Dissecting non-coding and pathogen RNA-protein interactomes
Ontology highlight
ABSTRACT: RNA-protein interactions are central to biological regulation. Cross-linking immunoprecipitation (CLIP)-seq is a powerful tool for genome-wide interrogation of RNA-protein interactomes, but current CLIP methods are limited by challenging biochemical steps and fail to detect many classes of noncoding and non-human RNAs. Here we present FAST-iCLIP, an integrated pipeline with improved CLIP biochemistry and an automated informatic pipeline for comprehensive analysis across protein coding, noncoding, repetitive, retroviral, and non-human transcriptomes. FAST-iCLIP of Poly-C binding protein 2 (PCBP2) showed that PCBP2 bound CU-rich motifs in different topologies to recognize mRNAs and noncoding RNAs with distinct biological functions. FAST-iCLIP of PCBP2 in hepatitis C virus-infected cells enabled a joint analysis of the PCBP2 interactome with host and viral RNAs and their interplay. These results show that FAST-iCLIP can be used to rapidly discover and decipher mechanisms of RNA-protein recognition across the diversity of human and pathogen RNAs. Characterization of non-coding and pathogen RNA-protein interactions using an automated computational pipeline and improved iCLIP biochemistry
Project description:RNA-protein interactions are central to biological regulation. Cross-linking immunoprecipitation (CLIP)-seq is a powerful tool for genome-wide interrogation of RNA-protein interactomes, but current CLIP methods are limited by challenging biochemical steps and fail to detect many classes of noncoding and non-human RNAs. Here we present FAST-iCLIP, an integrated pipeline with improved CLIP biochemistry and an automated informatic pipeline for comprehensive analysis across protein coding, noncoding, repetitive, retroviral, and non-human transcriptomes. FAST-iCLIP of Poly-C binding protein 2 (PCBP2) showed that PCBP2 bound CU-rich motifs in different topologies to recognize mRNAs and noncoding RNAs with distinct biological functions. FAST-iCLIP of PCBP2 in hepatitis C virus-infected cells enabled a joint analysis of the PCBP2 interactome with host and viral RNAs and their interplay. These results show that FAST-iCLIP can be used to rapidly discover and decipher mechanisms of RNA-protein recognition across the diversity of human and pathogen RNAs.
Project description:DEAD-box RNA helicases are vital for the regulation of various aspects of the RNA life cycle, but the molecular underpinnings of their involvement, particularly in mammalian cells, remain poorly understood. Here we show that the DEAD-box RNA helicase DDX21 can sense transcriptional status of both RNA Pol I and Pol II to control transcriptional and post-transcriptional steps of ribosome biogenesis in human cells. We demonstrate that DDX21 widely associates with Pol I- and Pol II-transcribed genes and with diverse species of protein-coding and noncoding RNAs. Although broad, these molecular interactions, both at the chromatin and at the RNA level, exhibit a remarkable specificity for the ribosomal pathway. In the nucleolus, DDX21 occupies the transcribed rDNA locus, directly contacts both rRNA and snoRNAs and, as a functional component of the snoRNA ribonucleoprotein (snoRNP) complex, promotes modification of rRNA. In the nucleoplasm, DDX21 is incorporated into the 7SK snRNP complex, which facilitates DDX21 association with promoters of Pol II-transcribed genes encoding ribosomal proteins and snoRNAs. Promoter-bound DDX21 facilitates the release of P-TEFb from the 7SK snRNP, enhancing productive Pol II elongation. Altogether, we present a unifying mechanism for the coordinated regulation of ribosomal genes across nuclear compartments, and provide first evidence implicating a mammalian RNA helicase in RNA modification and Pol II elongation control. Examination of DDX21 chromatin association and DDX21 RNA interacting partners in HEK293 cells
Project description:UV cross-linking and immunoprecipitation (CLIP) and individual-nucleotide resolution CLIP (iCLIP) are the most frequently used methods to study protein-RNA interactions in the intact cells and tissues, but their relative advantages or inherent biases have not been evaluated. To benchmark CLIP and iCLIP method, we performed iCLIP with Nova protein, which is the most extensively studied protein by CLIP. Further, we assessed UV-C-induced cross-linking preferences, by exploiting the UV-independent formation of covalent RNA cross-links of the mutant RNA methylase NSUN2.
