Project description:To identify QKI targets, we performed QKI knockdown in BEAS2B cells and analyzed alternative splicing patterns by high-throughput RNA sequencing. The mRNA profiles of control- and QKI-knockdown BEAS2B cells were generated by deep sequencing using Illumina GAIIx sequencer.
Project description:Members of the miR-200 family are critical gatekeepers of the epithelial state, restraining expression of pro-mesenchymal genes that drive epithelial-mesenchymal transition (EMT) and contribute to metastatic cancer progression. Here, we show that miR-200c and another epithelial-enriched miRNA, miR-375, exert widespread control of alternative splicing in cancer cells. This is achieved by their strong suppression of the RNA binding protein Quaking (QKI), which is required to mediate the splicing changes regulated by these miRNAs. During EMT, QKI-5 directly binds to and regulates hundreds of alternative splicing events and exerts pleiotropic effects, such as increasing cell migration and invasion and restraining tumour growth, without appreciably affecting mRNA levels. QKI-5 is both necessary and sufficient to direct EMT alternative splicing changes, and this splicing signature is broadly conserved across many epithelial-derived cancer types. Importantly, several actin cytoskeleton-associated genes are directly targeted both by QKI and miR-200c, revealing coordinated control of alternative splicing and mRNA abundance during EMT. These findings demonstrate the existence of a miR-200/miR-375/QKI axis that impacts cancer-associated epithelial cell plasticity through widespread control of alternative splicing. The purpose of the CLIP experiment was to determine direct targets of QKI.
Project description:To identify QKI targets, we performed QKI knockdown in BEAS2B cells and analyzed alternative splicing patterns by high-throughput RNA sequencing.
Project description:Expression levels of the RNA-binding protein Quaking (QKI) are low in monocytes of early, human atherosclerotic lesions, but abundant in macrophages of advanced plaques. Specific depletion of QKI protein impaired monocyte adhesion, migration, differentiation into macrophages, and foam cell formation in vitro and in vivo. RNA-seq and microarray analysis of human monocyte and macrophage transcriptomes, including those of a unique QKI haploinsufficient patient, revealed striking changes in QKI-dependent mRNA levels and splicing of RNA transcripts. RNA-seq analysis of primary monocytes and macrophages from a QKI haploinsufficient patient and their (control) sibling.
Project description:Expression levels of the RNA-binding protein Quaking (QKI) are low in monocytes of early, human atherosclerotic lesions, but abundant in macrophages of advanced plaques. Specific depletion of QKI protein impaired monocyte adhesion, migration, differentiation into macrophages, and foam cell formation in vitro and in vivo. RNA-seq and microarray analysis of human monocyte and macrophage transcriptomes, including those of a unique QKI haploinsufficient patient, revealed striking changes in QKI-dependent mRNA levels and splicing of RNA transcripts. Microarray analysis of gene expression and splicing in THP-1 cells transfected with shRNAs, with or without PMA treatment to induce differentiation. 12 total samples were analyzed: THP-1 monocytic cell line transfected with QKI or control shRNAs; samples taken at day 0 or day 3 of PMA-induced differentiation into macrophages.
Project description:Alternative splicing is critical for development. However, its role in the specification of the three embryonic germ layers is poorly understood. By performing RNA-Seq on human embryonic stem cells (hESCs) and derived endoderm, cardiac mesoderm, and ectoderm cell lineages, we detect distinct alternative splicing programs associated with each lineage. The most prominent splicing program differences are observed between definitive endoderm and cardiac mesoderm. Integrative multi-omics analyses link each program with lineage-specific RNA binding protein regulators, and further suggest a widespread role for Quaking (QKI) in the specification of cardiac mesoderm. Remarkably, knockout of QKI disrupts the cardiac mesoderm-associated alternative splicing program and formation of myocytes. These changes likely arise in part through reduced expression of BIN1 splice variants linked to cardiac development. Collectively, our results thus uncover alternative splicing programs associated with the three germ lineages and demonstrate an important role for QKI in the formation of cardiac mesoderm.
Project description:Alternative splicing of pre-mRNA is a prominent mechanism to generate protein diversity, yet its regulation is poorly understood. Here, we demonstrate a direct role for histone modifications in alternative splicing. We find distinctive histone modification signatures which correlate with splicing outcome in a set of human genes. Modulation of histone modifications causes splice site switching. The mechanism for histone-mediated splice site selection involves a histone mark which is read by a chromatin protein, which in turn recruits a splicing regulator. These results outline an adaptor system for reading of histone marks by the pre-mRNA splicing machinery. To obtain an estimate of how many PTB-dependent alternative splicing events are regulated by SET2/MRG15-mediated recruitment of PTB, we carried out a genomewide comparative analysis of alternative splicing in hMSC cells depleted of either SETD2, MRG15 or PTB using specific siRNAs, or mock-depleted using a control siRNA.