Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1107229 | ENA |
REPOSITORIES: ENA
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Project description:Targeting RNA with small molecules offers a strategy to modulate gene expression at undruggable targets. Traditional screens favor thermodynamically stable, low-entropy RNA motifs with defined conformations, yet these provide limited energetic leverage for functional modulation. Many RNAs instead sample dynamic structural ensembles that small molecules can stabilize or redirect. Using group I self-splicing introns as a model, we identified the antineoplastic drug Mitoxantrone as a competitive inhibitor of RNA self-splicing (IC50 = 4.3 μM) that stabilizes the native conformation of the T4 td intron. Structure-activity analysis showed the anthraquinone scaffold alone is insufficient, and basic amine side chains are required for RNA structural modulation. Transcriptome-wide chemical probing in human cells revealed preferential binding to GC-rich structured regions, although only a subset showed structural change. Furthermore, global analysis of 5′ UTR ensembles showed reduced structural heterogeneity and increased translation, demonstrating functional repartitioning of RNA conformational landscapes.
2026-02-17 | GSE302505 | GEO
Project description:RNAs are often studied in non-native sequence contexts to facilitate structural studies. However, seemingly innocuous changes to an RNA sequence may perturb the native structure and generate inaccurate or ambiguous structural models. To facilitate the investigation of native RNA secondary structure by selective 2′ hydroxyl acylation analyzed by primer extension (SHAPE), we engineered an approach that couples minimal enzymatic steps to RNA chemical probing and mutational profiling (MaP) reverse transcription (RT) methods - a process we call template switching and mutational profiling (Switch-MaP). In Switch-MaP, RT templates and additional library sequences are added post-probing through ligation and template switching, capturing reactivities for every nucleotide. For a candidate SAM-I riboswitch, we compared RNA structure models generated by the Switch-MaP approach to those of traditional primer-based MaP, including RNAs with or without appended structure cassettes. Primer-based MaP masked reactivity data in the 5′ and 3′ ends of the RNA, producing ambiguous ensembles inconsistent with the conserved SAM-I riboswitch secondary structure. Structure cassettes enabled unambiguous modeling of an aptamer construct but introduced non-native interactions in the full-length riboswitch. In contrast, Switch-MaP provided reactivity data for each nucleotide in each RNA and enabled unambiguous modeling of secondary structure, consistent with the conserved SAM-I fold. Switch-MaP is an alternative approach to primer-based and cassette-based chemical probing methods that precludes primer masking and the formation of alternative secondary structures due to non-native sequence elements.
2024-12-26 | GSE274121 | GEO
Project description:DMS chemical probing experiments on the hTR
| PRJEB88555 | ENA
Project description:RNA structure heterogeneity is a major challenge when querying RNA structures with chemical probing. We introduce DRACO, an algorithm for the deconvolution of coexisting RNA conformations from mutational profiling experiments. Analysis of the SARS-CoV-2 genome using dimethyl sulfate mutational profiling with sequencing (DMS-MaPseq) and DRACO, identifies multiple regions that fold into two mutually exclusive conformations, including a conserved structural switch in the 3′ untranslated region. This work may open the way to dissecting the heterogeneity of the RNA structurome.
2020-12-23 | GSE158052 | GEO
Project description:Single-molecule correlated chemical probing (smCCP) is an experimentally concise strategy for characterizing higher-order structural interactions in RNA. smCCP data yield rich, but complex, structural information on base pairing, conformational ensembles, and tertiary interactions. To date, through-space communication specifically measuring RNA tertiary structure has been difficult to isolate from structural communication reflective of other interactions. Here we introduce mutual information as a filtering metric to isolate tertiary structure communication contained within smCCP data and use this strategy to characterize the structural ensemble of the SAM-III riboswitch. We identified a smCCP fingerprint that is selective for states containing tertiary structure that forms concurrently with cognate ligand binding. We then successfully applied mutual information filters to independent RNAs and isolated through-space tertiary interactions in riboswitches and large RNAs with complex structures. smCCP, coupled with mutual information criteria, can now be used as a tertiary structure discovery tool, including to identify specific states in an ensemble that have higher-order structure. These studies pave the way for use of the straightforward smCCP experiment for discovery and characterization of tertiary structure motifs in complex RNAs.
