Project description:We present Structure-seq2, which provides nucleotide-resolution RNA structural information in vivo and genome-wide. This optimized version of our original Structure-seq method increases sensitivity and data quality by minimizing formation of a deleterious by-product, reducing ligation bias, and improving read coverage. Structure-seq2 can employ a biotinylated nucleotide to facilitate the protocol. We have benchmarked Structure-seq2 on both mRNA and rRNA structure in rice (Oryza sativa) and apply Structure-seq2 to provide evidence of hidden breaks in chloroplast rRNA and a previously unreported N1-methyladenosine (m1A) in a nuclear-encoded rRNA.
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: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:RNA binding proteins can modulate RNA secondary structures, thus participating in post-transcriptional regulation. The DEAH-box helicase 36 (DHX36) has a remarkable ability to bind and unwind RNA G-quadruplex (rG4) and duplex. However, the transcriptome-wide RNA structure dynamic induced by DHX36 and how structure change subsequently influences RNA fate remain poorly understood. Here, we first identify the endogenous binding sites and specificity of DHX36 based on binding profiles. Next, we capture in vivo RNA structuromes to investigate the structure change of DHX36-bound mRNAs following DHX36 knockout. DHX36 induces structure remodeling on not only the localized binding sites but also the other sites across the entire mRNA especially in 3’UTR. DHX36-induced more accessible structures of 3’UTR are revealed to correlate with post-transcriptional mRNA decrease. Furthermore, we demonstrate that DHX36 binding sites are enriched for N6-methyladenosine (m6A) modification and YTHDF1 binding. Finally, we experimentally validate that YTHDF1 binding is repelled to DHX36 loss-induced structure inaccessibility and YTHDF1 loss-induced mRNA stabilization could be a source of DHX36 loss-induced mRNA increase. Altogether, our findings uncover the effect of DHX36 binding on in vivo mRNA structure and propose a plausible mechanism of how RNA secondary structure change involves in post-transcriptional regulation through orchestrating YTHDF1 binding.
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:RNA binding proteins can modulate RNA secondary structures, thus participating in post-transcriptional regulation. The DEAH-box helicase 36 (DHX36) has a remarkable ability to bind and unwind RNA G-quadruplex (rG4) and duplex. However, the transcriptome-wide RNA structure dynamic induced by DHX36 and how structure change subsequently influences RNA fate remain poorly understood. Here, we first identify the endogenous binding sites and specificity of DHX36 based on binding profiles. Next, we capture in vivo RNA structuromes to investigate the structure change of DHX36-bound mRNAs following DHX36 knockout. DHX36 induces structure remodeling on not only the localized binding sites but also the other sites across the entire mRNA especially in 3’UTR. DHX36-induced more accessible structures of 3’UTR are revealed to correlate with post-transcriptional mRNA decrease. Furthermore, we demonstrate that DHX36 binding sites are enriched for N6-methyladenosine (m6A) modification and YTHDF1 binding. Finally, we experimentally validate that YTHDF1 binding is repelled to DHX36 loss-induced structure inaccessibility and YTHDF1 loss-induced mRNA stabilization could be a source of DHX36 loss-induced mRNA increase. Altogether, our findings uncover the effect of DHX36 binding on in vivo mRNA structure and propose a plausible mechanism of how RNA secondary structure change involves in post-transcriptional regulation through orchestrating YTHDF1 binding.