Project description:Low and disturbed blood flow drives the progression of arterial diseases including atherosclerosis and aneurysms. The endothelial response to flow and its interactions with recruited platelets and leukocytes determine disease progression. Here, we report widespread changes in alternative splicing of pre-mRNA in the flow-activated murine arterial endothelium in vivo. Alternative splicing was suppressed by depletion of platelets and macrophages recruited to the arterial endothelium under low and disturbed flow. Binding motifs for the Rbfox-family are enriched adjacent to many of the regulated exons. Endothelial deletion of Rbfox2, the only family member expressed in arterial endothelium, suppresses a subset of the changes in transcription and RNA splicing induced by low flow. Our data reveal an alternative splicing program activated by Rbfox2 in the endothelium on recruitment of platelets and macrophages and demonstrate its relevance in transcriptional responses during flow-driven vascular inflammation.
Project description:We generated a global analysis of Rbfox2 splicing regulation combined with a highly specific, single nucleotide-resolution Rbfox2 RNA binding map. We found that Rbfox2 regulates the splicing and expression of many previously unknown targets, and particularly a number of RNA binding proteins (RBPs), by modulating alternative splicing coupled-NMD. Based on our observations of RBP-Rbfox2 co-regulation with a polarity predicted by Rbfox2 binding, we propose a model whereby Rbfox2 tunes autoregulatory splicing events to control RBP expression levels and in turn alter their respective splicing networks. iCLIP for epitope-tagged Rbfox2 and control untagged Rbfox2; RNAseq of control and Rbfox2 knockdown in mouse embryonic stem cells
Project description:Exposure of the arterial endothelium to low and disturbed flow is a risk factor for the erosion and rupture of atherosclerotic plaques and aneurysms. Circulating and locally produced proteins are known to contribute to an altered matrix composition at the site of lesions, and to contribute to inflammatory processes within the lesions by altering the sub-endothelial matrix. We have previously shown that immune-cell regulated alternative splicing of Fibronectin (FN) protects against flow-induced hemorrhage. Here, we perform quantitative proteomic analysis of enriched extracellular matrix preparations from murine carotid arteries exposed to low and disturbed flow in vivo and examine serum derived and endothelial cell contributions to the sub-endothelial matrix in vitro. Our results reveal the extent of the dynamic alterations in extracellular matrix composition in the acute response to low and disturbed flow, and show how changes in the splicing of FN, a common response in vascular inflammation and remodeling, affects matrix composition.
Project description:We generated a global analysis of Rbfox2 splicing regulation combined with a highly specific, single nucleotide-resolution Rbfox2 RNA binding map. We found that Rbfox2 regulates the splicing and expression of many previously unknown targets, and particularly a number of RNA binding proteins (RBPs), by modulating alternative splicing coupled-NMD. Based on our observations of RBP-Rbfox2 co-regulation with a polarity predicted by Rbfox2 binding, we propose a model whereby Rbfox2 tunes autoregulatory splicing events to control RBP expression levels and in turn alter their respective splicing networks.
Project description:RBFOX2 is an RNA binding protein that directs alternative splicing. In this study, we characterized RBFOX2-mediated alternative splicing in pancreatic cancer (PDAC) In this dataset, we assayed gene-level and exon-level expression differences in pancreatic cancer cell lines replete and depleted for RBFOX2 expression and in 8 pairs of orthotopic pancreas tumors and related liver metastases generated from human 4039 or Panc1 cell lines replete or depleted for RBFOX2.
Project description:Purpose: The goals of this study are to compare transcriptomes using RNA-seq of mouse myoblasts (C2C12 cell line) in undifferentiated and differentiated states and with siRNA-mediated knock down of the RNA binding proteins, Rbfox1 (only expressed in differentiated state) and Rbfox2 (expressed in both undifferentiated and differentiated states). Methods: Differentiated and undifferentiated C2C12 cultures treated with Rbfox1 (differentiated only) or Rbfox2 siRNAs or a mock siRNA transfection were used for RNA-Seq analysis using Illumina HiSeq2000. 101x2 paired-end RNA-seq reads were first uniquely aligned to the mouse genome (mm9) using TopHat 1.4.1. RSEM was used to count the number of reads mapped to genes using UCSC database, followed by edgeR to call differentially expressed genes with false discovery rate less than 0.01. Cufflinks was used to reconstruct isoforms and analyze alternative splicing and percent spliced in (PSI) was calculated. PSI values were validated by RT-PCR. Results: 58-88% of the RNA-seq reads from technical and biological replicates mapped uniquely to the mouse genome. Analysis of gene expression and alternative splicing changes are published in Singh et al. Molecular Cell (2014). Conclusions: Our study has identified gene expression and alternative splicing transitions that occur during myoblast differentiation, demonstrate that 30% of the splicing transitions are regulated by Rbfox2, demonstrated that Rbfox2 is required for a late step of myoblast differentiation and identified two Rbfox2-regulated splicing transitions that are required for differentiation. Undifferentiated and differentiated C2C12 cultures with Rbfox2 depletion or Rbfox1 depletion (differentiated only) in at least duplicate samples analyzed by deep sequencing on Illumina HiSeq2000.
