Splicing factor U2AF2 promotes inclusion of exons with poor nucleosome phasing
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE270327 | GEO | 2025/04/10
REPOSITORIES: GEO
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Project description:Splicing factor U2AF2 promotes inclusion of exons with poor nucleosome phasing
| PRJNA1126206 | ENA
Project description:Long introns with short exons in vertebrate genes are thought to require spliceosome assembly across exons (exon definition), rather than introns, thereby requiring transcription of an exon to splice an upstream intron. Here, we developed CoLa-seq (co-transcriptional lariat sequencing) to investigate the timing and determinants of co-transcriptional splicing genome wide. Unexpectedly, 90% of all introns, including long introns, can splice before transcription of a downstream exon, indicating that exon definition is not obligatory for most human introns. Still, splicing timing varies dramatically across introns, and various genetic elements determine this variation. Strong U2AF2 binding to the polypyrimidine tract predicts early splicing, explaining exon definition-independent splicing. Together, our findings question the essentiality of exon definition and reveal features beyond intron and exon length that are determinative for splicing timing.
2022-11-26 | GSE204834 | GEO
Project description:This work provides the first evidence that Qk is a global regulator of splicing in vertebrates, defines a new splicing regulatory network in muscle, and suggests that overlapping splicing networks contribute to the complexity of changes in alternative splicing during differentiation. Alternative splicing contributes to muscle development and differentiation, but the complete set of muscle splicing factors and their combinatorial interactions are not known. Previously work identifies ACUAA (STAR motif) as an enriched sequence near muscle-specific alternative exons such as Capzb exon 9. We did mass spectrometry of proteins selected by wild type and mutant Capzb intron 9 RNA affinity chromatography, and identified Quaking (Qk), a protein known to regulate mRNA function through ACUAA motifs in 3' UTRs. We show that in myoblasts, Qk promotes inclusion of Capzb exon 9 in opposition to repression by PTB. Qk knockdown in myoblasts has little effect on transcript levels, but alters inclusion of 824 cassette exons whose adjacent intron sequences are enriched in ACUAA motifs. During differentiation to myotubes, Qk levels increase 2-3 fold, suggesting a mechanism for Qk-responsive exon regulation. We captured the PTB splicing regulatory network and intersected it with the Qk network, identifying overlap between the functions of Qk and PTB. Approximately 60% of exons whose inclusion is altered during myogenesis appear to be under control of one or both of these splicing factors in myoblasts. This series is the C2C12 differentiation data. It is 9 arrays, 3 timepoints, with 3 replicates. The time points are 0 hrs, 24 hrs, and 72hrs.
2013-06-05 | E-GEOD-40956 | biostudies-arrayexpress
Project description:This work provides the first evidence that Qk is a global regulator of splicing in vertebrates, defines a new splicing regulatory network in muscle, and suggests that overlapping splicing networks contribute to the complexity of changes in alternative splicing during differentiation. Alternative splicing contributes to muscle development and differentiation, but the complete set of muscle splicing factors and their combinatorial interactions are not known. Previously work identifies ACUAA (STAR motif) as an enriched sequence near muscle-specific alternative exons such as Capzb exon 9. We did mass spectrometry of proteins selected by wild type and mutant Capzb intron 9 RNA affinity chromatography, and identified Quaking (Qk), a protein known to regulate mRNA function through ACUAA motifs in 3' UTRs. We show that in myoblasts, Qk promotes inclusion of Capzb exon 9 in opposition to repression by PTB. Qk knockdown in myoblasts has little effect on transcript levels, but alters inclusion of 824 cassette exons whose adjacent intron sequences are enriched in ACUAA motifs. During differentiation to myotubes, Qk levels increase 2-3 fold, suggesting a mechanism for Qk-responsive exon regulation. We captured the PTB splicing regulatory network and intersected it with the Qk network, identifying overlap between the functions of Qk and PTB. Approximately 60% of exons whose inclusion is altered during myogenesis appear to be under control of one or both of these splicing factors in myoblasts. This series is the C2C12 Qk and PTB siRNA data. It is 12 arrays: 3 PTB siRNA arrays , 3 Qk siRNA arrays, and 6 mock siRNA arrays.
2013-06-05 | E-GEOD-40961 | biostudies-arrayexpress
Project description:This work provides the first evidence that Qk is a global regulator of splicing in vertebrates, defines a new splicing regulatory network in muscle, and suggests that overlapping splicing networks contribute to the complexity of changes in alternative splicing during differentiation. Alternative splicing contributes to muscle development and differentiation, but the complete set of muscle splicing factors and their combinatorial interactions are not known. Previously work identifies ACUAA (STAR motif) as an enriched sequence near muscle-specific alternative exons such as Capzb exon 9. We did mass spectrometry of proteins selected by wild type and mutant Capzb intron 9 RNA affinity chromatography, and identified Quaking (Qk), a protein known to regulate mRNA function through ACUAA motifs in 3' UTRs. We show that in myoblasts, Qk promotes inclusion of Capzb exon 9 in opposition to repression by PTB. Qk knockdown in myoblasts has little effect on transcript levels, but alters inclusion of 824 cassette exons whose adjacent intron sequences are enriched in ACUAA motifs. During differentiation to myotubes, Qk levels increase 2-3 fold, suggesting a mechanism for Qk-responsive exon regulation. We captured the PTB splicing regulatory network and intersected it with the Qk network, identifying overlap between the functions of Qk and PTB. Approximately 60% of exons whose inclusion is altered during myogenesis appear to be under control of one or both of these splicing factors in myoblasts.
