scholarly journals Production and Application of Stable Isotope-Labeled Internal Standards for RNA Modification Analysis

Genes ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 26 ◽  
Author(s):  
Kayla Borland ◽  
Jan Diesend ◽  
Taku Ito-Kureha ◽  
Vigo Heissmeyer ◽  
Christian Hammann ◽  
...  
Keyword(s):  
Messenger Rna ◽  
Isotope Labeling ◽  
Rna Stability ◽  
Internal Standard ◽  
Modified Nucleosides ◽  
Rna Modification ◽  
Mouse Tissue ◽  
Rna Modifications ◽  
Internal Standards ◽  
Translation Fidelity

Post-transcriptional RNA modifications have been found to be present in a wide variety of organisms and in different types of RNA. Nucleoside modifications are interesting due to their already known roles in translation fidelity, enzyme recognition, disease progression, and RNA stability. In addition, the abundance of modified nucleosides fluctuates based on growth phase, external stress, or possibly other factors not yet explored. With modifications ever changing, a method to determine absolute quantities for multiple nucleoside modifications is required. Here, we report metabolic isotope labeling to produce isotopically labeled internal standards in bacteria and yeast. These can be used for the quantification of 26 different modified nucleosides. We explain in detail how these internal standards are produced and show their mass spectrometric characterization. We apply our internal standards and quantify the modification content of transfer RNA (tRNA) from bacteria and various eukaryotes. We can show that the origin of the internal standard has no impact on the quantification result. Furthermore, we use our internal standard for the quantification of modified nucleosides in mouse tissue messenger RNA (mRNA), where we find different modification profiles in liver and brain tissue.

scholarly journals Rapid and dynamic transcriptome regulation by RNA editing and RNA modifications

2016 ◽  
Vol 213 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Konstantin Licht ◽  
Michael F. Jantsch
Keyword(s):  
Gene Expression ◽  
Mass Spectrometry ◽  
Rna Editing ◽  
Messenger Rna ◽  
Gene Expression Regulation ◽  
Rna Modification ◽  
Rna Modifications ◽  
Transcriptome Regulation ◽  
Affect Gene Expression ◽  
Generation Sequencing

Advances in next-generation sequencing and mass spectrometry have revealed widespread messenger RNA modifications and RNA editing, with dramatic effects on mammalian transcriptomes. Factors introducing, deleting, or interpreting specific modifications have been identified, and analogous with epigenetic terminology, have been designated “writers,” “erasers,” and “readers.” Such modifications in the transcriptome are referred to as epitranscriptomic changes and represent a fascinating new layer of gene expression regulation that has only recently been appreciated. Here, we outline how RNA editing and RNA modification can rapidly affect gene expression, making both processes as well suited to respond to cellular stress and to regulate the transcriptome during development or circadian periods.

scholarly journals The Stress-Dependent Dynamics of Saccharomyces cerevisiae tRNA and rRNA Modification Profiles

Genes ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1344
Author(s):  
Yasemin Yoluç ◽  
Erik van de Logt ◽  
Stefanie Kellner-Kaiser
Keyword(s):  
Isotope Labeling ◽  
Model Organism ◽  
Rna Degradation ◽  
Rna Modification ◽  
Rna Modifications ◽  
Profile Changes ◽  
Stressed Cells ◽  
As Stress ◽  
Stress Dependent ◽  
Internal And External Factors

