Project description:Progression through the mitotic cell cycle requires periodic regulation of gene function at the levels of transcription, translation, protein-protein interactions, post-translational modification and degradation. However, the role of alternative splicing (AS) in the temporal control of cell cycle is not well understood. By sequencing the human transcriptome through two continuous cell cycles, we identify ~1,300 genes with cell cycle-dependent AS changes. These genes are significantly enriched in functions linked to cell cycle control, yet they do not significantly overlap genes subject to periodic changes in steady-state transcript levels. Many of the periodically spliced genes are controlled by the SR protein kinase CLK1, whose level undergoes cell cycle-dependent fluctuations via an auto-inhibitory circuit. Disruption of CLK1 causes pleiotropic cell cycle defects and loss of proliferation, whereas CLK1 over-expression is associated with various cancers. These results thus reveal a large program of CLK1-regulated periodic AS intimately associated with cell cycle control.
Project description:Progression through the mitotic cell cycle requires periodic regulation of gene function at the levels of transcription, translation, protein-protein interactions, post-translational modification and degradation. However, the role of alternative splicing (AS) in the temporal control of cell cycle is not well understood. By sequencing the human transcriptome through two continuous cell cycles, we identify ~1,300 genes with cell cycle-dependent AS changes. These genes are significantly enriched in functions linked to cell cycle control, yet they do not significantly overlap genes subject to periodic changes in steady-state transcript levels. Many of the periodically spliced genes are controlled by the SR protein kinase CLK1, whose level undergoes cell cycle-dependent fluctuations via an auto-inhibitory circuit. Disruption of CLK1 causes pleiotropic cell cycle defects and loss of proliferation, whereas CLK1 over-expression is associated with various cancers. These results thus reveal a large program of CLK1-regulated periodic AS intimately associated with cell cycle control.
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:Cell cycle is the center of cellular activities and is orchestrated by complex regulatory mechanisms, among which transcriptional regulation is one of the most important parts. Alternative splicing dramatically expands the regulatory network by producing transcript isoforms of genes to exquisitely control the cell cycle. However, the patterns of transcript isoform expression in the cell cycle are unclear. Therapies targeting cell cycle checkpoints are commonly used as anticancer therapies, but none of them were designed and have been evaluated at alternative splicing transcripts level. To explore alternative splicing patterns during cell cycle progression, we performed sequential transcriptomic assays following cell cycle synchronization in breast cancer MDA-MB-231 cell lines, used flow cytometry and reference cell cycle transcripts to confirm the cell cycle phases of samples.
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 achieves coordinated changes in post-transcriptional gene expression programs through the activities of diverse RNA binding proteins. Epithelial Splicing Regulatory Proteins 1 and 2 (ESRP1 and ESRP2) are cell type-specific regulators of transcripts that switch splicing during the Epithelial Mesenchymal Transition (EMT). To define a comprehensive program of alternative splicing that is regulated during the EMT, we identified an extensive ESRP-regulated splicing network of hundreds of alternative splicing events within numerous genes with roles in cell-cell adhesion, polarity, and migration. Loss of this global ESRP-regulated epithelial splicing program induces the phenotypic changes in cell morphology that are observed during the EMT. Components of this splicing signature provide novel molecular markers that can be used to characterize the EMT. Bioinformatics and experimental approaches revealed a high affinity ESRP binding motif and a predictive RNA map that governs their activity. This work establishes the ESRPs as coordinators of a complex alternative splicing network that adds an important post-transcriptional layer to the changes in gene expression that underlie epithelial-mesenchymal transitions during development and disease. Keywords: control / knockdown comparison and control / ectopic expression comparison
Project description:The eukaryotic cell cycle, driven by both transcriptional and post-translational mechanisms, is the central molecular oscillator underlying tissue growth throughout animals. While genome-wide studies have investigated cell cycle-associated transcription in unicellular systems, global patterns of periodic transcription in multicellular tissues remain largely unexplored. Here we define the cell cycle-associated transcriptome of the developing Drosophila wing epithelium and compare it with that of cultured Drosophila S2 cells, revealing a core set of periodic genes as well as a surprising degree of context-specificity in periodic transcription. We further employ RNAi-mediated phenotypic profiling to define functional requirements for over 300 periodic genes, with a focus on those required for cell proliferation in vivo. Finally, we investigate the role of novel genes required for interkinetic nuclear migration. Combined, these findings provide a global perspective on cell cycle control in vivo, and highlight a critical need to understand the context-specific regulation of cell proliferation. Cells from developing Drosophila wing epithelium, and cultured S2 cells are FACS sorted into G1 and G2 populations based on DNA content and compared in triplicate on Affymetrix microarrays to identify differences in the transcriptional program of the cell cycle by cell type.
Project description:The long noncoding MALAT1 RNA is upregulated in cancer tissues and its elevated expression is associated with hyper-proliferation, but the underlying mechanism is poorly understood. We demonstrate that MALAT1 levels are regulated during normal cell cycle progression. Genome-wide transcriptome analyses in normal human diploid fibroblasts reveal that MALAT1 modulates the expression of cell cycle genes, and is required for G1/S and mitotic progression. Depletion of MALAT1 leads to activation of p53 and its target genes. The cell cycle defects observed in MALAT1-depleted cells are sensitive to p53 levels, indicating that p53 is a major downstream mediator of MALAT1 activity. Furthermore, MALAT1-depleted cells display reduced expression of B-MYB (Mybl2), an oncogenic transcription factor involved in G2/M progression, due to altered binding of splicing factors on B-MYB pre-mRNA and aberrant alternative splicing. In human cells, MALAT1 promotes cellular proliferation by modulating the expression and/or premRNA processing of cell cycle-regulated transcription factors. These findings provide mechanistic insights on the role of MALAT1 in regulating cellular proliferation. Keywords: MALAT1; MALAT-1, NEAT2, ncRNA; E2F, alternative splicing; pre-mRNA splicing factors WI38 cells (normal human diploid fibroblasts) were transfected with a control oligo (CTR) or antisense oligos to MALAT1 and RNA was isolated after 48 hr. Two antisense oligos were use for MALAT1 (AS-1 and AS-2). Arrays were done for 3 sets of samples in triplicate (control, AS-1 and AS-2).
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.
Project description:The long noncoding MALAT1 RNA is upregulated in cancer tissues and its elevated expression is associated with hyper-proliferation, but the underlying mechanism is poorly understood. We demonstrate that MALAT1 levels are regulated during normal cell cycle progression. Genome-wide transcriptome analyses in normal human diploid fibroblasts reveal that MALAT1 modulates the expression of cell cycle genes, and is required for G1/S and mitotic progression. Depletion of MALAT1 leads to activation of p53 and its target genes. The cell cycle defects observed in MALAT1-depleted cells are sensitive to p53 levels, indicating that p53 is a major downstream mediator of MALAT1 activity. Furthermore, MALAT1-depleted cells display reduced expression of B-MYB (Mybl2), an oncogenic transcription factor involved in G2/M progression, due to altered binding of splicing factors on B-MYB pre-mRNA and aberrant alternative splicing. In human cells, MALAT1 promotes cellular proliferation by modulating the expression and/or premRNA processing of cell cycle-regulated transcription factors. These findings provide mechanistic insights on the role of MALAT1 in regulating cellular proliferation. Keywords: MALAT1; MALAT-1, NEAT2, ncRNA; E2F, alternative splicing; pre-mRNA splicing factors