Project description:This work provides the first evidence that Qk is a global regulator of splicing in vertebrates, defines a new splicing regulatory network in muscle, and suggests that overlapping splicing networks contribute to the complexity of changes in alternative splicing during differentiation. Alternative splicing contributes to muscle development and differentiation, but the complete set of muscle splicing factors and their combinatorial interactions are not known. Previously work identifies ACUAA (STAR motif) as an enriched sequence near muscle-specific alternative exons such as Capzb exon 9. We did mass spectrometry of proteins selected by wild type and mutant Capzb intron 9 RNA affinity chromatography, and identified Quaking (Qk), a protein known to regulate mRNA function through ACUAA motifs in 3' UTRs. We show that in myoblasts, Qk promotes inclusion of Capzb exon 9 in opposition to repression by PTB. Qk knockdown in myoblasts has little effect on transcript levels, but alters inclusion of 824 cassette exons whose adjacent intron sequences are enriched in ACUAA motifs. During differentiation to myotubes, Qk levels increase 2-3 fold, suggesting a mechanism for Qk-responsive exon regulation. We captured the PTB splicing regulatory network and intersected it with the Qk network, identifying overlap between the functions of Qk and PTB. Approximately 60% of exons whose inclusion is altered during myogenesis appear to be under control of one or both of these splicing factors in myoblasts. This series is the C2C12 differentiation data. It is 9 arrays, 3 timepoints, with 3 replicates. The time points are 0 hrs, 24 hrs, and 72hrs.
Project description:This work provides the first evidence that Qk is a global regulator of splicing in vertebrates, defines a new splicing regulatory network in muscle, and suggests that overlapping splicing networks contribute to the complexity of changes in alternative splicing during differentiation. Alternative splicing contributes to muscle development and differentiation, but the complete set of muscle splicing factors and their combinatorial interactions are not known. Previously work identifies ACUAA (STAR motif) as an enriched sequence near muscle-specific alternative exons such as Capzb exon 9. We did mass spectrometry of proteins selected by wild type and mutant Capzb intron 9 RNA affinity chromatography, and identified Quaking (Qk), a protein known to regulate mRNA function through ACUAA motifs in 3' UTRs. We show that in myoblasts, Qk promotes inclusion of Capzb exon 9 in opposition to repression by PTB. Qk knockdown in myoblasts has little effect on transcript levels, but alters inclusion of 824 cassette exons whose adjacent intron sequences are enriched in ACUAA motifs. During differentiation to myotubes, Qk levels increase 2-3 fold, suggesting a mechanism for Qk-responsive exon regulation. We captured the PTB splicing regulatory network and intersected it with the Qk network, identifying overlap between the functions of Qk and PTB. Approximately 60% of exons whose inclusion is altered during myogenesis appear to be under control of one or both of these splicing factors in myoblasts. This series is the C2C12 Qk and PTB siRNA data. It is 12 arrays: 3 PTB siRNA arrays , 3 Qk siRNA arrays, and 6 mock siRNA arrays.
Project description:This work provides the first evidence that Qk is a global regulator of splicing in vertebrates, defines a new splicing regulatory network in muscle, and suggests that overlapping splicing networks contribute to the complexity of changes in alternative splicing during differentiation. Alternative splicing contributes to muscle development and differentiation, but the complete set of muscle splicing factors and their combinatorial interactions are not known. Previously work identifies ACUAA (STAR motif) as an enriched sequence near muscle-specific alternative exons such as Capzb exon 9. We did mass spectrometry of proteins selected by wild type and mutant Capzb intron 9 RNA affinity chromatography, and identified Quaking (Qk), a protein known to regulate mRNA function through ACUAA motifs in 3' UTRs. We show that in myoblasts, Qk promotes inclusion of Capzb exon 9 in opposition to repression by PTB. Qk knockdown in myoblasts has little effect on transcript levels, but alters inclusion of 824 cassette exons whose adjacent intron sequences are enriched in ACUAA motifs. During differentiation to myotubes, Qk levels increase 2-3 fold, suggesting a mechanism for Qk-responsive exon regulation. We captured the PTB splicing regulatory network and intersected it with the Qk network, identifying overlap between the functions of Qk and PTB. Approximately 60% of exons whose inclusion is altered during myogenesis appear to be under control of one or both of these splicing factors in myoblasts.
