Hsa-miR-92a knock down in Flp-in T-REx 293-PTH-AGO1 cells
ABSTRACT: transcriptome profiling of miR-92a inhibitor treated and control cells with the aim of measuring miR-92a influence on its mRNA targets Abstract: MicroRNAs (miRNAs) play key roles in gene regulation, but reliable bioinformatic or experimental identification of their targets remains difficult. To provide an unbiased view of human miRNA targets we developed a technique for ligation and sequencing of miRNA-target RNA duplexes associated with human Ago1. Here we report datasets of more than 18,000 high-confidence miRNA-mRNA interactions. The binding of most miRNAs includes the 5' seed region, but around 60% of seed interactions are noncanonical, containing bulged or mismatched nucleotides. Moreover, seed interactions are generally accompanied by specific, non-seed basepairing. 18% of miRNA-mRNA interactions involve the miRNA 3' end, with little evidence for 5' contacts, and some of these were functionally validated. Analyses of miRNA:mRNA basepairing showed that miRNA species systematically differ in their target RNA interactions, and strongly overrepresented motifs were found in the interaction sites of several miRNAs. We speculate that these affect the response of RISC to miRNA-target binding. In total 10 samples were analyzed, 5 repeats for each experimental condition.
Project description:Purpose: Identification of miRNA-mRNA interactions in human cells. Method: We used the CLASH technique with PTH-tagged AGO1 protein as a bait. Results: In 6 experiments we identified more than 18,000 miRNA-mRNA interactions in human HEK293 cells, corresponding to targets of 399 miRNAs. Conclusions: The binding of most miRNAs includes the 5' seed region, but around 60% of seed interactions are noncanonical, containing bulged or mismatched nucleotides. Moreover, seed interactions are generally accompanied by specific, non-seed basepairing. 18% of miRNA-mRNA interactions involve the miRNA 3' end, with little evidence for 5' contacts, and some of these were functionally validated. Analyses of miRNA:mRNA basepairing showed that miRNA species systematically differ in their target RNA interactions, and strongly overrepresented motifs were found in the interaction sites of several miRNAs. We speculate that these affect the response of RISC to miRNA-target binding. 6 samples (E1-E6) were prepared with comparable but not identical protocols, described in more detail in Helwak et al. Cell 2013. Samples E7-E10 were used for the determination of the background of the method resulting from RNA-RNA interactions formed after cell lysis.
Project description:To obtain evidence that Argonaute (AGO) crosslink-centered regions (CCRs) indeed contain functional miRNA-binding sites, we blocked 25 of the most abundant miRNAs in HEK 293 cells (Figure 5C of PMID 20371350) by transfection of a cocktail of 2'-O-methyl-modified antisense oligoribonucleotides and monitored the changes in mRNA stability by microarrays (Figure 7A of PMID 20371350). Consistent with previous studies of individual miRNAs (Grimson et al., 2007), the magnitude of the destabilization effects of transcripts containing at least one CCR depended on the length of the seed-complementary region and dropped from 9-mer to 8-mer to 7-mer to 6-mer matches (Figure 7B of PMID 20371350). We did not find evidence for significant destabilization of transcripts that only contained imperfectly paired seed regions. The top 25 expressed miRNAs expressed in HEK 293 cells were inhibited by transfection of a cocktail of 25 antisense 2'-O-Me oligoribonucleotides and the gene expression was compared to mock-transfected cells.
Project description:This SuperSeries is composed of the following subset Series: GSE21574: Transcriptome-wide identification of RNA-binding protein and microRNA target sites by PAR-CLIP: QKI data GSE21575: Transcriptome-wide identification of RNA-binding protein and microRNA target sites by PAR-CLIP: IGF2BP data GSE21577: Transcriptome-wide identification of RNA-binding protein and microRNA target sites by PAR-CLIP: miRNA inhibition data GSE21918: Transcriptome-wide identification of RNA-binding protein and microRNA target sites by PAR-CLIP: sequencing data Refer to individual Series
Project description:LIN28 is a conserved RNA binding protein implicated in pluripotency, reprogramming and oncogenesis. Previously shown to act primarily by blocking let-7 microRNA (miRNA) biogenesis, here we elucidate distinct roles of LIN28 regulation via its direct messenger RNA (mRNA) targets. Through cross-linking and immunoprecipitation coupled with high-throughput sequencing (CLIP-seq) in human embryonic stem cells and somatic cells expressing exogenous LIN28, we have defined discrete LIN28 binding sites in a quarter of human transcripts. These sites revealed that LIN28 binds to GGAGA sequences enriched within loop structures in mRNAs, reminiscent of its interaction with let-7 miRNA precursors. Among LIN28 mRNA targets, we found evidence for LIN28 autoregulation and also direct but differing effects on the protein abundance of splicing regulators in somatic and pluripotent stem cells. Splicing-sensitive microarrays demonstrated that exogenous LIN28 expression causes widespread downstream alternative splicing changes. These findings identify important regulatory functions of LIN28 via direct mRNA interactions. In triplicate, polyA-selected RNA was extracted from untreated Flp-In-293 cells, stable LIN28V5 293 cells, TDP-43 over-expressed Flp-In-293 cells, control over-expressed Flp-In-293 cells, LIN28 depleted hES cells, and control depleted hES cells, and hybridized to custom human splicing sensitive microarrays
