scholarly journals An improved iCLIP protocol

2021 ◽  
Author(s):  
Flora C. Y. Lee ◽  
Anob M. Chakrabarti ◽  
Heike Hänel ◽  
Elisa Monzón-Casanova ◽  
Martina Hallegger ◽  
...  
Keyword(s):  
Cdna Library ◽  
Binding Sites ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Library Preparation ◽  
Powerful Technique ◽  
Uv Crosslinking ◽  
Nucleotide Resolution ◽  
Cdna Library Preparation

AbstractCrosslinking and Immunoprecipitation (CLIP) is a powerful technique to obtain transcriptome-wide maps of in vivo protein-RNA interactions, which are important to understand the post-transcriptional mechanisms mediated by RNA binding proteins (RBPs). Many variant CLIP protocols have been developed to improve the efficiency and convenience of cDNA library preparation. Here we describe an improved individual nucleotide resolution CLIP protocol (iiCLIP), which can be completed within 4 days from UV crosslinking to libraries for sequencing. For benchmarking, we directly compared PTBP1 iiCLIP libraries with the iCLIP2 protocol produced under standardised conditions, and with public eCLIP and iCLIP PTBP1 data. We visualised enriched motifs surrounding the identified crosslink positions and RNA maps of these crosslinks around the alternative exons regulated by PTBP1. Notably, motif enrichment was higher in iiCLIP and iCLIP2 in comparison to public eCLIP and iCLIP, and we show how this impacts the specificity of RNA maps. In conclusion, iiCLIP is technically convenient and efficient, and enables production of highly specific datasets for identifying RBP binding sites.

scholarly journals Global identification of RsmA/N binding sites in Pseudomonas aeruginosa by in vivo UV CLIP-seq

2020 ◽  
Author(s):  
Kotaro Chihara ◽  
Lars Barquist ◽  
Kenichi Takasugi ◽  
Naohiro Noda ◽  
Satoshi Tsuneda
Keyword(s):  
Gene Expression ◽  
Pseudomonas Aeruginosa ◽  
Binding Sites ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Chronic Infections ◽  
Uv Crosslinking ◽  
Rna Interaction

ABSTRACTPosttranscriptional regulation of gene expression in bacteria is performed by a complex and hierarchical signaling cascade. Pseudomonas aeruginosa harbors two redundant RNA-binding proteins RsmA/RsmN (RsmA/N), which play a critical role in balancing acute and chronic infections. However, in vivo binding sites on target transcripts and the overall impact on the physiology remains unclear. In this study, we applied in vivo UV crosslinking immunoprecipitation followed by RNA-sequencing (UV CLIP-seq) to detect RsmA/N binding sites at single-nucleotide resolution and mapped more than 500 peaks to approximately 400 genes directly bound by RsmA/N in P. aeruginosa. This also demonstrated the ANGGA sequence in apical loops skewed towards 5’UTRs as a consensus motif for RsmA/N binding. Genetic analysis combined with CLIP-seq results identified previously unrecognized RsmA/N targets involved in LPS modification. Moreover, the small non-coding RNAs RsmY/RsmZ, which sequester RsmA/N away from target mRNAs, are positively regulated by the RsmA/N-mediated translational repression of hptB, encoding a histidine phosphotransfer protein, and cafA, encoding a cytoplasmic axial filament protein, thus providing a possible mechanistic explanation for homeostasis of the Rsm system. Our findings present the global RsmA/N-RNA interaction network that exerts pleiotropic effects on gene expression in P. aeruginosa.IMPORTANCEThe ubiquitous bacterium Pseudomonas aeruginosa is notorious as an opportunistic pathogen causing life-threatening acute and chronic infections in immunocompromised patients. P. aeruginosa infection processes are governed by two major gene regulatory systems, namely, the GacA/GacS (GacAS) two-component system and the RNA-binding proteins RsmA/RsmN (RsmA/N). RsmA/N basically function as a translational repressor or activator directly by competing with the ribosome. In this study, we identified hundreds of RsmA/N regulatory target RNAs and the consensus motifs for RsmA/N bindings by UV crosslinking in vivo. Moreover, our CLIP-seq revealed that RsmA/N posttranscriptionally regulate cell wall organization and exert feedback control on GacAS-RsmA/N systems. Many genes including small regulatory RNAs identified in this study are attractive targets for further elucidating the regulatory mechanisms of RsmA/N in P. aeruginosa.

scholarly journals Modeling RNA-binding protein specificity in vivo by precisely registering protein-RNA crosslink sites