Project description:ABSTRACT 20-30% of patients with nasopharyngeal carcinoma (NPC) develop distant metastasis or recurrence leading to poor survival, of which the underlying key molecular events have yet to be addressed. Here we profiled alternative splicing events in 85 NPC samples using transcriptome analysis and revealed that the long isoform of GOLIM4 (-L) with exon-7 was highly expressed in NPC and associated with poor prognosis. Lines of evidence demonstrated the pro-tumorigenic function of GOLIM4-L in NPC cells. We further revealed that RBFOX2 binds to a GGAA motif in exon-7 and promotes its inclusion forming GOLIM4-L. RBFOX2 knockdown suppressed the tumorigenesis of NPC cells, phenocopying GOLIM4-L knockdown, which was significantly rescued by GOLIM4-L overexpression. Moreover, high expression of RBFOX2 was correlated with the exon-7 inclusion of GOLIM4 in NPC biopsies and associated with worse prognosis. Furthermore, we observed that RBFOX2 and GOLIM4 could influence vesicle-mediated transport through maintaining the organization of Golgi apparatus. Finally, we revealed that RAB26 interacted with GOLIM4 and mediated its tumorigenic potentials in NPC cells. Taken together, our findings provide insights into how alternative splicing contributes to NPC development, by highlighting a functional link between GOLIM4-L and its splicing regulator RBFOX2 activating vesicle-mediated transport involving RAB26. Keywords: GOLIM4, RBFOX2, Nasopharyngeal carcinoma (NPC), Alternative splicing, RAB26
Project description:Alternative splicing (AS) creates proteomic diversity from a limited size genome by generating numerous transcripts from a single protein-coding gene. Tissue-specific regulators of AS are essential components of the gene regulatory network, required for normal cellular function, tissue patterning, and embryonic development. However, their cell-autonomous function in neural crest development has not been explored. Here, we demonstrate that splicing factor Rbfox2 is expressed in the neural crest cells (NCCs) and deletion of Rbfox2 in NCCs leads to cleft palate and defects in craniofacial bone development. RNA-Seq analysis revealed that Rbfox2 regulates splicing and expression of numerous genes essential for neural crest/craniofacial development. We demonstrate that Rbfox2-TGF-β-Tak1 signaling axis is deregulated by Rbfox2 deletion. Furthermore, restoration of TGF-β signaling by Tak1 overexpression can rescue the proliferation defect seen in Rbfox2 mutants. We also identified a positive feedback loop in which TGF-β signaling promotes expression of Rbfox2 in NCCs.
Project description:Purpose: The goals of this study are to compare transcriptomes using RNA-seq of mouse myoblasts (C2C12 cell line) in undifferentiated and differentiated states and with siRNA-mediated knock down of the RNA binding proteins, Rbfox1 (only expressed in differentiated state) and Rbfox2 (expressed in both undifferentiated and differentiated states). Methods: Differentiated and undifferentiated C2C12 cultures treated with Rbfox1 (differentiated only) or Rbfox2 siRNAs or a mock siRNA transfection were used for RNA-Seq analysis using Illumina HiSeq2000. 101x2 paired-end RNA-seq reads were first uniquely aligned to the mouse genome (mm9) using TopHat 1.4.1. RSEM was used to count the number of reads mapped to genes using UCSC database, followed by edgeR to call differentially expressed genes with false discovery rate less than 0.01. Cufflinks was used to reconstruct isoforms and analyze alternative splicing and percent spliced in (PSI) was calculated. PSI values were validated by RT-PCR. Results: 58-88% of the RNA-seq reads from technical and biological replicates mapped uniquely to the mouse genome. Analysis of gene expression and alternative splicing changes are published in Singh et al. Molecular Cell (2014). Conclusions: Our study has identified gene expression and alternative splicing transitions that occur during myoblast differentiation, demonstrate that 30% of the splicing transitions are regulated by Rbfox2, demonstrated that Rbfox2 is required for a late step of myoblast differentiation and identified two Rbfox2-regulated splicing transitions that are required for differentiation.
Project description:Rbfox proteins regulate alternative splicing, mRNA stability and translation. These proteins are involved in neurogenesis and have been associated with various neurological conditions. We generated expression profile in adult and developing mouse retinas which lacks in Rbfox2 expression by RNA sequencing. The goals of this study is to identify the affected pathways in Rbfox2 KO mouse retina as well as potential splicing targets of Rbfox2.