RNA interactome capture in E. coli to identify RNA-binding proteins
Ontology highlight
ABSTRACT:
ORGANISM(S): Escherichia coli str. K-12 substr. MG1655
PROVIDER: GSE217569 | GEO | 2022/11/13
REPOSITORIES: GEO
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Project description:RNA-binding proteins (RPBs) are deeply involved in many fundamental cellular processes in bacteria and are vital for their survival. Despite this, few studies have so far been dedicated to globally identifying bacterial RBPs. We have adapted the RNA interactome capture (RIC) technique, originally developed for eukaryotic systems, to globally identify RBPs in bacteria. RIC takes advantage of the base pairing potential of poly(A) tails to pull-down mRNA-protein complexes. By overexpressing the poly(A) polymerase I, we drastically increase the frequency of polyadenylated RNA in E. coli, allowing us to pull down RNA-protein complexes using immobilized oligo-d(T) as bait. With this approach, we identified 167 putative RBPs, roughly half of which are already annotated as RNA-binding. We experimentally verified the RNA-binding ability of several proteins previously unknown to interact with RNA, including the uncharacterized protein YhgF. YhgF is exceptionally well conserved not only in bacteria, but also in archaea and eukaryotes. We identified YhgF in vivo RNA targets using CLIP-seq, two of which were verified using electromobility shift assays. Our findings present a simple and robust strategy for RBP identification in bacteria, provide a resource of new bacterial RBPs, and lays the foundation for further studies of the strongly conserved RBP Yhg
2023-03-30 | PXD032939 | Pride
Project description:Here, we performed RNA-interactome capture (RIC) on nuclear fractions from human embryonic stem cells (hESCs). The poly(A)+ RNA-bound proteome was determined by UV light-mediated cross-linking (CL) of RNAs to proteins in living cells, followed by nuclei isolation, oligo(dT) purification of poly(A)-RNA-protein complexes, and mass spectrometry analysis of captured proteins. As a control, we applied a similar strategy to non-cross-linked (non-CL) samples. RIC was performed in four independent biological replicates. This data accompanies the manuscript: "Uncovering the RNA-binding protein landscape in the pluripotency network of human embryonic stem cells". Abstract: "Embryonic stem cell (ESC) self-renewal and cell-fate decisions are driven by a broad array of molecular signals. While transcriptional regulators have been extensively studied in human ESCs (hESCs), the extent to which RNA-binding proteins (RBPs) contribute to human pluripotency remains unclear. Here, we carry out a proteome-wide screen and identify 810 proteins that directly bind RNA in hESCs. We reveal that RBPs are preferentially expressed in hESCs and dynamically regulated during exit from pluripotency and early lineage specification. Moreover, we show that nearly 200 RBPs are affected by knockdown of OCT4, a master regulator of pluripotency, several dozen of which are directly bound by this factor. Intriguingly, over 20 percent of the proteins detected in our study are putative DNA- and RNA-binding proteins (DRBPs), among them key transcription factors (TFs). Using fluorescently labeled RNA and seCLIP (single-end enhanced crosslinking and immunoprecipitation) experiments, we discover that the pluripotency-associated STAT3 and OCT4 TFs interact with RNA in hESCs and confirm the direct binding of STAT3 to the conserved NORAD long-noncoding RNA. Taken together, our findings indicate that RBPs have a more widespread role in human pluripotency than previously appreciated, reinforcing the importance of post-transcriptional regulation in stem cell biology".
2023-05-05 | PXD025262 | Pride
Project description:RNA-binding proteins (RBPs) play important roles in bacterial gene expression and physiology but their true number and functional scope remain little understood even in model microbes. To advance global RBP discovery in bacteria, we here establish glycerol gradient sedimentation with RNase treatment and mass spectrometry (GradR). Applied to Salmonella enterica, GradR confirms many known RBPs by their RNase-sensitive sedimentation profiles, and discovers the FopA protein as a new member of the emerging family of FinO/ProQ-like RBPs. FopA, encoded on resistance plasmid pCol1B9, primarily targets a small RNA associated with plasmid replication. The target suite of FopA dramatically differs from the related global RBP ProQ, revealing context-dependent selective RNA recognition by FinO-domain RBPs. Numerous other unexpected RNase-induced changes in gradient profiles suggest that cellular RNA helps to organize macromolecular complexes in bacteria. By enabling poly(A)-independent generic RBP discovery, GradR provides an important element for building a comprehensive catalogue of microbial RBPs.
