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Michael D. Cleary - One of the best experts on this subject based on the ideXlab platform.
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EC-tagging allows cell type-specific RNA analysis.
Nucleic acids research, 2017Co-Authors: Naoki Hida, Mohamed Y. Aboukilila, Dana A. Burow, Rakesh Paul, Marc M. Greenberg, Michael Fazio, Samantha Beasley, Robert C. Spitale, Michael D. ClearyAbstract:Purification of cell type-specific RNAs remains a significant challenge. One solution involves biosynthetic tagging of target RNAs. RNA tagging via incorporation of 4-Thiouracil (TU) in cells expressing transgenic uracil phosphoribosyltransferase (UPRT), a method known as TU-tagging, has been used in multiple systems but can have limited specificity due to endogenous pathways of TU incorporation. Here, we describe an alternative method that requires the activity of two enzymes: cytosine deaminase (CD) and UPRT. We found that the sequential activity of these enzymes converts 5-ethynylcytosine (EC) to 5-ethynyluridine monophosphate that is subsequently incorporated into nascent RNAs. The ethynyl group allows efficient detection and purification of tagged RNAs. We show that 'EC-tagging' occurs in tissue culture cells and Drosophila engineered to express CD and UPRT. Additional control can be achieved through a split-CD approach in which functional CD is reconstituted from independently expressed fragments. We demonstrate the sensitivity and specificity of EC-tagging by obtaining cell type-specific gene expression data from intact Drosophila larvae, including transcriptome measurements from a small population of central brain neurons. EC-tagging provides several advantages over existing techniques and should be broadly useful for investigating the role of differential RNA expression in cell identity, physiology and pathology.
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tu tagging cell type specific rna isolation from intact complex tissues
Nature Methods, 2009Co-Authors: Michael R Miller, Michael D. Cleary, Kristin J Robinson, Chris Q DoeAbstract:We found that the combination of spatially restricted uracil phosphoribosyltransferase (UPRT) expression with 4-Thiouracil delivery can be used to label and purify cell type-specific RNA from intact complex tissues in Drosophila melanogaster. This method is useful for isolating RNA from cell types that are difficult to isolate by dissection or dissociation methods and should work in many organisms, including mammals and other vertebrates.
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rna analysis by biosynthetic tagging using 4 Thiouracil and uracil phosphoribosyltransferase
Methods of Molecular Biology, 2008Co-Authors: Gusti M Zeiner, Ashley E Fouts, Christopher D Meiring, Edward S Mocarski, Michael D. Cleary, John C BoothroydAbstract:: RNA analysis by biosynthetic tagging (RABT) enables sensitive and specific queries of (a) how gene expression is regulated on a genome-wide scale and (b) transcriptional profiling of a single cell or tissue type in vivo. RABT can be achieved by exploiting unique properties of Toxoplasma gondii uracil phosphoribosyltransferase (TgUPRT), a pyrimidine salvage enzyme that couples ribose-5-phosphate to the N1 nitrogen of uracil to yield uridine monophosphate (UMP). When 4-Thiouracil is provided as a TgUPRT substrate, the resultant product is 4-thiouridine monophosphate which can, ultimately, be incorporated into RNA. Thio-substituted nucleotides are not a natural component of nucleic acids and are readily tagged, detected, and purified with commercially available reagents. Thus, one can do pulse/chase experiments to measure synthesis and decay rates and/or use cell-specific expression of the TgUPRT to tag only RNA synthesized in a given cell type. This chapter updates the original RABT protocol (1) and addresses methodological details associated with RABT that were beyond the scope or space allotment of the initial report.
