Rochester School of Medicine & Dentistry, Rochester, New York 14642
- The Center for Biomedical Informatics, University of Rochester School of Medicine & Dentistry, Rochester, New York 14642
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4
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Meyer MO, Yamagami R, Choi S, Keating CD, Bevilacqua PC. RNA folding studies inside peptide-rich droplets reveal roles of modified nucleosides at the origin of life. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.27.530264. [PMID: 36909509 PMCID: PMC10002651 DOI: 10.1101/2023.02.27.530264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
Compartmentalization of RNA in biopolymer-rich membraneless organelles is now understood to be pervasive and critical for the function of extant biology and has been proposed as a prebiotically-plausible way to accumulate RNA. However, compartment-RNA interactions that drive encapsulation have the potential to influence RNA structure and function in compartment- and RNA sequence-dependent ways. Herein, we detail Next-Generation Sequencing (NGS) experiments performed for the first time in membraneless compartments called complex coacervates to characterize the fold of many different transfer RNAs (tRNAs) simultaneously under the potentially denaturing conditions of these compartments. Strikingly, we find that natural modifications favor the native fold of tRNAs in these compartments. This suggests that covalent RNA modifications could have played a critical role in metabolic processes at the origin of life. One Sentence Summary We demonstrate that RNA folds into native secondary and tertiary structures in protocell models and that this is favored by covalent modifications, which is critical for the origins of life.
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Ferrero-Serrano Á, Sylvia MM, Forstmeier PC, Olson AJ, Ware D, Bevilacqua PC, Assmann SM. Experimental demonstration and pan-structurome prediction of climate-associated riboSNitches in Arabidopsis. Genome Biol 2022; 23:101. [PMID: 35440059 PMCID: PMC9017077 DOI: 10.1186/s13059-022-02656-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 03/20/2022] [Indexed: 11/23/2022] Open
Abstract
Background Genome-wide association studies (GWAS) aim to correlate phenotypic changes with genotypic variation. Upon transcription, single nucleotide variants (SNVs) may alter mRNA structure, with potential impacts on transcript stability, macromolecular interactions, and translation. However, plant genomes have not been assessed for the presence of these structure-altering polymorphisms or “riboSNitches.” Results We experimentally demonstrate the presence of riboSNitches in transcripts of two Arabidopsis genes, ZINC RIBBON 3 (ZR3) and COTTON GOLGI-RELATED 3 (CGR3), which are associated with continentality and temperature variation in the natural environment. These riboSNitches are also associated with differences in the abundance of their respective transcripts, implying a role in regulating the gene's expression in adaptation to local climate conditions. We then computationally predict riboSNitches transcriptome-wide in mRNAs of 879 naturally inbred Arabidopsis accessions. We characterize correlations between SNPs/riboSNitches in these accessions and 434 climate descriptors of their local environments, suggesting a role of these variants in local adaptation. We integrate this information in CLIMtools V2.0 and provide a new web resource, T-CLIM, that reveals associations between transcript abundance variation and local environmental variation. Conclusion We functionally validate two plant riboSNitches and, for the first time, demonstrate riboSNitch conditionality dependent on temperature, coining the term “conditional riboSNitch.” We provide the first pan-genome-wide prediction of riboSNitches in plants. We expand our previous CLIMtools web resource with riboSNitch information and with 1868 additional Arabidopsis genomes and 269 additional climate conditions, which will greatly facilitate in silico studies of natural genetic variation, its phenotypic consequences, and its role in local adaptation. Supplementary Information The online version contains supplementary material available at 10.1186/s13059-022-02656-4.
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Affiliation(s)
- Ángel Ferrero-Serrano
- Department of Biology, Pennsylvania State University, University Park, State College, PA, 16802, USA.
| | - Megan M Sylvia
- Department of Biology, Pennsylvania State University, University Park, State College, PA, 16802, USA
| | - Peter C Forstmeier
- Department of Biochemistry, Microbiology, and Molecular Biology, Pennsylvania State University, University Park, State College, PA, 16802, USA
| | - Andrew J Olson
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
| | - Doreen Ware
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA.,USDA ARS NAA Robert W. Holley Center for Agriculture and Health, Ithaca, NY, 14853, USA
| | - Philip C Bevilacqua
- Department of Biochemistry, Microbiology, and Molecular Biology, Pennsylvania State University, University Park, State College, PA, 16802, USA.,Department of Chemistry, Pennsylvania State University, University Park, State College, PA, 16802, USA.,Center for RNA Molecular Biology, Pennsylvania State University, University Park, State College, PA, 16802, USA
| | - Sarah M Assmann
- Department of Biology, Pennsylvania State University, University Park, State College, PA, 16802, USA. .,Center for RNA Molecular Biology, Pennsylvania State University, University Park, State College, PA, 16802, USA.
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6
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Bagshaw CR, Hentschel J, Stone MD. The Processivity of Telomerase: Insights from Kinetic Simulations and Analyses. Molecules 2021; 26:7532. [PMID: 34946615 PMCID: PMC8705835 DOI: 10.3390/molecules26247532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 12/01/2021] [Accepted: 12/08/2021] [Indexed: 11/16/2022] Open
Abstract
Telomerases are moderately processive reverse transcriptases that use an integral RNA template to extend the 3' end of linear chromosomes. Processivity values, defined as the probability of extension rather than dissociation, range from about 0.7 to 0.99 at each step. Consequently, an average of tens to hundreds of nucleotides are incorporated before the single-stranded sDNA product dissociates. The RNA template includes a six nucleotide repeat, which must be reset in the active site via a series of translocation steps. Nucleotide addition associated with a translocation event shows a lower processivity (repeat addition processivity, RAP) than that at other positions (nucleotide addition processivity, NAP), giving rise to a characteristic strong band every 6th position when the product DNA is analyzed by gel electrophoresis. Here, we simulate basic reaction mechanisms and analyze the product concentrations using several standard procedures to show how the latter can give rise to systematic errors in the processivity estimate. Complete kinetic analysis of the time course of DNA product concentrations following a chase with excess unlabeled DNA primer (i.e., a pulse-chase experiment) provides the most rigorous approach. This analysis reveals that the higher product concentrations associated with RAP arise from a stalling of nucleotide incorporation reaction during translocation rather than an increased rate constant for the dissociation of DNA from the telomerase.
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Affiliation(s)
- Clive R. Bagshaw
- Department of Chemistry and Biochemistry, University of California at Santa Cruz, Santa Cruz, CA 95064, USA;
| | - Jendrik Hentschel
- Department of Chemistry and Biochemistry, University of California at Santa Cruz, Santa Cruz, CA 95064, USA;
- Element Biosciences, 9880 Campus Point Drive, San Diego, CA 92121, USA
| | - Michael D. Stone
- Department of Chemistry and Biochemistry, University of California at Santa Cruz, Santa Cruz, CA 95064, USA;
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7
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Turcotte MA, Garant JM, Cossette-Roberge H, Perreault JP. Guanine Nucleotide-Binding Protein-Like 1 (GNL1) binds RNA G-quadruplex structures in genes associated with Parkinson's disease. RNA Biol 2020; 18:1339-1353. [PMID: 33305682 PMCID: PMC8354592 DOI: 10.1080/15476286.2020.1847866] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
RNAs are highly regulated at the post-transcriptional level in neurodegenerative diseases and just a few mutations can significantly affect the fate of neuronal cells. To date, the impact of G-quadruplex (G4) regulation in neurodegenerative diseases like Parkinson’s disease (PD) has not been analysed. In this study, in silico potential G4s located in deregulated genes related to the nervous system were initially identified and were found to be significantly enriched. Several G4 sequences found in the 5ʹ untranslated regions (5ʹUTR) of mRNAs associated with Parkinson’s disease were demonstrated to in fact fold in vitro by biochemical assays. Subcloning of the full-length 5ʹUTRs of these candidates upstream of a luciferase reporter system led to the demonstration that the G4s of both Parkin RBR E3 Ubiquitin Protein Ligase (PRKN) and Vacuolar Protein Sorting-Associated Protein 35 (VPS35) significantly repressed the translation of both genes in SH-SY5Y cells. Subsequently, a strategy of using label-free RNA affinity purification assays with either of these two G4 sequences as bait isolated the Guanine Nucleotide-Binding Protein-Like 1 (GNL1). The latter was shown to have a higher affinity for the G4 sequences than for their mutated version. This study sheds light on new RNA G-quadruplexes located in genes dysregulated in Parkinson disease and a new G4-binding protein, GNL1.
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Affiliation(s)
- Marc-Antoine Turcotte
- Department of Biochemistry, Pavillon de Recherche Appliquée Sur le Cancer, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Jean-Michel Garant
- Department of Biochemistry, Pavillon de Recherche Appliquée Sur le Cancer, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Hélène Cossette-Roberge
- Department of Biochemistry, Pavillon de Recherche Appliquée Sur le Cancer, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Jean-Pierre Perreault
- Department of Biochemistry, Pavillon de Recherche Appliquée Sur le Cancer, Université de Sherbrooke, Sherbrooke, Québec, Canada
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8
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Prebiotically-relevant low polyion multivalency can improve functionality of membraneless compartments. Nat Commun 2020; 11:5949. [PMID: 33230101 PMCID: PMC7683531 DOI: 10.1038/s41467-020-19775-w] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 10/27/2020] [Indexed: 12/02/2022] Open
Abstract
Multivalent polyions can undergo complex coacervation, producing membraneless compartments that accumulate ribozymes and enhance catalysis, and offering a mechanism for functional prebiotic compartmentalization in the origins of life. Here, we evaluate the impact of lower, more prebiotically-relevant, polyion multivalency on the functional performance of coacervates as compartments. Positively and negatively charged homopeptides with 1–100 residues and adenosine mono-, di-, and triphosphate nucleotides are used as model polyions. Polycation/polyanion pairs are tested for coacervation, and resulting membraneless compartments are analyzed for salt resistance, ability to provide a distinct internal microenvironment (apparent local pH, RNA partitioning), and effect on RNA structure formation. We find that coacervates formed by phase separation of the shorter polyions more effectively generated distinct pH microenvironments, accumulated RNA, and preserved duplexes than those formed by longer polyions. Hence, coacervates formed by reduced multivalency polyions are not only viable as functional compartments for prebiotic chemistries, they can outperform higher molecular weight analogues. Short cationic peptides and nucleotides can form complex coacervates, but the influence of reduced multivalency on coacervate functionality was not investigated. Here, the authors report that coacervates formed from short polyions generate distinct pH microenvironments, accumulate RNA and preserve nucleic acid duplexes more efficiently than their longer counterparts.
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9
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Poudyal RR, Meyer MO, Bevilacqua PC. Measuring the activity and structure of functional RNAs inside compartments formed by liquid-liquid phase separation. Methods Enzymol 2020; 646:307-327. [PMID: 33453930 DOI: 10.1016/bs.mie.2020.06.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Liquid-liquid phase separation (LLPS) has been known to drive formation of biomolecular compartments, which can encapsulate RNA and proteins among other cosolutes. Such compartments, which lack a lipid membrane, have been implicated in origins of life scenarios as they can easily uptake and concentrate biomolecules, similar to intracellular condensates. Indeed, chemical interactions that drive LLPS in vitro have also been shown to lead to similar sub-cellular compartments in vivo. Here we describe methods to prepare compartments formed by complex coacervates, which are driven by LLPS of oppositely-charged polyions, and to probe the structures and functions of RNAs in them. These methods can be adapted to study RNA biochemistry in compartments formed by diverse artificial and biological macromolecules.
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Affiliation(s)
- Raghav R Poudyal
- Department of Chemistry, Pennsylvania State University, University Park, PA, United States; Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA, United States
| | - McCauley O Meyer
- Department of Biochemistry, Microbiology, and Molecular Biology, Pennsylvania State University, University Park, PA, United States; Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA, United States
| | - Philip C Bevilacqua
- Department of Chemistry, Pennsylvania State University, University Park, PA, United States; Department of Biochemistry, Microbiology, and Molecular Biology, Pennsylvania State University, University Park, PA, United States; Center for RNA Molecular Biology, Pennsylvania State University, University Park, PA, United States.
