Project description:SOX9 is known as a crucial transcription factor for various developmental processes and for tissue homeostasis. We examined here its potential role in alternative splicing by analyzing global splicing changes, using RNA-seq of colon tumor cells. We show that SOX9 knockdown alters the splicing of hundreds of genes without affecting their expression levels, revealing that SOX9 controls distinct splicing and transcriptional programs. SOX9 does not affect splicing patterns through the control of splicing factors expression. We identify mutants that uncouple SOX9 splicing function from its transcriptional activity. We demonstrate that SOX9 binds to RNA and associates with several RNA-binding proteins, including the core Exon Junction Complex component Y14. Half of SOX9 splicing targets are also modulated by Y14 and are no longer regulated by SOX9 upon Y14 depletion. Altogether, our work reveals that SOX9 is a moonlighting protein which modulates either transcription or splicing of distinct sets of targets.
Project description:Type 2 Diabetes Mellitus (T2D), a multifactorial disease, can result from perturbations in numerous pancreatic genes. We describe a previously unanticipated role for Sox9, a transcriptional regulator of embryonic pancreas and endocrine cell development, in mature beta cells. Our data demonstrate that Sox9 has continued function in beta cells as they mature, and elimination of Sox9 compromises beta cell activities. Sox9-depleted rodent beta cells fail to appropriately secrete insulin and exhibit glucose intolerance in aging animals, mimicking the progressive degeneration observed in T2D. Human beta cells lacking SOX9 are functionally impaired with stunted first phase insulin secretion. In both rodent and human, Sox9 loss in beta cells disrupts alternative splicing patterns, with significant implications for maintenance of cellular function. Thus, our data uncover a novel, unprecedented role for a developmental transcription factor in mature beta cell function.
Project description:Type 2 Diabetes Mellitus (T2D), a multifactorial disease, can result from perturbations in numerous pancreatic genes. We describe a previously unanticipated role for Sox9, a transcriptional regulator of embryonic pancreas and endocrine cell development, in mature beta cells. Our data demonstrate that Sox9 has continued function in beta cells as they mature, and elimination of Sox9 compromises beta cell activities. Sox9-depleted rodent beta cells fail to appropriately secrete insulin and exhibit glucose intolerance in aging animals, mimicking the progressive degeneration observed in T2D. Human beta cells lacking SOX9 are functionally impaired with stunted first phase insulin secretion. In both rodent and human, Sox9 loss in beta cells disrupts alternative splicing patterns, with significant implications for maintenance of cellular function. Thus, our data uncover a novel, unprecedented role for a developmental transcription factor in mature beta cell function.
Project description:Epigenetic dysregulation is a universal feature of cancer that results in altered patterns of gene expression that drive malignancy. Brain tumors exhibit subtype-specific epigenetic alterations, however the molecular mechanisms responsible for these diverse epigenetic states remain unclear. Here we show that the developmental transcription factor Sox9 differentially regulates epigenomic states in high-grade glioma (HGG) and ependymoma (EPN). These contrasting roles for Sox9 correspond with protein interactions with histone deacetylating complexes in HGG, and association with the Rela oncofusion in EPN. Together, our studies demonstrate how epigenomic states are differentially regulated in distinct subtypes of brain tumors, while revealing divergent roles for Sox9 in HGG and EPN tumorigenesis.
