Project description:The investigation of spliceosomal processes is currently a topic of intense research in molecular biology. In the molecular mechanism of alternative splicing, a multi-protein–RNA complex – the spliceosome – plays a crucial role. To understand the biological processes of alternative splicing, it is essential to comprehend the biogenesis of the spliceosome.
In this paper, we propose the first abstract model of the regulatory assembly pathway of the human spliceosomal subunit U1. Using Petri nets, we describe its highly ordered assembly that takes place in a stepwise manner.
Project description:The spliceosome is a multimolecular ribonucleoprotein complex, which catalyzes the removal of introns from pre-mRNA and extends the complexity of genetic information by defining alternative transcripts. Here we analyzed the in vivo function of CD2BP2, which is a marker of early spliceosomal complexes. Using gene targeting in mice, we show that constitutive or mesoderm- specific ablation of the CD2BP2 gene causes embryonic lethality by E10.5 associated with delayed development, growth retardation and pericard effusion. Transcriptome analysis in CD2BP2 deficient bone-marrow-derived macrophages (BMM) and podocytes revealed dramatic alterations in the alternative splicing pattern of several mRNAs including VEGFA. Consistent with a previously described critical role of specific VEGFA isoforms for podocyte integrity, mice, which specifically lack CD2BP2flox/flox in this cell type, develop progressive albuminuria followed by lethal kidney failure. We further identified the phosphatase PP1 as a GYF domain independent CD2BP2 interaction partner, suggesting that CD2BP2 acts as an important modulator for spliceosome dephosphorylation, thereby affecting alternative splicing of physiologically highly relevant transcripts.
Project description:Splicing factor SRSF10 is known to function as a sequence-specific splicing activator. Here, we used RNA-seq coupled with bioinformatics analysis to identify the extensive splicing network regulated by SRSF10 in chicken cells. We found that SRSF10 promoted both exon inclusion and exclusion. Functionally, many of SRSF10-verified alternative exons are linked to pathways of stress and apoptosis. Importantly, reconstituted SRSF10 in knockout cells recovered wild-type splicing patterns and considerably rescued the stress-related defects. Together, our results provide mechanistic insight into SRSF10-regulated alternative splicing events in vivo and demonstrate that SRSF10 plays a crucial role in cell survival under stress conditions. RNA-seq for wide type (WT) and SRSF10-deficient (KO) chicken DT40 cells
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:Transcriptome analysis of total RNA samples from heart tissue of knockout mice Alternative splicing is the main mechanism to increase protein diversity from an mRNA. Heterogeneous ribonucleoprotein (hnRNP) family members are vital regulators of alternative splicing. The hnRNP A1 is the most well-known protein in this family, but its role in embryonic development is not well understood. We generated hnRNP A1 knockout mice to study the function of hnRNP A1 in vivo. The hnRNP A1-depleted mice showed embryonic lethality because of muscle developmental defects. In a previous study, cellular hnRNP A2/B1 was reported to be capable of compensating for the expression of hnRNP A1. However, this phenomenon did not occur in the hnRNP A1 heterozygous mice in vivo. We demonstrated that hnRNP A1 regulated muscle-related genes expression and alternative splicing. In summary, our data demonstrated that hnRNP A1 plays a critical role in embryonic muscle development. Understanding the effects of hnRNP A1 in vivo may help to define the function of hnRNP A1 in alternative splicing.
Project description:This SuperSeries is composed of the following subset Series: GSE30995: An Alternative Splicing Switch Regulates Embryonic Stem Cell Pluripotency and Reprogramming [RNA-Seq] GSE31006: An Alternative Splicing Switch Regulates Embryonic Stem Cell Pluripotency and Reprogramming [ChIP-Seq] GSE31007: An Alternative Splicing Switch Regulates Embryonic Stem Cell Pluripotency and Reprogramming [protein binding microarray] GSE31948: An Alternative Splicing Switch Regulates Embryonic Stem Cell Pluripotency and Reprogramming [AS microarray] Refer to individual Series
Project description:Tumor metastasis is the most lethal attribute of breast cancer, and the epithelial-mesenchymal transition (EMT) plays an important role in this process. Alternative splicing has been shown to causally contribute to EMT; however, the scope of critical splicing events and the regulatory network of splicing factors that govern them remain largely unexplored. Here we report the identification of A-Kinase Anchor Protein (AKAP8) as an EMT splicing regulatory factor that impedes EMT and breast cancer metastasis. AKAP8 not only is capable of inhibiting splicing activity of the EMT-promoting splicing regulator hnRNPM through protein-protein interaction, it also binds to RNA directly and alters splicing outcomes. Genome-wide analysis revealed that AKAP8-mediated splicing events, specifically in epithelial cells, are reversely regulated during EMT, suggesting that AKAP8 maintains an epithelial cell-state splicing program. Experimental manipulation of a newly identified AKAP8 splicing target calsyntenin-1 (CLSTN1) revealed that splice isoform switching of CLSTN1 is crucial for EMT. Mining breast cancer patient data supports the experimental findings and AKAP8 expression and the alternative splicing of CLSTN1 predict patient survival. Our work demonstrates the essentiality of RNA metabolism that impinges on metastatic breast cancer.
Project description:Splicing factor SRSF10 is known to function as a sequence-specific splicing activator. Here, we used RNA-seq coupled with bioinformatics analysis to identify the extensive splicing network regulated by SRSF10 in chicken cells. We found that SRSF10 promoted both exon inclusion and exclusion. Functionally, many of SRSF10-verified alternative exons are linked to pathways of stress and apoptosis. Importantly, reconstituted SRSF10 in knockout cells recovered wild-type splicing patterns and considerably rescued the stress-related defects. Together, our results provide mechanistic insight into SRSF10-regulated alternative splicing events in vivo and demonstrate that SRSF10 plays a crucial role in cell survival under stress conditions.