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10
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The 5' NAD Cap of RNAIII Modulates Toxin Production in Staphylococcus aureus Isolates. J Bacteriol 2020; 202:JB.00591-19. [PMID: 31871032 DOI: 10.1128/jb.00591-19] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 12/18/2019] [Indexed: 01/14/2023] Open
Abstract
Nicotinamide adenosine dinucleotide (NAD) has been found to be covalently attached to the 5' ends of specific RNAs in many different organisms, but the physiological consequences of this modification are largely unknown. Here, we report the occurrence of several NAD-RNAs in the opportunistic pathogen Staphylococcus aureus Most prominently, RNAIII, a central quorum-sensing regulator of this bacterium's physiology, was found to be 5' NAD capped in a range from 10 to 35%. NAD incorporation efficiency into RNAIII was found to depend in vivo on the -1 position of the P3 promoter. An increase in RNAIII's NAD content led to a decreased expression of alpha- and delta-toxins, resulting in reduced cytotoxicity of the modified strains. These effects seem to be caused neither by changes in RNAIII's secondary structure nor by a different translatability upon NAD attachment, as indicated by unaltered patterns in in vitro chemical probing and toeprinting experiments. Even though we did not observe any effect of this modification on RNAIII's secondary structure or translatability in vitro, additional unidentified factors might account for the modulation of exotoxins in vivo Ultimately, the study constitutes a step forward in the discovery of new roles of the NAD molecule in bacteria.IMPORTANCE Numerous organisms, including bacteria, are endowed with a 5' NAD cap in specific RNAs. While the presence of the 5' NAD cap modulates the stability of the modified RNA species, a significant biological function and phenotype have not been assigned so far. Here, we show the presence of a 5' NAD cap in RNAIII from S. aureus, a dual-function regulatory RNA involved in quorum-sensing processes and regulation of virulence factor expression. We also demonstrate that altering the natural NAD modification ratio of RNAIII leads to a decrease in exotoxin production, thereby modulating the bacterium's virulence. Our work unveils a new layer of regulation of RNAIII and the agr system that might be linked to the redox state of the NAD molecule in the cell.
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11
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Karner H, Webb CH, Carmona S, Liu Y, Lin B, Erhard M, Chan D, Baldi P, Spitale RC, Sun S. Functional Conservation of LncRNA JPX Despite Sequence and Structural Divergence. J Mol Biol 2019; 432:283-300. [PMID: 31518612 DOI: 10.1016/j.jmb.2019.09.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 08/29/2019] [Accepted: 09/02/2019] [Indexed: 02/02/2023]
Abstract
Long noncoding RNAs (lncRNAs) have been identified in all eukaryotes and are most abundant in the human genome. However, the functional importance and mechanisms of action for human lncRNAs are largely unknown. Using comparative sequence, structural, and functional analyses, we characterize the evolution and molecular function of human lncRNA JPX. We find that human JPX and its mouse homolog, lncRNA Jpx, have deep divergence in their nucleotide sequences and RNA secondary structures. Despite such differences, both lncRNAs demonstrate robust binding to CTCF, a protein that is central to Jpx's role in X chromosome inactivation. In addition, our functional rescue experiment using Jpx-deletion mutant cells shows that human JPX can functionally complement the loss of Jpx in mouse embryonic stem cells. Our findings support a model for functional conservation of lncRNAs independent from sequence and structural divergence. This study provides mechanistic insight into the evolution of lncRNA function.
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Affiliation(s)
- Heather Karner
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California Irvine, Irvine, CA 92697, USA
| | - Chiu-Ho Webb
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California Irvine, Irvine, CA 92697, USA
| | - Sarah Carmona
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California Irvine, Irvine, CA 92697, USA
| | - Yu Liu
- Department of Computer Science, Institute for Genomics and Bioinformatics, University of California Irvine, Irvine, CA 92697, USA
| | - Benjamin Lin
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California Irvine, Irvine, CA 92697, USA
| | - Micaela Erhard
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California Irvine, Irvine, CA 92697, USA
| | - Dalen Chan
- Department of Pharmaceutical Sciences, College of Health Sciences, University of California Irvine, Irvine, CA 92697, USA
| | - Pierre Baldi
- Department of Computer Science, Institute for Genomics and Bioinformatics, University of California Irvine, Irvine, CA 92697, USA
| | - Robert C Spitale
- Department of Pharmaceutical Sciences, College of Health Sciences, University of California Irvine, Irvine, CA 92697, USA
| | - Sha Sun
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California Irvine, Irvine, CA 92697, USA.
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12
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He L, Wang Q, Gu Z, Liao Q, Palukaitis P, Du Z. A conserved RNA structure is essential for a satellite RNA-mediated inhibition of helper virus accumulation. Nucleic Acids Res 2019; 47:8255-8271. [PMID: 31269212 PMCID: PMC6735963 DOI: 10.1093/nar/gkz564] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 05/30/2019] [Accepted: 06/20/2019] [Indexed: 12/15/2022] Open
Abstract
As a class of parasitic, non-coding RNAs, satellite RNAs (satRNAs) have to compete with their helper virus for limited amounts of viral and/or host resources for efficient replication, by which they usually reduce viral accumulation and symptom expression. Here, we report a cucumber mosaic virus (CMV)-associated satRNA (sat-T1) that ameliorated CMV-induced symptoms, accompanied with a significant reduction in the accumulation of viral genomic RNAs 1 and 2, which encode components of the viral replicase. Intrans replication assays suggest that the reduced accumulation is the outcome of replication competition. The structural basis of sat-T1 responsible for the inhibition of viral RNA accumulation was determined to be a three-way branched secondary structure that contains two biologically important hairpins. One is indispensable for the helper virus inhibition, and the other engages in formation of a tertiary pseudoknot structure that is essential for sat-T1 survival. The secondary structure containing the pseudoknot is the first RNA element with a biological phenotype experimentally identified in CMV satRNAs, and it is structurally conserved in most CMV satRNAs. Thus, this may be a generic method for CMV satRNAs to inhibit the accumulation of the helper virus via the newly-identified RNA structure.
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Affiliation(s)
- Lu He
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, China
| | - Qian Wang
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, China
| | - Zhouhang Gu
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, China
| | - Qiansheng Liao
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, China
| | - Peter Palukaitis
- Department of Horticultural Sciences, Seoul Women's University, Nowon-gu, Seoul 01797, Republic of Korea
| | - Zhiyou Du
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, China
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13
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Dong X, Ranganathan S, Qu G, Piazza CL, Belfort M. Structural accommodations accompanying splicing of a group II intron RNP. Nucleic Acids Res 2019; 46:8542-8556. [PMID: 29790987 PMCID: PMC6144810 DOI: 10.1093/nar/gky416] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 05/03/2018] [Indexed: 01/21/2023] Open
Abstract
Group II introns, the putative progenitors of spliceosomal introns and retrotransposons, are ribozymes that are capable of self-splicing and DNA invasion. In the cell, group II introns form ribonucleoprotein (RNP) complexes with an intron-encoded protein, which is essential to folding, splicing and retromobility of the intron. To understand the structural accommodations underlying splicing, in preparation for retromobility, we probed the endogenously expressed Lactococcus lactis Ll.LtrB group II intron RNP using SHAPE. The results, which are consistent in vivo and in vitro, provide insights into the dynamics of the intron RNP as well as RNA-RNA and RNA-protein interactions. By comparing the excised intron RNP with mutant RNPs in the precursor state, confined SHAPE profile differences were observed, indicative of rearrangements at the active site as well as disengagement at the functional RNA-protein interface in transition between the two states. The exon-binding sequences in the intron RNA, which interact with the 5' exon and the target DNA, show increased flexibility after splicing. In contrast, stability of major tertiary and protein interactions maintains the scaffold of the RNA through the splicing transition, while the active site is realigned in preparation for retromobility.
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Affiliation(s)
- Xiaolong Dong
- Department of Biological Sciences and RNA Institute, University at Albany, Albany, NY 12222, USA
| | - Srivathsan Ranganathan
- Department of Biological Sciences and RNA Institute, University at Albany, Albany, NY 12222, USA
| | - Guosheng Qu
- Department of Biological Sciences and RNA Institute, University at Albany, Albany, NY 12222, USA
| | - Carol Lyn Piazza
- Department of Biological Sciences and RNA Institute, University at Albany, Albany, NY 12222, USA
| | - Marlene Belfort
- Department of Biological Sciences and RNA Institute, University at Albany, Albany, NY 12222, USA
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14
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Gasser C, Gebetsberger J, Gebetsberger M, Micura R. SHAPE probing pictures Mg2+-dependent folding of small self-cleaving ribozymes. Nucleic Acids Res 2019; 46:6983-6995. [PMID: 29924364 PMCID: PMC6101554 DOI: 10.1093/nar/gky555] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 06/07/2018] [Indexed: 12/28/2022] Open
Abstract
Self-cleaving ribozymes are biologically relevant RNA molecules which catalyze site-specific cleavage of the phosphodiester backbone. Gathering knowledge of their three-dimensional structures is critical toward an in-depth understanding of their function and chemical mechanism. Equally important is collecting information on the folding process and the inherent dynamics of a ribozyme fold. Over the past years, Selective-2′-Hydroxyl Acylation analyzed by Primer Extension (SHAPE) turned out to be a significant tool to probe secondary and tertiary interactions of diverse RNA species at the single nucleotide level under varying environmental conditions. Small self-cleaving ribozymes, however, have not been investigated by this method so far. Here, we describe SHAPE probing of pre-catalytic folds of the recently discovered ribozyme classes twister, twister-sister (TS), pistol and hatchet. The study has implications on Mg2+-dependent folding and reveals potentially dynamic residues of these ribozymes that are otherwise difficult to identify. For twister, TS and pistol ribozymes the new findings are discussed in the light of their crystal structures, and in case of twister also with respect to a smFRET folding analysis. For the hatchet ribozyme where an atomic resolution structure is not yet available, the SHAPE data challenge the proposed secondary structure model and point at selected residues and putative long-distance interactions that appear crucial for structure formation and cleavage activity.
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Affiliation(s)
- Catherina Gasser
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck CMBI, Leopold-Franzens University, Innrain 80-82, Innsbruck 6020, Austria
| | - Jennifer Gebetsberger
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck CMBI, Leopold-Franzens University, Innrain 80-82, Innsbruck 6020, Austria
| | - Manuel Gebetsberger
- Division for Biomedical Physics, Medical University of Innsbruck, Müllerstraße 44, Innsbruck 6020, Austria
| | - Ronald Micura
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck CMBI, Leopold-Franzens University, Innrain 80-82, Innsbruck 6020, Austria
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15
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Chahal J, Gebert LF, Gan HH, Camacho E, Gunsalus KC, MacRae IJ, Sagan SM. miR-122 and Ago interactions with the HCV genome alter the structure of the viral 5' terminus. Nucleic Acids Res 2019; 47:5307-5324. [PMID: 30941417 PMCID: PMC6547439 DOI: 10.1093/nar/gkz194] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 03/11/2019] [Accepted: 03/20/2019] [Indexed: 12/12/2022] Open
Abstract
Hepatitis C virus (HCV) is a positive-sense RNA virus that interacts with the liver-specific microRNA, miR-122. miR-122 binds to two sites in the 5' untranslated region (UTR) and this interaction promotes HCV RNA accumulation, although the precise role of miR-122 in the HCV life cycle remains unclear. Using biophysical analyses and Selective 2' Hydroxyl Acylation analyzed by Primer Extension (SHAPE) we investigated miR-122 interactions with the 5' UTR. Our data suggests that miR-122 binding results in alteration of nucleotides 1-117 to suppress an alternative secondary structure and promote functional internal ribosomal entry site (IRES) formation. Furthermore, we demonstrate that two hAgo2:miR-122 complexes are able to bind to the HCV 5' terminus simultaneously and SHAPE analyses revealed further alterations to the structure of the 5' UTR to accommodate these complexes. Finally, we present a computational model of the hAgo2:miR-122:HCV RNA complex at the 5' terminus of the viral genome as well as hAgo2:miR-122 interactions with the IRES-40S complex that suggest hAgo2 is likely to form additional interactions with SLII which may further stabilize the HCV IRES. Taken together, our results support a model whereby hAgo2:miR-122 complexes alter the structure of the viral 5' terminus and promote formation of the HCV IRES.