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cell type specific analysis of mrna synthesis and decay in vivo with uracil phosphoribosyltransferase and 4 Thiouracil
Methods in Enzymology, 2008Co-Authors: Michael D. ClearyAbstract:Abstract Microarray‐based analysis of mRNA expression has provided a genome‐wide understanding of the genes and pathways involved in many biological processes. However, two limitations are often associated with traditional microarray experiments. First, standard methods of microarray analysis measure mRNA abundance, not mRNA synthesis or mRNA decay, and, therefore, do not provide any information regarding the mechanisms regulating transcript levels. Second, microarrays are often performed with mRNA from a mixed population of cells, and data for a specific cell‐type of interest can be difficult to obtain. This chapter describes a method, referred to here as “4TU‐tagging,” which can be used to overcome these limitations. 4TU‐Tagging uses cell type–specific expression of the uracil phosphoribosyltransferase gene of Toxoplasma gondii and the uracil analog 4‐Thiouracil (4TU) to selectively tag and purify RNA. Pulse‐labeling of newly synthesized RNA with 4TU followed by a “chase” with unmodified uracil allows in vivo measurements of mRNA synthesis and decay in specific cells. Experimental design considerations for applying 4TU‐tagging to different systems and protocols for cell type–specific RNA tagging, purification, and microarray analysis are covered in this chapter.
David Tollervey - One of the best experts on this subject based on the ideXlab platform.
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defining the rna interactome by total rna associated protein purification
Molecular Systems Biology, 2019Co-Authors: Vadim Shchepachev, Stefan Bresson, Christos Spanos, Elisabeth Petfalski, Lutz Fischer, Juri Rappsilber, David TollerveyAbstract:Abstract The RNA binding proteome (RBPome) was previously investigated using UV crosslinking and purification of poly(A)‐associated proteins. However, most cellular transcripts are not polyadenylated. We therefore developed total RNA‐associated protein purification (TRAPP) based on 254 nm UV crosslinking and purification of all RNA–protein complexes using silica beads. In a variant approach (PAR‐TRAPP), RNAs were labelled with 4‐Thiouracil prior to 350 nm crosslinking. PAR‐TRAPP in yeast identified hundreds of RNA binding proteins, strongly enriched for canonical RBPs. In comparison, TRAPP identified many more proteins not expected to bind RNA, and this correlated strongly with protein abundance. Comparing TRAPP in yeast and E. coli showed apparent conservation of RNA binding by metabolic enzymes. Illustrating the value of total RBP purification, we discovered that the glycolytic enzyme enolase interacts with tRNAs. Exploiting PAR‐TRAPP to determine the effects of brief exposure to weak acid stress revealed specific changes in late 60S ribosome biogenesis. Furthermore, we identified the precise sites of crosslinking for hundreds of RNA–peptide conjugates, using iTRAPP, providing insights into potential regulation. We conclude that TRAPP is a widely applicable tool for RBPome characterization.
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Defining the RNA interactome by total RNA‐associated protein purification
'EMBO', 2019Co-Authors: Vadim Shchepachev, Stefan Bresson, Christos Spanos, Elisabeth Petfalski, Lutz Fischer, Juri Rappsilber, David TollerveyAbstract:Abstract The RNA binding proteome (RBPome) was previously investigated using UV crosslinking and purification of poly(A)‐associated proteins. However, most cellular transcripts are not polyadenylated. We therefore developed total RNA‐associated protein purification (TRAPP) based on 254 nm UV crosslinking and purification of all RNA–protein complexes using silica beads. In a variant approach (PAR‐TRAPP), RNAs were labelled with 4‐Thiouracil prior to 350 nm crosslinking. PAR‐TRAPP in yeast identified hundreds of RNA binding proteins, strongly enriched for canonical RBPs. In comparison, TRAPP identified many more proteins not expected to bind RNA, and this correlated strongly with protein abundance. Comparing TRAPP in yeast and E. coli showed apparent conservation of RNA binding by metabolic enzymes. Illustrating the value of total RBP purification, we discovered that the glycolytic enzyme enolase interacts with tRNAs. Exploiting PAR‐TRAPP to determine the effects of brief exposure to weak acid stress revealed specific changes in late 60S ribosome biogenesis. Furthermore, we identified the precise sites of crosslinking for hundreds of RNA–peptide conjugates, using iTRAPP, providing insights into potential regulation. We conclude that TRAPP is a widely applicable tool for RBPome characterization
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defining the rna interactome by total rna associated protein purification