2013-06-05 | GSE40961 | GEO
Project description:This work provides the first evidence that Qk is a global regulator of splicing in vertebrates, defines a new splicing regulatory network in muscle, and suggests that overlapping splicing networks contribute to the complexity of changes in alternative splicing during differentiation. Alternative splicing contributes to muscle development and differentiation, but the complete set of muscle splicing factors and their combinatorial interactions are not known. Previously work identifies ACUAA (STAR motif) as an enriched sequence near muscle-specific alternative exons such as Capzb exon 9. We did mass spectrometry of proteins selected by wild type and mutant Capzb intron 9 RNA affinity chromatography, and identified Quaking (Qk), a protein known to regulate mRNA function through ACUAA motifs in 3' UTRs. We show that in myoblasts, Qk promotes inclusion of Capzb exon 9 in opposition to repression by PTB. Qk knockdown in myoblasts has little effect on transcript levels, but alters inclusion of 824 cassette exons whose adjacent intron sequences are enriched in ACUAA motifs. During differentiation to myotubes, Qk levels increase 2-3 fold, suggesting a mechanism for Qk-responsive exon regulation. We captured the PTB splicing regulatory network and intersected it with the Qk network, identifying overlap between the functions of Qk and PTB. Approximately 60% of exons whose inclusion is altered during myogenesis appear to be under control of one or both of these splicing factors in myoblasts.
2013-06-05 | GSE40956 | GEO
Project description:22 Normal adult mouse tissues on custom alternative transcript sensitive Affymetrix microarray used to address differeneces in tissue specific alternative splicing. Abstract: Alternative splicing contributes to both gene regulation and protein diversity. To discover broad relationships between regulation of alternative splicing and sequence conservation, we applied a systems approach, using oligonucleotide microarrays designed to capture splicing information across the mouse genome. In a set of 22 adult tissues, we observe expression of RNA containing at least two alternative splice junctions for about a third of the 3200 alternative events we could detect. Statistical comparisons identify 171 cassette exons whose inclusion or skipping is different in brain relative to other tissues, and another 28 exons whose splicing is different in muscle. A subset of these exons is associated with unusual blocks of intron sequence whose conservation in vertebrates rivals that of protein-coding exons. By focusing on sets of exons with similar regulatory patterns, we have identified new sequence motifs implicated in brain and muscle splicing regulation. Of note is a motif strikingly similar to the branchpoint consensus, but which is located downstream of the 5' splice site of exons included in muscle. Analysis of three paralogous membrane-associated guanylate kinase (MAGUK) genes reveals that each contains a paralogous tissue regulated exon with a similar tissue inclusion pattern. While the intron sequences flanking these exons remain highly conserved among mammalian orthologs, the paralogous flanking intron sequences have diverged considerably, suggesting unusually complex evolution of the regulation of alternative splicing in multigene families. Keywords: Alternative splicing isoform specific, adult mouse tissues
2006-01-19 | GSE3063 | GEO
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.
2017-06-01 | GSE83923 | GEO
Project description:How the splicing machinery defines exons or introns as the spliced unit has remained a puzzle for 30 years. Here we demonstrate that peripheral and central regions of the nucleus harbor genes with two distinct exon-intron GC content architectures that differ in the splicing outcome. Genes with low GC content exons, flanked by long introns with lower GC content, are localized in the periphery, and the exons are defined as the spliced unit. Alternative splicing of these genes results in exon skipping. In contrast, the nuclear center contains genes with a high GC content in the exons and short flanking introns. Most splicing of these genes occurs via intron definition, and aberrant splicing leads to intron retention. We demonstrate that the nuclear periphery and center generate different environments for the regulation of alternative splicing, and that two sets of splicing factors form discrete regulatory subnetworks for the two gene architectures. Our study connects 3D genome organization and splicing, thus demonstrating that exon and intron definition modes of splicing occur in different nuclear regions.
2021-05-14 | GSE174396 | GEO
Project description:Background: Substantial progress has been made in the identification of sequence elements that control mRNA splicing and the genetic variants in these elements that alter mRNA splicing (referred to as splicing quantitative trait loci -- sQTLs). Genetic variants that affect mRNA splicing in trans are harder to identify because their effects can be more subtle and diffuse, and the variants are not co-located with their targets. We carried out a transcriptome-wide analysis of the effects of a mutation in a ubiquitous splicing factor that causes retinitis pigmentosa (RP) on mRNA splicing, using exon microarrays. Results: Exon microarray data was generated from whole blood samples obtained from four individuals with a mutation in the splicing factor PRPF8 and four sibling controls. Although the mutation has no known phenotype in blood, there was evidence of widespread differences in splicing between cases and controls (affecting between 10\% and 25\% of exons). Most probesets with significantly different inclusion (defined as the expression intensity of the exon divided by the expression of the corresponding transcript) between cases and controls had higher inclusion in cases and corresponded to exons that were shorter than average, AT-rich, located towards the 5' end of the gene and flanked by long introns. Introns flanking affected probesets were particularly depleted for the shortest category of introns, associated with splicing via intron definition. Conclusions: Our results show that a mutation in a splicing factor, with a phenotype that is restricted to retinal tissue, acts as a trans-sQTL cluster in whole blood samples. Characteristics of the affected exons suggest that they are spliced co-transcriptionally and via exon definition. Eight samples consisting of four sibling pairs were analysed. One individual in each pair harboured an RP-causing mutation on the PRPF8 gene (cases). Unaffected siblings were used as controls.
2012-12-25 | E-GEOD-43134 | biostudies-arrayexpress