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Affiliation(s)
- Jasmin Chahal
- Department of Microbiology & Immunology, McGill University, Montréal, QC H3G 1Y6, Canada
| | - Luca F R Gebert
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Hin Hark Gan
- Center for Genomics and Systems Biology, Department of Biology, New York University, 12 Waverly Place, New York, NY 10003, USA
| | - Edna Camacho
- Department of Biochemistry, McGill University, Montréal, QC H3G 1Y6, Canada
| | - Kristin C Gunsalus
- Center for Genomics and Systems Biology, Department of Biology, New York University, 12 Waverly Place, New York, NY 10003, USA
- Division of Biology, New York University Abu Dhabi, Abu Dhabi, UAE
| | - Ian J MacRae
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Selena M Sagan
- Department of Microbiology & Immunology, McGill University, Montréal, QC H3G 1Y6, Canada
- Department of Biochemistry, McGill University, Montréal, QC H3G 1Y6, Canada
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16
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Vicens Q, Mondragón E, Reyes FE, Coish P, Aristoff P, Berman J, Kaur H, Kells KW, Wickens P, Wilson J, Gadwood RC, Schostarez HJ, Suto RK, Blount KF, Batey RT. Structure-Activity Relationship of Flavin Analogues That Target the Flavin Mononucleotide Riboswitch. ACS Chem Biol 2018; 13:2908-2919. [PMID: 30107111 DOI: 10.1021/acschembio.8b00533] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The flavin mononucleotide (FMN) riboswitch is an emerging target for the development of novel RNA-targeting antibiotics. We previously discovered an FMN derivative, 5FDQD, that protects mice against diarrhea-causing Clostridium difficile bacteria. Here, we present the structure-based drug design strategy that led to the discovery of this fluoro-phenyl derivative with antibacterial properties. This approach involved the following stages: (1) structural analysis of all available free and bound FMN riboswitch structures; (2) design, synthesis, and purification of derivatives; (3) in vitro testing for productive binding using two chemical probing methods; (4) in vitro transcription termination assays; and (5) resolution of the crystal structures of the FMN riboswitch in complex with the most mature candidates. In the process, we delineated principles for productive binding to this riboswitch, thereby demonstrating the effectiveness of a coordinated structure-guided approach to designing drugs against RNA.
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Affiliation(s)
- Quentin Vicens
- Department of Chemistry and Biochemistry, University of Colorado, 596 UCB, Boulder, Colorado 80309, United States
| | - Estefanía Mondragón
- Department of Chemistry and Biochemistry, University of Colorado, 596 UCB, Boulder, Colorado 80309, United States
| | - Francis E. Reyes
- Department of Chemistry and Biochemistry, University of Colorado, 596 UCB, Boulder, Colorado 80309, United States
| | - Philip Coish
- BioRelix Inc., 124 Washington Street, Foxborough, Massachusetts 02035, United States
| | - Paul Aristoff
- Aristoff Consulting LLC, 3726 Green Spring Drive, Fort Collins, Colorado 80528, United States
| | - Judd Berman
- Dalton Pharma Services, 349 Wildcat Road, Toronto, ON M3J 2S3, Canada
| | - Harpreet Kaur
- Dalton Pharma Services, 349 Wildcat Road, Toronto, ON M3J 2S3, Canada
| | - Kevin W. Kells
- Dalton Pharma Services, 349 Wildcat Road, Toronto, ON M3J 2S3, Canada
| | - Phil Wickens
- Dalton Pharma Services, 349 Wildcat Road, Toronto, ON M3J 2S3, Canada
| | - Jeffery Wilson
- Dalton Pharma Services, 349 Wildcat Road, Toronto, ON M3J 2S3, Canada
| | - Robert C. Gadwood
- Kalexsyn, Inc., 4502 Campus Drive, Kalamazoo, Michigan 49008, United States
| | | | - Robert K. Suto
- Xtal BioStructures, Inc., 12 Michigan Drive, Natick, Massachusetts 01760, United States
| | - Kenneth F. Blount
- BioRelix Inc., 124 Washington Street, Foxborough, Massachusetts 02035, United States
| | - Robert T. Batey
- Department of Chemistry and Biochemistry, University of Colorado, 596 UCB, Boulder, Colorado 80309, United States
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17
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Dutta D, Belashov IA, Wedekind JE. Coupling Green Fluorescent Protein Expression with Chemical Modification to Probe Functionally Relevant Riboswitch Conformations in Live Bacteria. Biochemistry 2018; 57:4620-4628. [PMID: 29897738 DOI: 10.1021/acs.biochem.8b00316] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Noncoding RNAs engage in numerous biological activities including gene regulation. To fully understand RNA function it is necessary to probe biologically relevant conformations in living cells. To address this challenge, we coupled RNA-mediated regulation of the green fluorescent protein (GFP)uv-reporter gene to icSHAPE (in cell Selective 2'-Hydroxyl Acylation analyzed by Primer Extension). Our transcript-specific approach provides sensitive, fluorescence-based readout of the regulatory-RNA status as a means to coordinate chemical modification experiments. We chose a plasmid-based reporter compatible with Escherichia coli to allow use of knockout strains that eliminate endogenous effector biosynthesis. The approach was piloted using the Lactobacillus rhamnosus ( Lrh) preQ1-II riboswitch, which senses the pyrrolopyrimidine metabolite preQ1. Using an E. coli Δ queF strain incapable of preQ1 anabolism, the Lrh riboswitch yielded nearly one log unit of GFPuv-gene repression resulting from exogenously added preQ1. We then subjected cells in gene "on" and "off" states to icSHAPE. The resulting differential analysis indicated reduction in Lrh riboswitch flexibility in the P3 helix of the pseudoknot, which comprises the ribosome-binding site (RBS) paired with the anti-RBS. Such expression platform modulation was not observed by in vitro chemical probing and demonstrates that the crowded cellular environment does not preclude detection of compact and loose RNA-regulatory conformations. Here we describe the design, methods, interpretation, and caveats of Reporter Coupled (ReCo) icSHAPE. We also describe mapping of the differential ReCo-icSHAPE results onto the Lrh riboswitch-preQ1 cocrystal structure. The approach should be readily applicable to functional RNAs triggered by effectors or environmental variations.
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Affiliation(s)
- Debapratim Dutta
- Department of Biochemistry & Biophysics and Center for RNA Biology , University of Rochester School of Medicine & Dentistry , Rochester , New York 14642 , United States
| | - Ivan A Belashov
- Department of Biochemistry & Biophysics and Center for RNA Biology , University of Rochester School of Medicine & Dentistry , Rochester , New York 14642 , United States
| | - Joseph E Wedekind
- Department of Biochemistry & Biophysics and Center for RNA Biology , University of Rochester School of Medicine & Dentistry , Rochester , New York 14642 , United States
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18
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Cellular conditions of weakly chelated magnesium ions strongly promote RNA stability and catalysis. Nat Commun 2018; 9:2149. [PMID: 29858572 PMCID: PMC5984629 DOI: 10.1038/s41467-018-04415-1] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 04/23/2018] [Indexed: 01/06/2023] Open
Abstract
Most RNA folding studies have been performed under non-physiological conditions of high concentrations (≥10 mM) of Mg2+free, while actual cellular concentrations of Mg2+free are only ~1 mM in a background of greater than 50 mM Mg2+total. To uncover cellular behavior of RNA, we devised cytoplasm mimic systems that include biological concentrations of amino acids, which weakly chelate Mg2+. Amino acid-chelated Mg2+ (aaCM) of ~15 mM dramatically increases RNA folding and prevents RNA degradation. Furthermore, aaCM enhance self-cleavage of several different ribozymes, up to 100,000-fold at Mg2+free of just 0.5 mM, indirectly through RNA compaction. Other metabolites that weakly chelate magnesium offer similar beneficial effects, which implies chelated magnesium may enhance RNA function in the cell in the same way. Overall, these results indicate that the states of Mg2+ should not be limited to free and bound only, as weakly bound Mg2+ strongly promotes RNA function under cellular conditions.
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19
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Du Z, Alekhina OM, Vassilenko KS, Simon AE. Concerted action of two 3' cap-independent translation enhancers increases the competitive strength of translated viral genomes. Nucleic Acids Res 2017; 45:9558-9572. [PMID: 28934492 PMCID: PMC5766195 DOI: 10.1093/nar/gkx643] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 07/14/2017] [Indexed: 11/13/2022] Open
Abstract
Several families of plant viruses evolved cap-independent translation enhancers (3'CITE) in the 3' untranslated regions of their genomic (g)RNAs to compete with ongoing cap-dependent translation of cellular mRNAs. Umbravirus Pea enation mosaic virus (PEMV)2 is the only example where three 3'CITEs enhance translation: the eIF4E-binding Panicum mosaic virus-like translational enhancer (PTE) and ribosome-binding 3' T-shaped structure (TSS) have been found in viruses of different genera, while the ribosome-binding kl-TSS that provides a long-distance interaction with the 5' end is unique. We report that the PTE is the key translation promoting element, but inhibits translation in cis and in trans in the absence of the kl-TSS by sequestering initiation factor eIF4G. PEMV2 strongly outcompeted a cellular mRNA mimic for translation, indicating that the combination of kl-TSS and PTE is highly efficient. Transferring the 3'-5' interaction from the kl-TSS to the PTE (to fulfill its functionality as found in other viruses) supported translationin vitro, but gRNA did not accumulate to detectable levels in protoplasts in the absence of the kl-TSS. It was shown that the PTE in conjunction with the kl-TSS did not markedly affect the translation initiation rate but rather increased the number of gRNAs available for translation. A model is proposed to explain how 3'CITE-based regulation of ribosome recruitment enhances virus fitness.
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Affiliation(s)
- Zhiyou Du
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Olga M Alekhina
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russia
| | - Konstantin S Vassilenko
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Moscow Region 142290, Russia
| | - Anne E Simon
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD 20742, USA
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20
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Miras M, Truniger V, Querol‐Audi J, Aranda MA. Analysis of the interacting partners eIF4F and 3'-CITE required for Melon necrotic spot virus cap-independent translation. MOLECULAR PLANT PATHOLOGY 2017; 18:635-648. [PMID: 27145354 PMCID: PMC6638222 DOI: 10.1111/mpp.12422] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 04/26/2016] [Accepted: 04/28/2016] [Indexed: 05/17/2023]
Abstract
We have shown previously that the translation of Melon necrotic spot virus (MNSV, family Tombusviridae, genus Carmovirus) RNAs is controlled by a 3'-cap-independent translation enhancer (CITE), which is genetically and functionally dependent on the eukaryotic translation initiation factor (eIF) 4E. Here, we describe structural and functional analyses of the MNSV-Mα5 3'-CITE and its translation initiation factor partner. We first mapped the minimal 3'-CITE (Ma5TE) to a 45-nucleotide sequence, which consists of a stem-loop structure with two internal loops, similar to other I-shaped 3'-CITEs. UV crosslinking, followed by gel retardation assays, indicated that Ma5TE interacts in vitro with the complex formed by eIF4E + eIF4G980-1159 (eIF4Fp20 ), but not with each subunit alone or with eIF4E + eIF4G1003-1092 , suggesting binding either through interaction with eIF4E following a conformational change induced by its binding to eIF4G980-1159 , or through a double interaction with eIF4E and eIF4G980-1159 . Critical residues for this interaction reside in an internal bulge of Ma5TE, so that their mutation abolished binding to eIF4E + eIF4G1003-1092 and cap-independent translation. We also developed an in vivo system to test the effect of mutations in eIF4E in Ma5TE-driven cap-independent translation, showing that conserved amino acids in a positively charged RNA-binding motif around amino acid position 228, implicated in eIF4E-eIF4G binding or belonging to the cap-recognition pocket, are essential for cap-independent translation controlled by Ma5TE, and thus for the multiplication of MNSV.