bioRxiv, 2018Co-Authors: Vadim Shchepachev, Stefan Bresson, Christos Spanos, Elisabeth Petfalski, Lutz Fischer, Juri Rappsilber, David TollerveyAbstract:ABSTRACT UV crosslinking can be used to identify precise RNA targets for individual proteins, transcriptome-wide. We sought to develop a technique to generate reciprocal data, identifying precise sites of RNA-binding proteome-wide. The resulting technique, total RNA-associated protein purification (TRAPP), was applied to yeast (S. cerevisiae) and bacteria (E. coli). In all analyses, SILAC labelling was used to quantify protein recovery in the presence and absence of irradiation. For S. cerevisiae, we also compared crosslinking using 254 nm (UVC) irradiation (TRAPP) with 4-Thiouracil (4tU) labelling combined with ~350 nm (UVA) irradiation (PAR-TRAPP). Recovery of proteins not anticipated to show RNA-binding activity was substantially higher in TRAPP compared to PAR-TRAPP. As an example of preferential TRAPP-crosslinking, we tested enolase (Eno1) and demonstrated its binding to tRNA loops in vivo. We speculate that many protein-RNA interactions have biophysical effects on localization and/or accessibility, by opposing or promoting phase separation for highly abundant protein. Homologous metabolic enzymes showed RNA crosslinking in S. cerevisiae and E. coli, indicating conservation of this property. TRAPP allows alterations in RNA interactions to be followed and we initially analyzed the effects of weak acid stress. This revealed specific alterations in RNA-protein interactions; for example, during late 60S ribosome subunit maturation. Precise sites of crosslinking at the level of individual amino acids (iTRAPP) were identified in 395 peptides from 155 unique proteins, following phospho-peptide enrichment combined with a bioinformatics pipeline (Xi). TRAPP is quick, simple and scalable, allowing rapid characterization of the RNA-bound proteome in many systems.
Anna Pasternak - One of the best experts on this subject based on the ideXlab platform.
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novel isoguanine derivative of unlocked nucleic acid investigations of thermodynamics and biological potential of modified thrombin binding aptamer
PLOS ONE, 2018Co-Authors: Weronika Kotkowiak, Tomasz Czapik, Anna PasternakAbstract:Thrombin binding aptamer (TBA), is a short DNA 15-mer that forms G-quadruplex structure and possesses anticoagulant properties. Some chemical modifications, including unlocked nucleic acids (UNA), 2'-deoxy-isoguanosine and 2'-deoxy-4-thiouridine were previously found to enhance the biological activity of TBA. In this paper, we present thermodynamic and biological characteristics of TBA variants that have been modified with novel isoguanine derivative of UNA as well as isoguanosine. Additionally, UNA-4-Thiouracil and 4-thiouridine were also introduced simultaneously with isoguanine derivatives. Thermodynamic analysis indicates that the presence of isoguanosine in UNA or RNA series significantly decreases the stability of G-quadruplex structure. The highest destabilization is observed for substitution at one of the G-tetrad position. Addition of 4-thiouridine in UNA or RNA series usually decreases the unfavorable energetic cost of the presence of UNA or RNA isoguanine. Circular dichroism and thermal denaturation spectra in connection with thrombin time assay indicate that the introduction of UNA-isoguanine or isoguanosine into TBA negatively affects G-quadruplex folding and TBA anticoagulant properties. These findings demonstrate that the highly-ordered structure of TBA is essential for inhibition of thrombin activity.
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Novel isoguanine derivative of unlocked nucleic acid—Investigations of thermodynamics and biological potential of modified thrombin binding aptamer
2018Co-Authors: Weronika Kotkowiak, Tomasz Czapik, Anna PasternakAbstract:Thrombin binding aptamer (TBA), is a short DNA 15-mer that forms G-quadruplex structure and possesses anticoagulant properties. Some chemical modifications, including unlocked nucleic acids (UNA), 2′-deoxy-isoguanosine and 2′-deoxy-4-thiouridine were previously found to enhance the biological activity of TBA. In this paper, we present thermodynamic and biological characteristics of TBA variants that have been modified with novel isoguanine derivative of UNA as well as isoguanosine. Additionally, UNA-4-Thiouracil and 4-thiouridine were also introduced simultaneously with isoguanine derivatives. Thermodynamic analysis indicates that the presence of isoguanosine in UNA or RNA series significantly decreases the stability of G-quadruplex structure. The highest destabilization is observed for substitution at one of the G-tetrad position. Addition of 4-thiouridine in UNA or RNA series usually decreases the unfavorable energetic cost of the presence of UNA or RNA isoguanine. Circular dichroism and thermal denaturation spectra in connection with thrombin time assay indicate that the introduction of UNA-isoguanine or isoguanosine into TBA negatively affects G-quadruplex folding and TBA anticoagulant properties. These findings demonstrate that the highly-ordered structure of TBA is essential for inhibition of thrombin activity.
