711 results on '"RNA modifications"'
Search Results
702. Methods for the Detection of Adenosine-to-Inosine Editing Events in Cellular RNA.
- Author
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Oakes E, Vadlamani P, and Hundley HA
- Subjects
- Adenosine metabolism, Animals, Humans, Inosine metabolism, RNA, Messenger metabolism, Adenosine genetics, Inosine genetics, RNA Editing, RNA, Messenger genetics, Reverse Transcriptase Polymerase Chain Reaction methods, Sequence Analysis, RNA methods
- Abstract
Modification of RNA is essential for properly expressing the repertoire of RNA transcripts necessary for both cell type and developmental specific functions. RNA modifications serve to dynamically re-wire and fine-tune the genetic information carried by an invariable genome. One important type of RNA modification is RNA editing and the most common and well-studied type of RNA editing is the hydrolytic deamination of adenosine to inosine. Inosine is a biological mimic of guanosine; therefore, when RNA is reverse transcribed, inosine is recognized as guanosine by the reverse transcriptase and a cytidine is incorporated into the complementary DNA (cDNA) strand. During PCR amplification, guanosines pair with the newly incorporated cytidines. As a result, the adenosine-to-inosine (A-to-I) editing events are recognized as adenosine to guanosine changes when comparing the sequences of the genomic DNA to the cDNA. This chapter describes the methods for extracting endogenous RNA for subsequent analyses of A-to-I RNA editing using reverse transcriptase-based approaches. We discuss techniques for the detection of A-to-I RNA editing events in messenger RNA (mRNA), including analyzing editing levels at specific adenosines within the total pool of mRNA versus analyzing editing patterns that occur in individual transcripts and a method for detecting editing events across the entire transcriptome. The detection of RNA editing events and editing levels can be used to better understand normal biological processes and disease states.
- Published
- 2017
- Full Text
- View/download PDF
703. CoverageAnalyzer (CAn): A Tool for Inspection of Modification Signatures in RNA Sequencing Profiles.
- Author
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Hauenschild R, Werner S, Tserovski L, Hildebrandt A, Motorin Y, and Helm M
- Subjects
- Computational Biology methods, High-Throughput Nucleotide Sequencing, Software, User-Computer Interface, Gene Expression Profiling methods, Sequence Analysis, RNA methods
- Abstract
Combination of reverse transcription (RT) and deep sequencing has emerged as a powerful instrument for the detection of RNA modifications, a field that has seen a recent surge in activity because of its importance in gene regulation. Recent studies yielded high-resolution RT signatures of modified ribonucleotides relying on both sequence-dependent mismatch patterns and reverse transcription arrests. Common alignment viewers lack specialized functionality, such as filtering, tailored visualization, image export and differential analysis. Consequently, the community will profit from a platform seamlessly connecting detailed visual inspection of RT signatures and automated screening for modification candidates. CoverageAnalyzer (CAn) was developed in response to the demand for a powerful inspection tool. It is freely available for all three main operating systems. With SAM file format as standard input, CAn is an intuitive and user-friendly tool that is generally applicable to the large community of biomedical users, starting from simple visualization of RNA sequencing (RNA-Seq) data, up to sophisticated modification analysis with significance-based modification candidate calling., Competing Interests: The authors declare no conflict of interest.
- Published
- 2016
- Full Text
- View/download PDF
704. Electrophilic RNA for Peptidyl-RNA Synthesis and Site-Specific Cross-Linking with tRNA-Binding Enzymes.
- Author
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Fonvielle M, Sakkas N, Iannazzo L, Le Fournis C, Patin D, Mengin-Lecreulx D, El-Sagheer A, Braud E, Cardon S, Brown T, Arthur M, and Etheve-Quelquejeu M
- Subjects
- Aminoacyltransferases chemistry, Cross-Linking Reagents chemistry, Models, Molecular, Molecular Conformation, Peptides chemistry, RNA chemistry, RNA, Transfer chemistry, Uridine Diphosphate N-Acetylmuramic Acid chemistry, Uridine Diphosphate N-Acetylmuramic Acid metabolism, Aminoacyltransferases metabolism, Cross-Linking Reagents metabolism, Peptides metabolism, RNA biosynthesis, RNA, Transfer metabolism, Uridine Diphosphate N-Acetylmuramic Acid analogs & derivatives
- Abstract
RNA functionalization is challenging due to the instability of RNA and the limited range of available enzymatic reactions. We developed a strategy based on solid phase synthesis and post-functionalization to introduce an electrophilic site at the 3' end of tRNA analogues. The squarate diester used as an electrophile enabled sequential amidation and provided asymmetric squaramides with high selectivity. The squaramate-RNAs specifically reacted with the lysine of UDP-MurNAc-pentapeptide, a peptidoglycan precursor used by the aminoacyl-transferase FemX
Wv for synthesis of the bacterial cell wall. The peptidyl-RNA obtained with squaramate-RNA and unprotected UDP-MurNAc-pentapeptide efficiently inhibited FemXWv . The squaramate unit also promoted specific cross-linking of RNA to the catalytic Lys of FemXWv but not to related transferases recognizing different aminoacyl-tRNAs. Thus, squaramate-RNAs provide specificity for cross-linking with defined groups in complex biomolecules due to its unique reactivity., (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)- Published