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Affiliation(s)
- Manuel Miras
- Centro de Edafología y Biología Aplicada del Segura (CEBAS) ‐ CSICApdo. correos 164, 30100 EspinardoMurciaSpain
| | - Verónica Truniger
- Centro de Edafología y Biología Aplicada del Segura (CEBAS) ‐ CSICApdo. correos 164, 30100 EspinardoMurciaSpain
| | - Jordi Querol‐Audi
- Molecular Biology Institute of Barcelona (IBMB‐CSIC)Parc Científic de Barcelona, Baldiri i Reixac 10Barcelona08028Spain
| | - Miguel A. Aranda
- Centro de Edafología y Biología Aplicada del Segura (CEBAS) ‐ CSICApdo. correos 164, 30100 EspinardoMurciaSpain
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21
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Duval M, Marenna A, Chevalier C, Marzi S. Site-Directed Chemical Probing to map transient RNA/protein interactions. Methods 2016; 117:48-58. [PMID: 28027957 DOI: 10.1016/j.ymeth.2016.12.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 12/11/2016] [Accepted: 12/21/2016] [Indexed: 12/24/2022] Open
Abstract
RNA-protein interactions are at the bases of many biological processes, forming either tight and stable functional ribonucleoprotein (RNP) complexes (i.e. the ribosome) or transitory ones, such as the complexes involving RNA chaperone proteins. To localize the sites where a protein interacts on an RNA molecule, a common simple and inexpensive biochemical method is the footprinting technique. The protein leaves its footprint on the RNA acting as a shield to protect the regions of interaction from chemical modification or cleavages obtained with chemical or enzymatic nucleases. This method has proven its efficiency to study in vitro the organization of stable RNA-protein complexes. Nevertheless, when the protein binds the RNA very dynamically, with high off-rates, protections are very often difficult to observe. For the analysis of these transient complexes, we describe an alternative strategy adapted from the Site Directed Chemical Probing (SDCP) approach and we compare it with classical footprinting. SDCP relies on the modification of the RNA binding protein to tether an RNA probe (usually Fe-EDTA) to specific protein positions. Local cleavages on the regions of interaction can be used to localize the protein and position its domains on the RNA molecule. This method has been used in the past to monitor stable complexes; we provide here a detailed protocol and a practical example of its application to the study of Escherichia coli RNA chaperone protein S1 and its transitory complexes with mRNAs.
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Affiliation(s)
- Mélodie Duval
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, F-67000 Strasbourg, France
| | - Alessandra Marenna
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, F-67000 Strasbourg, France
| | - Clément Chevalier
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, F-67000 Strasbourg, France
| | - Stefano Marzi
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, F-67000 Strasbourg, France.
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22
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Stewart H, Bingham R, White SJ, Dykeman EC, Zothner C, Tuplin AK, Stockley PG, Twarock R, Harris M. Identification of novel RNA secondary structures within the hepatitis C virus genome reveals a cooperative involvement in genome packaging. Sci Rep 2016; 6:22952. [PMID: 26972799 PMCID: PMC4789732 DOI: 10.1038/srep22952] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Accepted: 02/19/2016] [Indexed: 12/11/2022] Open
Abstract
The specific packaging of the hepatitis C virus (HCV) genome is hypothesised to be driven by Core-RNA interactions. To identify the regions of the viral genome involved in this process, we used SELEX (systematic evolution of ligands by exponential enrichment) to identify RNA aptamers which bind specifically to Core in vitro. Comparison of these aptamers to multiple HCV genomes revealed the presence of a conserved terminal loop motif within short RNA stem-loop structures. We postulated that interactions of these motifs, as well as sub-motifs which were present in HCV genomes at statistically significant levels, with the Core protein may drive virion assembly. We mutated 8 of these predicted motifs within the HCV infectious molecular clone JFH-1, thereby producing a range of mutant viruses predicted to possess altered RNA secondary structures. RNA replication and viral titre were unaltered in viruses possessing only one mutated structure. However, infectivity titres were decreased in viruses possessing a higher number of mutated regions. This work thus identified multiple novel RNA motifs which appear to contribute to genome packaging. We suggest that these structures act as cooperative packaging signals to drive specific RNA encapsidation during HCV assembly.
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MESH Headings
- Aptamers, Nucleotide/chemistry
- Aptamers, Nucleotide/genetics
- Aptamers, Nucleotide/metabolism
- Base Sequence
- Blotting, Western
- Cell Line, Tumor
- Gene Expression Regulation, Viral
- Genome, Viral/genetics
- Hepacivirus/genetics
- Hepacivirus/metabolism
- Humans
- Mutation
- Nucleic Acid Conformation
- Nucleotide Motifs/genetics
- Protein Binding
- RNA, Viral/chemistry
- RNA, Viral/genetics
- RNA, Viral/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- SELEX Aptamer Technique
- Viral Core Proteins/genetics
- Viral Core Proteins/metabolism
- Viral Proteins/genetics
- Viral Proteins/metabolism
- Virus Assembly/genetics
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Affiliation(s)
- H. Stewart
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - R.J. Bingham
- York Centre for Complex Systems Analysis, Departments of Mathematics and Biology, University of York, York, YO10 5DD, United Kingdom
| | - S. J. White
- Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - E. C. Dykeman
- York Centre for Complex Systems Analysis, Departments of Mathematics and Biology, University of York, York, YO10 5DD, United Kingdom
| | - C. Zothner
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - A. K. Tuplin
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
- Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - P. G. Stockley
- Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - R. Twarock
- York Centre for Complex Systems Analysis, Departments of Mathematics and Biology, University of York, York, YO10 5DD, United Kingdom
| | - M. Harris
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
- Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
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23
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Guedich S, Puffer-Enders B, Baltzinger M, Hoffmann G, Da Veiga C, Jossinet F, Thore S, Bec G, Ennifar E, Burnouf D, Dumas P. Quantitative and predictive model of kinetic regulation by E. coli TPP riboswitches. RNA Biol 2016; 13:373-90. [PMID: 26932506 PMCID: PMC4841613 DOI: 10.1080/15476286.2016.1142040] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Riboswitches are non-coding elements upstream or downstream of mRNAs that, upon binding of a specific ligand, regulate transcription and/or translation initiation in bacteria, or alternative splicing in plants and fungi. We have studied thiamine pyrophosphate (TPP) riboswitches regulating translation of thiM operon and transcription and translation of thiC operon in E. coli, and that of THIC in the plant A. thaliana. For all, we ascertained an induced-fit mechanism involving initial binding of the TPP followed by a conformational change leading to a higher-affinity complex. The experimental values obtained for all kinetic and thermodynamic parameters of TPP binding imply that the regulation by A. thaliana riboswitch is governed by mass-action law, whereas it is of kinetic nature for the two bacterial riboswitches. Kinetic regulation requires that the RNA polymerase pauses after synthesis of each riboswitch aptamer to leave time for TPP binding, but only when its concentration is sufficient. A quantitative model of regulation highlighted how the pausing time has to be linked to the kinetic rates of initial TPP binding to obtain an ON/OFF switch in the correct concentration range of TPP. We verified the existence of these pauses and the model prediction on their duration. Our analysis also led to quantitative estimates of the respective efficiency of kinetic and thermodynamic regulations, which shows that kinetically regulated riboswitches react more sharply to concentration variation of their ligand than thermodynamically regulated riboswitches. This rationalizes the interest of kinetic regulation and confirms empirical observations that were obtained by numerical simulations.
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Affiliation(s)
- Sondés Guedich
- a IBMC-CNRS, Biophysique et Biologie Structurale, Architecture et Réactivité de l'ARN, Université de Strasbourg , Strasbourg , France
| | - Barbara Puffer-Enders
- a IBMC-CNRS, Biophysique et Biologie Structurale, Architecture et Réactivité de l'ARN, Université de Strasbourg , Strasbourg , France
| | - Mireille Baltzinger
- b IBMC-CNRS, Régulations post-transcriptionnelles et nutrition, Architecture et Réactivité de l'ARN, Université de Strasbourg , Strasbourg , France
| | | | - Cyrielle Da Veiga
- a IBMC-CNRS, Biophysique et Biologie Structurale, Architecture et Réactivité de l'ARN, Université de Strasbourg , Strasbourg , France
| | - Fabrice Jossinet
- d IBMC-CNRS, Evolution des ARN non codants chez la levure, Architecture et Réactivité de l'ARN, Université de Strasbourg , Strasbourg , France
| | - Stéphane Thore
- e Université de Bordeaux, Institut Européen de Chimie et Biologie, ARNA laboratory; INSERM-U1212; CNRS-UMR5320 ; Bordeaux , France
| | - Guillaume Bec
- a IBMC-CNRS, Biophysique et Biologie Structurale, Architecture et Réactivité de l'ARN, Université de Strasbourg , Strasbourg , France
| | - Eric Ennifar
- a IBMC-CNRS, Biophysique et Biologie Structurale, Architecture et Réactivité de l'ARN, Université de Strasbourg , Strasbourg , France
| | - Dominique Burnouf
- a IBMC-CNRS, Biophysique et Biologie Structurale, Architecture et Réactivité de l'ARN, Université de Strasbourg , Strasbourg , France
| | - Philippe Dumas
- a IBMC-CNRS, Biophysique et Biologie Structurale, Architecture et Réactivité de l'ARN, Université de Strasbourg , Strasbourg , France
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24
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Sharma SD, Kraft JJ, Miller WA, Goss DJ. Recruitment of the 40S ribosome subunit to the 3'-untranslated region (UTR) of a viral mRNA, via the eIF4 complex, facilitates cap-independent translation. J Biol Chem 2015; 290:11268-81. [PMID: 25792742 DOI: 10.1074/jbc.m115.645002] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Indexed: 02/05/2023] Open
Abstract
Barley yellow dwarf virus mRNA, which lacks both cap and poly(A) tail, has a translation element (3'-BTE) in its 3'-UTR essential for efficient translation initiation at the 5'-proximal AUG. This mechanism requires eukaryotic initiation factor 4G (eIF4G), subunit of heterodimer eIF4F (plant eIF4F lacks eIF4A), and 3'-BTE-5'-UTR interaction. Using fluorescence anisotropy, SHAPE (selective 2'-hydroxyl acylation analyzed by primer extension) analysis, and toeprinting, we found that (i) 40S subunits bind to BTE (Kd = 350 ± 30 nm), (ii) the helicase complex eIF4F-eIF4A-eIF4B-ATP increases 40S subunit binding (Kd = 120 ± 10 nm) to the conserved stem-loop I of the 3'-BTE by exposing more unpaired bases, and (iii) long distance base pairing transfers this complex to the 5'-end of the mRNA, where translation initiates. Although 3'-5' interactions have been recognized as important in mRNA translation, barley yellow dwarf virus employs a novel mechanism utilizing the 3'-UTR as the primary site of ribosome recruitment.
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Affiliation(s)
- Sohani Das Sharma
- From the Department of Chemistry, Hunter College and the Graduate Center, City University of New York, New York, New York 10065 and
| | | | - W Allen Miller
- the Departments of Plant Pathology and Microbiology and Biochemistry, Biophysics, Molecular Biology, and Microbiology, Iowa State University, Ames, Iowa 50011
| | - Dixie J Goss
- From the Department of Chemistry, Hunter College and the Graduate Center, City University of New York, New York, New York 10065 and
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25
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Sloma MF, Mathews DH. Improving RNA secondary structure prediction with structure mapping data. Methods Enzymol 2015; 553:91-114. [PMID: 25726462 DOI: 10.1016/bs.mie.2014.10.053] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Methods to probe RNA secondary structure, such as small molecule modifying agents, secondary structure-specific nucleases, inline probing, and SHAPE chemistry, are widely used to study the structure of functional RNA. Computational secondary structure prediction programs can incorporate probing data to predict structure with high accuracy. In this chapter, an overview of current methods for probing RNA secondary structure is provided, including modern high-throughput methods. Methods for guiding secondary structure prediction algorithms using these data are explained, and best practices for using these data are provided. This chapter concludes by listing a number of open questions about how to best use probing data, and what these data can provide.