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Thermodynamic, Anticoagulant, and Antiproliferative Properties of Thrombin Binding Aptamer Containing Novel UNA Derivative
Elsevier, 2018Co-Authors: Weronika Kotkowiak, Jolanta Lisowiec-wachnicka, Jakub Grynda, Ryszard Kierzek, Jesper Wengel, Anna PasternakAbstract:Thrombin is a serine protease that plays a crucial role in hemostasis, fibrinolysis, cell proliferation, and migration. Thrombin binding aptamer (TBA) is able to inhibit the activity of thrombin molecule via binding to its exosite I. This 15-nt DNA oligonucleotide forms an intramolecular, antiparallel G-quadruplex structure with a chair-like conformation. In this paper, we report on our investigations on the influence of certain modified nucleotide residues on thermodynamic stability, folding topology, and biological properties of TBA variants. In particular, the effect of single incorporation of a novel 4-Thiouracil derivative of unlocked nucleic acid (UNA), as well as single incorporation of 4-thiouridine and all four canonical UNAs, was evaluated. The studies presented herein have shown that 4-thiouridine in RNA and UNA series, as well as all four canonical UNAs, can efficiently modulate G-quadruplex thermodynamic and biological stability, and that the effect is strongly position dependent. Interestingly, TBA variants containing the modified nucleotide residues are characterized by unchanged folding topology. Thrombin time assay revealed that incorporation of certain UNA residues may improve G-quadruplex anticoagulant properties. Noteworthy, some TBA variants, characterized by decreased ability to inhibit thrombin activity, possess significant antiproliferative properties reducing the viability of the HeLa cell line even by 95% at 10 μM concentration
Juri Rappsilber - One of the best experts on this subject based on the ideXlab platform.
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defining the rna interactome by total rna associated protein purification
Molecular Systems Biology, 2019Co-Authors: Vadim Shchepachev, Stefan Bresson, Christos Spanos, Elisabeth Petfalski, Lutz Fischer, Juri Rappsilber, David TollerveyAbstract:Abstract The RNA binding proteome (RBPome) was previously investigated using UV crosslinking and purification of poly(A)‐associated proteins. However, most cellular transcripts are not polyadenylated. We therefore developed total RNA‐associated protein purification (TRAPP) based on 254 nm UV crosslinking and purification of all RNA–protein complexes using silica beads. In a variant approach (PAR‐TRAPP), RNAs were labelled with 4‐Thiouracil prior to 350 nm crosslinking. PAR‐TRAPP in yeast identified hundreds of RNA binding proteins, strongly enriched for canonical RBPs. In comparison, TRAPP identified many more proteins not expected to bind RNA, and this correlated strongly with protein abundance. Comparing TRAPP in yeast and E. coli showed apparent conservation of RNA binding by metabolic enzymes. Illustrating the value of total RBP purification, we discovered that the glycolytic enzyme enolase interacts with tRNAs. Exploiting PAR‐TRAPP to determine the effects of brief exposure to weak acid stress revealed specific changes in late 60S ribosome biogenesis. Furthermore, we identified the precise sites of crosslinking for hundreds of RNA–peptide conjugates, using iTRAPP, providing insights into potential regulation. We conclude that TRAPP is a widely applicable tool for RBPome characterization.
