Cancer associated SF3B1 hotspot mutations induce cryptic 3' splice site selection through use of a different branch point
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ABSTRACT:
PROVIDER: PRJNA295064 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR2313070_1.fastq.gz | Fastqsanger.gz | |||
| SRR2313070_2.fastq.gz | Fastqsanger.gz | |||
| SRR2313080_1.fastq.gz | Fastqsanger.gz | |||
| SRR2313080_2.fastq.gz | Fastqsanger.gz | |||
| SRR2313090_1.fastq.gz | Fastqsanger.gz |
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Project description:Recurrent mutations in the spliceosome are observed in several human cancers but their functional and therapeutic significance remain elusive. SF3B1, the most frequently mutated component of the spliceosome in cancer, is involved in the recognition of the branch point sequence (BPS) during selection of the 3’ splice site (ss) in RNA splicing. Here, we report that common and tumor-specific splicing aberrations are induced by SF3B1 mutations and establish aberrant 3’ ss selection as the most frequent splicing defect. Strikingly, mutant SF3B1 utilizes a BPS that differs from that used by wild-type SF3B1 and requires the canonical 3’ ss to enable aberrant splicing during the second step. Approximately 50% of the aberrantly spliced mRNAs are subjected to nonsense-mediated decay resulting in downregulation of gene and protein expression. These findings ascribe functional significance to the consequences of SF3B1 mutations in cancer. 72 samples, including two sets of patient data and cell lines with two additional technical replicates each
2015-09-08 | E-GEOD-72790 | biostudies-arrayexpress
Project description:Recurrent mutations in the spliceosome are observed in several human cancers but their functional and therapeutic significance remain elusive. SF3B1, the most frequently mutated component of the spliceosome in cancer, is involved in the recognition of the branch point sequence (BPS) during selection of the 3’ splice site (ss) in RNA splicing. Here, we report that common and tumor-specific splicing aberrations are induced by SF3B1 mutations and establish aberrant 3’ ss selection as the most frequent splicing defect. Strikingly, mutant SF3B1 utilizes a BPS that differs from that used by wild-type SF3B1 and requires the canonical 3’ ss to enable aberrant splicing during the second step. Approximately 50% of the aberrantly spliced mRNAs are subjected to nonsense-mediated decay resulting in downregulation of gene and protein expression. These findings ascribe functional significance to the consequences of SF3B1 mutations in cancer.
2015-09-08 | GSE72790 | GEO
Project description:We address define differential usage of branchpoint (BP) in by wild-type SF3B1 SF3B1-K700E using a synthetic mini-gene synthetic library with variable 3' spice sites (3'SS). Minigene-specific libraries were prepared and sequenced on the illumina platform to determine differnces in splice-site usage.
2018-10-30 | GSE115547 | GEO
Project description:Hotspot mutations in the spliceosomal component gene SF3B1 underpin a number of cancers and have a neomorphic function leading to global disruption of canonical splicing and aberrant splicing of hundreds of transcripts. However, the functional consequences of this misplicing and resultant genetic vulnerabilities imposed by these events are poorly understood. Through a synthetic-lethal approach we identify that SF3B1 mutant cells are selectively sensitive to PARP inhibitors. This vulnerability is preserved across multiple cell line and patent derived tumour models, independent of SF3B1 hotspot mutation and is manifested both in vitro and in vivo. These data provide the pre-clinical and mechanistic rationale for assessing SF3B1 mutations as a biomarker of single-agent PARP inhibitor response in a new patient population and may extend the clinical utility of these agents beyond BRCA mutated cancers.
2023-04-19 | PXD019046 | Pride
Project description:Regulation and functionality of species-specific alternative splicing has remained enigmatic for many years. Calcium/calmodulin-dependent protein kinase IIβ (CaMKIIβ) is expressed in several splice variants and plays a key role in learning and memory. Here, we identify and characterize several primate-specific CAMK2B splice isoforms, which show altered kinetic properties and changes in substrate specificity. Furthermore, we demonstrate that primate-specific Camk2β alternative splicing is achieved through branch point weakening during evolution. We show that reducing branch point and splice site strength during evolution globally renders constitutive exons alternative, thus providing a paradigm for cis-directed species-specific alternative splicing regulation. Using CRISPR/Cas9 we introduced the weaker human branch point into the mouse genome, resulting in human-like CAMK2B splicing in the brain of mutant mice. We observe a strong impairment of long-term potentiation in CA3-CA1 synapses of mutant mice, thus connecting branch point-controlled, species-specific alternative splicing with a fundamental function in learning and memory.
2022-12-19 | PXD035346 | Pride
Project description:Regulation and functionality of species-specific alternative splicing has remained enigmatic for many years. Calcium/calmodulin-dependent protein kinase IIβ (CaMKIIβ) is expressed in several splice variants and plays a key role in learning and memory. Here, we identify and characterize several primate-specific CAMK2B splice isoforms, which show altered kinetic properties and changes in substrate specificity. Furthermore, we demonstrate that primate-specific Camk2β alternative splicing is achieved through branch point weakening during evolution. We show that reducing branch point and splice site strength during evolution globally renders constitutive exons alternative, thus providing a paradigm for cis-directed species-specific alternative splicing regulation. Using CRISPR/Cas9 we introduced the weaker human branch point into the mouse genome, resulting in human-like CAMK2B splicing in the brain of mutant mice. We observe a strong impairment of long-term potentiation in CA3-CA1 synapses of mutant mice, thus connecting branch point-controlled, species-specific alternative splicing with a fundamental function in learning and memory.
