Widespread Use of Non-Productive Alternative Splice Sites in Saccharomyces cerevisiae
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ABSTRACT:
ORGANISM(S): Saccharomyces cerevisiae BY4741
PROVIDER: GSE55213 | GEO | 2014/02/21
SECONDARY ACCESSION(S): PRJNA238899
REPOSITORIES: GEO
Similar Datasets
Project description:Using RNA-Seq analysis of nonsense-mediated mRNA decay (NMD) mutant strains, we show that many Saccharomyces cerevisiae intron-containing genes exhibit usage of alternative splice sites, but most transcripts generated by splicing from these sites are non-functional because they introduce premature termination codons leading to transcript degradation by NMD. Analysis of splicing mutants combined with NMD inactivation revealed the role of specific splicing factors in governing the use of these alternative splice sites and identified novel functions for Prp17p in enhancing the use of branchpoint-proximal upstream 3M-bM-^@M-^Y splice sites and for Prp18p in suppressing the usage of a non-canonical AUG 3M-bM-^@M-^Y-splice site. The use of non-productive alternative splice sites can limit the expression of some transcripts and can be increased in stress conditions in a promoter-dependent manner, contributing to the down-regulation of genes during stress. These results reveal that alternative splicing is frequent in S.cerevisiae but masked by RNA degradation and that the use of alternative splice sites is mostly aimed at controlling transcript levels rather than increasing proteome diversity. mRNA-Seq profiling of 3 mutants in the nonsense-mediated mRNA decay pathway and wildtype yeast
2014-02-21 | E-GEOD-55213 | biostudies-arrayexpress
Project description:Adjacent alternative 3’ splice sites, those separated by ≤18nt, provide a unique problem in the study of alternative splicing regulation; there is overlap of the cis-elements that define the adjacent sites. Identification of the intron's 3' end depends upon sequence elements that define the branchpoint, polypyrimidine tract and terminal AG dinucleotide. Starting with RNA-seq data from germline-enriched and somatic cell-enriched C. elegans samples, we identify hundreds of introns with adjacent alternative 3’ splice sites. We identify 203 events that undergo tissue-specific alternative splicing. For these, the regulation is mono-directional, with somatic cells preferring to splice at the distal 3' splice site and germline cells showing a distinct shift towards usage of the adjacent proximal 3' splice site. Splicing patterns in somatic cells follow consensus rules of 3’ splice site definition, using sites with a short stretch of pyrimidines and an AG dinucleotide. Splicing in germline cells occurs at proximal 3' splice sites that frequently lack a polypyrimidine tract or, occasionally, the AG dinucleotide. We provide evidence that use of germline-specific proximal 3' splice sites is conserved across Caenorhabditis species. We propose that divergent mechanisms exist between germline and somatic cells in determining an intron terminus at adjacent alternative 3’ splice sites. Examination of alternative splicing changes between germline- and somatic-cell enriched samples as well as nonsense-mediated decay mutants.
2015-04-22 | E-GEOD-64672 | biostudies-arrayexpress
Project description:Adjacent alternative 3’ splice sites, those separated by ≤18nt, provide a unique problem in the study of alternative splicing regulation; there is overlap of the cis-elements that define the adjacent sites. Identification of the intron's 3' end depends upon sequence elements that define the branchpoint, polypyrimidine tract and terminal AG dinucleotide. Starting with RNA-seq data from germline-enriched and somatic cell-enriched C. elegans samples, we identify hundreds of introns with adjacent alternative 3’ splice sites. We identify 203 events that undergo tissue-specific alternative splicing. For these, the regulation is mono-directional, with somatic cells preferring to splice at the distal 3' splice site and germline cells showing a distinct shift towards usage of the adjacent proximal 3' splice site. Splicing patterns in somatic cells follow consensus rules of 3’ splice site definition, using sites with a short stretch of pyrimidines and an AG dinucleotide. Splicing in germline cells occurs at proximal 3' splice sites that frequently lack a polypyrimidine tract or, occasionally, the AG dinucleotide. We provide evidence that use of germline-specific proximal 3' splice sites is conserved across Caenorhabditis species. We propose that divergent mechanisms exist between germline and somatic cells in determining an intron terminus at adjacent alternative 3’ splice sites.