2024-10-23 | GSE278422 | GEO
Project description:Chemical probing has the power to provide insight into RNA conformation in vivo and in vitro, but interpreting the results depends on methods to detect the chemically modified nucleotides. Traditionally, the presence of modified bases was inferred from their ability to halt reverse transcriptase during primer extension and the locations of termination sites observed by electrophoresis or sequencing. More recently, modification-induced mutations have been used as a readout for chemical probing data. Given variable propensity for mismatch incorporation and read-through with different reverse transcriptases, we examined how termination and mutation events compare to each other in the same chemical probing experiments. We found that mutations and terminations induced by dimethyl sulfate probing are both specific for methylated bases, but these two measures have surprisingly little correlation and represent largely non-overlapping indicators of chemical modification data. We also show that specific biases for modified bases depend partly on local sequence context, and that different reverse transcriptases show different biases toward reading a modification as a stop or a mutation. These results support approaches that incorporate analysis of both termination and mutation events into RNA probing experiments.
2017-09-26 | GSE97609 | GEO
Project description:Structure probing experiments were performed on in vitro transcripts and E. coli and human cell cultures under natively extracted (cell-free) and in-cell conditions to benchmark the performance of the newly introduced PAIR-MaP correlated chemical probing strategy for detecting RNA duplexes. Multiple-hit dimethyl sulfate (DMS) probing was done using new buffer conditions that facilitate DMS modification of all four nucleotides.
2019-08-01 | GSE135211 | GEO
Project description:RNA structure-based gene regulation remains under-explored in eukaryotes. While RNA can form different conformations in solution, the extent to which it folds into structure ensembles and how the different conformations regulate gene expression still needs to be fully understood. We coupled the SHAPE compound NAI-N3 with direct RNA sequencing to identify structure modifications along a single RNA molecule (sm-PORE-cupine). Using a combination of base mapping and direct signal alignment, we boosted the percentage of mappable RNA molecules from direct RNA sequencing. Using Bernoulli Mixture Model (BMM) clustering, we show that we can separate RNA structure ensembles from ligand-bound and unbound riboswitches accurately, identify isoform-specific structure ensembles along the SARS-CoV-2 genome, and determine RNA structure ensembles in the transcriptome of a eukaryote, C. albicans, at yeast (30°C) and hyphae (37°C) states. We observed that RNAs are more structurally homogenous at 37°C compared to 30°C, are more variable in vivo than in vitro, and show higher homogeneity in 3’UTRs than in the coding region. We also identified structure ensembles that are associated with changes in translation efficiency and decay in C. albicans at 30°C and 37°C and validated translational changes using reporter assays. Our work shows that single-molecule RNA structure probing using direct RNA sequencing can be applied to diverse transcriptomes to study the complexity and function of RNA structures.
2025-11-10 | GSE304703 | GEO
Project description:RNA structure-based gene regulation remains under-explored in eukaryotes. While RNA can form different conformations in solution, the extent to which it folds into structure ensembles and how the different conformations regulate gene expression still needs to be fully understood. We coupled the SHAPE compound NAI-N3 with direct RNA sequencing to identify structure modifications along a single RNA molecule (sm-PORE-cupine). Using a combination of base mapping and direct signal alignment, we boosted the percentage of mappable RNA molecules from direct RNA sequencing. Using Bernoulli Mixture Model (BMM) clustering, we show that we can separate RNA structure ensembles from ligand-bound and unbound riboswitches accurately, identify isoform-specific structure ensembles along the SARS-CoV-2 genome, and determine RNA structure ensembles in the transcriptome of a eukaryote, C. albicans, at yeast (30°C) and hyphae (37°C) states. We observed that RNAs are more structurally homogenous at 37°C compared to 30°C, are more variable in vivo than in vitro, and show higher homogeneity in 3’UTRs than in the coding region. We also identified structure ensembles that are associated with changes in translation efficiency and decay in C. albicans at 30°C and 37°C and validated translational changes using reporter assays. Our work shows that single-molecule RNA structure probing using direct RNA sequencing can be applied to diverse transcriptomes to study the complexity and function of RNA structures.
2025-11-10 | GSE304702 | GEO