- 2016
- Full Text
- View/download PDF
705. Deciphering the epitranscriptome: A green perspective.
- Author
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Burgess A, David R, and Searle IR
- Subjects
- 5-Methylcytosine metabolism, Adenosine analogs & derivatives, Adenosine metabolism, High-Throughput Nucleotide Sequencing, Pseudouridine metabolism, RNA Processing, Post-Transcriptional genetics, Arabidopsis genetics, Arabidopsis metabolism, Transcriptome genetics
- Abstract
The advent of high-throughput sequencing technologies coupled with new detection methods of RNA modifications has enabled investigation of a new layer of gene regulation - the epitranscriptome. With over 100 known RNA modifications, understanding the repertoire of RNA modifications is a huge undertaking. This review summarizes what is known about RNA modifications with an emphasis on discoveries in plants. RNA ribose modifications, base methylations and pseudouridylation are required for normal development in Arabidopsis, as mutations in the enzymes modifying them have diverse effects on plant development and stress responses. These modifications can regulate RNA structure, turnover and translation. Transfer RNA and ribosomal RNA modifications have been mapped extensively and their functions investigated in many organisms, including plants. Recent work exploring the locations, functions and targeting of N
6 -methyladenosine (m6 A), 5-methylcytosine (m5 C), pseudouridine (Ψ), and additional modifications in mRNAs and ncRNAs are highlighted, as well as those previously known on tRNAs and rRNAs. Many questions remain as to the exact mechanisms of targeting and functions of specific modified sites and whether these modifications have distinct functions in the different classes of RNAs., (© 2016 The Authors. Journal of Integrative Plant Biology Published by John Wiley & Sons Australia, Ltd on behalf of Institute of Botany, Chinese Academy of Sciences.)- Published
- 2016
- Full Text
- View/download PDF
706. The Discovery and Characterization of NAD-Linked RNA
- Author
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Chen, Ye Grace
- Subjects
- bacteria, NAD, RNA modifications, small molecule-RNA conjugates, molecular biology, chemistry
- Abstract
Over the past few decades, RNA has emerged as much more than just an intermediary in biology’s central dogma. RNA is now known to play a variety of catalytic, regulatory and defensive roles in living systems as demonstrated through the discoveries of ribozymes, riboswitches, microRNAs, small interfering RNAs, Piwi-interacting RNAs, small nuclear RNAs, clusters of regularly interspaced short palindromic repeat RNAs and long non-coding RNAs. In contrast to the functional diversity of RNA, the chemical diversity has remained primarily limited to canonical polyribonucleotides, the 5’ cap on mRNAs in eukaryotes, modified nucleotides and 3’-aminoacylated tRNAs. This disparity coupled with the powerful functional properties of small molecule-nucleic acid conjugates led us to speculate that novel small molecule-RNA conjugates existed in modern cells, either as evolutionary fossils or as RNAs whose functions are enabled by the small molecule moieties. We developed and applied a nuclease-based screen coupled with high-resolution liquid chromatography/mass spectrometry analysis to detect novel small molecule-RNA conjugates, broadly and sensitively. We discovered NAD-linked RNA in two types of bacteria and further characterized the small molecule and RNA in Escherichia coli. The NAD modification is found on the 5’ end of RNAs between 30 and 120 nucleotides long, and is surprisingly abundant at around 3,000 copies per cell. Subsequent experiments to characterize further NAD-linked RNA have been undertaken, including sequencing the RNAs to which NAD is attached and elucidating the biological functions of the small molecule-RNA conjugate. The development and application of a screen to detect novel nucleotide modifications that is independent of structure or biological context has the potential to increase our understanding of the functional and chemical diversity of RNA. The discovery and biological characterization of NAD-linked RNA can provide new examples of RNA biology and offer insight into the RNA world.