RNAs are key players in the cell, and to fulfil their functions, they are enzymatically modified. These modifications have been found to be dynamic and dependent on internal and external factors, such as stress. In this study we used nucleic acid isotope labeling coupled mass spectrometry (NAIL-MS) to address the question of which mechanisms allow the dynamic adaptation of RNA modifications during stress in the model organism S. cerevisiae. We found that both tRNA and rRNA transcription is stalled in yeast exposed to stressors such as H2O2, NaAsO2 or methyl methanesulfonate (MMS). From the absence of new transcripts, we concluded that most RNA modification profile changes observed to date are linked to changes happening on the pre-existing RNAs. We confirmed these changes, and we followed the fate of the pre-existing tRNAs and rRNAs during stress recovery. For MMS, we found previously described damage products in tRNA, and in addition, we found evidence for direct base methylation damage of 2′O-ribose methylated nucleosides in rRNA. While we found no evidence for increased RNA degradation after MMS exposure, we observed rapid loss of all methylation damages in all studied RNAs. With NAIL-MS we further established the modification speed in new tRNA and 18S and 25S rRNA from unstressed S. cerevisiae. During stress exposure, the placement of modifications was delayed overall. Only the tRNA modifications 1-methyladenosine and pseudouridine were incorporated as fast in stressed cells as in control cells. Similarly, 2′-O-methyladenosine in both 18S and 25S rRNA was unaffected by the stressor, but all other rRNA modifications were incorporated after a delay. In summary, we present mechanistic insights into stress-dependent RNA modification profiling in S. cerevisiae tRNA and rRNA.

scholarly journals Deep and accurate detection of m6A RNA modifications using miCLIP2 and m6Aboost machine learning

2020 ◽  
Author(s):  
Nadine Körtel ◽  
Cornelia Rücklé ◽  
You Zhou ◽  
Anke Busch ◽  
FX Reymond Sutandy ◽  
...  
Keyword(s):  
Machine Learning ◽  
Rna Stability ◽  
Rna Modification ◽  
List Type ◽  
Rna Modifications ◽  
Uv Crosslinking ◽  
Input Material ◽  
Machine Learning Model ◽  
Eukaryotic Mrnas ◽  
Nucleotide Resolution

AbstractN6-methyladenosine (m6A) is the most abundant internal RNA modification in eukaryotic mRNAs and influences many aspects of RNA processing, such as RNA stability and translation. miCLIP (m6A individual-nucleotide resolution UV crosslinking and immunoprecipitation) is an antibody-based approach to map m6A sites in the transcriptome with single-nucleotide resolution. However, due to broad antibody reactivity, reliable identification of m6A sites from miCLIP data remains challenging. Here, we present several experimental and computational innovations, that significantly improve transcriptome-wide detection of m6A sites. Based on the recently developed iCLIP2 protocol, the optimised miCLIP2 results in high-complexity libraries from less input material, which yields a more comprehensive representation of m6A sites. Next, we established a robust computational pipeline to identify true m6A sites from our miCLIP2 data. The analyses are calibrated with data from Mettl3 knockout cells to learn the characteristics of m6A deposition, including a significant number of m6A sites outside of DRACH motifs. In order to make these results universally applicable, we trained a machine learning model, m6Aboost, based on the experimental and RNA sequence features. Importantly, m6Aboost allows prediction of genuine m6A sites in miCLIP data without filtering for DRACH motifs or the need for Mettl3 depletion. Using m6Aboost, we identify thousands of high-confidence m6A sites in different murine and human cell lines, which provide a rich resource for future analysis. Collectively, our combined experimental and computational methodology greatly improves m6A identification.HighlightsmiCLIP2 produces complex libraries to map m6A RNA modificationsMettl3 KO miCLIP2 allows to identify Mettl3-dependent RNA modification sitesMachine learning predicts genuine m6A sites from human and mouse miCLIP2 data without Mettl3 KOm6A modifications frequently occur outside of DRACH motifs and associates with alternative splicing

scholarly journals Characterizing RNA Pseudouridylation by Convolutional Neural Networks

2017 ◽  
Author(s):  
Xuan He ◽  
Sai Zhang ◽  
Yanqing Zhang ◽  
Tao Jiang ◽  
Jianyang Zeng
Keyword(s):  
Transcriptional Regulation ◽  
Rna Structure ◽  
Large Scale ◽  
Rna Stability ◽  
Rna Modification ◽  
Functional Roles ◽  
Learning Framework ◽  
Translation Fidelity ◽  
Validation Tests ◽  
Post Transcriptional Regulation

