Project description:Alternative splicing drives transcriptome and proteome diversification. While splicing regulatory proteins govern this process, their global mechanisms remain enigmatic. We generated high resolution transcriptome-wide protein-RNA interaction maps to determine how the splicing repressor hnRNPA1 influences the global association of spliceosome assembly factor U2AF2 and SRSF1 with pre-mRNA. We observed changes in the distribution of U2AF2 crosslinking sites relative to the 3’ splice sites of cassette exons but not constitutive exons upon hnRNPA1 overexpression. By contrast, SRSF1 crosslinking patterns relative to splice sites are independent of hnRNPA1 expression levels. We also observed an hnRNPA1-dependent increase in U2AF2 but not SRSF1 crosslinking to exon proximal antisense Alu elements. Thus Alu elements can serve as splicing factor-responsive sinks for U2AF2. These results not only demonstrate a novel mechanism for alternative splicing regulation but also implicate retrotransposon-derived sequences in the evolution of species-specific alternative splicing.
Project description:T cell activation leads to dramatic changes in cellular phenotype. We used CD3/CD28-activated human CD4 T cells to study how RNA binding proteins define the post-transcriptional landscape. Using RIPseq, we identified the RNA interactome of U2AF2 and show at the global level that U2AF2 binds the majority of transcripts that are differentially expressed and/or alternatively spliced during CD4 T cell activation. A unique protein interactome centered on U2AF2 is assembled in response to activation. Knocking down specific U2AF2 interacting partners (U2AF1, SYNCRIP, SRRM2, ILF2) selectively affects cytokine secretion and expression of activation markers. Furthermore, the expression and/or alternative splicing of transcripts important for immune cell function are also affected by knocking down these U2AF2 interacting proteins. U2AF1 and SYNCRIP knockdowns affect the proteins and transcripts bound to U2AF2, altering the transcriptome. Our work highlights the importance of RNA binding protein complexes in regulating the differential expression and alternative splicing that defines T cell activation. U2AF2 RIPseq on a primary CD4 T cell culture at rest and 48 hours after anti-CD3/CD28 bead activation
Project description:T cell activation leads to dramatic changes in cellular phenotype. We used CD3/CD28-activated human CD4 T cells to study how RNA binding proteins define the post-transcriptional landscape. Using RIPseq, we identified the RNA interactome of U2AF2 and show at the global level that U2AF2 binds the majority of transcripts that are differentially expressed and/or alternatively spliced during CD4 T cell activation. A unique protein interactome centered on U2AF2 is assembled in response to activation. Knocking down specific U2AF2 interacting partners (U2AF1, SYNCRIP, SRRM2, ILF2) selectively affects cytokine secretion and expression of activation markers. Furthermore, the expression and/or alternative splicing of transcripts important for immune cell function are also affected by knocking down these U2AF2 interacting proteins. U2AF1 and SYNCRIP knockdowns affect the proteins and transcripts bound to U2AF2, altering the transcriptome. Our work highlights the importance of RNA binding protein complexes in regulating the differential expression and alternative splicing that defines T cell activation. RNAseq of total RNA from a primary CD4 T cell culture at rest and 48 hours after anti-CD3/CD28 bead activation
Project description:T cell activation leads to dramatic changes in cellular phenotype. We used CD3/CD28-activated human CD4 T cells to study how RNA binding proteins define the post-transcriptional landscape. Using RIPseq, we identified the RNA interactome of U2AF2 and show at the global level that U2AF2 binds the majority of transcripts that are differentially expressed and/or alternatively spliced during CD4 T cell activation. A unique protein interactome centered on U2AF2 is assembled in response to activation. Knocking down specific U2AF2 interacting partners (U2AF1, SYNCRIP, SRRM2, ILF2) selectively affects cytokine secretion and expression of activation markers. Furthermore, the expression and/or alternative splicing of transcripts important for immune cell function are also affected by knocking down these U2AF2 interacting proteins. U2AF1 and SYNCRIP knockdowns affect the proteins and transcripts bound to U2AF2, altering the transcriptome. Our work highlights the importance of RNA binding protein complexes in regulating the differential expression and alternative