2020-07-16 | PXD018422 | Pride
Project description:RNA-binding proteins (RBPs) have been relatively overlooked in cancer research despite their contribution to virtually every cancer hallmark. Here, we use RNA interactome capture (RIC) to characterize the melanoma RBPome and uncover novel RBPs involved in melanoma progression. Comparison of RIC profiles of two melanoma cell lines with different aggressiveness revealed prevalent changes in RNA binding capacities that were not associated with changes in RBP levels. Extensive functional validation of a selected group of 24 RBPs using five different in vitro assays unveiled unanticipated roles of RBPs in melanoma malignancy. As proof-of-principle we focused on PDIA6, an ER-lumen chaperone that displayed a novel RNA-binding activity. We show that PDIA6 is involved in metastatic progression and map its RNA-binding domain, which we find to be required for PDIA6 tumorigenic properties. These results exemplify how RIC technologies can be harnessed to uncover novel vulnerabilities of cancer cells
2022-07-11 | GSE174821 | GEO
Project description:RNA-binding proteins (RBPs) have been relatively overlooked in cancer research despite their contribution to virtually every cancer hallmark. Here, we use RNA interactome capture(RIC) to characterize the melanoma RBPome and uncover novel RBPs involved in melanoma progression. Comparison of RIC profiles of two melanoma cell lines with different aggressiveness revealed prevalent changes in RNA binding capacities that were not associated with changes in RBP levels. Extensive functional validation of a selected group of 24 RBPs using five differentin vitroassays unveiled unanticipated roles of RBPs in melanoma malignancy. As proof-of-principle we focused on PDIA6, an ER-lumen chaperone that displayed a novel RNA-binding activity. We show that PDIA6 is involved in metastatic progression and map its RNA-binding domain, which we find to be required for PDIA6 tumorigenic properties. These results exemplify how RIC technologies can be harnessed to uncover novelvulnerabilities of cancer cells.
2022-07-19 | PXD029927 | Pride
Project description:Embryonic stem cell (ESC) self-renewal and cell-fate decisions are driven by a broad array of molecular signals. While transcriptional regulators have been extensively studied in human ESCs (hESCs), the extent to which RNA-binding proteins (RBPs) contribute to human pluripotency remains unclear. Here, we carried out a proteome-wide screen and identified 810 proteins that directly bind RNA in hESCs. We determined the RBP catalog by using RNA-interactome capture (RIC), a method based on UV light-mediated cross-linking (CL) of RNAs to proteins in living cells, followed by oligo(dT) purification of poly(A)-RNA-protein complexes and mass spectrometry analysis of captured proteins. As control, we applied a similar strategy to non-cross-linked (non-CL) samples. To uncover the identity of the eluted proteins, we performed in-solution tryptic digestion of CL and non-CL eluates and analyzed their contents by a high-resolution mass spectrometer (Q-Exactive Plus). We then performed differential proteome analysis between CL and non-CL eluates, resulting in a set of 810 high-confidence protein groups, defined as the hESC RNA-interactome. RIC was carried out in four independent biological replicates. This data accompanies the manuscript: "Uncovering the RNA-binding protein landscape in the pluripotency network of human embryonic stem cells".
2023-05-05 | PXD025194 | Pride
Project description:Recent methodological advances allowed the identification of an increasing number of RNAbinding proteins (RBPs) and their RNA-binding sites. RNA interactome capture is, however, limited to proteins interacting with polyadenylated RNAs while RBPs associating with nonadenylate RNA classes cannot be purified. Moreover, the vast majority of species that lack poly-A tails in their mRNAs (including all archea and bacteria) are not amenable to RNA interactome capture studies. To overcome these limitations, we have developed a novel protocol, Phenol Toluol extraction (PTex), that does not rely on a specific RNA sequence or motif for isolation of cross-linked ribonucleoproteins (RNPs), but rather purifies them based entirely on their physicochemical properties. PTex captures RBPs that bind to poly-A RNA, but also proteins associating with non-adenylate RNA species (rRNA, tRNA) as short as 30nt. PTex can be used to simplify complex work ows such as PAR-CLIP and reliably recovers RBPs from tissues and bacteria thus significantly expanding the experimental toolbox to species that could previously not be assessed experimentally.