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Affiliation(s)
- Michael F Sloma
- Department of Biochemistry & Biophysics, University of Rochester Medical Center, Box 712, Rochester, New York, USA; Center for RNA Biology, University of Rochester Medical Center, Box 712, Rochester, New York, USA
| | - David H Mathews
- Department of Biochemistry & Biophysics, University of Rochester Medical Center, Box 712, Rochester, New York, USA; Center for RNA Biology, University of Rochester Medical Center, Box 712, Rochester, New York, USA.
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26
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Nitzan M, Fechter P, Peer A, Altuvia Y, Bronesky D, Vandenesch F, Romby P, Biham O, Margalit H. A defense-offense multi-layered regulatory switch in a pathogenic bacterium. Nucleic Acids Res 2015; 43:1357-69. [PMID: 25628364 PMCID: PMC4330369 DOI: 10.1093/nar/gkv001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Cells adapt to environmental changes by efficiently adjusting gene expression programs. Staphylococcus aureus, an opportunistic pathogenic bacterium, switches between defensive and offensive modes in response to quorum sensing signal. We identified and studied the structural characteristics and dynamic properties of the core regulatory circuit governing this switch by deterministic and stochastic computational methods, as well as experimentally. This module, termed here Double Selector Switch (DSS), comprises the RNA regulator RNAIII and the transcription factor Rot, defining a double-layered switch involving both transcriptional and post-transcriptional regulations. It coordinates the inverse expression of two sets of target genes, immuno-modulators and exotoxins, expressed during the defensive and offensive modes, respectively. Our computational and experimental analyses show that the DSS guarantees fine-tuned coordination of the inverse expression of its two gene sets, tight regulation, and filtering of noisy signals. We also identified variants of this circuit in other bacterial systems, suggesting it is used as a molecular switch in various cellular contexts and offering its use as a template for an effective switching device in synthetic biology studies.
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Affiliation(s)
- Mor Nitzan
- Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, The Hebrew University, Jerusalem 91120, Israel
| | - Pierre Fechter
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, Strasbourg F-67084, France
| | - Asaf Peer
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, The Hebrew University, Jerusalem 91120, Israel
| | - Yael Altuvia
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, The Hebrew University, Jerusalem 91120, Israel
| | - Delphine Bronesky
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, Strasbourg F-67084, France
| | - François Vandenesch
- CIRI, International Center for Infectiology Research,Lyon, France Inserm, U1111, Lyon, France École Normale Supérieure de Lyon, Lyon, France Université Lyon 1, Lyon, France CNRS, UMR5308, Lyon, France
| | - Pascale Romby
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC, Strasbourg F-67084, France
| | - Ofer Biham
- Racah Institute of Physics, The Hebrew University, Jerusalem 91904, Israel
| | - Hanah Margalit
- Department of Microbiology and Molecular Genetics, IMRIC, Faculty of Medicine, The Hebrew University, Jerusalem 91120, Israel
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27
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Sloane JL, Greenberg MM. Interstrand cross-link and bioconjugate formation in RNA from a modified nucleotide. J Org Chem 2014; 79:9792-8. [PMID: 25295850 PMCID: PMC4201359 DOI: 10.1021/jo501982r] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
![]()
RNA
oligonucleotides containing a phenyl selenide derivative of
5-methyluridine were chemically synthesized by solid-phase synthesis.
The phenyl selenide is rapidly converted to an electrophilic, allylic
phenyl seleneate under mild oxidative conditions. The phenyl seleneate
yields interstrand cross-links when part of a duplex and is useful
for synthesizing oligonucleotide conjugates. Formation of the latter
is illustrated by reaction of an oligonucleotide containing the phenyl
selenide with amino acids in the presence of mild oxidant. The products
formed are analogous to those observed in tRNA that are believed to
be formed posttranslationally via a biosynthetic intermediate that
is chemically homologous to the phenyl seleneate.
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Affiliation(s)
- Jack L Sloane
- Department of Chemistry, Johns Hopkins University , 3400 N. Charles Street, Baltimore, Maryland 21218, United States
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28
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Soulière MF, Micura R. Use of SHAPE to select 2AP substitution sites for RNA-ligand interactions and dynamics studies. Methods Mol Biol 2014; 1103:227-39. [PMID: 24318898 DOI: 10.1007/978-1-62703-730-3_17] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Most regulatory RNA molecules must adopt a precise secondary fold and tertiary structure to allow their function in cells. A number of experimental approaches, such as the 2-Aminopurine-Based RNA Folding Analysis (2ApFold), have therefore been developed to offer insights into the folding and folding dynamics of RNA. A crucial requirement for this method is the selection of proper 2AP labeling positions. In that regard, we recently discovered that Selective 2'-Hydroxyl Acylation analyzed by Primer Extension (SHAPE) offers a reliable path to identify appropriate nucleotides for 2AP substitution on a target RNA. This chapter describes the straightforward procedure to select 2AP substitution sites in RNA molecules using SHAPE probing. The protocols detail the preparation of the target RNA by transcription, and the SHAPE steps including (1) probing of the RNA, (2) reverse transcription with a radiolabeled primer, (3) sequencing gel, and (4) analysis of the obtained band pattern.
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Affiliation(s)
- Marie F Soulière
- Institute of Organic Chemistry, Center for Chemistry and Biomedicine, Leopold Franzens University, Innsbruck, Austria
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29
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Jodoin R, Bauer L, Garant JM, Mahdi Laaref A, Phaneuf F, Perreault JP. The folding of 5'-UTR human G-quadruplexes possessing a long central loop. RNA (NEW YORK, N.Y.) 2014; 20:1129-1141. [PMID: 24865610 PMCID: PMC4114690 DOI: 10.1261/rna.044578.114] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 04/21/2014] [Indexed: 05/31/2023]
Abstract
G-quadruplexes are widespread four-stranded structures that are adopted by G-rich regions of both DNA and RNA and are involved in essential biological processes such as mRNA translation. They are formed by the stacking of two or more G-quartets that are linked together by three loops. Although the maximal loop length is usually fixed to 7 nt in most G-quadruplex-predicting software, it has already been demonstrated that artificial DNA G-quadruplexes containing two distal loops that are limited to 1 nt each and a central loop up to 30 nt long are likely to form in vitro. This report demonstrates that such structures possessing a long central loop are actually found in the 5'-UTRs of human mRNAs. Firstly, 1453 potential G-quadruplex-forming sequences (PG4s) were identified through a bioinformatic survey that searched for sequences respecting the requirement for two 1-nt long distal loops and a long central loop of 2-90 nt in length. Secondly, in vitro in-line probing experiments confirmed and characterized the folding of eight candidates possessing central loops of 10-70 nt long. Finally, the biological effect of several G-quadruplexes with a long central loop on mRNA expression was studied in cellulo using a luciferase gene reporter assay. Clearly, the actual definition of G-quadruplex-forming sequences is too conservative and must be expanded to include the long central loop. This greatly expands the number of expected PG4s in the transcriptome. Consideration of these new candidates might aid in elucidating the potentially important biological implications of the G-quadruplex structure.
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Affiliation(s)
- Rachel Jodoin
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Pavillon de Recherche Appliquée au Cancer, Université de Sherbrooke, Québec, Canada J1E 4K8
| | - Lubos Bauer
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Pavillon de Recherche Appliquée au Cancer, Université de Sherbrooke, Québec, Canada J1E 4K8
| | - Jean-Michel Garant
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Pavillon de Recherche Appliquée au Cancer, Université de Sherbrooke, Québec, Canada J1E 4K8
| | - Abdelhamid Mahdi Laaref
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Pavillon de Recherche Appliquée au Cancer, Université de Sherbrooke, Québec, Canada J1E 4K8
| | - Francis Phaneuf
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Pavillon de Recherche Appliquée au Cancer, Université de Sherbrooke, Québec, Canada J1E 4K8
| | - Jean-Pierre Perreault
- Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Pavillon de Recherche Appliquée au Cancer, Université de Sherbrooke, Québec, Canada J1E 4K8
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30
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Mickleburgh I, Kafasla P, Cherny D, Llorian M, Curry S, Jackson RJ, Smith CWJ. The organization of RNA contacts by PTB for regulation of FAS splicing. Nucleic Acids Res 2014; 42:8605-20. [PMID: 24957602 PMCID: PMC4117754 DOI: 10.1093/nar/gku519] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Post-transcriptional steps of gene expression are regulated by RNA binding proteins. Major progress has been made in characterizing RNA-protein interactions, from high resolution structures to transcriptome-wide profiling. Due to the inherent technical challenges, less attention has been paid to the way in which proteins with multiple RNA binding domains engage with target RNAs. We have investigated how the four RNA recognition motif (RRM) domains of Polypyrimidine tract binding (PTB) protein, a major splicing regulator, interact with FAS pre-mRNA under conditions in which PTB represses FAS exon 6 splicing. A combination of tethered hydroxyl radical probing, targeted inactivation of individual RRMs and single molecule analyses revealed an unequal division of labour between the four RRMs of PTB. RNA binding by RRM4 is the most important for function despite the low intrinsic binding specificity and the complete lack of effect of disrupting individual RRM4 contact points on the RNA. The ordered RRM3-4 di-domain packing provides an extended binding surface for RNA interacting at RRM4, via basic residues in the preceding linker. Our results illustrate how multiple alternative low-specificity binding configurations of RRM4 are consistent with repressor function as long as the overall ribonucleoprotein architecture provided by appropriate di-domain packing is maintained.
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Affiliation(s)
- Ian Mickleburgh
- Department of Biochemistry, University of Cambridge, Downing Site, Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Panagiota Kafasla
- Department of Biochemistry, University of Cambridge, Downing Site, Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Dmitry Cherny
- Department of Biochemistry, Henry Wellcome Building, University of Leicester, Lancaster Road, Leicester LE1 9HN, UK
| | - Miriam Llorian
- Department of Biochemistry, University of Cambridge, Downing Site, Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Stephen Curry
- Division of Cell and Molecular Biology, Imperial College, Exhibition Road, London SW7 2AZ, UK
| | - Richard J Jackson
- Department of Biochemistry, University of Cambridge, Downing Site, Tennis Court Road, Cambridge, CB2 1QW, UK
| | - Christopher W J Smith
- Department of Biochemistry, University of Cambridge, Downing Site, Tennis Court Road, Cambridge, CB2 1QW, UK
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31
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Abstract
Enzymatic probing is a rapid, straightforward method for determining which regions of a folded RNA are structurally constrained. It can be carried out using very small amounts of material, and is especially suitable for short RNAs. Here we report a protocol that we have found to be useful and readily adaptable to the evaluation of RNAs up to 150-200 nucleotides in length. Considerations for optimization are also included. In brief, the method includes folding end-labeled RNA into its native conformation, partial digestion with structure-sensitive nucleases, and identification of the cleavage sites by electrophoretic separation of the cleavage fragments.
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Affiliation(s)
- Elisa Biondi
- Department of Molecular Microbiology and Immunology, University of Missouri, Columbia, MO, USA
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32
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Ranpura H, Bialonska D, Bolton PH. Finding and characterizing the complexes of drug like molecules with quadruplex DNA: combined use of an enhanced hydroxyl radical cleavage protocol and NMR. PLoS One 2014; 9:e96218. [PMID: 24763734 PMCID: PMC3999192 DOI: 10.1371/journal.pone.0096218] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 04/04/2014] [Indexed: 11/19/2022] Open
Abstract
Structural information on the complexes of drug like molecules with quadruplex DNAs can aid the development of therapeutics and research tools that selectively target specific quadruplex DNAs. Screening can identify candidate molecules that require additional evaluation. An enhanced hydroxyl radical cleavage protocol is demonstrated that can efficiently provide structural information on the complexes of the candidate molecules with quadruplex DNA. NMR methods have been used to offer additional structural information about the complexes as well as validate the results of the hydroxyl radical approach. This multi-step protocol has been demonstrated on complexes of the chair type quadruplex formed by the thrombin binding aptamer, d(GGTTGGTGTGGTTGG). The hydroxyl radical results indicate that NSC 176319, Cain’s quinolinium that was found by screening, exhibits selective binding to the two TT loops. The NMR results are consistent with selective disruption of the hydrogen bonding between T4 and T13 as well as unstacking of these residues from the bottom quartet. Thus, the combination of screening, hydroxyl radical footprinting and NMR can find new molecules that selectively bind to quadruplex DNAs as well as provide structural information about their complexes.