2018 ◽  
Author(s):  
Huijuan Feng ◽  
Suying Bao ◽  
Sebastien M. Weyn-Vanhentenryck ◽  
Aziz Khan ◽  
Justin Wong ◽  
...  
Keyword(s):  
Binding Sites ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Binding Specificity ◽  
Computational Method ◽  
Sr Protein ◽  
Genome Wide ◽  
Sequence Elements ◽  
Nucleotide Resolution

AbstractRNA-binding proteins (RBPs) regulate post-transcriptional gene expression by recognizing short and degenerate sequence elements in their target transcripts. Despite the expanding list of RBPs with in vivo binding sites mapped genomewide using crosslinking and immunoprecipitation (CLIP), defining precise RBP binding specificity remains challenging. We previously demonstrated that the exact protein-RNA crosslink sites can be mapped using CLIP data at single-nucleotide resolution and observed that crosslinking frequently occurs at specific positions in RBP motifs. Here we have developed a computational method, named mCross, to jointly model RBP binding specificity while precisely registering the crosslinking position in motif sites. We applied mCross to 112 RBPs using ENCODE eCLIP data and validated the reliability of the resulting motifs by genome-wide analysis of allelic binding sites also detected by CLIP. We found that the prototypical SR protein SRSF1 recognizes GGA clusters to regulate splicing in a much larger repertoire of transcripts than previously appreciated.

scholarly journals SSMART: Sequence-structure motif identification for RNA-binding proteins

2018 ◽  
Author(s):  
Alina Munteanu ◽  
Neelanjan Mukherjee ◽  
Uwe Ohler
Keyword(s):  
Binding Sites ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Sequence Motif ◽  
Primary Sequence ◽  
Sequence Structure ◽  
Rna Targets

AbstractMotivationRNA-binding proteins (RBPs) regulate every aspect of RNA metabolism and function. There are hundreds of RBPs encoded in the eukaryotic genomes, and each recognize its RNA targets through a specific mixture of RNA sequence and structure properties. For most RBPs, however, only a primary sequence motif has been determined, while the structure of the binding sites is uncharacterized.ResultsWe developed SSMART, an RNA motif finder that simultaneously models the primary sequence and the structural properties of the RNA targets sites. The sequence-structure motifs are represented as consensus strings over a degenerate alphabet, extending the IUPAC codes for nucleotides to account for secondary structure preferences. Evaluation on synthetic data showed that SSMART is able to recover both sequence and structure motifs implanted into 3‘UTR-like sequences, for various degrees of structured/unstructured binding sites. In addition, we successfully used SSMART on high-throughput in vivo and in vitro data, showing that we not only recover the known sequence motif, but also gain insight into the structural preferences of the RBP.AvailabilitySSMART is freely available at https://ohlerlab.mdc-berlin.de/software/SSMART_137/[email protected]

scholarly journals The key protein of endosomal mRNP transport Rrm4 binds translational landmark sites of cargo mRNAs

2018 ◽  
Author(s):  
Lilli Olgeiser ◽  
Carl Haag ◽  
Susan Boerner ◽  
Jernej Ule ◽  
Anke Busch ◽  
...  
Keyword(s):  
Rna Binding ◽  
Rna Binding Proteins ◽  
Specific Binding ◽  
Hyphal Growth ◽  
Binding Motif ◽  
Uv Crosslinking ◽  
Rrm Domain ◽  
Messenger Ribonucleoprotein ◽  
Close Proximity ◽  
Nucleotide Resolution

AbstractRNA-binding proteins (RBPs) determine spatiotemporal gene expression by mediating active transport and local translation of cargo mRNAs. Here, we cast a transcriptome-wide view on the transported mRNAs and cognate RBP binding sites during endosomal messenger ribonucleoprotein (mRNP) transport in Ustilago maydis. Using individual-nucleotide resolution UV crosslinking and immunoprecipitation (iCLIP), we compare the key transport RBP Rrm4 and the newly identified endosomal mRNP component Grp1 that is crucial to coordinate hyphal growth. Both RBPs bind predominantly in the 3’ untranslated region of thousands of shared cargo mRNAs, often in close proximity. Intriguingly, Rrm4 precisely binds at stop codons, which constitute landmark sites of translation, suggesting an intimate connection of mRNA transport and translation. Towards uncovering the code of recognition, we identify UAUG as specific binding motif of Rrm4 that is bound by its third RRM domain. Altogether, we provide first insights into the positional organisation of co-localising RBPs on individual cargo mRNAs.