Project description:We report HERV-K rec iCLIP-seq binding data, ribosome profiling data, and RNA-seq from ELF1 naïve hESC and RNA-seq from NCCIT cells. HERV-K Rec iCLIP-seq: 2 replicates in NCCIT. Ribosome profiling: 4 replicates each of Rec-overexpressing NCCIT vs. control NCCIT; RNAseq: 3 replicates each of HERV-K Rec siRNA vs. control siRNA in NCCIT; RNA-seq: 3 replicates each of ELF1 naïve hESC vs. primed hESC.
Project description:XIST is a long non-coding RNA (lncRNA) that mediates transcriptional silencing of X chromosome genes. Here we show that XIST is highly methylated with at least 78 N6-methyladenosine (m6A) residues, a reversible base modification whose function in lncRNAs is unknown. We show that m6A formation in XIST, as well as cellular mRNAs, is mediated by RBM15 and its paralog RBM15B, which bind the m6A-methylation complex and recruit it to specific sites in RNA. This results in methylation of adenosines in adjacent m6A consensus motifs. Furthermore, knockdown of RBM15 and RBM15B, or knockdown of the m6A methyltransferase METTL3 impairs XIST-mediated gene silencing. A systematic comparison of m6A-binding proteins shows that YTHDC1 preferentially recognizes m6A in XIST and is required for XIST function. Additionally, artificial tethering of YTHDC1 to XIST rescues XIST-mediated silencing upon loss of m6A. These data reveal a pathway of m6A formation and recognition required for XIST-mediated transcriptional repression. Three to four biological HEK293T replicates were used to perform iCLIP of endogenous YTH proteins, RBM15, and RBM15B. Crosslinking induced truncations were identified using CIMS-CITS pipeline.
Project description:We identified the precise genome-wide binding sites for all SR proteins, using iCLIP-seq SR proteins were encoded on stable transgenes, transfected in S2 cells, FLAG-tag immunopurified, and the bound RNA purified and subjected to RNA-seq. The resulting reads (CLIP tags) were aligned to the Drosophila genome and generated 38,695-5,900,000 unique CLIP tags for each SR-protein replicate.
Project description:About half of all human and mouse miRNA genes are located within introns of protein-coding genes. Despite this, little is known about functional interactions between miRNAs and their host genes. The intronic miRNA miR-128 regulates neuronal excitability and controls dendrite outgrowth of projection neurons during development of the mouse cerebral cortex. Its host genes R3hdm1 and Arpp21 encode highly conserved, putative RNA-binding proteins. Here we use iCLIP to describe the RNA-binding activity of ARPP21, which recognizes uridine-rich sequences with exquisite sensitivity for 3UTRs. Surprisingly, ARPP21 antagonizes miR-128 activity by co-regulating a subset of miR-128 target mRNAs enriched for neurodevelopmental functions. In contrast to miR-128, we show that ARPP21 acts as a positive post-transcriptional regulator, at least in part through interaction with the eukaryotic translation initiation complex eIF4F. This molecular antagonism is also reflected in inverse activities during dendritogenesis: miR-128 overexpression or knockdown of ARPP21 reduces dendritic complexity; ectopic ARPP21 leads to an increase. The regulatory interaction between ARPP21 and miR-128 is a unique example of convergent function by two products of a single gene.
Project description:We determined the genomic landscape of FBF-1 and FBF-2 binding in germline stem cells using iCLIP, a method that allows identification of protein-RNA interactions at high resolution. We first developed reagents to explore the genomic binding landscapes of full-length FBF-1 and FBF-2 in vivo and then used our iCLIP data to test the precision of several commonly used methods for CLIP peak calling. Based on this iCLIP data, we discovered that FBF-1 and FBF-2 have similar global protein-RNA interaction profiles and that they both target conserved cell cycle regulators and lincRNAs. We found that FBF-1 and FBF-2 regulate their targets through canonical as well as unexpected motif sequences. We elucidated the first in vivo crosslink site analysis for a PUF protein from which we precisely determined FBF-1 and FBF-2 binding sites. Taken together, our data provide an updated model of PUF binding in stem cells. Our study also provides new insight on the control of gene expression in stem cells by RNA binding proteins.
Project description:In this study, we employed a combination of RIP-seq and short- and long-wave iCLIP technologies to identify transcripts associated with cytoplasmic RNPs containing the RNA-binding protein Drosophila Imp. We also made a Imp knockdown vs luciferase control experiment. Two biological iCLIP-seq, as well as two mRNAseq made on cells harvested on the same day. Two biological PAR-iCLIP-seq. Two biological RIP-seq, as well as two mRNAseq made on cells harvested on the same day. Three biological mRNAseq of imp dsRNA treated cells as well as three control mRNAseq of cells treated with Luciferase dsRNA.