AbstractThe most prevalent post-transcriptional RNA modification, pseudouridine (Ψ), also known as the fifth ribonucleoside, is widespread in rRNAs, tRNAs, snRNAs, snoRNAs and mRNAs. Pseudouridines in RNAs are implicated in many aspects of post-transcriptional regulation, such as the maintenance of translation fidelity, control of RNA stability and stabilization of RNA structure. However, our understanding of the functions, mechanisms as well as precise distribution of pseudourdines (especially in mRNAs) still remains largely unclear. Though thousands of RNA pseudouridylation sites have been identified by high-throughput experimental techniques recently, the landscape of pseudouridines across the whole transcriptome has not yet been fully delineated. In this study, we present a highly effective model, called PULSE (PseudoUridyLation Sites Estimator), to predict novel Ψ sites from large-scale profiling data of pseudouridines and characterize the contextual sequence features of pseudouridylation. PULSE employs a deep learning framework, called convolutional neural network (CNN), which has been successfully and widely used for sequence pattern discovery in the literature. Our extensive validation tests demonstrated that PULSE can outperform conventional learning models and achieve high prediction accuracy, thus enabling us to further characterize the transcriptome-wide landscape of pseudouridine sites. Overall, PULSE can provide a useful tool to further investigate the functional roles of pseudouridylation in post-transcriptional regulation.

Benefits of stable isotope labeling in RNA analysis

2019 ◽  
Vol 400 (7) ◽  
pp. 847-865 ◽  
Author(s):  
Paria Asadi-Atoi ◽  
Pierre Barraud ◽  
Carine Tisne ◽  
Stefanie Kellner
Keyword(s):  
Mass Spectrometry ◽  
Stable Isotope ◽  
Rna Structure ◽  
Isotope Labeling ◽  
Stable Isotope Labeling ◽  
Modified Nucleosides ◽  
Rna Modification ◽  
Metabolic Labeling ◽  
Signal Loss ◽  
Labeled Rna

Abstract RNAs are key players in life as they connect the genetic code (DNA) with all cellular processes dominated by proteins. They contain a variety of chemical modifications and many RNAs fold into complex structures. Here, we review recent progress in the analysis of RNA modification and structure on the basis of stable isotope labeling techniques. Mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy are the key tools and many breakthrough developments were made possible by the analysis of stable isotope labeled RNA. Therefore, we discuss current stable isotope labeling techniques such as metabolic labeling, enzymatic labeling and chemical synthesis. RNA structure analysis by NMR is challenging due to two major problems that become even more salient when the size of the RNA increases, namely chemical shift overlaps and line broadening leading to complete signal loss. Several isotope labeling strategies have been developed to provide solutions to these major issues, such as deuteration, segmental isotope labeling or site-specific labeling. Quantification of modified nucleosides in RNA by MS is only possible through the application of stable isotope labeled internal standards. With nucleic acid isotope labeling coupled mass spectrometry (NAIL-MS), it is now possible to analyze the dynamic processes of post-transcriptional RNA modification and demodification. The trend, in both NMR and MS RNA analytics, is without doubt shifting from the analysis of snapshot moments towards the development and application of tools capable of analyzing the dynamics of RNA structure and modification profiles.

scholarly journals Cell culture NAIL-MS allows insight into human RNA modification dynamics in vivo

2020 ◽  
Author(s):  
Matthias Heiss ◽  
Felix Hagelskamp ◽  
Stefanie Kellner
Keyword(s):  
Cell Culture ◽  
Stable Isotope ◽  
Human Cell ◽  
Isotope Labeling ◽  
Stable Isotope Labeling ◽  
Modified Nucleosides ◽  
Rna Modification ◽  
Growth Media ◽  
Human Cell Culture ◽  
The Impact

