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 use dimethyl sulfate mutational profiling with sequencing (DMS-MaPseq) to conduct a target-specific and genome-wide profile of in vivo RNA secondary structure in rice (Oryza sativa). Our study presents an optimized DMS-MaPseq for probing in vivo RNA structure in rice.
Project description:The goal of this study was to understand the underlying structure of nucleotides 403-780 of the lncRNA SLNCR1, in-cell and when extracted from nuclear and cytoplasmic fractions. SHAPE and DMS probing revealed that the region is largely unstructured inside and outside of the cell, and appears protein-bound in primary melanoma cells.
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: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:Deciphering the conformations of RNAs in their cellular environment allows identification of RNA elements with potentially functional roles within biological contexts. Insight into the conformation of RNA in cells has been achieved using chemical probes that were developed to react specifically with flexible RNA nucleotides, or the Watson-Crick face of single-stranded nucleotides. The most widely used probes are either selective SHAPE (2'-hydroxyl acylation and primer extension) reagents that probe nucleotide flexibility, or dimethyl sulfate (DMS), which probes the base-pairing at adenine and cytosine but is unable to interrogate guanine or uracil. The constitutively charged carbodiimide N-cyclohexyl-N'-(2-morpholinoethyl)carbodiimide metho-p-toluenesulfonate (CMC) is widely used for probing G and U nucleotides, but has not been established for probing RNA in cells. Here, we report the use of a smaller and conditionally charged reagent, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), as a chemical probe of RNA conformation, and the first reagent validated for structure probing of unpaired G and U nucleotides in intact cells. We showed that EDC demonstrates similar reactivity to CMC when probing transcripts in vitro. We found that EDC specifically reacted with accessible nucleotides in the 7SK noncoding RNA in intact cells. We probed structured regions within the Xist lncRNA with EDC and integrated these data with DMS probing data. Together, EDC and DMS allowed us to refine predicted structure models for the 3’ extension of repeat C within Xist. These results highlight how complementing DMS probing experiments with EDC allows the analysis of Watson-Crick base-pairing at all four nucleotides of RNAs in their cellular context.