- Published
- 2012
707. 5ʹ and 3ʹ modifications controlling RNA degradation : from safeguards to executioners
- Author
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Gagliardi, Dominique and Dziembowski, Andrzej
- Published
- 2018
708. Synthetic and structural contributions to RNA modifications and catalytic RNAs
- Abstract
Der erste Teil dieser Dissertation befasst sich mit dem Twister Sister Ribozym, welches zur Klasse der kleinen selbst-spaltenden Ribozyme zugeordnet wird. Ribozyme sind katalytisch aktive RNA Moleküle, die eine wichtige Spezies nichtkodierender RNAs darstellen. Sie spielen eine essentielle Rolle in verschieden biochemischen Prozessen wie dem Splicing, der Reifung der tRNA und oder bei Replikation subgenomischer Elemente. Eine Untergruppe von Ribozymen umfasst die Klasse der kleinen nukleolytischen,selbstspaltenden Ribozyme. Die jüngste Entdeckung von Twister, Twister-Sister, Pistol und Hatchet hat das Interesse an dieser Ribozyme-Unterklasse neu entfacht. In Zusammenarbeit mit den Arbeitsgruppen rund um Aiming Ren (Zhejiang University) und Dinshaw Patel (MSKCC) wurden Twister-Sister Ribozym Konstrukte für die Röntgenstrukturanalyse entworfen. Von einem Vier-Wege Twister-Sister Ribozym konnte schlussendlich die 3-dimensionale Struktur gelöst werden. Diese erhaltene Kristallstruktur veranschaulicht die Faltungstopologie und liefert tiefe Einblicke in die Architektur des aktiven Zentrums. Mit Hilfe eines HPLC-basierten Spaltungsassays wurde der Einfluss von Mutationen gemäß der Strukturorganisation wichtiger Nukleosidpositionen bewertet. Die umfassenden Studien zeigen auch die entscheidenden Nuktleotide im katalytischen Zentrum auf, die möglicherweiße den Mechanismus der Schneideaktivität des Ribozyms unterstützen.Der zweite Teil meiner Arbeit stellt eine neue Syntheseroute zur Dartellung von 3-Deazaguanosine und dem entsprechenden Phosphoramidit-Baustein für die RNA Festphasensynthese dar. Zur Vervollständigung wurde auch die freie Nukleobase 3-Deazaguanine auf einem neuen effizienten Weg hergestellt. Insbesondere das 3-Deazaguanosinphosphoramidit füllt eine lange Lücke in Bezug auf atomare Mutagenesestudien von funktioneller RNA, da bisher weder effiziente Synthesewege veröffentlicht wurden, noch dieser Baustein kommerziell erhältlich ist. Eine erste Anwendung von c3, The first part of this thesis concerns the small nucleolytic twister sister ribozyme. Ribozymes are catalytically active RNAs and represent an important class of non-coding RNAs that play prominent roles in splicing, tRNA maturation, and replication of sub-genomic elements. Additionally, they may have played a crucial role at an early stage in the evolution of life. One subgroup of ribozymes includes the class of small nucleolytic self-cleaving ribozymes. The recent discovery of twister, twister-sister, hatchet and pistol motif sparked a widespread interest into this ribozyme subclass. In the course of this thesis, I designed and synthesized twister sister ribozyme constructs that were key to crystallize and solve the three-dimensional structure of a four-way junctional twister sister ribozyme at 2.0 Å resolution, in close collaboration with the laboratories of Aiming Ren (Zhejiang University) and Dinshaw Patel (MSKCC). To this end, I developed a HPLC-based, two strand cleavage assay to evaluate the impact of mutations at nucleosides positions that are deemed functionally important according to the structural organization. Together, this comprehensive study provides deep insights into overall folding topology and pre-catalytic active site architecture of the ribozyme, and it pinpoints at the crucial nucleotides at the cleavage site that are likely involved in catalysis.The second part of my thesis presents a novel synthesis of 3-deazaguanosine (c3G) and the corresponding phosphoramidite building block for RNA solid-phase synthesis. To complete the full set of the c3G family, the free nucleobase 3-deazaguanine has also been prepared by a new efficient route. In particular, the 3-deazaguanosine phosphoramidite fills a long-standing gap with respect to atomic mutagenesis studies of functional RNA since neither efficient synthetic routes have been published to date, nor has this building block been commercially available. A first application with respect of its influenc, Elisabeth Mairhofer, MSc., Kumulative Dissertation aus drei Artikeln, Im Artikel sind die Zahlen hochgestellt, Dissertation Universtität Innsbruck 2019
