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:We design and test a novel di-azido LASER reagent capable enrichment through attachment of biotin with strain-promoted azide alkyne cycloaddition (SPAAC). We term this approach in vivo click LASER or icLASER. Aligned with the goal of extending transcriptome-wide measurements of RNA structure and to develop an approach that takes advantage of combinatorial RNA structure probing,we then use this novel bi-functional probe to interrogate LASER reactivity transcriptome-wide, revealing the first solvent accessibility transcriptome map. We also directly compare icSHAPE (hydroxyl acylation; flexibility) and icLASER (solvent accessibility) to demonstrate the power of utilizing them together to predict RNA-protein interactions and RNA polyadenylation.Our results demonstrate that combinatorial RNA structure probing can be employed to compliment orthogonal methods to better understand RNA structure and processing in cells transcriptome-wide.
Project description:Structure probing combined with next-generation sequencing (NGS) has provided novel insights into RNA structure-function relationships. To date such studies have focused largely on bacteria and eukaryotes, with little attention given to the third domain of life, archaea. Furthermore, functional RNAs have not been extensively studied in archaea, leaving open questions about RNA structure and function within this domain of life. With archaeal species being diverse and having many similarities to both bacteria and eukaryotes, the archaea domain has the potential to be an evolutionary bridge. In this study, we introduce a method for probing RNA structure in vivo in the archaea domain of life. We investigated the structure of ribosomal RNA (rRNA) from Methanosarcina acetivorans, a well-studied anaerobic archaeal species, grown with either methanol or acetate. After probing the RNA in vivo with dimethyl sulfate (DMS), Structure-seq2 libraries were generated, sequenced, and analyzed. We mapped the reactivity of DMS onto the secondary structure of the ribosome, which we determined independently with comparative analysis, and confirmed the accuracy of DMS probing in M. acetivorans. Accessibility of the rRNA to DMS in the two carbon sources was found to be quite similar, although some differences were found. Overall, this study establishes the Structure-seq2 pipeline in the archaea domain of life and informs about ribosomal structure within M. acetivorans.
Project description:To accelerate previous RNA structure probing approaches, which focus on analyzing one RNA sequence at a time, we have developed FragSeq, a high-throughput RNA structure probing method that uses high-throughput RNA sequencing to identify single-stranded RNA (ssRNA) regions from fragments generated by nuclease P1, which is specific for single-stranded nucleic acids. In the accompanying study, we show that we can accurately and simultaneously map ssRNA regions in multiple non-coding RNAs with known structure in experiments probing the entire mouse nuclear transcriptome. We carried out probing in two cell types to assess reproducibility. We also identified and experimentally validated structured regions in ncRNAs never previously probed.
Project description:We present an approach for globally monitoring RNA structure in native conditions in vivo with single nucleotide precision. This method is based on in vivo modification with dimethyl sulfate (DMS), which reacts with unpaired adenine and cytosine residues9, followed by deep sequencing to monitor modifications. Our data from yeast and mammalian cells are in excellent agreement with known mRNA structures and with the high-resolution crystal structure of the Saccharomyces cerevisiae ribosome10. Comparison between in vivo and in vitro data reveals that in rapidly dividing cells there are vastly fewer structured mRNA regions in vivo than in vitro. Even thermostable RNA structures are often denatured in cells, highlighting the importance of cellular processes in regulating RNA structure. Indeed, analysis of mRNA structure under ATP-depleted conditions in yeast reveals that energy-dependent processes strongly contribute to the predominantly unfolded state of mRNAs inside cells. Our studies broadly enable the functional analysis of physiological RNA structures and reveal that, in contrast to the Anfinsen view of protein folding, thermodynamics play an incomplete role in determining mRNA structure in vivo. We use Dimethyl Sulfate to probe the structure of rRNA and mRNA in yeast in vivo, in vitro, and at different temperatures in vitro. We obtain a great agreement between in vivo data and known mRNA structures as well as the ribosome crystal structure. We find that in contrast to ribosomal rna, mRNAs are less structured in vivo than in vitro, and the structures present in vivo can only partially be explained by thermodynamic stability. In addition, we identify new regulatory structures present in vivo. Examination of RNA structure in yeast under different conditions - in vivo and in vitro at five different temperatures (30,45,60,75,95) We adapt our DMS-seq assay for use in mammalian cells and probe RNA structure genome-wide in K562 cells. We probe the RNA structure of primary fibroblast using DMS on a genome-wide scale to confirm the presence of more structures in vitro. In addition we probe the RNA structure in yeast upon ATP depleted conditions to investigate whether active (ATP-dependent) processed are modulating RNA structure in vivo.
Project description:To accelerate previous RNA structure probing approaches, which focus on analyzing one RNA sequence at a time, we have developed FragSeq, a high-throughput RNA structure probing method that uses high-throughput RNA sequencing to identify single-stranded RNA (ssRNA) regions from fragments generated by nuclease P1, which is specific for single-stranded nucleic acids. In the accompanying study, we show that we can accurately and simultaneously map ssRNA regions in multiple non-coding RNAs with known structure in experiments probing the entire mouse nuclear transcriptome. We carried out probing in two cell types to assess reproducibility. We also identified and experimentally validated structured regions in ncRNAs never previously probed. We examined mouse nuclear RNA from two cell types: undifferentiated embryonic stem cells (UNDIFF) and cells differentiated into neural precursors (D5NP). For each cell type, nuclear RNA was purified and deproteinized, denatured, and refolded in vitro, from which we prepared three barcoded samples: "nuclease" (RNA partially digested with P1 ssRNA-specific nuclease, yielding 5'-PO4/3'-OH end chemistry at each cleavage site), "control" (control for "nuclease" sample to idenfity endogenous 5'-PO4/3'-OH), and "PNK" (same as "control" but followed by a polynucleotide kinase treatment to convert 5'-OH/3'-cyclic-phosphate ends to clonable 5'-PO4/3'-OH ends). Resulting RNA fragments were cloned using the SOLiD Small RNA Expression Kit (SREK) protocol, which ligates linkers only to 5'-PO4/3'-OH containing RNA, enriching for clones of products resulting from P1 cleavage in "nuclease" sample and selecting against random degradation. Two cell types, three treatments each, thus resulted in six barcoded samples total (barcodes 01, 02, 04, 05, 07, 08). Four other barcoded samples were prepared for separate experiments not used in our study (barcodes 03, 06, 09, 10), so their preparation is not described here. The total run of ten barcodes was done on the ABI SOLiD3 platform and a custom algorithm (FragSeq v0.0.1) was used to compute "cutting scores" (as described in our paper) that show ssRNA regions in hundreds of ncRNAs.