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Defining the RNA interactome by total RNA‐associated protein purification
'EMBO', 2019Co-Authors: Vadim Shchepachev, Stefan Bresson, Christos Spanos, Elisabeth Petfalski, Lutz Fischer, Juri Rappsilber, David TollerveyAbstract:Abstract The RNA binding proteome (RBPome) was previously investigated using UV crosslinking and purification of poly(A)‐associated proteins. However, most cellular transcripts are not polyadenylated. We therefore developed total RNA‐associated protein purification (TRAPP) based on 254 nm UV crosslinking and purification of all RNA–protein complexes using silica beads. In a variant approach (PAR‐TRAPP), RNAs were labelled with 4‐Thiouracil prior to 350 nm crosslinking. PAR‐TRAPP in yeast identified hundreds of RNA binding proteins, strongly enriched for canonical RBPs. In comparison, TRAPP identified many more proteins not expected to bind RNA, and this correlated strongly with protein abundance. Comparing TRAPP in yeast and E. coli showed apparent conservation of RNA binding by metabolic enzymes. Illustrating the value of total RBP purification, we discovered that the glycolytic enzyme enolase interacts with tRNAs. Exploiting PAR‐TRAPP to determine the effects of brief exposure to weak acid stress revealed specific changes in late 60S ribosome biogenesis. Furthermore, we identified the precise sites of crosslinking for hundreds of RNA–peptide conjugates, using iTRAPP, providing insights into potential regulation. We conclude that TRAPP is a widely applicable tool for RBPome characterization
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defining the rna interactome by total rna associated protein purification
bioRxiv, 2018Co-Authors: Vadim Shchepachev, Stefan Bresson, Christos Spanos, Elisabeth Petfalski, Lutz Fischer, Juri Rappsilber, David TollerveyAbstract:ABSTRACT UV crosslinking can be used to identify precise RNA targets for individual proteins, transcriptome-wide. We sought to develop a technique to generate reciprocal data, identifying precise sites of RNA-binding proteome-wide. The resulting technique, total RNA-associated protein purification (TRAPP), was applied to yeast (S. cerevisiae) and bacteria (E. coli). In all analyses, SILAC labelling was used to quantify protein recovery in the presence and absence of irradiation. For S. cerevisiae, we also compared crosslinking using 254 nm (UVC) irradiation (TRAPP) with 4-Thiouracil (4tU) labelling combined with ~350 nm (UVA) irradiation (PAR-TRAPP). Recovery of proteins not anticipated to show RNA-binding activity was substantially higher in TRAPP compared to PAR-TRAPP. As an example of preferential TRAPP-crosslinking, we tested enolase (Eno1) and demonstrated its binding to tRNA loops in vivo. We speculate that many protein-RNA interactions have biophysical effects on localization and/or accessibility, by opposing or promoting phase separation for highly abundant protein. Homologous metabolic enzymes showed RNA crosslinking in S. cerevisiae and E. coli, indicating conservation of this property. TRAPP allows alterations in RNA interactions to be followed and we initially analyzed the effects of weak acid stress. This revealed specific alterations in RNA-protein interactions; for example, during late 60S ribosome subunit maturation. Precise sites of crosslinking at the level of individual amino acids (iTRAPP) were identified in 395 peptides from 155 unique proteins, following phospho-peptide enrichment combined with a bioinformatics pipeline (Xi). TRAPP is quick, simple and scalable, allowing rapid characterization of the RNA-bound proteome in many systems.
Vadim Shchepachev - One of the best experts on this subject based on the ideXlab platform.
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defining the rna interactome by total rna associated protein purification
Molecular Systems Biology, 2019Co-Authors: Vadim Shchepachev, Stefan Bresson, Christos Spanos, Elisabeth Petfalski, Lutz Fischer, Juri Rappsilber, David TollerveyAbstract:Abstract The RNA binding proteome (RBPome) was previously investigated using UV crosslinking and purification of poly(A)‐associated proteins. However, most cellular transcripts are not polyadenylated. We therefore developed total RNA‐associated protein purification (TRAPP) based on 254 nm UV crosslinking and purification of all RNA–protein complexes using silica beads. In a variant approach (PAR‐TRAPP), RNAs were labelled with 4‐Thiouracil prior to 350 nm crosslinking. PAR‐TRAPP in yeast identified hundreds of RNA binding proteins, strongly enriched for canonical RBPs. In comparison, TRAPP identified many more proteins not expected to bind RNA, and this correlated strongly with protein abundance. Comparing TRAPP in yeast and E. coli showed apparent conservation of RNA binding by metabolic enzymes. Illustrating the value of total RBP purification, we discovered that the glycolytic enzyme enolase interacts with tRNAs. Exploiting PAR‐TRAPP to determine the effects of brief exposure to weak acid stress revealed specific changes in late 60S ribosome biogenesis. Furthermore, we identified the precise sites of crosslinking for hundreds of RNA–peptide conjugates, using iTRAPP, providing insights into potential regulation. We conclude that TRAPP is a widely applicable tool for RBPome characterization.