709. Labeled RNA - synthesis, features and applications
- Abstract
vorgelegt von Eva Neuner, MSc., Abweichender Titel laut Übersetzung der Verfasserin/des Verfassers, Zusammenfassung in deutscher Sprache, Dissertation Universität Innsbruck 2019, Arbeit gesperrt
710. Exploring ribozymes, riboswitches and RNA modifications
- Abstract
Ribonukleinsäuren (RNA) haben verschiedene Elemente mit denen sie die Regulation von Genen steuern können. Während einige durch Konformationsänderungen aktiv werden, wie zum Beispiel Ribozyme und Riboschalter, stützen sich andere RNAs auf Modifikationen wie schwefelhaltige Nukleobasen, welche während der Translation das Leseraster aufrechterhalten. Diese Dissertation befasst sich mit drei unterschiedlichen Genregulatoren, welche unter verschiedenen Aspekten analysiert werden. Ribozyme sind biologisch relevante, selbst-schneidende RNA-Moleküle, welche die Spaltung intramolekularen Phosphordiesterbindungen ohne Hilfe von weiteren Enzymen katalysieren. Auch wenn die verschiedenen Klassen an Ribozymen ein und dieselbe Reaktion durchführen, falten sie sich in einzigartige Sekundär- und Tertiärstrukturen. Somit sind die Faltung und die einhergehenden strukturellen Dynamiken dieser Moleküle essentiell um das aktive Zentrum, welches die Katalyse durchführt, zu bilden. Kristallopgraphie wird hierbei angewendet um die Struktur von Ribozymen und die kritischen Nucleotide des katalytischen Zentrums zu enthüllen. Jedoch die Analyse und Herstellung von Röntgenstrukturen sind sehr komplex und mit viel Arbeit verbunden. Außerdem repräsentieren Kristalle Momentaufnahmen und mangeln so an Informationen bezüglich Faltung und Dynamik. Hier, werden magnesium- und temperaturabhängige Faltungsfunktionen der kürzlich entdeckten Ribozyme Twister, Pistol, Twister-sister und Hatchet präsentiert. Selektive 2´-hydroxyl Acylierung analysiert mit Primer Extension (SHAPE) wird hierbei benutzt um Veränderung in der Sekundär- und Tertiarstruktur auf dem Level von einzelnen Nukleobasen zu überwachen. Die neuen Entdeckungen werden für Twister, Pistol und Twister-Sister anhand ihrer Kristallstruktur diskutiert. Für das Hatchet Ribozyme, für welches noch keine Kristallstruktur vorliegt, bestätigen die SHAPE Daten jedoch nicht die vorhergesagte Sekundärstruktur. Dennoch werden wichtige Nukleotide und ver, Ribonucleic acids (RNA) have more than one element with which they can regulate gene expression. Some are triggered by structural rearrangements such as ribozymes and riboswitches whereas other rely on modifications such as thiolated nucleobases by maintaining the reading-frame during translation. In this thesis, three gene controlling elements are investigated under different synthetic aspects. Ribozymes are biologically relevant, self-cleaving RNA molecules, which catalyse the cleavage of intramolecular phosphodiester bonds without the help of protein enzymes.1 Although the different ribozyme families all perform the same reaction, they fold into unique secondary and tertiary structures. Consequently, the folding path and the structural dynamics of the molecules are essential to create an active site that performs catalysis.2 To reveal a ribozyme’s structure and the critical nucleotides of the active site, crystallography is usually applied. However, the analysis of an X-ray structure is often complex and in general very laborious. Furthermore, crystals represent structural snapshots and thus lack information on the folding process and the inherent dynamics of an RNA fold. Here, magnesium and temperature-dependent features of folding of the recently discovered ribozyme classes twister, pistol, twister-sister and hatchet have been revealed and are presented. Selective 2´-hydroxyl acylation analysed by primer extension (SHAPE) is used to simultaneously monitor changes in secondary and tertiary nucleobase interactions of different domains at the single base-level. For twister, twister-sister and pistol ribozymes the new findings are discussed with the help of their crystal structures. For the hatchet ribozyme, where no crystal structure is available, the SHAPE data does not confirm the proposed secondary structure, however selected residues and putative long-distance interactions are pointed out. The second part deals with switching aptamer regions, so called riboswi, Catherina Gasser, MSc., Kumulative Dissertation aus drei Artikeln, Zusammenfassung in deutscher Sprache, Dissertation University Innsbruck 2018