Project description:This work provides the first evidence that Qk is a global regulator of splicing in vertebrates, defines a new splicing regulatory network in muscle, and suggests that overlapping splicing networks contribute to the complexity of changes in alternative splicing during differentiation. Alternative splicing contributes to muscle development and differentiation, but the complete set of muscle splicing factors and their combinatorial interactions are not known. Previously work identifies ACUAA (STAR motif) as an enriched sequence near muscle-specific alternative exons such as Capzb exon 9. We did mass spectrometry of proteins selected by wild type and mutant Capzb intron 9 RNA affinity chromatography, and identified Quaking (Qk), a protein known to regulate mRNA function through ACUAA motifs in 3' UTRs. We show that in myoblasts, Qk promotes inclusion of Capzb exon 9 in opposition to repression by PTB. Qk knockdown in myoblasts has little effect on transcript levels, but alters inclusion of 824 cassette exons whose adjacent intron sequences are enriched in ACUAA motifs. During differentiation to myotubes, Qk levels increase 2-3 fold, suggesting a mechanism for Qk-responsive exon regulation. We captured the PTB splicing regulatory network and intersected it with the Qk network, identifying overlap between the functions of Qk and PTB. Approximately 60% of exons whose inclusion is altered during myogenesis appear to be under control of one or both of these splicing factors in myoblasts.
Project description:Quaking are RNA binding proteins, which are known to regulate the expression of different genes at the post-transcriptional level. Genetic interference with quaking a (qkia) and quaking c (qkic) leads to major myofibril defects during zebrafish development, without affecting early muscle differentiation. In order to understand how qkia and qkic jointly regulate myofibril formation, we performed a comparative analysis of the transcriptome of qkia/qkic (qkia mutant injected with qkic morpholino) versus control embryos. We show that Quaking activity is required for accumulation of the muscle-specific tropomyosin 3 transcript, tpm3.1. Whereas interference with tmp3.1 function disrupts myofibril formation, reintroducing tpm3.1 transcripts into embryos with reduced Quaking activity can restore structured myofibrils. Thus, we identify tropomyosin as an essential component in the process of myofibril formation and as a relay downstream of the regulator proteins Quaking.
Project description:22 Normal adult mouse tissues on custom alternative transcript sensitive Affymetrix microarray used to address differeneces in tissue specific alternative splicing. Abstract: Alternative splicing contributes to both gene regulation and protein diversity. To discover broad relationships between regulation of alternative splicing and sequence conservation, we applied a systems approach, using oligonucleotide microarrays designed to capture splicing information across the mouse genome. In a set of 22 adult tissues, we observe expression of RNA containing at least two alternative splice junctions for about a third of the 3200 alternative events we could detect. Statistical comparisons identify 171 cassette exons whose inclusion or skipping is different in brain relative to other tissues, and another 28 exons whose splicing is different in muscle. A subset of these exons is associated with unusual blocks of intron sequence whose conservation in vertebrates rivals that of protein-coding exons. By focusing on sets of exons with similar regulatory patterns, we have identified new sequence motifs implicated in brain and muscle splicing regulation. Of note is a motif strikingly similar to the branchpoint consensus, but which is located downstream of the 5' splice site of exons included in muscle. Analysis of three paralogous membrane-associated guanylate kinase (MAGUK) genes reveals that each contains a paralogous tissue regulated exon with a similar tissue inclusion pattern. While the intron sequences flanking these exons remain highly conserved among mammalian orthologs, the paralogous flanking intron sequences have diverged considerably, suggesting unusually complex evolution of the regulation of alternative splicing in multigene families. Keywords: Alternative splicing isoform specific, adult mouse tissues
Project description:A number of microRNAs have been shown to regulate skeletal muscle development and differentiation. MicroRNA-222 is downregulated during myogenic differentiation and its overexpression leads to alteration of muscle differentiation process and specialized structures. By using RNA induced silencing complex (RISC) pulldown followed by RNA sequencing, combined with in silico microRNA target prediction, we have identified two new targets of microRNA-222 involved in the regulation of myogenic differentiation, Ahnak and Rbm24. Specifically, the RNA binding protein Rbm24 is a major regulator of muscle specific alternative splicing and its downregulation by microRNA-222 results in defective exon inclusion impairing the production of muscle-specific isoforms of Coro6, Fxr1 and NACA transcripts. Reconstitution of normal levels of Rbm24 in cells overexpressing microRNA-222 rescues muscle-specific splicing. In conclusion, we have identified a new function of microRNA-222 leading to alteration of myogenic differentiation at the level of alternative splicing, and we provide evidence that this effect is mediated by Rbm24 protein. We built linear models using 2 different experiments and two conditions (miR222 over expression (n=1) and control siRNA(n=2)) with the linear formula (~condition + experiment).
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.