2019-03-12 | PXD009571 | Pride
Project description:The compendium of RNA-binding proteins (RBPs) has been greatly expanded by the development of RNA interactome capture (RIC). However, it remained unknown if the complement of RBPs changes in response to environmental perturbations and whether these rearrangements are important. To answer these questions, we developed ‘comparative RIC’ and applied it to cells challenged with an RNA virus, called sindbis (SINV). Over two hundred RBPs display differential interaction with RNA upon SINV infection. These alterations are mainly driven by the loss of cellular mRNAs and the emergence of viral RNA. RBPs stimulated by the infection redistribute to viral replication factories and regulate the capacity of the virus to infect. For example, ablation of XRN1 causes cells to be refractory to SINV, while GEMIN5 moonlights as a regulator of SINV gene expression. In summary, RNA availability controls RBP localisation and function in SINV-infected cells.
2019-02-21 | GSE125182 | GEO
Project description:Much of our current knowledge about cellular RNA–protein complexes in bacteria is derived from analyses in gram-negative model organisms, with the discovery of RNA-binding proteins (RBPs) generally lagging behind in Gram-positive species. Here, we have applied Grad-seq analysis of native RNA–protein complexes to a major Gram-positive human pathogen, Clostridioides difficile, whose RNA biology remains largely unexplored. Our analysis resolves in-gradient distributions for ∼88% of all annotated transcripts and ∼50% of all proteins, thereby providing a comprehensive resource for the discovery of RNA–protein and protein–protein complexes in C. difficile and related microbes. The sedimentation profiles together with pulldown approaches identify KhpB, previously identified in Streptococcus pneumoniae, as an uncharacterized, pervasive RBP in C. difficile. Global RIP-seq analysis establishes a large suite of mRNA and small RNA targets of KhpB, similar to the scope of the Hfq targetome in C. difficile. The KhpB-bound transcripts include several functionally related mRNAs encoding virulence-associated metabolic pathways and toxin A whose transcript levels are observed to be increased in a khpB deletion strain. Moreover, the production of toxin protein is also increased upon khpB deletion. In summary, this study expands our knowledge of cellular RNA protein interactions in C. difficile and supports the emerging view that KhpB homologues constitute a new class of globally acting RBPs in Gram-positive bacteria.
2021-05-01 | GSE165672 | GEO
Project description:The general role of RNA in the cell beyond protein biosynthesis is only beginning to emerge with little knowledge about the structural or organizational functions of RNA. In turn, functional non-coding RNAs (ncRNAs) are often identified by their regulation or impact on cellular phenotypes. However, the huge number and diversity of ncRNAs highly complicate the task of their molecular characterization and rationalization into cellular processes. For the vast majority of ncRNAs as well as for non-coding functions of known mRNAs, the mechanisms underlying their modes of action as well as their impact on protein complexes are unknown. Thus, the greatest challenge in the field of RNA biology today is the elucidation of molecular mechanisms and functional interaction partners of RNA molecules.
Since RNAs do not act alone, but often interact with specific protein partners, proteomic approaches have been developed to study RNA-binding proteins (RBPs) and aim at revealing the molecular mechanisms underlying RNA function. Large-scale studies aiming at globally identifying RNA-binding proteins principally focused on poly(A)-RNA transcripts. A notable limitation of such approaches is that many ncRNAs are not polyadenylated, so that their interaction partners were not detected in these screens. Most importantly however, the overlap between the numerous studies aiming to identify RBPs is limited and their specificity remains unclear. Moreover, the previous studies were based on the identification of RBPs omitting their participation in protein-protein complexes and more interestingly in RNA-dependent protein-protein complexes.
Here, we introduce the concept of "RNA dependence" to overcome these challenges. We define a protein as RNA-dependent if its interactome (hence likely its function) depends on RNA without necessarily directly binding to RNA. Based on this new concept, we developed a proteome-wide screening approach to gain mechanistic insight into the function of RNAs - both coding and non-coding - in RNA-protein complexes and their impact on the function of such complexes.
2018-06-13 | MSV000082468 | MassIVE