scholarly journals LIN28 selectively modulates a subclass of let-7 microRNAs

2017 ◽  
Author(s):  
Dmytro Ustianenko ◽  
Hua-Sheng Chiu ◽  
Sebastien M. Weyn-Vanhentenryck ◽  
Pavel Sumazin ◽  
Chaolin Zhang
Keyword(s):  
Binding Sites ◽  
Rna Binding ◽  
Class I ◽  
Single Nucleotide ◽  
Potential Implication ◽  
Disease States ◽  
Resolution Mapping ◽  
Cold Shock Domain ◽  
Nucleotide Resolution

AbstractLIN28 is a bipartite RNA-binding protein that post-transcriptionally inhibits let-7 microRNAs to regulate development and influence disease states. However, the mechanisms of let-7 suppression remains poorly understood, because LIN28 recognition depends on coordinated targeting by both the zinc knuckle domain (ZKD)—which binds a GGAG-like element in the precursor—and the cold shock domain (CSD), whose binding sites have not been systematically characterized. By leveraging single-nucleotide-resolution mapping of LIN28 binding sites in vivo, we determined that the CSD recognizes a (U)GAU motif. This motif partitions the let-7 family into Class I precursors with both CSD and ZKD binding sites and Class II precursors with ZKD but no CSD binding sites. LIN28 in vivo recognition—and subsequent 3′ uridylation and degradation—of Class I precursors is more efficient, leading to their stronger suppression in LIN28-activated cells and cancers. Thus, CSD binding sites amplify the effects of the LIN28 activation with potential implication in development and cancer.

scholarly journals SEQing: web-based visualization of iCLIP and RNA-seq data in an interactive python framework

2019 ◽  
Author(s):  
Martin Lewinski ◽  
Yannik Bramkamp ◽  
Tino Köster ◽  
Dorothee Staiger
Keyword(s):  
Binding Sites ◽  
Binding Proteins ◽  
Target Genes ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Rna Seq ◽  
Web Based ◽  
Genome Wide ◽  
Functional Relevance ◽  
Nucleotide Resolution

AbstractBackgroundRNA-binding proteins interact with their target RNAs at specific sites. These binding sites can be determined genome-wide through individual nucleotide resolution crosslinking immunoprecipitation (iCLIP). Subsequently, the binding sites have to be visualized. So far, no visualization tool exists that is easily accessible but also supports restricted access so that data can be shared among collaborators.ResultsHere we present SEQing, a customizable interactive dashboard to visualize crosslink sites on target genes of RNA-binding proteins that have been obtained by iCLIP. Moreover, SEQing supports RNA-seq data that can be displayed in a diffrerent window tab. This allows, e.g. crossreferencing the iCLIP data with genes differentially expressed in mutants of the RBP and thus obtain some insights into a potential functional relevance of the binding sites. Additionally, detailed information on the target genes can be incorporated in another tab.ConclusionSEQing is written in Python3 and runs on Linux. The web-based access makes iCLIP data easily accessible, even with mobile devices. SEQing is customizable in many ways and has also the option to be secured by a password. The source code is available at https://github.com/malewins/SEQing.

scholarly journals Substrate Specificity of the TRAMP Nuclear Surveillance Complexes

2020 ◽  
Author(s):  
Clémentine Delan-Forino ◽  
Christos Spanos ◽  
Juri Rappsilber ◽  
David Tollervey
Keyword(s):  
Gene Expression ◽  
Mass Spectrometry ◽  
Binding Sites ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Rna Binding Protein ◽  
Rna Helicase ◽  
Nuclear Rna ◽  
Rna Exosome

ABSTRACTDuring nuclear surveillance in yeast, the RNA exosome functions together with the TRAMP complexes. These include the DEAH-box RNA helicase Mtr4 together with an RNA-binding protein (Air1 or Air2) and a poly(A) polymerase (Trf4 or Trf5). To better determine how RNA substrates are targeted, we analyzed protein and RNA interactions for TRAMP components. Mass spectrometry identified three distinct TRAMP complexes formed in vivo. These complexes preferentially assemble on different classes of transcripts. Unexpectedly, on many substrates, including pre-rRNAs and pre-mRNAs, binding specificity was apparently conferred by Trf4 and Trf5. Clustering of mRNAs by TRAMP association showed co-enrichment for mRNAs with functionally related products, supporting the significance of surveillance in regulating gene expression. We compared binding sites of TRAMP components with multiple nuclear RNA binding proteins, revealing preferential colocalization of subsets of factors. TRF5 deletion reduced Mtr4 recruitment and increased RNA abundance for mRNAs specifically showing high Trf5 binding.

scholarly journals HNRNPA1 promotes recognition of splice site decoys by U2AF2 in vivo