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Affiliation(s)
- Harikrushan Ranpura
- Chemistry Department, Wesleyan University, Middletown, Connecticut, United States of America
| | - Dobroslawa Bialonska
- Chemistry Department, Wesleyan University, Middletown, Connecticut, United States of America
| | - Philip H. Bolton
- Chemistry Department, Wesleyan University, Middletown, Connecticut, United States of America
- * E-mail:
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33
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Fu Y, Deiorio-Haggar K, Soo MW, Meyer MM. Bacterial RNA motif in the 5' UTR of rpsF interacts with an S6:S18 complex. RNA (NEW YORK, N.Y.) 2014; 20:168-76. [PMID: 24310371 PMCID: PMC3895269 DOI: 10.1261/rna.041285.113] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Approximately half the transcripts encoding ribosomal proteins in Escherichia coli include a structured RNA motif that interacts with a specific ribosomal protein to inhibit gene expression, thus allowing stoichiometric production of ribosome components. However, many of these RNA structures are not widely distributed across bacterial phyla. It is increasingly common for RNA motifs associated with ribosomal protein genes to be identified using comparative genomic methods, yet these are rarely experimentally validated. In this work, we characterize one such motif that precedes operons containing rpsF and rpsR, which encode ribosomal proteins S6 and S18. This RNA structure is widely distributed across many phyla of bacteria despite differences within the downstream operon, and examples are present in both E. coli and Bacillus subtilis. We demonstrate a direct interaction between an example of the RNA from B. subtilis and an S6:S18 complex using in vitro binding assays, verify our predicted secondary structure, and identify a putative protein-binding site. The proposed binding site bears a strong resemblance to the S18 binding site within the 16S rRNA, suggesting molecular mimicry. This interaction is a valuable addition to the canon of ribosomal protein mRNA interactions. This work shows how experimental verification translates computational results into concrete knowledge of biological systems.
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Ruiz de los Mozos I, Vergara-Irigaray M, Segura V, Villanueva M, Bitarte N, Saramago M, Domingues S, Arraiano CM, Fechter P, Romby P, Valle J, Solano C, Lasa I, Toledo-Arana A. Base pairing interaction between 5'- and 3'-UTRs controls icaR mRNA translation in Staphylococcus aureus. PLoS Genet 2013; 9:e1004001. [PMID: 24367275 PMCID: PMC3868564 DOI: 10.1371/journal.pgen.1004001] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 10/20/2013] [Indexed: 11/18/2022] Open
Abstract
The presence of regulatory sequences in the 3′ untranslated region (3′-UTR) of eukaryotic mRNAs controlling RNA stability and translation efficiency is widely recognized. In contrast, the relevance of 3′-UTRs in bacterial mRNA functionality has been disregarded. Here, we report evidences showing that around one-third of the mapped mRNAs of the major human pathogen Staphylococcus aureus carry 3′-UTRs longer than 100-nt and thus, potential regulatory functions. We selected the long 3′-UTR of icaR, which codes for the repressor of the main exopolysaccharidic compound of the S. aureus biofilm matrix, to evaluate the role that 3′-UTRs may play in controlling mRNA expression. We showed that base pairing between the 3′-UTR and the Shine-Dalgarno (SD) region of icaR mRNA interferes with the translation initiation complex and generates a double-stranded substrate for RNase III. Deletion or substitution of the motif (UCCCCUG) within icaR 3′-UTR was sufficient to abolish this interaction and resulted in the accumulation of IcaR repressor and inhibition of biofilm development. Our findings provide a singular example of a new potential post-transcriptional regulatory mechanism to modulate bacterial gene expression through the interaction of a 3′-UTR with the 5′-UTR of the same mRNA. At both sides of the protein-coding region, the mRNA molecule contains sequences that are not translated to protein. In eukaryotes, the untranslated 3′ region (3′-UTR), which comprises from the last codon used in translation to the 3′ end of the mRNA, controls mRNA stability, location and translation efficiency. In contrast, knowledge about the functions of 3′-UTRs in bacterial physiology is scarce. Here, we demonstrate that bacterial 3′-UTRs might play regulatory functions that might resemble those already described in eukaryotes. Transcriptome analysis of the human pathogen Staphylococcus aureus revealed that at least 30% of mRNAs contain long 3′-UTRs. Using the 3′-UTR of the mRNA encoding the main biofilm repressor IcaR as a model, we show that the 3′-UTR interferes with the translation initiation complex and promotes mRNA decay through base pairing with the ribosome binding site. This event contributes to adjusting IcaR level and modulating exopolysaccharide production and biofilm development in S. aureus. Our data illustrate that bacterial 3′-UTRs can provide strategies for fine-tuning control of gene expression.
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Affiliation(s)
- Igor Ruiz de los Mozos
- Laboratory of Microbial Biofilms. Instituto de Agrobiotecnología (IDAB). Universidad Pública de Navarra-CSIC-Gobierno de Navarra. Campus de Arrosadía. Pamplona, Spain
| | - Marta Vergara-Irigaray
- Laboratory of Microbial Biofilms. Instituto de Agrobiotecnología (IDAB). Universidad Pública de Navarra-CSIC-Gobierno de Navarra. Campus de Arrosadía. Pamplona, Spain
| | - Victor Segura
- Genomics, Proteomics and Bioinformatics Unit. Center for Applied Medical Research. University of Navarra. Pamplona, Spain
| | - Maite Villanueva
- Laboratory of Microbial Biofilms. Instituto de Agrobiotecnología (IDAB). Universidad Pública de Navarra-CSIC-Gobierno de Navarra. Campus de Arrosadía. Pamplona, Spain
| | - Nerea Bitarte
- Laboratory of Microbial Biofilms. Instituto de Agrobiotecnología (IDAB). Universidad Pública de Navarra-CSIC-Gobierno de Navarra. Campus de Arrosadía. Pamplona, Spain
| | - Margarida Saramago
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa. Oeiras, Portugal
| | - Susana Domingues
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa. Oeiras, Portugal
| | - Cecilia M. Arraiano
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa. Oeiras, Portugal
| | - Pierre Fechter
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC. Strasbourg, France
| | - Pascale Romby
- Architecture et Réactivité de l'ARN, Université de Strasbourg, CNRS, IBMC. Strasbourg, France
| | - Jaione Valle
- Laboratory of Microbial Biofilms. Instituto de Agrobiotecnología (IDAB). Universidad Pública de Navarra-CSIC-Gobierno de Navarra. Campus de Arrosadía. Pamplona, Spain
| | - Cristina Solano
- Laboratory of Microbial Biofilms. Instituto de Agrobiotecnología (IDAB). Universidad Pública de Navarra-CSIC-Gobierno de Navarra. Campus de Arrosadía. Pamplona, Spain
| | - Iñigo Lasa
- Laboratory of Microbial Biofilms. Instituto de Agrobiotecnología (IDAB). Universidad Pública de Navarra-CSIC-Gobierno de Navarra. Campus de Arrosadía. Pamplona, Spain
- * E-mail: (IL); (ATA)
| | - Alejandro Toledo-Arana
- Laboratory of Microbial Biofilms. Instituto de Agrobiotecnología (IDAB). Universidad Pública de Navarra-CSIC-Gobierno de Navarra. Campus de Arrosadía. Pamplona, Spain
- * E-mail: (IL); (ATA)
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35
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Kwok CK, Ding Y, Tang Y, Assmann SM, Bevilacqua PC. Determination of in vivo RNA structure in low-abundance transcripts. Nat Commun 2013; 4:2971. [DOI: 10.1038/ncomms3971] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 11/19/2013] [Indexed: 01/19/2023] Open
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Duval M, Korepanov A, Fuchsbauer O, Fechter P, Haller A, Fabbretti A, Choulier L, Micura R, Klaholz BP, Romby P, Springer M, Marzi S. Escherichia coli ribosomal protein S1 unfolds structured mRNAs onto the ribosome for active translation initiation. PLoS Biol 2013; 11:e1001731. [PMID: 24339747 PMCID: PMC3858243 DOI: 10.1371/journal.pbio.1001731] [Citation(s) in RCA: 119] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 10/25/2013] [Indexed: 11/24/2022] Open
Abstract
Regulation of translation initiation is well appropriate to adapt cell growth in response to stress and environmental changes. Many bacterial mRNAs adopt structures in their 5' untranslated regions that modulate the accessibility of the 30S ribosomal subunit. Structured mRNAs interact with the 30S in a two-step process where the docking of a folded mRNA precedes an accommodation step. Here, we used a combination of experimental approaches in vitro (kinetic of mRNA unfolding and binding experiments to analyze mRNA-protein or mRNA-ribosome complexes, toeprinting assays to follow the formation of ribosomal initiation complexes) and in vivo (genetic) to monitor the action of ribosomal protein S1 on the initiation of structured and regulated mRNAs. We demonstrate that r-protein S1 endows the 30S with an RNA chaperone activity that is essential for the docking and the unfolding of structured mRNAs, and for the correct positioning of the initiation codon inside the decoding channel. The first three OB-fold domains of S1 retain all its activities (mRNA and 30S binding, RNA melting activity) on the 30S subunit. S1 is not required for all mRNAs and acts differently on mRNAs according to the signals present at their 5' ends. This work shows that S1 confers to the ribosome dynamic properties to initiate translation of a large set of mRNAs with diverse structural features.
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Affiliation(s)
- Mélodie Duval
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire-CNRS, Strasbourg, France
| | - Alexey Korepanov
- CNRS UPR9073, University Paris Diderot, Sorbonne Paris Cité, Institut de Biologie Physico-Chimique, Paris, France
- Institute of Protein Research, Russian Academy of Sciences, Pushchino, Russia
| | - Olivier Fuchsbauer
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire-CNRS, Strasbourg, France
| | - Pierre Fechter
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire-CNRS, Strasbourg, France
| | - Andrea Haller
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold Franzens University, Innsbruck, Austria
| | - Attilio Fabbretti
- Laboratory of Genetics, Department of Biology MCA, University of Camerino, Camerino, Italy
| | - Laurence Choulier
- CNRS UMR 7213, Université de Strasbourg, Faculté de pharmacie, Illkirch, France
| | - Ronald Micura
- Institute of Organic Chemistry and Center for Molecular Biosciences, Leopold Franzens University, Innsbruck, Austria
| | - Bruno P. Klaholz
- Department of Integrated Structural Biology, Institute of Genetics and of Molecular and Cellular Biology, UMR 7104-CNRS, U964-INSERM, Illkirch, France; and Université de Strasbourg, Strasbourg, France
| | - Pascale Romby
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire-CNRS, Strasbourg, France
| | - Mathias Springer
- CNRS UPR9073, University Paris Diderot, Sorbonne Paris Cité, Institut de Biologie Physico-Chimique, Paris, France
| | - Stefano Marzi
- Architecture et Réactivité de l'ARN, Université de Strasbourg, Institut de Biologie Moléculaire et Cellulaire-CNRS, Strasbourg, France
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Beaudoin JD, Perreault JP. Exploring mRNA 3'-UTR G-quadruplexes: evidence of roles in both alternative polyadenylation and mRNA shortening. Nucleic Acids Res 2013; 41:5898-911. [PMID: 23609544 PMCID: PMC3675481 DOI: 10.1093/nar/gkt265] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Guanine-rich RNA sequences can fold into non-canonical, four stranded helical structures called G-quadruplexes that have been shown to be widely distributed within the mammalian transcriptome, as well as being key regulatory elements in various biological mechanisms. That said, their role within the 3'-untranslated region (UTR) of mRNA remains to be elucidated and appreciated. A bioinformatic analysis of the 3'-UTRs of mRNAs revealed enrichment in G-quadruplexes. To shed light on the role(s) of these structures, those found in the LRP5 and FXR1 genes were characterized both in vitro and in cellulo. The 3'-UTR G-quadruplexes were found to increase the efficiencies of alternative polyadenylation sites, leading to the expression of shorter transcripts and to possess the ability to interfere with the miRNA regulatory network of a specific mRNA. Clearly, G-quadruplexes located in the 3'-UTRs of mRNAs are cis-regulatory elements that have a significant impact on gene expression.
