RNA tertiary structure and conformational dynamics revealed by BASH MaP
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ABSTRACT:
PROVIDER: PRJNA1133698 | ENA |
REPOSITORIES: ENA
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Project description:The functional effects of an RNA can arise from complex three-dimensional folds known as tertiary structures. However, predicting the tertiary structure of an RNA and whether an RNA adopts distinct tertiary conformations remains challenging. To address this, we developed BASH MaP, a single-molecule dimethyl sulfate (DMS) footprinting method and DAGGER, a computational pipeline, to identify alternative tertiary structures adopted by different molecules of RNA. BASH MaP utilizes potassium borohydride to reveal the chemical accessibility of the N7 position of guanosine, a key mediator of tertiary structures. We used BASH MaP to identify diverse conformational states and dynamics of RNA G-quadruplexes, an important RNA tertiary motif, in vitro and in cells. BASH MaP and DAGGER analysis of the fluorogenic aptamer Spinach reveals that it adopts alternative tertiary conformations which determine its fluorescence states. BASH MaP thus provides an approach for structural analysis of RNA by revealing previously undetectable tertiary structures.
2024-10-14 | GSE271825 | 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:We show that DANCE-MaP permits measurement of state-specific per-nucleotide reactivities, direct secondary structure PAIRs, and tertiary RINGs for RNA structural ensembles. Here, we demonstrate DANCE-MaP on the V. vulnificus add riboswitch.
2022-03-23 | GSE182552 | GEO
Project description:New regulatory roles continue to emerge for both natural and engineered noncoding RNAs, many of which have specific secondary and tertiary structures essential to their function. Thus there is a growing need to develop technologies that enable rapid characterization of structural features within complex RNA populations. We have developed a high-throughput technique, SHAPE-Seq, that can simultaneously measure quantitative, single nucleotide-resolution secondary and tertiary structural information for hundreds of RNA molecules of arbitrary sequence. SHAPE-Seq combines selective 2â²-hydroxyl acylation analyzed by primer extension (SHAPE) chemistry with multiplexed paired-end deep sequencing of primer extension products. This generates millions of sequencing reads, which are then analyzed using a fully automated data analysis pipeline, based on a rigorous maximum likelihood model of the SHAPE-Seq experiment. We demonstrate the ability of SHAPE-Seq to accurately infer secondary and tertiary structural information, detect subtle conformational changes due to single nucleotide point mutations, and simultaneously measure the structures of a complex pool of different RNA molecules. SHAPE-Seq thus represents a powerful step toward making the study of RNA secondary and tertiary structures high throughput and accessible to a wide array of scientific pursuits, from fundamental biological investigations to engineering RNA for synthetic biological systems. We sequenced in-vitro transcribed RNaseP in wild type and barcoded variants and probed them with SHAPE-Seq. Comparison to existing crystalography data and previous SHAPE experiments verified the accuracy of the technique and the absence of bias due to our multiplexiing strategy.
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Project description:The key role of tertiary lymphoid structures in autoimmune and non-autoimmune conditions has been recently appreciated. While many of the molecular mechanisms involved in tertiary lymphoid structure formation have been identified, their cellular sources and temporal and spatial relationship remain unknown. Using single-cell RNA-sequencing, spatial transcriptomics and proteomics of minor salivary glands of patients with Sjogren’s disease and Sicca Syndrome, ex-vivo and in vivo functional studies, we construct a cellular and spatial map of key components involved in the formation and function of tertiary lymphoid structures. We confirm the presence of a fibroblast cell state and identify an undescribed pericyte/mural cell state with potential immunological functions. The identification of novel cellular properties associated with these structures and the molecular and functional interactions identified by this analysis provide key therapeutic cues for tertiary lymphoid structures associated conditions in autoimmunity and cancer.
2024-07-17 | GSE272409 | GEO
Project description:The key role of tertiary lymphoid structures in autoimmune and non-autoimmune conditions has been recently appreciated. While many of the molecular mechanisms involved in tertiary lymphoid structure formation have been identified, their cellular sources and temporal and spatial relationship remain unknown. Using single-cell RNA-sequencing, spatial transcriptomics and proteomics of minor salivary glands of patients with Sjogren’s disease and Sicca Syndrome, ex-vivo and in vivo functional studies, we construct a cellular and spatial map of key components involved in the formation and function of tertiary lymphoid structures. We confirm the presence of a fibroblast cell state and identify an undescribed pericyte/mural cell state with potential immunological functions. The identification of novel cellular properties associated with these structures and the molecular and functional interactions identified by this analysis provide key therapeutic cues for tertiary lymphoid structures associated conditions in autoimmunity and cancer.