Project description:This SuperSeries is composed of the following subset Series: GSE23513: Position-dependent alternative splicing activity revealed by global profiling of alternative splicing events regulated by PTB (HJAY) GSE23514: Position-dependent alternative splicing activity revealed by global profiling of alternative splicing events regulated by PTB (Exon array) Refer to individual Series
Project description:Background: Despite the prevalence and biological relevance of both signalling pathways and alternative pre-mRNA splicing, our knowledge of how intracellular signalling impacts on alternative splicing regulation remains fragmentary. We report a genome-wide analysis of changes in alternative splicing using splicing-sensitive microarrays, induced by activation of two distinct signalling pathways, insulin and wingless, in Drosophila cells in culture. Results: Alternative splicing changes induced by insulin affect more than 150 genes and more than 50 genes are regulated by wingless activation. About 40% of the genes showing changes in alternative splicing also show regulation of mRNA levels, suggesting distinct but also significantly overlapping programs of transcriptional and posttranscriptional regulation. Distinct functional sets of genes are regulated by each pathway and, remarkably, a significant overlap is observed between functional categories of genes regulated transcriptionally and at the level of alternative splicing. Functions related with carbohydrate metabolism and cellular signalling are enriched among genes regulated by insulin and wingless, respectively. Computational searches identify pathway-specific sequence motifs enriched near regulated 5â splice sites. Conclusion: Taken together, our data indicate that signalling cascades trigger pathway-specific and biologically coherent regulatory programs of alternative splicing regulation. They also reveal that alternative splicing can provide a novel molecular mechanism for cross-talk between different signalling pathways. To monitor transcriptional and alternative splicing changes induced by activation of the insulin and wingless pathways, a custom-designed microarray platform was employed featuring probes for all Drosophila genes for which different mRNA isoforms generated by alternative splicing have been described (see Blanchette M, Green RE, Brenner SE, Rio DC: Global analysis of positive and negative pre-mRNA splicing regulators in Drosophila. Genes Dev 2005, 19(11):1306-1314.). Three biological replicates of total RNA isolated after pathway activation or controls (untreated cells for insulin, control dsRNA for wingless) were purified, reverse transcribed into cDNA and labelled with Cy5 or Cy3 fluorochromes and the cDNA was hybridized to the microarray,
Project description:Alternative polyadenylation has been implicated as an important regulator of gene expression. In some cases, alternative polyadenylation is known to couple with alternative splicing to influence last intron removal. However, it is unknown whether alternative polyadenylation events influence alternative splicing decisions at upstream exons. Knockdown of the polyadenylation factors CFIm25 or CstF64 was used as an approach in identifying alternative polyadenylation and alternative splicing events on a genome-wide scale. Although hundreds of alternative splicing events were found to be differentially spliced in the knockdown of CstF64, genes associated with alternative polyadenylation did not exhibit an increased incidence of alternative splicing. These results demonstrate that the coupling between alternative polyadenylation and alternative splicing is usually limited to defining the last exon. The striking influence of CstF64 knockdown on alternative splicing can be explained through its effects on UTR selection of known splicing regulators such as hnRNP A2/B1, thereby indirectly influencing splice site selection. We conclude that changes in the expression of the polyadenylation factor CstF64 influences alternative splicing through indirect effects. HeLa cell line was stably transfected with shRNA plasmids targeting CstF64. Total RNA was isolated from CstF64 KD cells and wild-type control cells using Trizol according to manufacturerâs protocols. Samples were deep sequenced in duplicate using the Illumina GAIIx system.
Project description:Background The complete sequencing of the human genome and its subsequent analysis revealed a predominant role for alternative splicing in the generation of proteome diversity. Splice switching oligonucleotides (SSOs) are a powerful and specific tool to experimentally control alternative splicing of endogenous messenger RNAs in living cells. SSOs also have therapeutic potential to treat diseases that are caused by aberrant splicing. The assignment of biological roles to alternative splicing events of currently unknown function promises to provide a largely untapped source of potential new therapeutic targets. Here we have developed a protocol that combines high sensitivity microarrays with the transfection of SSOs to monitor global changes in gene expression downstream of alternate, endogenous splice events. Findings When applied to a well-characterized splicing event in the Bcl-x gene, the application of high sensitivity microarrays revealed a link between the induction of the Bcl-xS isoform and the repression of genes involved in protein synthesis. Conclusions The strategy introduced herein provides a useful approach to define the biological impact of any given alternative splicing event on global gene expression patterns. Furthermore, our data provide the first link between Bcl-xS expression and the repression of ribosomal protein gene expression. Biological triplicates, 2 conditions: control oligonucleotide, Bcl-x oligonucleotide
Project description:We analyzed alternative splicing with Shh medulloblastoma. This dataset contains bam files of whole genome sequencing from 4 cases. Genomic DNA was isolated from both tumor and matched control specimens. We performed whole genome sequence on Illumina Hiseq.