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Affiliation(s)
| | - Jean-Pierre Perreault
- *To whom correspondence should be addressed. Tel: +1 819 821 8000 (ext. 75310); Fax: +1 819 564-5284;
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Zhao C, Bachu R, Popović M, Devany M, Brenowitz M, Schlatterer JC, Greenbaum NL. Conformational heterogeneity of the protein-free human spliceosomal U2-U6 snRNA complex. RNA (NEW YORK, N.Y.) 2013; 19:561-73. [PMID: 23426875 PMCID: PMC3677266 DOI: 10.1261/rna.038265.113] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 01/16/2013] [Indexed: 05/24/2023]
Abstract
The complex formed between the U2 and U6 small nuclear (sn)RNA molecules of the eukaryotic spliceosome plays a critical role in the catalysis of precursor mRNA splicing. Here, we have used enzymatic structure probing, (19)F NMR, and analytical ultracentrifugation techniques to characterize the fold of a protein-free biophysically tractable paired construct representing the human U2-U6 snRNA complex. Results from enzymatic probing and (19)F NMR for the complex in the absence of Mg(2+) are consistent with formation of a four-helix junction structure as a predominant conformation. However, (19)F NMR data also identify a lesser fraction (up to 14% at 25°C) of a three-helix conformation. Based upon this distribution, the calculated ΔG for inter-conversion to the four-helix structure from the three-helix structure is approximately -4.6 kJ/mol. In the presence of 5 mM Mg(2+), the fraction of the three-helix conformation increased to ∼17% and the Stokes radius, measured by analytical ultracentrifugation, decreased by 2%, suggesting a slight shift to an alternative conformation. NMR measurements demonstrated that addition of an intron fragment to the U2-U6 snRNA complex results in displacement of U6 snRNA from the region of Helix III immediately 5' of the ACAGAGA sequence of U6 snRNA, which may facilitate binding of the segment of the intron adjacent to the 5' splice site to the ACAGAGA sequence. Taken together, these observations indicate conformational heterogeneity in the protein-free human U2-U6 snRNA complex consistent with a model in which the RNA has sufficient conformational flexibility to facilitate inter-conversion between steps of splicing in situ.
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Affiliation(s)
- Caijie Zhao
- Department of Chemistry and Biochemistry, Hunter College of the City University of New York, New York, New York 10065, USA
- The Graduate Center, City University of New York, New York, New York 10016, USA
| | - Ravichandra Bachu
- Department of Chemistry and Biochemistry, Hunter College of the City University of New York, New York, New York 10065, USA
- The Graduate Center, City University of New York, New York, New York 10016, USA
| | - Milena Popović
- Department of Chemistry and Biochemistry, Hunter College of the City University of New York, New York, New York 10065, USA
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, USA
| | - Matthew Devany
- Department of Chemistry and Biochemistry, Hunter College of the City University of New York, New York, New York 10065, USA
| | - Michael Brenowitz
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Jörg C. Schlatterer
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | - Nancy L. Greenbaum
- Department of Chemistry and Biochemistry, Hunter College of the City University of New York, New York, New York 10065, USA
- The Graduate Center, City University of New York, New York, New York 10016, USA
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Beaudoin JD, Jodoin R, Perreault JP. In-line probing of RNA G-quadruplexes. Methods 2013; 64:79-87. [PMID: 23500045 DOI: 10.1016/j.ymeth.2013.02.017] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Revised: 02/19/2013] [Accepted: 02/25/2013] [Indexed: 10/27/2022] Open
Abstract
Although the majority of the initial G-quadruplex studies were performed on DNA molecules, there currently exists a rapidly growing interest in the investigation of those formed in RNA molecules that possess high potential of acting as gene expression regulatory elements. Indeed, G-quadruplexes found in the 5'-untranslated regions of mRNAs have been reported to be widespread within the human transcriptome and to act as general translational repressors. In addition to translation regulation, several other mRNA maturation steps and events, including mRNA splicing, polyadenylation and localization, have been shown to be influenced by the presence of these RNA G-quadruplexes. Bioinformatic approaches have identified thousands of potential RNA G-quadruplex sequences in the human transcriptome. Clearly there is a need for the development of rapid, simple and informative techniques and methodologies with which the ability of these sequences, and of any potential new regulatory elements, to fold into G-quadruplexes in vitro can be examined. This report describes an integrated methodology for monitoring RNA G-quadruplexes formation that combines bioinformatic algorithms, secondary structure prediction, in-line probing with semi-quantification analysis and structural representation software. The power of this approach is illustrated, step-by-step, with the determination of the structure adopted by a potential G-quadruplex sequence found in the 5'-untranslated region of the cAMP responsive element modulator (CREM) mRNA. The results unambiguously show that the CREM sequence folds into a G-quadruplex structure in the presence of a physiological concentration of potassium ions. This in-line probing-based method is easy to use, robust, reproducible and informative in the study of RNA G-quadruplex formation.
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Affiliation(s)
- Jean-Denis Beaudoin
- RNA Group/Groupe ARN, Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Pavillon de Recherche Appliquée au Cancer, Université de Sherbrooke, QC, Canada J1E 4K8
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Xu W, Bolduc F, Hong N, Perreault JP. The use of a combination of computer-assisted structure prediction and SHAPE probing to elucidate the secondary structures of five viroids. MOLECULAR PLANT PATHOLOGY 2012; 13:666-76. [PMID: 22243942 PMCID: PMC6638829 DOI: 10.1111/j.1364-3703.2011.00776.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The elucidation of the structures of viroids, noncoding infectious RNA species, is paramount to obtain an understanding of the various aspects of their life cycles (including replication, transport and pathogenesis). In general, the secondary structures of viroids have been predicted using computer software programs which have been shown to possess several important limitations. Clearly, the predicted structure of a viroid needs to receive physical support prior to its use in the accurate interpretation of any mechanistic studies. Here, SHAPE probing coupled to computer-assisted structure prediction using the RNAstructure software program was employed to determine the structures of five viroids. These species belong to four genera of the Pospiviroidae family, and none have had their structure characterized in solution. In addition, several interesting questions were addressed by either studying various sequence variants or varying the SHAPE conditions. More importantly, this approach is novel in the study of viroids, and should be of significant aid in the determination of the structures of other RNA species.
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Affiliation(s)
- Wenxing Xu
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China.
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41
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Fourmy D, Yoshizawa S. Protein-RNA footprinting: an evolving tool. WILEY INTERDISCIPLINARY REVIEWS-RNA 2012; 3:557-66. [PMID: 22566372 DOI: 10.1002/wrna.1119] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
As more RNA molecules with important cellular functions are discovered, there is a strong need to characterize their structures, functions, and interactions. Chemical and enzymatic footprinting methods are used to map RNA secondary and tertiary structure, to monitor ligand interactions and conformational changes, and in the study of protein-RNA interactions. These methods provide data at single-nucleotide resolution that nicely complements the structural information available from X-ray diffraction, nuclear magnetic resonance spectroscopy (NMR), or cryo-electron microscopy. Footprinting methods also complement the dynamic information derived from single-molecule Förster resonance energy transfer. RNA footprinting tools have been used for decades, but we have recently seen spectacular advances, for instance, the use in combination with massive parallel sequencing techniques. Large libraries of RNA molecules (small or large in size) can now be probed in high-throughput manner when RNA footprinting methods are combined with fluorescent probe technologies and automation. In this article, after a brief historical overview, we summarize recent advances in RNA-protein footprinting methodologies that now integrate tools for massive parallel analysis.
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Affiliation(s)
- Dominique Fourmy
- Centre de Génétique Moléculaire UPR 3404, CNRS, Université Paris-Sud, Gif-sur-Yvette, France.
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42
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Burnouf D, Ennifar E, Guedich S, Puffer B, Hoffmann G, Bec G, Disdier F, Baltzinger M, Dumas P. kinITC: a new method for obtaining joint thermodynamic and kinetic data by isothermal titration calorimetry. J Am Chem Soc 2011; 134:559-65. [PMID: 22126339 DOI: 10.1021/ja209057d] [Citation(s) in RCA: 138] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Isothermal titration calorimetry (ITC) is the method of choice for obtaining thermodynamic data on a great variety of systems. Here we show that modern ITC apparatus and new processing methods allow researchers to obtain a complete kinetic description of systems more diverse than previously thought, ranging from simple ligand binding to complex RNA folding. We illustrate these new features with a simple case (HIV-1 reverse transcriptase/inhibitor interaction) and with the more complex case of the folding of a riboswitch triggered by the binding of its ligand. The originality of the new kinITC method lies in its ability to dissect, both thermodynamically and kinetically, the two components: primary ligand binding and subsequent RNA folding. We are not aware of another single method that can yield, in a simple way, such deep insight into a composite process. Our study also rationalizes common observations from daily ITC use.
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Affiliation(s)
- Dominique Burnouf
- Architecture et Réactivité de l'ARN, Biophysique et Biologie Structurale, Institut de Biologie Moléculaire et Cellulaire du CNRS, Université de Strasbourg, 15, rue René Descartes, 67084 Strasbourg, France
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43
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Vicens Q, Mondragón E, Batey RT. Molecular sensing by the aptamer domain of the FMN riboswitch: a general model for ligand binding by conformational selection. Nucleic Acids Res 2011; 39:8586-98. [PMID: 21745821 PMCID: PMC3201879 DOI: 10.1093/nar/gkr565] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 06/20/2011] [Accepted: 06/21/2011] [Indexed: 12/25/2022] Open
Abstract
Understanding the nature of the free state of riboswitch aptamers is important for illuminating common themes in gene regulation by riboswitches. Prior evidence indicated the flavin mononucleotide (FMN)-binding riboswitch aptamer adopted a 'bound-like' structure in absence of FMN, suggesting only local conformational changes upon ligand binding. In the scope of pinpointing the general nature of such changes at the nucleotide level, we performed SHAPE mapping experiments using the aptamer domain of two phylogenetic variants, both in absence and in presence of FMN. We also solved the crystal structures of one of these domains both free (3.3 Å resolution) and bound to FMN (2.95 Å resolution). Our comparative study reveals that structural rearrangements occurring upon binding are restricted to a few of the joining regions that form the binding pocket in both RNAs. This type of binding event with minimal structural perturbations is reminiscent of binding events by conformational selection encountered in other riboswitches and various RNAs.
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Affiliation(s)
| | | | - Robert T. Batey
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, CO 80309-0215, USA
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Dubé A, Bolduc F, Bisaillon M, Perreault JP. Mapping studies of the Peach latent mosaic viroid reveal novel structural features. MOLECULAR PLANT PATHOLOGY 2011; 12:688-701. [PMID: 21726370 PMCID: PMC3256235 DOI: 10.1111/j.1364-3703.2010.00703.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Knowledge of the structure of a viroid is critically important to elucidate the roles played by the various RNA motifs in the steps of the viroid's life cycle. A new technique, RNA-selective 2'-hydroxyl acylation analysed by primer extension (SHAPE), has recently been shown to be fast, reliable and applicable to the study of various RNA molecules. Consequently, this method was used to probe sequence variants of Peach latent mosaic viroid (PLMVd). Initially, probing data from RNA strands of both polarities of the Siberian C variant confirmed the secondary structures previously determined using both conventional and fastidious approaches. Subsequently, analysis of an Alberta variant showed an identical structure for the strand of (-) polarity, but the (+) polarity strand exhibited two differences from the Siberian C variant: the P11-L11 stem-loop domain formed a cruciform structure, and nucleotides from loops L1 and L11 were involved in the formation of a pseudoknot. The existence of both of these motifs was confirmed by site-directed mutagenesis. The subsequent probing of 12 natural sequence variants led to the elucidation of the criteria governing the formation of this novel pseudoknot. Importantly, this study revealed that the heterogeneity of a viroid is not limited to its nucleotide sequence, but may also occur at the structural level.