splicing that defines T cell activation. HTA 2.0 microarray results of U2AF2 RIP RNA from a primary CD4 T cell culture after treatment with siRNAs (Control, U2AF1, and SYNCRIP) and 24 hours after anti-CD3/CD28 bead activation Please note that the Series supplementary 'U2AF2RIP_HTA2_all_siRNA_100414.xlsx' file includes multiple worksheets containing: 1) Differentially expressed genes in ctrl siRNA vs. U2AF1 siRNA; 2) Differntially spliced genes in ctrl siRNA vs. U2AF1 siRNA; 3) Differentially spliced exons in ctrl siRNA vs. U2AF1 siRNA; 4) Differentially expressed genes in ctrl siRNA vs. SYNCRIP siRNA; 5) Differntially spliced genes in ctrl siRNA vs. SYNCRIP siRNA; 6) Differentially spliced exons in ctrl siRNA vs. SYNCRIP siRNA
Project description:T cell activation leads to dramatic changes in cellular phenotype. We used activated human CD4 T cells to study how RNA binding proteins define the post-transcriptional landscape. Using RIPseq, we identified the RNA interactome of U2AF2 and show that U2AF2 binds the majority of transcripts that are differentially expressed and/or alternatively spliced during activation. Using RIP mass spectrometry, a unique protein interactome centered on U2AF2 is assembled by activation and comprised of both directly bound central members (RNAse-resistant) and indirectly bound peripheral members (RNAse-sensitive). Knocking down specific U2AF2 interactome members (U2AF1, SYNCRIP, SRRM2, ILF2) selectively affects cytokine secretion and activation markers. The expression and/or alternative splicing of transcripts important for immune cell function are also affected by knocking down these interactome members, both peripheral and central. Furthermore, we show that knockdown of interactome members can affect the proteins and transcripts bound to U2AF2, altering the transcriptome of activated T cells. Our work highlights the importance of understanding the assembly of RNA binding protein complexes as regulators of T cell activation and function.
Project description:T cell activation leads to dramatic changes in cellular phenotype. We used activated human CD4 T cells to study how RNA binding proteins define the post-transcriptional landscape. Using RIPseq, we identified the RNA interactome of U2AF2 and show that U2AF2 binds the majority of transcripts that are differentially expressed and/or alternatively spliced during activation. Using RIP mass spectrometry, a unique protein interactome centered on U2AF2 is assembled by activation and comprised of both directly bound central members (RNAse-resistant) and indirectly bound peripheral members (RNAse-sensitive). Knocking down specific U2AF2 interactome members (U2AF1, SYNCRIP, SRRM2, ILF2) selectively affects cytokine secretion and activation markers. The expression and/or alternative splicing of transcripts important for immune cell function are also affected by knocking down these interactome members, both peripheral and central. Furthermore, we show that knockdown of interactome members can affect the proteins and transcripts bound to U2AF2, altering the transcriptome of activated T cells. Our work highlights the importance of understanding the assembly of RNA binding protein complexes as regulators of T cell activation and function.
Project description:The essential pre-mRNA splicing factor U2AF2 (also called U2AF65) identifies polypyrimidine (Py) tract signals of nascent transcripts, despite length and sequence variations. Previous studies have shown that the U2AF2 RNA recognition motifs (RRM1 and RRM2) preferentially bind uridine-rich RNAs. Nonetheless, the specificity of the RRM1/RRM2 interface for the central Py tract nucleotide has yet to be investigated. Enhanced crosslinking and immunoprecipitation of endogenous U2AF2 in human erythroleukemia cells showed uridine-sensitive binding sites with lower sequence conservation at the central nucleotide positions of otherwise uridine-rich, U2AF2-bound splice sites. Altogether, these results highlight the importance of RNA flexibility for protein recognition and take a step towards relating splice site motifs to pre-mRNA splicing efficiencies. Keywords: splicing, RNA binding, U2AF2, U2AF65, 3'SS, 3' splice site, eCLIP, polypyrimidine tract, RNA recognition motif, RRM, U-rich, Py-tract
Project description:The 2-oxoglutarate dependent protein JMJD6 acts as a lysyl hydroxylase on specific residues of the splicing factor U2AF2. To understand the molecular roles of JMJD6 in normal haematopoiesis and identify any role of JMJD6 in splicing, we performed RNA-sequencing on Lin-Sca1+Kit+ (LSK) haematopoietic stem and progenitor cells (HSPCs) derived from young mice.
