Project description:We developed a high-throughput mutagenesis screen to comprehensively identify the cis-regulatory elements that control a target splicing event from the MST1R gene that codes for the RON receptor tyrosine kinase. Skipping of alternative exon 11 results in a constitutively active isoform that promotes epithelial to mesenchymal transition and thereby contributes to the invasive phenotype of tumors. We identified the RNA binding protein hnRNP H as an important regulator of RON exon 11 splicing. To map hnRNP H binding sites on the RON minigene with either wildtype or hnRNP H binding site mutant background, we performed hnRNP H iCLIP with RON wildtype or mutant minigene transfected HEK293T cells. iCLIP was performed according to a previously published protocol (PMID: 26463384). The iCLIP libraries were made from two (G331C and G348C) or three replicates (wildtype and G305A) of HEK293T cells at 24 h after RON minigene transfection. The cells were irradiated with 150 mJ/cm2 UV light at 254 nm. For the immunoprecipitation step, we used 7.5 µg of a polyclonal rabbit anti-HNRNPH antibody from Abcam (AB10374). RNase digestion was performed by adding 10 µl of 1/100 diluted RNase I (Ambion) to each sample. We performed the sequencing on an Illumina MiSeq or NextSeq500 with 75-nt single-end reads.
Project description:We developed a high-throughput mutagenesis screen to comprehensively identify the cis-regulatory elements that control a target splicing event from the MST1R gene that codes for the RON receptor tyrosine kinase. Skipping of alternative exon 11 results in a constitutively active isoform that promotes epithelial to mesenchymal transition and thereby contributes to the invasive phenotype of tumors. We identified the RNA binding protein hnRNP H as an important regulator of RON exon 11 splicing. To map hnRNP H binding sites on the RON minigene, we performed hnRNP H iCLIP with RON wildtype minigene transfected HEK293T cells. iCLIP was performed according to a previously published protocol (PMID: 26463384). The iCLIP libraries were made from two replicates of HEK293T cells at 24 h after RON minigene transfection. The cells were irradiated with 150 mJ/cm2 UV light at 254 nm. For the immunoprecipitation step, we used 7.5 µg of a polyclonal rabbit anti-HNRNPH antibody from Abcam (AB10374). RNase digestion was performed by adding 10 µl of 1/100 diluted RNase I (Ambion) to each sample. We performed the sequencing on an Illumina HiSeq2000 (75-nt single-end reads).
Project description:This experiment identifies hnRNP A1 binding sites transcriptome-wide in Hela cells. HeLa cells with inducible expression of T7-tagged hnRNP A1 were grown to approximately 90% confluence and then subject to iCLIP analysis (following the protocol from Huppertz et al. 2014 (iCLIP: protein-RNA interactions at nucleotide resolution)). The iCLIP library was sequenced using Illumina's HighSeq 1500
Project description:We developed a high-throughput mutagenesis screen to comprehensively identify the cis-regulatory elements that control a target splicing event from the MST1R gene that codes for the RON receptor tyrosine kinase. Skipping of alternative exon 11 results in a constitutively active isoform that promotes epithelial to mesenchymal transition and thereby contributes to the invasive phenotype of tumors. First, we created a library of mutated minigenes via mutagenic PCR. Importantly, the reverse primer introduced a random barcode sequence, which labels the associated mutations. Next, the plasmid library was transfected as a pool and depending on the mutations, the transcripts exhibit changes in alternative splicing. The minigene library and the splicing outcome were analyzed by next-generation sequencing and subsequent integration of the datasets resulted in a map of splicing regulatory sites. The RNA binding protein hnRNP H was identified as an important regulator of RON exon 11 splicing. Thus, we performed RNA-seq experiments from minigene library transfected MCF7 cells under control and hnRNP H knockdown conditions in order to quantify the transcript isoforms originating from the minigene library. For preparation of high-throughput RNA sequencing (RNA-seq) libraries, MCF7 cells were first treated with single small interfering RNA (siRNA) against HNRNPH (5′-GGAGCUGGCUUUGAGAGGA[dT][dT] -3′, PMID: 21512137, Sigma-Aldrich) or non-targeting control siRNA (5′-UGGUUUACAUGUCGACUAA[dT][dT]-3′, Sigma-Aldrich) at a final concentration of 20 nM. Next, cells were transfected with the minigene library the day after. A day later, RNA was extracted and subsequently enriched for mRNA by performing polyA selection of 20 µg of total RNA using Dynabeads® Oligo (dT)25 beads (Invitrogen) according to the manufacturer’s protocol. Reverse transcription was carried out using 500 ng of enriched mRNA under the abovementioned conditions. To prevent the formation of chimeric amplicons, the libraries were amplified using emulsion PCR (PMID: 16791213), with Phusion DNA Polymerase (NEB) and cDNA derived from polyA-selected RNA. To amplify fragments for RNA-seq, the following primers containing Illumina sequencing adaptors were used: 5′-CAAGCAGAAGACGGCATACGAGATCGGTCTCGGCATTCCTGCTGAACCGCTCTTCCGATCTNNNNNNNNNNGTTCCACTGAAGCCTGAG-3′ (forward primer) and 5′-AATGATACGGCGACCACCGAGATCTACACTCTTTCCCTACACGACGCTCTTCCGATCTNNNNNNNNNNATAGAATAGGGCCCTCTAGA-3′ (reverse primer). PCR products were purified using Agencourt AMPure XP beads (Beckman Coulter). Purified products were first analysed with the TapeStation 2200 capillary gel electrophoresis instrument (Agilent) and then fluorimetrically quantified using a Qubit fluorimeter (Thermo Scientific). Sequencing was carried out on the Illumina MiSeq platform using paired-end reads of 300 nt length and a 10% PhiX spike-in to increase sequence complexity.
Project description:iCLIP experiment to assess the binding of the highly abundant nuclear RNA-binding protein hnRNP C and core splicing factor U2AF65 on a genomic scale. To investigate how both proteins compete for binding at a subset of sites, U2AF65 iCLIP experiments were performed from both HNRNPC knockdown and control HeLa cells.
Project description:UNC13A contains a cryptic exon which is normally repressed by TDP-43. To better understand the mechanism by which TDP-43 represses this cryptic splicing, and how common SNPs (rs12973192(G) and rs12608932(C)) perturb this regulation, we transfected HEK293T cells with minigenes featuring UNC13A exons 20 and 21, and intron 20. We used two variants of the minigene: one with rs12973192(C) and rs12608932(G) (2x healthy) and the other with rs12973192(G) and rs12973192(C) (2x risk), then performed TDP-43 iCLIP on these cells. We used two replicates for each.