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Affiliation(s)
- Audrey Dubé
- RNA Group/Groupe ARN, Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Sherbrooke, QC, Canada, J1H 5N4
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Bindewald E, Wendeler M, Legiewicz M, Bona MK, Wang Y, Pritt MJ, Le Grice SF, Shapiro BA. Correlating SHAPE signatures with three-dimensional RNA structures. RNA (NEW YORK, N.Y.) 2011; 17:1688-96. [PMID: 21752927 PMCID: PMC3162334 DOI: 10.1261/rna.2640111] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Accepted: 05/27/2011] [Indexed: 05/16/2023]
Abstract
Selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE) is a facile technique for quantitative analysis of RNA secondary structure. In general, low SHAPE signal values indicate Watson-Crick base-pairing, and high values indicate positions that are single-stranded within the RNA structure. However, the relationship of SHAPE signals to structural properties such as non-Watson-Crick base-pairing or stacking has thus far not been thoroughly investigated. Here, we present results of SHAPE experiments performed on several RNAs with published three-dimensional structures. This strategy allows us to analyze the results in terms of correlations between chemical reactivities and structural properties of the respective nucleotide, such as different types of base-pairing, stacking, and phosphate-backbone interactions. We find that the RNA SHAPE signal is strongly correlated with cis-Watson-Crick/Watson-Crick base-pairing and is to a remarkable degree not dependent on other structural properties with the exception of stacking. We subsequently generated probabilistic models that estimate the likelihood that a residue with a given SHAPE score participates in base-pairing. We show that several models that take SHAPE scores of adjacent residues into account perform better in predicting base-pairing compared with individual SHAPE scores. This underscores the context sensitivity of SHAPE and provides a framework for an improved interpretation of the response of RNA to chemical modification.
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Affiliation(s)
- Eckart Bindewald
- Basic Science Program, SAIC-Frederick, Inc., NCI-Frederick, Frederick, Maryland 21702, USA
| | - Michaela Wendeler
- RT Biochemistry Section, HIV Drug Resistance Program, NCI-Frederick, Frederick, Maryland 21702, USA
| | - Michal Legiewicz
- RT Biochemistry Section, HIV Drug Resistance Program, NCI-Frederick, Frederick, Maryland 21702, USA
| | - Marion K. Bona
- Basic Science Program, SAIC-Frederick, Inc., NCI-Frederick, Frederick, Maryland 21702, USA
| | - Yi Wang
- RT Biochemistry Section, HIV Drug Resistance Program, NCI-Frederick, Frederick, Maryland 21702, USA
| | - Mark J. Pritt
- Center for Cancer Research Nanobiology Program, NCI-Frederick, Frederick, Maryland 21702, USA
| | - Stuart F.J. Le Grice
- RT Biochemistry Section, HIV Drug Resistance Program, NCI-Frederick, Frederick, Maryland 21702, USA
| | - Bruce A. Shapiro
- Center for Cancer Research Nanobiology Program, NCI-Frederick, Frederick, Maryland 21702, USA
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Rocca-Serra P, Bellaousov S, Birmingham A, Chen C, Cordero P, Das R, Davis-Neulander L, Duncan CD, Halvorsen M, Knight R, Leontis NB, Mathews DH, Ritz J, Stombaugh J, Weeks KM, Zirbel CL, Laederach A. Sharing and archiving nucleic acid structure mapping data. RNA (NEW YORK, N.Y.) 2011; 17:1204-12. [PMID: 21610212 PMCID: PMC3138558 DOI: 10.1261/rna.2753211] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Nucleic acids are particularly amenable to structural characterization using chemical and enzymatic probes. Each individual structure mapping experiment reveals specific information about the structure and/or dynamics of the nucleic acid. Currently, there is no simple approach for making these data publically available in a standardized format. We therefore developed a standard for reporting the results of single nucleotide resolution nucleic acid structure mapping experiments, or SNRNASMs. We propose a schema for sharing nucleic acid chemical probing data that uses generic public servers for storing, retrieving, and searching the data. We have also developed a consistent nomenclature (ontology) within the Ontology of Biomedical Investigations (OBI), which provides unique identifiers (termed persistent URLs, or PURLs) for classifying the data. Links to standardized data sets shared using our proposed format along with a tutorial and links to templates can be found at http://snrnasm.bio.unc.edu.
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Affiliation(s)
| | - Stanislav Bellaousov
- Department of Biochemistry and Biophysics and Center for RNA Biology, University of Rochester, Rochester, New York 14642, USA
| | | | - Chunxia Chen
- Biology Department, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA
| | - Pablo Cordero
- Biochemistry Department, Stanford University, Stanford, California 94305, USA
| | - Rhiju Das
- Biochemistry Department, Stanford University, Stanford, California 94305, USA
| | - Lauren Davis-Neulander
- Biology Department, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA
| | - Caia D.S. Duncan
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA
| | - Matthew Halvorsen
- Biology Department, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA
| | - Rob Knight
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
- Howard Hughes Medical Institute, Boulder, Colorado 80309, USA
| | - Neocles B. Leontis
- Department of Chemistry, Bowling Green State University, Bowling Green, Ohio 43403, USA
| | - David H. Mathews
- Department of Biochemistry and Biophysics and Center for RNA Biology, University of Rochester, Rochester, New York 14642, USA
| | - Justin Ritz
- Biology Department, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA
| | - Jesse Stombaugh
- Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309, USA
| | - Kevin M. Weeks
- Department of Chemistry, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA
| | - Craig L. Zirbel
- Department of Mathematics and Statistics, Bowling Green State University, Bowling Green, Ohio 43403, USA
| | - Alain Laederach
- Biology Department, University of North Carolina, Chapel Hill, North Carolina 27599-3290, USA
- Corresponding author.E-mail .
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Kafasla P, Lin H, Curry S, Jackson RJ. Activation of picornaviral IRESs by PTB shows differential dependence on each PTB RNA-binding domain. RNA (NEW YORK, N.Y.) 2011; 17:1120-1131. [PMID: 21518806 PMCID: PMC3096044 DOI: 10.1261/rna.2549411] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Accepted: 03/11/2011] [Indexed: 05/30/2023]
Abstract
Polypyrimidine tract binding protein (PTB) is an RNA-binding protein with four RNA-binding domains (RBDs). It is a major regulator of alternative splicing and also stimulates translation initiation at picornavirus IRESs (internal ribosome entry sites). The sites of interaction of each RBD with two picornaviral IRESs have previously been mapped. To establish which RBD-IRES interactions are essential for IRES activation, point mutations were introduced into the RNA-binding surface of each RBD. Three such mutations were sufficient to inactivate RNA-binding by any one RBD, but the sites of the other three RBD-IRES interactions remained unperturbed. Poliovirus IRES activation was abrogated by inactivation of RBD1, 2, or 4, but the RBD3-IRES interaction was superfluous. Stimulation of the encephalomyocarditis virus IRES was reduced by inactivation of RBD1, 3, or 4, and abrogated by mutation of RBD2, or both RBDs 3 and 4. Surprisingly, therefore, the binding of PTB in its normal orientation does not guarantee IRES activation; three native RBDs are sufficient for correct binding but not for activation if the missing RBD-IRES interaction is critical.
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Affiliation(s)
- Panagiota Kafasla
- Department of Biochemistry, University of Cambridge, Cambridge CB21QW, United Kingdom
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Yoon S, Kim J, Hum J, Kim H, Park S, Kladwang W, Das R. HiTRACE: high-throughput robust analysis for capillary electrophoresis. ACTA ACUST UNITED AC 2011; 27:1798-805. [PMID: 21561922 DOI: 10.1093/bioinformatics/btr277] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
MOTIVATION Capillary electrophoresis (CE) of nucleic acids is a workhorse technology underlying high-throughput genome analysis and large-scale chemical mapping for nucleic acid structural inference. Despite the wide availability of CE-based instruments, there remain challenges in leveraging their full power for quantitative analysis of RNA and DNA structure, thermodynamics and kinetics. In particular, the slow rate and poor automation of available analysis tools have bottlenecked a new generation of studies involving hundreds of CE profiles per experiment. RESULTS We propose a computational method called high-throughput robust analysis for capillary electrophoresis (HiTRACE) to automate the key tasks in large-scale nucleic acid CE analysis, including the profile alignment that has heretofore been a rate-limiting step in the highest throughput experiments. We illustrate the application of HiTRACE on 13 datasets representing 4 different RNAs, 3 chemical modification strategies and up to 480 single mutant variants; the largest datasets each include 87 360 bands. By applying a series of robust dynamic programming algorithms, HiTRACE outperforms prior tools in terms of alignment and fitting quality, as assessed by measures including the correlation between quantified band intensities between replicate datasets. Furthermore, while the smallest of these datasets required 7-10 h of manual intervention using prior approaches, HiTRACE quantitation of even the largest datasets herein was achieved in 3-12 min. The HiTRACE method, therefore, resolves a critical barrier to the efficient and accurate analysis of nucleic acid structure in experiments involving tens of thousands of electrophoretic bands.
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Affiliation(s)
- Sungroh Yoon
- School of Electrical Engineering, Korea University, Seoul 136-713, Republic of Korea.
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Reymond C, Lévesque D, Bisaillon M, Perreault JP. Developing three-dimensional models of putative-folding intermediates of the HDV ribozyme. Structure 2011; 18:1608-16. [PMID: 21134640 DOI: 10.1016/j.str.2010.09.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Revised: 09/13/2010] [Accepted: 09/17/2010] [Indexed: 01/23/2023]
Abstract
Both the role and the interacting partners of an RNA molecule can change depending on its tertiary structure. Consequently, it is important to be able to accurately predict the complete folding pathway of an RNA molecule. The hepatitis delta virus (HDV) ribozyme is a small catalytic RNA with the greatest number of folding intermediates making it the model of choice with which to address this problem. The tertiary structures of the known putative intermediates along the folding pathway of the HDV ribozyme were predicted using the Macromolecular Conformations Symbolic programming (MC-Sym) software. The structures obtained by this method received physical support from Selective 2'-Hydroxyl Acylation analyzed by Primer Extension (SHAPE). The analysis of these structures elucidated several features of the HDV ribozyme. In addition, this report represents an application for MC-Sym that permits progression one step further toward the computer prediction of an RNA molecule-folding pathway.
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Affiliation(s)
- Cédric Reymond
- RNA Group/Groupe ARN, Département de Biochimie, Faculté de Médecine et des Sciences de la Santé, Université de Sherbrooke, Québec J1H5N4, Canada
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Huang L, Yin P, Zhu X, Zhang Y, Ye K. Crystal structure and centromere binding of the plasmid segregation protein ParB from pCXC100. Nucleic Acids Res 2010; 39:2954-68. [PMID: 21123191 PMCID: PMC3074162 DOI: 10.1093/nar/gkq915] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Plasmid pCXC100 from the Gram-positive bacterium Leifsonia xyli subsp. cynodontis uses a type Ib partition system that includes a centromere region, a Walker-type ATPase ParA and a centromere-binding protein ParB for stable segregation. However, ParB shows no detectable sequence homology to any DNA-binding motif. Here, we study the ParB centromere interaction by structural and biochemical approaches. The crystal structure of the C-terminal DNA-binding domain of ParB at 1.4 Å resolution reveals a dimeric ribbon-helix-helix (RHH) motif, supporting the prevalence of RHH motif in centromere binding. Using hydroxyl radical footprinting and quantitative binding assays, we show that the centromere core comprises nine uninterrupted 9-nt direct repeats that can be successively bound by ParB dimers in a cooperative manner. However, the interaction of ParB with a single subsite requires 18 base pairs covering one immediate repeat as well as two halves of flanking repeats. Through mutagenesis, sequence specificity was determined for each position of an 18-bp subsite. These data suggest an unique centromere recognition mechanism by which the repeat sequence is jointly specified by adjacent ParB dimers bound to an overlapped region.
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Affiliation(s)
- Lin Huang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, Hubei 430072, China
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