Project description:T cell activation leads to dramatic changes in cellular phenotype. We used CD3/CD28-activated human CD4 T cells to study how RNA binding proteins define the post-transcriptional landscape. Using RIPseq, we identified the RNA interactome of U2AF2 and show at the global level that U2AF2 binds the majority of transcripts that are differentially expressed and/or alternatively spliced during CD4 T cell activation. A unique protein interactome centered on U2AF2 is assembled in response to activation. Knocking down specific U2AF2 interacting partners (U2AF1, SYNCRIP, SRRM2, ILF2) selectively affects cytokine secretion and expression of activation markers. Furthermore, the expression and/or alternative splicing of transcripts important for immune cell function are also affected by knocking down these U2AF2 interacting proteins. U2AF1 and SYNCRIP knockdowns affect the proteins and transcripts bound to U2AF2, altering the transcriptome. Our work highlights the importance of RNA binding protein complexes in regulating the differential expression and alternative splicing that defines T cell activation. HTA 2.0 microarray results of total from a primary CD4 T cell culture after treatment with siRNAs (Control, U2AF1, SRRM2, SYNCRIP, and ILF2) and 24 hours after anti-CD3/CD28 bead activation Please note that the Series supplementary 'TotalRNA_HTA2_all_siRNA_100414.xslx' file has multiple worksheets containing: 1) Differentially expressed genes in ctrl siRNA vs. U2AF1 siRNA; 2) Differntially spliced genes in ctrl siRNA vs. U2AF1 siRNA; 3) Differentially spliced exons in ctrl siRNA vs. U2AF1 siRNA; 4) Differentially expressed genes in ctrl siRNA vs. SRRM2 siRNA; 5) Differntially spliced genes in ctrl siRNA vs. SRRM2 siRNA; 6) Differentially spliced exons in ctrl siRNA vs. SRRM2 siRNA; 7) Differentially expressed genes in ctrl siRNA vs. SYNCRIP siRNA; 8) Differntially spliced genes in ctrl siRNA vs. SYNCRIP siRNA; 9) Differentially spliced exons in ctrl siRNA vs. SYNCRIP siRNA; 10) Differentially expressed genes in ctrl siRNA vs. ILF2 siRNA; 11) Differntially spliced genes in ctrl siRNA vs. ILF2 siRNA; 12) Differentially spliced exons in ctrl siRNA vs. ILF2 siRNA
Project description:Splicing factor mutations are common among cancers, recently emerging as drivers of myeloid malignancies. U2AF1 carries hotspot mutations in its RNA binding motifs; yet how they affect splicing and promote cancer remains unclear. The U2AF1/U2AF2 heterodimer is critical for 3’ splice site (3’SS) definition. To specifically unmask changes in U2AF1 function in vivo, we developed a crosslinking and immunoprecipitation procedure detecting contacts between U2AF1 and the 3’SS AG at single-nucleotide resolution (fractionated eCLIP-seq or freCLIP-seq). Our data reveal that U2AF1 S34F and Q157R mutants establish new 3’SS contacts at -3 and +1 nucleotides, respectively. These effects compromise U2AF2-RNA interactions, resulting predominantly in intron retention and exon exclusion. Integrating RNA binding (eCLIP-seq and freCLIP-seq), splicing (RNA-seq) and turnover (TimeLapse-seq or TL-seq) data, we predicted that U2AF1 mutations directly affect stress granule components. Remarkably, U2AF1-mutant cell lines and patient-derived MDS/AML blasts displayed a heightened stress granule response, pointing to a novel role for biomolecular condensates in adaptive oncogenic strategies. Keywords: splicing, RNA binding, U2AF1, U2AF2, S34F, Q157R, hotspot mutations, 3'SS, 3' splice site, myeloid malignancies, eCLIP, freCLIP, RNA-seq, RNA turnover, TimeLapse-seq, TL-seq, RNA granules, stress granules, stress response, biomolecular condensates, MDS, AML