Project description:We develop an enhanced MaP protocol based on MarathonRT and bioinformatic optimizations which enables robust DMS probing of all four RNA nucleotides within living cells. We demonstrate this on RNA from E. coli and HEK293 cell lines.
Project description:Ribosomes are among the largest folded RNAs, whose function depends on their structure. Nonetheless, in vitro studies indicate a propensity of rRNAs to misfold. We use a combination of DMS-MaPseq, structural analyses, biochemical experiments, and yeast genetics to dissect the final RNA folding steps of the small ribosomal subunit head.
Project description:Ribosomes are among the largest folded RNAs, whose function depends on their structure. Nonetheless, in vitro studies indicate a propensity of rRNAs to misfold. We use a combination of DMS-MaPseq, structural analyses, biochemical experiments, and yeast genetics to dissect the final RNA folding steps of the small ribosomal subunit head.
Project description:To delineate the native structure of SF3A3 5'UTR, RNA was harvested from IMR90 human fibroblasts. Using specific primers and DMS-MaPSeq pipeline, we validated individual base pairing probabilities within the endogenous 5'UTR of SF3A3 (samples described as 'in vivo' transcribed). DMS-MaP-Seq is based on the principle that DMS is highly reactive to solvent-accessible, unpaired adenine (A) and cytosine (C) residues, but remains inert toward base-paired A and C engaged in Watson-Crick interactions (Rouskin et al., 2014). Using this methodology, we identify stable stem-loop structure (SL3) positioned within SF3A3 5'UTR. To further validate the functional importance of SL3, the structural point mutant (SF3A3 5'UTR mut: A55C and U95A) and rescue (SF3A3 5'UTR res: A55C and U95A and rescuing point mutations G61U and U100G) sequences of SF3A3 5'UTR were cloned into the reporter plasmid. For the validation of these mutate-and-rescue constructs, plasmids were in vitro transcribed and either used directly (samples described as 'in vitro') for DMS-MaP-Seq probing.
Project description:Here we present dimethyl sulfate mutational profiling with sequencing (DMS-MaPseq), which encodes DMS modifications as mismatches using a thermostable group II intron reverse transcriptase (TGIRT). DMS-MaPseq yields a high signal-to-noise ratio, can report multiple structural features for each molecule, and allows genome-wide studies as well as focused investigations of low abundance RNAs. We apply DMS-MaPseq to Drosophila melanogaster ovaries—the first experimental analysis of RNA structure in an animal tissue—and demonstrate its utility in the discovery of a functional RNA structure involved in the non-canonical GUG translation initiation of the human FXR2 mRNA. Additionally, we use DMS-MaPseq to compare the in vivo structure of messages in their pre-mRNA and mature forms. These applications illustrate DMS-MaPseq’s capacity to dramatically expand our ability to monitor RNA structure in vivo.
Project description:While various methods exist for examining and visualizing the structure of RNA molecules, dimethyl sulfate-mutational profiling and sequencing (DMS-MaPseq) stands out for its simplicity and versatility. This technique has proven effective for studying RNA structures both in vitro and in complex biological settings. We've updated the protocol for using DMS-MaPseq, and it can also be employed to identify the binding of antisense oligonucleotides (ASOs) to RNA. By applying this updated protocol, we successfully characterized the structural ensemble of the HIV1 Rev Response Element (RRE), along with its two alternative structures. The findings align with previously published research. Additionally, we resolved the structure of the long non-coding RNA PANDA, which was previously unknown. Moreover, we used PANDA as a basis for designing ASOs and confirmed their binding through a substantial decrease in DMS-reactivities at the anticipated ASO binding locations.
Project description:RNA structural switches are key regulators of gene expression in bacteria, yet their characterization in Metazoa remains limited. Here we present SwitchSeeker, a comprehensive computational and experimental approach for systematic identification of functional RNA structural switches. We applied SwitchSeeker to the human transcriptome and identified 245 putative RNA switches. To validate our approach, we characterized a previously unknown RNA switch in the 3’UTR of the RORC transcript. In vivo DMS-MaPseq, coupled with cryogenic electron microscopy, confirmed its existence as two alternative structural conformations. Furthermore, we used genome-scale CRISPR screens to identify trans factors that regulate gene expression through this RNA structural switch. We found that nonsense-mediated mRNA decay acts on this element in a conformation-specific manner. SwitchSeeker provides an unbiased, experimentally-driven method for discovering RNA structural switches that shape the eukaryotic gene expression landscape.