Project description:Understanding the targeting and spreading patterns of lncRNAs on chromatin requires a technique that can detect both high intensity binding sites and reveal genome-wide spreading patterns with high confidence. We developed an improved hybridization capture protocol to determine lncRNA localization using biotinylated LNA-containing oligonucleotides that hybridize to the target RNA and enhance capture specificity by including a protecting oligonucleotide that competitively displaces contaminating species, leading to highly specific RNA capture. This approach revealed the spreading pattern of roX2, a lncRNA involved in dosage compensation in D. melanogaster, how this pattern relates to chromatin features, and how spreading of roX2 changes upon cellular stress. Upon heat shock, roX2 displays reduced spreading on X chromosome and surprising relocalization to sites on autosomes, revealing how this improved hybridization capture approach can reveal previously uncharacterized changes in the targeting and spreading of lncRNAs on chromatin.
Project description:Understanding the targeting and spreading patterns of lncRNAs on chromatin requires a technique that can detect both high intensity binding sites and reveal genome-wide spreading patterns with high confidence. We developed an improved hybridization capture protocol to determine lncRNA localization using biotinylated LNA-containing oligonucleotides that hybridize to the target RNA and enhance capture specificity by including a protecting oligonucleotide that competitively displaces contaminating species, leading to highly specific RNA capture. This approach revealed the spreading pattern of roX2, a lncRNA involved in dosage compensation in D. melanogaster, how this pattern relates to chromatin features, and how spreading of roX2 changes upon cellular stress. Upon heat shock, roX2 displays reduced spreading on X chromosome and surprising relocalization to sites on autosomes, revealing how this improved hybridization capture approach can reveal previously uncharacterized changes in the targeting and spreading of lncRNAs on chromatin. This SuperSeries is composed of the SubSeries listed below.
Project description:Accumulating evidence highlights the role of long non-coding RNAs (lncRNA) in cellular homeostasis, and their dysregulation in disease settings. Most lncRNAs function by interacting with proteins or protein complexes. While several orthogonal methods have been developed to identify these proteins, each method has its inherent strengths and limitations. Here, we combine two RNA-centric methods ChIRP-MS and RNA-BioID to obtain a comprehensive list of proteins that interact with the well-known lncRNA HOTAIR. Overexpression of HOTAIR has been associated with a metastasis-promoting phenotype in various cancers. Although HOTAIR is known to bind with PRC2 and LSD1 protein complexes, an unbiased and comprehensive method to map its interactome has not yet been performed. Both ChIRP-MS and RNA-BioID data sets show an association of HOTAIR with mitoribosomes, suggesting HOTAIR has functions independent of its (post-)transcriptional mode-of-action.
Project description:Understanding the targeting and spreading patterns of lncRNAs on chromatin requires a technique that can detect both high intensity binding sites and reveal genome-wide spreading patterns with high confidence. We developed an improved hybridization capture protocol to determine lncRNA localization using biotinylated LNA-containing oligonucleotides that hybridize to the target RNA and enhance capture specificity by including a protecting oligonucleotide that competitively displaces contaminating species, leading to highly specific RNA capture. This approach revealed the spreading pattern of roX2, a lncRNA involved in dosage compensation in D. melanogaster, how this pattern relates to chromatin features, and how spreading of roX2 changes upon cellular stress. Upon heat shock, roX2 displays reduced spreading on X chromosome and surprising relocalization to sites on autosomes, revealing how this improved hybridization capture approach can reveal previously uncharacterized changes in the targeting and spreading of a lncRNAs on chromatin.
Project description:The MLE DExH helicase and the roX lncRNAs are essential components of the chromatin modifying Dosage Compensation Complex (DCC) in Drosophila. To explore the mechanism of ribonucleoprotein complex assembly, we designed vitRIP, an unbiased, transcriptome-wide in vitro assay that reveals RNA binding specificity. We found that MLE has intrinsic specificity for U-rich sequences and tandem stem-loop structures. In vitro, the helicase binds and remodels many RNAs beyond its main target, roX2. Unwinding of roX2 by the helicase triggers their selective association with the DCC, via the MSL2 subunit. Whereas the core DCC alone does not show intrinsic RNA binding specificity, the presentation of remodeled roX2 by MLE induces a highly selective RNA binding surface in the unstructured C-terminus of MSL2. The exquisite selectivity of roX2 incorporation into the DCC thus originates from intimate cooperation between the helicase and the core DCC involving two distinct RNA selection principles and their mutual refinement.
Project description:Long non-coding RNAs (lncRNAs) have important regulatory roles and can function at the level of chromatin. To determine where lncRNAs bind to chromatin, we developed CHART, a hybridization-based technique that specifically enriches endogenous RNAs along with their targets from reversibly-crosslinked chromatin extracts. CHART was used to enrich the DNA and protein targets of endogenous lncRNAs from fly and human. This analysis was extended to genome-wide mapping of roX2, a well-studied ncRNA involved in dosage-compensation in Drosophila. CHART revealed that roX2 binds at specific genomic sites that coincide with the binding sites of proteins from the MSL-complex that affects dosage compensation. These results reveal the genomic targets of roX2 and demonstrate how CHART can be used to study RNAs in a manner analogous to ChIP for proteins. Examination of the binding sites of roX2 ncRNA from S2 cells using two different elution strategies compared with a sense control or input control. Processed data file 'roX2.2.peaks.bed' (for roX2 CHART RNase eluted, combined replicates) linked below as supplementary file.
Project description:Mass spectrometry based screening for interaction of lncRNA mitolnc with mitochondrial proteins using UV crosslinking and hydrofluoric acid mediated (HF) degradation of RNA
Project description:Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a long non-coding RNA (lncRNA) that was first discovered as a prognostic marker for lung cancer metastasis. MALAT1 has been implicated in the tumorigenesis of numerous tumor types. To further delineate the underlying molecular mechanism, we established a high-throughput strategy to characterize the interacting proteins of MALAT1 by combining RNA pull down, quantitative proteomics, bioinformatics analysis, and experimental validation.
Project description:In neurons, mRNAs and associated RNA-binding proteins assemble into ribonucleoprotein (RNP) granules essential to regulate mRNA trafficking, local translation, and turnover. Dysregulation of RNA-protein condensation can disturb synaptic plasticity. We report that the novel lncRNA mimi is a constitutive and essential component of large cytoplasmic condensates (RNP granules) in fly neurons. In order to identify direct mimi RNA binders we employ RAP assisted purification of mimi RNPs subsequent to UV-crosslinking of adult fly brain tissue (non UV irradiated samples serve as control). Applying relative Max Quant LFQ quantification (Max LFQ) we carry out a differential proteomic analysis of mimi RNP complexes in UV-irradiated versus non irradiated fly brains.