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Defining the RNA interactome by total RNA‐associated protein purification
'EMBO', 2019Co-Authors: Vadim Shchepachev, Stefan Bresson, Christos Spanos, Elisabeth Petfalski, Lutz Fischer, Juri Rappsilber, David TollerveyAbstract:Abstract The RNA binding proteome (RBPome) was previously investigated using UV crosslinking and purification of poly(A)‐associated proteins. However, most cellular transcripts are not polyadenylated. We therefore developed total RNA‐associated protein purification (TRAPP) based on 254 nm UV crosslinking and purification of all RNA–protein complexes using silica beads. In a variant approach (PAR‐TRAPP), RNAs were labelled with 4‐Thiouracil prior to 350 nm crosslinking. PAR‐TRAPP in yeast identified hundreds of RNA binding proteins, strongly enriched for canonical RBPs. In comparison, TRAPP identified many more proteins not expected to bind RNA, and this correlated strongly with protein abundance. Comparing TRAPP in yeast and E. coli showed apparent conservation of RNA binding by metabolic enzymes. Illustrating the value of total RBP purification, we discovered that the glycolytic enzyme enolase interacts with tRNAs. Exploiting PAR‐TRAPP to determine the effects of brief exposure to weak acid stress revealed specific changes in late 60S ribosome biogenesis. Furthermore, we identified the precise sites of crosslinking for hundreds of RNA–peptide conjugates, using iTRAPP, providing insights into potential regulation. We conclude that TRAPP is a widely applicable tool for RBPome characterization
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defining the rna interactome by total rna associated protein purification
bioRxiv, 2018Co-Authors: Vadim Shchepachev, Stefan Bresson, Christos Spanos, Elisabeth Petfalski, Lutz Fischer, Juri Rappsilber, David TollerveyAbstract:ABSTRACT UV crosslinking can be used to identify precise RNA targets for individual proteins, transcriptome-wide. We sought to develop a technique to generate reciprocal data, identifying precise sites of RNA-binding proteome-wide. The resulting technique, total RNA-associated protein purification (TRAPP), was applied to yeast (S. cerevisiae) and bacteria (E. coli). In all analyses, SILAC labelling was used to quantify protein recovery in the presence and absence of irradiation. For S. cerevisiae, we also compared crosslinking using 254 nm (UVC) irradiation (TRAPP) with 4-Thiouracil (4tU) labelling combined with ~350 nm (UVA) irradiation (PAR-TRAPP). Recovery of proteins not anticipated to show RNA-binding activity was substantially higher in TRAPP compared to PAR-TRAPP. As an example of preferential TRAPP-crosslinking, we tested enolase (Eno1) and demonstrated its binding to tRNA loops in vivo. We speculate that many protein-RNA interactions have biophysical effects on localization and/or accessibility, by opposing or promoting phase separation for highly abundant protein. Homologous metabolic enzymes showed RNA crosslinking in S. cerevisiae and E. coli, indicating conservation of this property. TRAPP allows alterations in RNA interactions to be followed and we initially analyzed the effects of weak acid stress. This revealed specific alterations in RNA-protein interactions; for example, during late 60S ribosome subunit maturation. Precise sites of crosslinking at the level of individual amino acids (iTRAPP) were identified in 395 peptides from 155 unique proteins, following phospho-peptide enrichment combined with a bioinformatics pipeline (Xi). TRAPP is quick, simple and scalable, allowing rapid characterization of the RNA-bound proteome in many systems.