2017 ◽  
Author(s):  
Jonathan M. Howard ◽  
Hai Lin ◽  
Garam Kim ◽  
Jolene M Draper ◽  
Maximilian Haeussler ◽  
...  
Keyword(s):  
Splice Site ◽  
Binding Sites ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Regulatory Elements ◽  
Splice Sites ◽  
Spliceosome Assembly ◽  
Over Expression

AbstractAlternative pre-mRNA splicing plays a major role in expanding the transcript output of human genes. This process is regulated, in part, by the interplay of trans-acting RNA binding proteins (RBPs) with myriad cis-regulatory elements scattered throughout pre-mRNAs. These molecular recognition events are critical for defining the protein coding sequences (exons) within pre-mRNAs and directing spliceosome assembly on non-coding regions (introns). One of the earliest events in this process is recognition of the 3’ splice site by U2 small nuclear RNA auxiliary factor 2 (U2AF2). Splicing regulators, such as the heterogeneous nuclear ribonucleoprotein A1 (HNRNPA1), influence spliceosome assembly both in vitro and in vivo, but their mechanisms of action remain poorly described on a global scale. HNRNPA1 also promotes proof reading of 3’ss sequences though a direct interaction with the U2AF heterodimer. To determine how HNRNPA1 regulates U2AF-RNA interactions in vivo, we analyzed U2AF2 RNA binding specificity using individual-nucleotide resolution crosslinking immunoprecipitation (iCLIP) in control- and HNRNPA1 over-expression cells. We observed changes in the distribution of U2AF2 crosslinking sites relative to the 3’ splice sites of alternative cassette exons but not constitutive exons upon HNRNPA1 over-expression. A subset of these events shows a concomitant increase of U2AF2 crosslinking at distal intronic regions, suggesting a shift of U2AF2 to “decoy” binding sites. Of the many non-canonical U2AF2 binding sites, Alu-derived RNA sequences represented one of the most abundant classes of HNRNPA1-dependent decoys. Splicing reporter assays demonstrated that mutation of U2AF2 decoy sites inhibited HNRNPA1-dependent exon skipping in vivo. We propose that HNRNPA1 regulates exon definition by modulating the interaction of U2AF2 with decoy or bona fide 3’ splice sites.

scholarly journals Transcriptome-wide profiles of circular RNA and RNA binding protein interactions reveal effects on circular RNA biogenesis and cancer pathway expression

2020 ◽  
Author(s):  
Trine Line Hauge Okholm ◽  
Shashank Sathe ◽  
Samuel S. Park ◽  
Andreas Bjerregaard Kamstrup ◽  
Asta Mannstaedt Rasmussen ◽  
...  
Keyword(s):  
Bladder Cancer ◽  
Protein Interactions ◽  
Binding Sites ◽  
Target Genes ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Circular Rna ◽  
Circular Rnas ◽  
Cancer Genes

AbstractCircular RNAs (circRNAs) are stable, often highly expressed RNA transcripts with potential to modulate other regulatory RNAs. A few circRNAs have been shown to bind RNA binding proteins (RBPs), however, little is known about the prevalence and strength of these interactions in different biological contexts. Here, we comprehensively evaluate the interplay between circRNAs and RBPs in the ENCODE cell lines, HepG2 and K562, by profiling the expression of circRNAs in fractionated total RNA-sequencing samples and analyzing binding sites of 150 RBPs in large eCLIP data sets. We show that KHSRP binding sites are enriched in flanking introns of circRNAs in both HepG2 and K562 cells, and that KHSRP depletion affects circRNA biogenesis. Additionally, we show that exons forming circRNAs are generally enriched with RBP binding sites compared to non-circularizing exons. To detect individual circRNAs with regulatory potency, we computationally identify circRNAs that are highly covered by RBP binding sites and experimentally validate circRNA-RBP interactions by RNA immunoprecipitations. We characterize circCDYL, a highly expressed circRNA with clinical and functional implications in bladder cancer, which is covered with GRWD1 binding sites. We confirm that circCDYL binds GRWD1 in vivo and functionally characterizes the effect of circCDYL-GRWD1 interactions on target genes in HepG2. Furthermore, we confirm interactions between circCDYL and RBPs in bladder cancer cells and demonstrate that circCDYL depletion affects hallmarks of cancer and perturbs the expression of key cancer genes, e.g. TP53 and MYC. Finally, we show that elevated levels of highly RBP-covered circRNAs, including circCDYL, are associated with overall survival of bladder cancer patients. Our study demonstrates transcriptome-wide and cell-type-specific circRNA-RBP interactions that could play important regulatory roles in tumorigenesis.

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