2024-07-17 | GSE272410 | GEO
Project description:Pyk2 is a multidomain non-receptor tyrosine kinase that undergoes a complex, multi-stage activation process. Ca2+-flux induces conformational rearrangements that relieve autoinhibitory FERM domain interactions. The kinase domain phosphorylates a key linker residue to recruit Src kinase. Pyk2 and Src mutually phosphorylate activation loop residues to confer full activation. While the mechanisms of autoinhibition are established, the conformational dynamics associated with autophosphorylation and Src recruitment remain unclear. Here, we employ hydrogen/deuterium exchange mass spectrometry (HDX-MS) to map the conformational changes associated with Src-mediated activation segment phosphorylation in a Pyk2 construct encompassing FERM and kinase domains (residues 20-692). Results reveal increased dynamics at regulatory interfaces spanning FERM and kinase domains. Phosphorylation of the activation segment stabilizes two antiparallel beta strands linking activation and catalytic loops. Increased dynamics of the C-terminal end of the activation loop propagate to the F-helix, explaining how phosphorylation prevents reversion to the autoinhibitory FERM interaction. HDX-guided site-directed mutagenesis and kinase activity profiling establish a mechanism for phosphorylation-induced active site sculpting to confer high activity.
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Project description:Nicotinamide nucleotide transhydrogenases are integral membrane proteins that utilizes the proton motive force to reduce NADP+ to NADPH while converting NADH to NAD+. Atomic structures of various transhydrogenases in different ligand-bound states have become available, and it is clear that the molecular mechanism involves major conformational changes. Here we utilized hydrogen-deuterium-exchange mass spectrometry (HDX-MS) to map ligand binding sites and analyzed the structural dynamics of E. coli transhydrogenase. We found different allosteric effects on the protein depending on the bound ligand (NAD+, NADH, NADP+, NADPH). The binding of either NADP+ or NADPH to domain III had pronounced effects on the transmembrane helices comprising the proton-conducting channel in domain II. We also made use of cyclic ion mobility separation mass spectrometry (cyclic IMS-MS) to maximize coverage and sensitivity in the transmembrane domain, showing for the first time that this technique can be used for HDX-MS studies. Using cyclic IMS-MS, we increased sequence coverage from 68% to 73% in the transmembrane segments. Taken together, our results provide important new insights into the transhydrogenase reaction cycle and demonstrate the benefit of this new technique for HDX-MS to study ligand binding and conformational dynamics in membrane proteins.
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Project description:The presence of B cells in tumors have been recently reported to predict the better prognosis of patients with cancer. B cells were found primarily in so-called tertiary lymphoid structures (TLSs) in tumor. TLSs are ectopic lymphoid aggregates that form at sites of micro-secondary lymphoid organs, including a B cell follicle with a network of follicular dendritic cells (FDCs) surrounded by T cell zone composed of CD4+ T follicular helper (Tfh) cells and CD8+ T cells and high endothelial venules (HEVs). The presence of TLS is associated with positive outcomes in several human malignancie and More importantly, TLSs enriched in B cells have been proven beneficial for response to ICB in multiple types of cancer. Here, we establish tobacco-associated HNSCC mouse model with TLS enrichment by overexpression of LIGHT in tumor to evaluate the TLS influence in HPV- HNSCC and immunotherapy in HPV- HNSCC.
2022-03-03 | GSE197559 | GEO
Project description:The discovery of tertiary lymphoid structures (TLS) within the tumor tissues provides a promising avenue to promote the response rate of cancer immunotherapy. Yet, the lack of effective strategies to promote TLS formation poses a substantial obstacle. Thus, the exploration of potential inducers for TLS formation is of great interest but remains challenging. Here, inspired by the mechanism of artificially cultivated pearls, a covalent organic frameworks (COFs) was employed to promote the formation of TLS. Single-cell sequencing analysis revealed that this was achieved by promoting the cytokine hypersecretion to facilitate the maturation, proliferation, and migration of T and B cells, critical for trigger TLS formation. Furthermore, the high efficacy of COF-mediated phototherapy in inducing TLS formation was validated in both the MC38 and 4MOSC1 tumor models. Moreover, an efficient synergism between COF-mediated phototherapy and αCTLA-4 was observed, which was able to effectively eradicate both primary and distant tumors, and inhibit tumor recurrence. This study underscores a new approach of boosting cancer immunotherapy through COF triggered TLS formation.
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