2015-04-22 | GSE64672 | GEO
Project description:Gene splicing requires three basal genetic elements; the 3M-bM-^@M-^Y and 5M-bM-^@M-^Y splice sites and the branchpoint to which the 5M-bM-^@M-^Y intron termini is ligated to form a closed lariat during the splicing reaction. The 5M-bM-^@M-^Y and 3M-bM-^@M-^Y splice sites that define exon boundaries have been widely identified, revealing pervasive transcription and splicing of human genes. However, the locations of the third requisite element, the branchpoint, are still largely unknown. Here we employ two complementary approaches, targeted RNA sequencing and exoribonuclease digestion, to distil sequenced reads that traverse the lariat junction and, via non-conventional alignment, locate human branchpoint nucleotides. Alignments identify 88,748 branchpoints that correspond to 20% of known introns, with 76% supported by diagnostic sequence mismatch errors. This affords a first genome-wide analysis of branchpoints, describing their distribution, selection, and the existence of a diverse array of overlapping sequence motifs with distinct usage, evolutionary histories, and co-variation with distal splicing elements. The overlap of branchpoints with noncoding human genetic variation also indicates a notable contribution to disease. This annotation and analysis incorporates branchpoints into transcriptomic research and reflects a core role for this element in the regulatory code that governs gene splicing and expression. CaptureSeq identification of branchpoint nucleotides
2014-10-01 | E-GEOD-53326 | biostudies-arrayexpress
Project description:Gene splicing requires three basal genetic elements; the 3M-bM-^@M-^Y and 5M-bM-^@M-^Y splice sites and the branchpoint to which the 5M-bM-^@M-^Y intron termini is ligated to form a closed lariat during the splicing reaction. The 5M-bM-^@M-^Y and 3M-bM-^@M-^Y splice sites that define exon boundaries have been widely identified, revealing pervasive transcription and splicing of human genes. However, the locations of the third requisite element, the branchpoint, are still largely unknown. Here we employ two complementary approaches, targeted RNA sequencing and exoribonuclease digestion, to distil sequenced reads that traverse the lariat junction and, via non-conventional alignment, locate human branchpoint nucleotides. Alignments identify 88,748 branchpoints that correspond to 20% of known introns, with 76% supported by diagnostic sequence mismatch errors. This affords a first genome-wide analysis of branchpoints, describing their distribution, selection, and the existence of a diverse array of overlapping sequence motifs with distinct usage, evolutionary histories, and co-variation with distal splicing elements. The overlap of branchpoints with noncoding human genetic variation also indicates a notable contribution to disease. This annotation and analysis incorporates branchpoints into transcriptomic research and reflects a core role for this element in the regulatory code that governs gene splicing and expression. RNaseR validation of branchpoint nucleotides
2014-10-01 | E-GEOD-53327 | biostudies-arrayexpress
Project description:Fidelity of 3´-splice site (3´SS) selection by the spliceosome is critical for proper gene expression but is a daunting task considering the low complexity of the 3´SS consensus YAG. Here we show that loss of the splicing factor Prp18p in budding yeast activates a diverse array of alternative 3´SS at more than half of all introns. Some alternative sites highly diverge from the YAG consensus, demonstrating a critical role for Prp18p in promoting spliceosome fidelity. Usage of alternative 3´SS is determined by distance from the branchpoint, local RNA secondary structures, upstream poly(U) content, and adenosine enrichment in exons. The 3´SS fidelity function of Prp18p can be genetically uncoupled from its role in splicing efficiency and is promoted by interactions with Slu7p and Prp8p. Taken together, these results provide a comprehensive mechanism into how the spliceosome achieves specificity of 3´SS selection and how it prevents aberrant activation of non-canonical splice sites.
2020-05-25 | GSE131797 | GEO
Project description:Gene splicing requires three basal genetic elements; the 3’ and 5’ splice sites and the branchpoint to which the 5’ intron termini is ligated to form a closed lariat during the splicing reaction. The 5’ and 3’ splice sites that define exon boundaries have been widely identified, revealing pervasive transcription and splicing of human genes. However, the locations of the third requisite element, the branchpoint, are still largely unknown. Here we employ two complementary approaches, targeted RNA sequencing and exoribonuclease digestion, to distil sequenced reads that traverse the lariat junction and, via non-conventional alignment, locate human branchpoint nucleotides. Alignments identify 88,748 branchpoints that correspond to 20% of known introns, with 76% supported by diagnostic sequence mismatch errors. This affords a first genome-wide analysis of branchpoints, describing their distribution, selection, and the existence of a diverse array of overlapping sequence motifs with distinct usage, evolutionary histories, and co-variation with distal splicing elements. The overlap of branchpoints with noncoding human genetic variation also indicates a notable contribution to disease. This annotation and analysis incorporates branchpoints into transcriptomic research and reflects a core role for this element in the regulatory code that governs gene splicing and expression.
