Cross-linking ligation and sequencing of hybrids (qCLASH) reveals an unpredicted miRNA targetome in melanoma cells
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ABSTRACT: In the quick cross-linking ligation and sequencing of hybrids (qCLASH) protocol, RNA-protein (RNP) complexes of interest are UV cross-linked in living cells. The protein of interest is purified by immunoprecipitation (in this case, AGO bound to the miRNA and the target gene). The two interacting RNA molecules (e.g. miRNA-mRNA) are physically bound to each other by intermolecular RNA-RNA ligation, followed by library preparation and sequencing oh hybrids.
Project description:We employ multi-step affinity purification followed by high-throughput sequencing to determine the location of EJC complexes assembled on a cellular transcriptome in Drosophila S2 cells, finding 6% of the intron-containing genes were not associated with EJCs, and within genes with multiple introns, only specific exon-exon junctions assembled an EJC. RIP-Seq, 3 samples
Project description:microRNAs (miRNAs) are essential components of gene regulation, but identification of miRNA targets remains a major challenge. Most target prediction and discovery relies on perfect complementarity of the miRNA seed to the 3’ untranslated region (UTR). However, it is unclear to what extent miRNAs target sites without seed matches. Here, we performed a transcriptome-wide identification of the endogenous targets of a single miRNA—miR-155—in a genetically controlled manner. We found that approximately forty percent of miR-155-dependent Argonaute binding occurs at sites without perfect seed matches. The majority of these non-canonical sites feature extensive complementarity to the miRNA seed with one mismatch. These non-canonical sites confer regulation of gene expression albeit less potently than canonical sites. Thus, non-canonical miRNA binding sites are widespread, often contain seed-like motifs, and can regulate gene expression, generating a continuum of targeting and regulation. Argonaute (AGO) HITS-CLIP Libraries generated from wild type and miR-155 knockout activated T cells. AGO HITS-CLIP libraries were generated from activated wild type and miR-155 knockout T cells with two different 3' linkers. Libraries were generated and sequenced with an 11nt index read that contained both a 5nt multiplexing index and a 6nt degenerate barcode. Files have been demultiplexed and the 6nt degenerate barcode has been appended as the first 6 nucleotides of the read.
Project description:Purpose: The establishment of cell lineages occurs via a dynamic progression of gene regulatory networks that underlie developmental commitment and differentiation. To investigate how microRNAs (miRs) function in this process, we compared miRs and miR targets at the initiation of the two major ectodermal lineages in Xenopus. Methods: We injected Xenopus laevis embryos with noggin or constitutively active BMP4 receptor (CABR) at two-cell stage and cut animal caps at stg. 8. Isolated animal caps were grown separately till mid gastrula and processed for either RNA isolation or immunoprecipitation. Results: We have identified over 400 miRNAs in early neural and epidermal ectoderm. The Ago-RNP RNAs from these tissues represent overlapping, yet distinct, subsets of genes. Moreover, the profile of Ago-RNP associated genes differs substantially from the profile of total RNAs in these tissues. Identification of microRNAs and microRNA targets in establishment of early ectodermal tissues in Xenopus.
Project description:S2 cells were infected with FHV deltaB2 particle and the S2 cells were harvested to isolate total RNA at 96 hpi. Small RNAs were separated on a denaturing 15% polyacrylamide gel. Ligation to adapters requires 5' monophosphate and 3' OH. Note: The base quality (.qual) file corresponding to the fasta format (.fna) file linked to Sample GSM306489 is unavailable. Small RNAs were sequenced from S2 cell after virus infection.
Project description:We performed Ago HITS-CLIP to identify targets of viral and human miRNAs in latently KSHV-infected PEL cells Ago HITS-CLIP was performed in two latently infected PEL cell lines, BCBL-1 and BC-3; Argonaute-immunoprecipitation of UV cross-linked Ago-miRNA-mRNA complexes, followed by RNA isolation, library construction, and high-throughput sequencing (Illumina GAxII); we performed 3 biological replicates for each cell line, two technical (sequencing) replicates of BCBL-1 biological replicate 1
Project description:During metaphase, in response to improper kinetochore-microtubule attachments, the spindle assembly checkpoint (SAC) activates the mitotic checkpoint complex (MCC) to inhibit the anaphase-promoting complex/cyclosome (APC/C). The Mad1-Mad2 complex provides a catalytic platform for MCC assembly. Mad1-bound Mad2 recruits open-Mad2 through asymmetric dimerization and Mad1 phosphorylation by Mps1 promotes conversion of Mad2 from an open (O-Mad2) to closed (C-Mad2) state, which binds Cdc20 to form the MCC. How Mad1 phosphorylation catalytically activates MCC formation is poorly understood. This study characterises Mad1 phosphorylation by Mps1 and provides structural and biochemical insights into a phosphorylation-specific Mad1-Cdc20 interaction, which allows for a tripartite assembly of Bub1-Mad1-Cdc20 on the C-terminal domain of Mad1. We also identify a folded state of Mad1-Mad2 complex, suggesting a model by which the Cdc20-Mad1 interaction brings the Cdc20 MIM motif near Mad2. The Cdc20 MIM motif is then entrapped by the Mad2 safety belt to form a stable complex, allowing spontaneous MCC assembly.