2022-12-02 | GSE208181 | GEO
Project description:SF3B1, which encodes an essential spliceosomal protein, is frequently mutated in myelodysplastic syndromes (MDS) and many cancers. However, the defect of mutant SF3B1 is unknown. Here, we analyzed RNA-sequencing data from MDS patients and confirmed that SF3B1 mutants use aberrant 3' splice sites. To elucidate the underlying mechanism, we purified complexes containing either wild-type or the hotspot K700E mutant SF3B1, and found that levels of a poorly studied spliceosomal protein, SUGP1, were reduced in mutant spliceosomes. Strikingly, SUGP1 knockdown completely recapitulated the splicing errors, whereas SUGP1 overexpression drove the protein, which our data suggests plays an important role in branchsite recognition, into the mutant spliceosome and partially rescued splicing. Other hotspot SF3B1 mutants showed similar altered splicing and diminished interaction with SUGP1. Our study demonstrates that SUGP1 loss is the sole defect of mutant SF3B1 spliceosomes and, since this defect can be rescued, suggests possibilities for therapeutic intervention.
2019-07-24 | GSE128805 | GEO
Project description:Recurrent mutations in RNA splicing factors SF3B1, U2AF1, and SRSF2 have been reported in hematologic cancers including myelodysplastic syndromes (MDS) and chronic lymphocytic leukemia (CLL). However, SF3B1 is the only splicing associated gene to be found mutated in CLL and has been shown to induce aberrant splicing. To investigate if any other genomic aberration caused similar transcriptome changes, we clustered RNASeq samples based on an alternative 3’ splice site (ss) pattern previously identified in SF3B1-mutant CLL patients. Out of 215 samples, we identified 37 (17%) with alternative 3’ ss usage, the majority of which harbored known SF3B1 hotspot mutations. Interestingly, 3 patient samples carried previously unreported in-frame deletions in SF3B1 around K700, the most frequent mutation hotspot. To study the functional effects of these deletions, we used various minigenes demonstrating that recognition of canonical 3’ ss and alternative branchsite are required for aberrant splicing, as observed for SF3B1 p.K700E. The common mechanism of action of these deletions and substitutions result in similar sensitivity of primary cells towards splicing inhibitor E7107. Altogether, these data demonstrate that novel SF3B1 in-frame deletion events identified in CLL result in aberrant splicing, a common biomarker in spliceosome-mutant cancers.
2017-06-27 | GSE95352 | GEO
Project description:Although mutations in the RNA splicing factor SF3B1 are frequently observed in multiple human cancers, their functional role in promoting tumorigenesis and therapeutic significance remain poorly understood. Here we characterize the splicing landscape of 79 tumors and 12 isogenic cell lines harboring SF3B1 hotspot mutations, identifying hundreds of cryptic 3’ splice site (ss) events shared as well as specific to different tumor types. Regulatory network analysis shows that tumors harboring the most common hotspot mutation in SF3B1 (SF3B1K700E) activate the MYC transcriptional program. SF3B1 mutations lead to a dramatic decay of transcripts encoding the key PP2A phosphatase subunit PPP2R5A due to aberrant 3’ss usage, resulting in increased c-MYC serine 62 phosphorylation (allowing MYC to escape ubiquitin-mediated degradation) and in increased BCL2 serine 70 phosphorylation (leading to anti-apoptotic effects). This effect of SF3B1K700E on c-MYC and BCL2 activation through post-translational regulation was conserved across human and mouse cells and could be rescued by restored expression of PPP2R5A. Consonant with this, mutant SF3B1 promoted c-MYC driven tumorigenesis could be restored by the PP2A activating agent FTY-720. This study reveals the functional contribution of mutant SF3B1 to tumorigenesis through regulation of established oncogenic pathways and provides therapeutic strategies for related tumors.
2020-05-01 | GSE116391 | GEO
Project description:Much remains unknown concerning the mechanism by which the splicing machinery pinpoints short exons within intronic sequences and how splicing factors are directed to their pre-mRNA targets. Part of the explanation probably lies in differences in chromatin organization between exons and introns. Proteomic, co-immunoprecipitation, and sedimentation analyses described here indicated that SF3B1, an essential splicing component of the U2 snRNP complex, is strongly associated with nucleosomes. ChIP-seq and RNA-seq analyses revealed that SF3B1 is specifically bound to nucleosomes located at exonic positions. SF3B1 binding is enriched at nucleosomes positioned over short exons flanked by long introns that are also characterized by differential GC content between exons and introns. Disruption of SF3B1 binding to such nucleosomes affected the splicing of these exons similarly to inhibition of SF3B1 expression. Our findings suggest that the association of SF3B1 with nucleosomes is functionally important for splice site recognition and that SF3B1 conveys splicing-relevant information embedded in chromatin structure. MNase-seq on Input and SF3B1 pull-down, mRNA-seq on control and SF3B1 si-RNA treated cells as well as on TSA (Trichostatin A) treated and untreated cells.
2015-04-22 | E-GEOD-65644 | biostudies-arrayexpress