AbstractIn the last years, studies about the dynamics of RNA modifications are among the most controversially discussed. As the main reason, we have identified the unavailability of a technique which allows to follow the temporal dynamics of RNA transcripts in human cell culture. Here, we present a NAIL-MS (nucleic acid isotope labeling coupled mass spectrometry) scheme for efficient stable isotope labeling in both RNA and DNA (>95% within 7 days) in common human cell lines and growth media. Validation experiments reveal that the labeling procedure itself does neither interfere with the isotope dilution MS quantification nor with RNA modification density. We design pulse chase NAIL-MS experiments and apply the new tool to study the temporal placement of modified nucleosides in e.g. tRNAPhe and 18S rRNA. In existing RNAs, we observe a constant loss of modified nucleosides over time which is masked by a post-transcriptional methylation mechanism and thus not detectable without NAIL-MS. During alkylation stress, NAIL-MS reveals an adaptation of tRNA modifications in new transcripts but not existing transcripts.Overall, we present a fast and reliable stable isotope labeling strategy which allows a more detailed study of RNA modification dynamics in human cell culture. With cell culture NAIL-MS it is finally possible to study the speed of both modification and demethylation reactions inside human cells. Thus it will be possible to study the impact of external stimuli and stress on human RNA modification kinetics and processing of mature RNA.

scholarly journals Quantitative tRNA-sequencing uncovers metazoan tissue-specific tRNA regulation

2021 ◽  
Author(s):  
Otis Pinkard ◽  
Sean Mcfarland ◽  
Thomas Sweet ◽  
Jeff Coller
Keyword(s):  
Messenger Rna ◽  
Protein Production ◽  
Rna Stability ◽  
Amino Acid Identity ◽  
Rna Modifications ◽  
Transfer Rnas ◽  
Trna Modifications ◽  
Mammalian Tissues ◽  
Trna Sequencing ◽  
Regulatory Landscape

Abstract Transfer RNAs (tRNA) are quintessential in deciphering the genetic code; disseminating nucleic acid triplets into correct amino acid identity. While this decoding function is clear, an emerging theme is that tRNA abundance and functionality can powerfully impact protein production rate, folding, activity, and messenger RNA stability. Importantly, however, the expression pattern of tRNAs is obliquely known. Here we present Quantitative Mature tRNA sequencing (QuantM-tRNA seq), a technique to monitor tRNA abundance and sequence variants secondary to RNA modifications. With QuantM-tRNA seq we assess the tRNA transcriptome in mammalian tissues. We observe dramatic distinctions in isodecoder expression and known tRNA modifications between tissues. Remarkably, despite dramatic changes in tRNA isodecoder gene expression, the overall anticodon pool of each tRNA family is similar across tissues. These findings suggest that while anticodon pools appear to be buffered via an unknown mechanism, underlying transcriptomic and epitranscriptomic differences suggest a more complex tRNA regulatory landscape.

scholarly journals A generic normalization method for proper quantification in untargeted proteomics screening

2018 ◽  
Author(s):  
Sandra Isabel Anjo ◽  
Isaura Simões ◽  
Pedro Castanheira ◽  
Mário Grãos ◽  
Bruno Manadas
Keyword(s):  
Biomarker Discovery ◽  
Isotope Labeling ◽  
Internal Standard ◽  
Cost Effective ◽  
Label Free ◽  
Internal Standards ◽  
Biological Regulation ◽  
Additional Advantage ◽  
Cost Effective Alternative ◽  
Proteome Changes

ABSTRACTThe label-free quantitative mass spectrometry methods, in particular, the SWATH-MS approach, have gained popularity and became a powerful technique for comparison of large datasets. In the present work, it is introduced the use of recombinant proteins as internal standards for untargeted label-free methods. The proposed internal standard strategy reveals a similar intragroup normalization capacity when compared with the most common normalization methods, with the additional advantage of maintaining the overall proteome changes between groups (which are lost using other methods). Therefore, the proposed strategy is able to maintain a good performance even when large qualitative and quantitative differences in sample composition are observed, such as the ones induced by biological regulation (as observed in secretome and other biofluids’ analyses) or by enrichment approaches (such as immunopurifications). Moreover, this approach corresponds to a cost-effective alternative, easier to implement than the current stable-isotope labeling internal standards, therefore being an appealing strategy for large quantitative screening, as clinical cohorts for biomarker discovery.