2014-10-01 | GSE53326 | GEO
Project description:Gene splicing requires three basal genetic elements; the 3’ and 5’ splice sites and the branchpoint to which the 5’ intron termini is ligated to form a closed lariat during the splicing reaction. The 5’ and 3’ splice sites that define exon boundaries have been widely identified, revealing pervasive transcription and splicing of human genes. However, the locations of the third requisite element, the branchpoint, are still largely unknown. Here we employ two complementary approaches, targeted RNA sequencing and exoribonuclease digestion, to distil sequenced reads that traverse the lariat junction and, via non-conventional alignment, locate human branchpoint nucleotides. Alignments identify 88,748 branchpoints that correspond to 20% of known introns, with 76% supported by diagnostic sequence mismatch errors. This affords a first genome-wide analysis of branchpoints, describing their distribution, selection, and the existence of a diverse array of overlapping sequence motifs with distinct usage, evolutionary histories, and co-variation with distal splicing elements. The overlap of branchpoints with noncoding human genetic variation also indicates a notable contribution to disease. This annotation and analysis incorporates branchpoints into transcriptomic research and reflects a core role for this element in the regulatory code that governs gene splicing and expression.
2014-10-01 | GSE53327 | GEO
Project description:Alternative splicing (AS) in human genes is widely viewed as a mechanism for enhancing proteomic diversity. AS can also impact gene expression levels without increasing protein diversity by producing “unproductive” transcripts that are targeted for rapid degradation by nonsense-mediated decay (NMD). However, the relative importance of this regulatory mechanism remains underexplored. To better understand the impact of AS-NMD relative to other regulatory mechanisms, we analyzed population-scale genomic data across eight molecular assays, covering various stages from transcription to cytoplasmic decay. We report threefold more unproductive splicing compared to prior estimates using steady-state RNA. This unproductive splicing compounds across multi-intronic genes, resulting in 15% of all transcript molecules from protein-coding genes being unproductive. Leveraging genetic variation across cell lines, we find that GWAS trait-associated loci explained by AS are as often associated with NMD-induced expression level differences as with differences in protein isoform usage. Employing the splice-switching drug risdiplam to manipulate AS at hundreds of genes, we find that ~3/4 of drug-induced isoforms are targeted by NMD, suggesting that most aberrant splicing influences expression levels. Our findings suggest much of the impact of AS is mediated by NMD-induced changes in gene expression rather than diversification of the proteome.
2024-05-10 | GSE252005 | GEO
Project description:Alternative splicing (AS) in human genes is widely viewed as a mechanism for enhancing proteomic diversity. AS can also impact gene expression levels without increasing protein diversity by producing “unproductive” transcripts that are targeted for rapid degradation by nonsense-mediated decay (NMD). However, the relative importance of this regulatory mechanism remains underexplored. To better understand the impact of AS-NMD relative to other regulatory mechanisms, we analyzed population-scale genomic data across eight molecular assays, covering various stages from transcription to cytoplasmic decay. We report threefold more unproductive splicing compared to prior estimates using steady-state RNA. This unproductive splicing compounds across multi-intronic genes, resulting in 15% of all transcript molecules from protein-coding genes being unproductive. Leveraging genetic variation across cell lines, we find that GWAS trait-associated loci explained by AS are as often associated with NMD-induced expression level differences as with differences in protein isoform usage. Employing the splice-switching drug risdiplam to manipulate AS at hundreds of genes, we find that ~3/4 of drug-induced isoforms are targeted by NMD, suggesting that most aberrant splicing influences expression levels. Our findings suggest much of the impact of AS is mediated by NMD-induced changes in gene expression rather than diversification of the proteome.
2024-05-10 | GSE252003 | GEO