Project description:Tristetraprolin/ZFP36/TTP and ELAVL1/HuR are two disease-relevant RNA-binding proteins (RBPs) that both interact with AU-rich sequences but have antagonistic roles. While ELAVL1 binding has been profiled in several studies, the precise in vivo binding specificity of ZFP36 has not been investigated on a global scale. We determined ZFP36 binding preferences using cross-linking and immunoprecipitation in human embyonic kidney cells and examined combinatorial regulation of AU-rich elements by ZFP36 and ELAVL1. Among the targets ZFP36 binds and negatively regulates the mRNA of genes encoding proteins necessary for immune function and cancer, and other RBPs. Using partial correlation analysis, we were able to quantify the association between ZFP36 binding sites and differential target RNA abundance from ZFP36 overexpression independent of effects from confounding features, such as 3’ UTR length. We identified thousands of overlapping ZFP36 and ELAVL1 binding sites, in 1,313 genes. ZFP36 preferentially interacts with and regulates AU-rich sequences while ELAVL1 prefers predominantly U- and CU-rich sequences. RNA target specificity identified by global in vivo ZFP36-mRNA interactions were quantitatively similar to previously reported in vitro binding affinities. ZFP36 and ELAVL1 both bind an overlapping spectrum of RNA sequences, yet with differential relative preferences that dictate combinatorial regulatory potential. Our findings and methodology delineate an approach to untangle the in vivo combinatorial regulation by RNA-binding proteins. Five biological replicates for each of the four sample classes -> Parental and EGFP-ZFP36 HEK293 cells treated with either doxycycline or water.
Project description:To test the influence of IGF2BPs on the stability of their interacting mRNAs, as reported previously for some targets (Yisraeli, 2005), we simultaneously depleted all three IGF2BP family members using siRNAs and compared the cellular RNA from knockdown and mock-transfected cells on microarrays. The levels of transcripts identified by PAR-CLIP decreased in IGF2BP-depleted cells, indicating that IGF2BP proteins stabilize their target mRNAs. Moreover, transcripts that yielded clusters with the highest T to C mutation frequency were most destabilized (Figure 4G of PMID 20371350), indicating that the ranking criterion that we derived based on the analysis of PUM2 and QKI data generalizes to other RNA-binding proteins (RBPs). The RBPs IGF2BP1-3 were depleted by siRNAs and the expression level was compared to mock-transfected HEK 293 cells.
Project description:To assess whether the transcripts identified by PAR-CLIP are regulated by the RNA-binding protein (RBP) Quaking (QKI), we analyzed the mRNA levels of mock-transfected and QKI-specific siRNA-transfected cells with microarrays. Transcripts crosslinked to QKI were significantly upregulated upon siRNA transfection, indicating that QKI negatively regulates bound mRNAs (Figure 3H of PMID 20371350), consistent with previous reports of QKI being a repressor. The RBP QKI was depleted by siRNAs and the expression level was compared to mock-transfected HEK 293 cells.
Project description:C2H2 zinc finger proteins represent the largest and most enigmatic class of human transcription factors. Their C2H2 arrays are highly variable, indicating that most will have unique DNA binding motifs. However, most of the binding motifs have not been directly determined. We have determined the binding sites and motifs of 119 C2H2 zinc finger proteins and the expression pattern of 80 cell lines overexpressing C2H2 zinc finger proteins in order to study the role of C2H2 zinc finger proteins in gene regulation. We expressed GFP-tagged C2H2-ZF proteins in stable transgenic HEK293 cells. Total RNA was isolated using Trizol and sequencing libraries were constructed using TruSeq Stranded Total RNA Library Prep Kit with Ribo-Zero Gold or TruSeq RNA Library Preparation Kit v2.
Project description:The largest and most diverse class of eukaryotic transcription factors contain Cys2-His2 zinc fingers (C2H2-ZFs), each of which typically binds a DNA nucleotide triplet within a larger binding site. Frequent recombination and diversification of their DNA-contacting residues suggests that these zinc fingers play a prevalent role in adaptive evolution. Very little is known about the function and evolution of the vast majority of C2H2-ZFs, including whether they even bind DNA. We determined in vivo binding sites of 39 human C2H2-ZF proteins, and correlated them with potential functions for these proteins. We expressed GFP-tagged C2H2-ZF proteins in stable transgenic HEK293 cells. Chromatin immunoprecipitation was performed as described before (Schmidt et al., Methods, 2009), and ChIP samples along with several control samples from different experimental batches were sequenced on Illumina HiSeq 2500. Reads were mapped to hg19 (GRCh37) assembly, and peaks were identified by MACS using an experiment-specific background that controls for various biases, such as the Sono-Seq effect as well as potential co-purification of targets of other (interacting) proteins.