scholarly journals Programmable System of Cas13-Mediated RNA Modification and Its Biological and Biomedical Applications

2021 ◽  
Vol 9 ◽  
Author(s):  
Tian Tang ◽  
Yingli Han ◽  
Yuran Wang ◽  
He Huang ◽  
Pengxu Qian
Keyword(s):  
Cell Fate ◽  
Rna Editing ◽  
Cell Biology ◽  
Rna Stability ◽  
Rna Modification ◽  
Translation Efficiency ◽  
Rna Modifications ◽  
History Of ◽  
Rna Interaction ◽  
Adenosine Deamination

Clustered regularly interspaced short palindromic repeats (CRISPR)-Cas13 has drawn broad interest to control gene expression and cell fate at the RNA level in general. Apart from RNA interference mediated by its endonuclease activity, the nuclease-deactivated form of Cas13 further provides a versatile RNA-guided RNA-targeting platform for manipulating kinds of RNA modifications post-transcriptionally. Chemical modifications modulate various aspects of RNA fate, including translation efficiency, alternative splicing, RNA–protein affinity, RNA–RNA interaction, RNA stability and RNA translocation, which ultimately orchestrate cellular biologic activities. This review summarizes the history of the CRISPR-Cas13 system, fundamental components of RNA modifications and the related physiological and pathological functions. We focus on the development of epi-transcriptional editing toolkits based on catalytically inactive Cas13, including RNA Editing for Programmable A to I Replacement (REPAIR) and xABE (adenosine base editor) for adenosine deamination, RNA Editing for Specific C-to-U Exchange (RESCUE) and xCBE (cytidine base editor) for cytidine deamination and dm6ACRISPR, as well as the targeted RNA methylation (TRM) and photoactivatable RNA m6A editing system using CRISPR-dCas13 (PAMEC) for m6A editing. We further highlight the emerging applications of these useful toolkits in cell biology, disease and imaging. Finally, we discuss the potential limitations, such as off-target editing, low editing efficiency and limitation for AAV delivery, and provide possible optimization strategies.

scholarly journals RNAmod: an integrated system for the annotation of mRNA modifications

2019 ◽  
Vol 47 (W1) ◽  
pp. W548-W555 ◽  
Author(s):  
Qi Liu ◽  
Richard I Gregory
Keyword(s):  
Cancer Progression ◽  
Messenger Rna ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Integrated System ◽  
Rna Modification ◽  
Specific Gene ◽  
Analysis Tool ◽  
Rna Modifications ◽  
Altered Expression

Abstract Dynamic and reversible RNA modifications such as N6-methyladenosine (m6A) can play important roles in regulating messenger RNA (mRNA) splicing, export, stability and translation. Defective mRNA modification through altered expression of the methyltransferase and/or demethylases results in developmental defects and cancer progression. Identifying modified mRNAs, annotating the distribution of modification sites across the mRNA, as well as characterizing and comparing other modification features are essential for studying the function and elucidating the mechanism of mRNA modifications. Several methods including methylated RNA immunoprecipitation and sequencing (MeRIP-seq) are available for the detection of mRNA modifications. However, a convenient and comprehensive tool to annotate diverse kinds of mRNA modifications in different species is lacking. Here, we developed RNAmod (https://bioinformatics.sc.cn/RNAmod), an interactive, one-stop, web-based platform for the automated analysis, annotation, and visualization of mRNA modifications in 21 species. RNAmod provides intuitive interfaces to show outputs including the distribution of RNA modifications, modification coverage for different gene features, functional annotation of modified mRNAs, and comparisons between different groups or specific gene sets. Furthermore, sites of known RNA modification, as well as binding site data for hundreds of RNA-binding proteins (RBPs) are integrated in RNAmod to help users compare their modification data with known modifications and to explore the relationship with the binding sites of known RBPs. RNAmod is freely available and meets the emerging need for a convenient and comprehensive analysis tool for the fast-developing RNA modification field.

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