Project description:Many biological processes are regulated by RNA-RNA interactions 1, nonetheless it remains formidable to analyze the entire RNA interactome. We developed a method, MARIO (MApping Rna-rna Interactions in vivO), to map protein-assisted RNA-RNA interactions in vivo. By circumventing the selection for a specific RNA-binding protein 2-5, our approach vastly expands the identifiable portion of the RNA interactome. Using this technology, we mapped the RNA interactome in mouse embryonic stem cells, which was composed of 46,780 RNA-RNA interactions. The RNA interactome was a scale-free network, with several lincRNAs and mRNAs emerging as hubs. We validated an interaction between two hubs, Malat1 and Slc2a3 using single molecule RNA fluorescence in situ hybridization. Base pairing was observed at the interaction sites of long RNAs, and was particularly strong in transposonRNA-mRNA and lincRNA-mRNA interactions. This reveals a new type of regulatory sequences acting in trans. Consistent with their hypothesized roles, the RNA interaction sites were more evolutionarily conserved than other regions of the transcripts. MARIO also provided new information on RNA structures, by simultaneously revealing the footprint of single stranded regions and the spatially proximal sites of each RNA. The unbiased mapping of the protein-assisted RNA interactome with minimum perturbation of cell physiology will greatly expand our capacity to investigate RNA functions. Three (3) ESC samples with different treatment (different digestion size and/or crosslinking method) and one (1) MEF sample were included to test our new approach for RNA-interactome mapping and the different samples were analyzed to show RNA interactome differences between them.
Project description:The COP9 signalosome (CSN) is an evolutionarily conserved protein complex that functions as a deneddylase to inactivate Cullin-RING E3 ligases for controlling protein ubiquitination. CSN possesses structural flexibility that is important for its activation upon binding to a diverse array of CRLs. The canonical and non-canonical CSN complexes consist of 8 (CSN1-8) and 9 (CSN1-9) subunits, respectively. Although CSN9 is not essential for CSN assembly and function, it appears to be important in non-catalytic regulation of CRLs by CSN. Here we employed a combinatory cross-linking mass spectrometry (XL-MS) approach to generate the largest PPI maps of human CSN complexes, which significantly enhanced the precision of integrative structural modeling. The resulting integrative structures allowed us not only to elucidate architectures of both complexes, but also to assess CSN structural dynamics that was not described in the crystal structure. In addition, we have determined CSN9 docking sites and its impact on the CSN structure. While CSN9 binding did not induce global conformational changes, it triggered subunit local reorientations that may be associated with CSN9 involvement in CSN-mediated steric regulation of CRLs.
Project description:RNA binding proteins (RBPs) interact with RNA targets to control an array of processes, including RNA splicing, stability, transport, and translation1-3. Dysfunctional RNA-RBP interactions contribute to pathogenesis of a plethora of human diseases1,4,5, underscoring the need for a greater understanding of the nature and dynamics of RNA-protein assemblies. The capacity to study native RNA-dependent protein assemblies in living cells, however, has been limited. To address this, non-isotopic ligation-based ultraviolet crosslinking immunoprecipitation6 was combined with mass spectrometry (irCLIP-RNP) to identify RNA-dependent associated proteins (RDAPs) co-bound to RNA with specific RBPs of interest. irCLIP-RNP defined landscapes of complex and multimeric protein assemblies on RNA, uncovering previously unknown patterns of RBP associations on RNA. This included cell-type-selective patterned relationships between RDAPs and primary RBPs, such as cell context-dependent reciprocal impacts of HNRNPU and NONO on each other’s RDAP landscapes. irCLIP-RNP also defined dynamic RDAP remodeling patterns in response to epidermal growth factor (EGF) and uncovered EGF-induced recruitment of UPF1 adjacent to HNRNPC to effect splicing surveillance of mRNAs that mediate cell proliferation. The development of sequential immunoprecipitation irCLIP (RE-irCLIP) supported the same-RNA-molecule co-localization of irCLIP-RNP-identified associations. Thus, irCLIP-RNP and RE-irCLIP provide a framework to identify and characterize dynamic RNA-protein assemblies in living cells.