711. Identifizierung, Lokalisierung und relative Quantifizierung von Ribonukleinsäure-Modifikationen mit top-down Massenspektrometrie
- Abstract
Die top-down Massenspektrometrie (MS) hat sich kürzlich zu einer vielversprechenden neuen Methode zur Charakterisierung von Ribonukleinsäure (Ribonucleic Acids, RNA) -Modifikationen entwickelt, die wichtige Regulatoren der Genexpression und Schlüsselelemente für die Entwicklung von RNA-basierten Therapeutika sind. Das Ziel dieser Dissertation war die Entwicklung neuer, top-down MS basierter Methoden zur umfassenden Charakterisierung von posttranskriptionalen und synthetischen RNA-Modifikationen, einschließlich detaillierter mechanistischer Studien zum Rückgratbruch bei kollisionsaktivierter Dissoziation (Collisionally Activated Dissociation, CAD) und Dissoziation durch Elektronenablösung (Electron Detachment Dissociation, EDD). Die neu entwickelten Ansätze können zur Identifikation (Welche Modifikationen?), Lokalisation (Welche Bausteine sind modifiziert?) und zur positions-spezifischen, relativen Quantifizierung (In welchem Ausmaß sind die Bausteine modifiziert?) von RNA-Modifikationen verwendet werden. Im ersten Teil dieser Arbeit wurde die top-down Massenspektrometrie zur markierungsfreien, direkten Lokalisation und relativen Quantifizierung der RNA Nukleobasen-Methylierungen N6-Methyladenin (m6A), 5-Methylcytosin (m5C), 3-Methyluracil (m3U) und 5-Methyluracil (m5U) entwickelt. Nukleobasen-Methylierungen sind ubiquitäre posttranskriptionale RNA-Modifikationen, welche die strukturelle Vielfalt von RNA in sehr dynamischer Art und Weise wesentlich vergrößern, mit Auswirkungen auf die Genexpression und menschliche Krankheiten. Die Hochdurchsatz-Tiefen-Sequenzierung bietet jedoch im Allgemeinen keine Informationen über posttranskriptionale Modifikationen (PTMs). Ein vielversprechender alternativer Ansatz zur Charakterisierung von PTMs, das heißt, deren Identifizierung, Lokalisierung und relative Quantifizierung ist top-down MS. Es wurde untersucht, wie spezifische Nukleobasen-Methylierungen die Ionisierung bei Elektrospray-Ionisation (ESI) und den Rückgratbruch bei CA, Top-down mass spectrometry (MS) has recently emerged as a promising new approach for the characterization of ribonucleic acid (RNA) modifications as important regulators of gene expression and key elements in the development of RNA-based therapeutics. The aim of this dissertation was the development of new top-down MS based methodology for the comprehensive characterization of posttranscriptional and synthetic RNA modifications through detailed mechanistic studies of RNA backbone cleavage by collisionally activated dissociation (CAD) and electron detachment dissociation (EDD). The new approaches can be used to identify RNA modifications (What types of modifications?), to localize modifications (Which residues are modified?), and for site-specific, relative quantitation of modifications (To what extent are the residues modified?). In the first part of this thesis, top-down mass spectrometry was developed for the label-free, direct localization and relative quantitation of the RNA nucleobase methylations N6-methyladenine (m6A), 5-methylcytosine (m5C), 3-methyluracil (m3U), and 5-methyluracil (m5U). Nucleobase methylations are ubiquitous posttranscriptional modifications of RNA that can substantially increase the structural diversity of RNA in a highly dynamic fashion with implications for gene expression and human disease. However, high throughput, deep sequencing does not generally provide information on posttranscriptional modifications (PTMs). A promising alternative approach for the characterization of PTMs, i.e., their identification, localization, and relative quantitation, is top-down MS. It was investigated how specific nucleobase methylations affect RNA ionization in electrospray ionization (ESI), and backbone cleavage in CAD and EDD. For this purpose, two new approaches for the characterization of RNA methylations in mixtures of either isomers of RNA or nonisomeric RNA forms have been developed. Fragment ions from dissociation experiments were analyzed to id, von Mag. rer. nat. Heidelinde Glasner, Abweichender Titel laut Übersetzung der Verfasserin, in englischer Sprache, Dissertation Universität Innsbruck 2018
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