Cancer-Causing Mutations in SF3B1 Alter Splicing by Disrupting Interaction with SUGP1
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA528926 | ENA |
REPOSITORIES: ENA
Similar Datasets
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: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 suggest 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 a common defect of spliceosomes with disease-causing SF3B1 mutations and, because this defect can be rescued, suggests possibilities for therapeutic intervention.
| S-EPMC7065273 | biostudies-literature
Project description:Pre-mRNA splicing and nuclear export are coordinated processes that ensure efficient and accurate gene expression. In recent years, disruptions in this process have been found to result in substantial gene expression aberrations, with potential contributions from SF3B1 mutations, whose mechanism remains elusive. The present study reveals that the K700E mutation in SF3B1 attenuates its interaction with THOC5, resulting in reduced mRNA binding by THOC5, and ultimately, the inhibition of mRNA nuclear export. Interestingly, overexpressing THOC5 can restore the attenuated interaction, facilitating mRNA nuclear export. Importantly, other cancer-associated SF3B1 mutations may exert a similar impact. Our research highlights the critical role of the THOC5–SF3B1 interaction in regulating mRNA nuclear export and provides valuable insights into the impact of SF3B1 mutations on this process.
2024-09-12 | GSE268355 | 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:Several DNA sequencing studies of chronic lymphocytic leukemia (CLL) revealed that the splicing factor SF3B1 accumulated somatic point mutations in about 10 percent of the patients. In most cases the mutations were located in the genomic regions coding for the C-terminal HEAT-repeat domain and in many cases, the mutations gave rise to specific amino acid substitutions. Here, we aimed to investigate differential usage of exons associated with the mutation K700E of SF3B1 in CLL tumuor cells. We generated RNA-Seq transcriptome data from two patients with mutations in SF3B1, two patient without mutations in SF3B1 and from healthy donors. We report interesting examples and possible consequences of the alternative exon usage in these genes. This dataset contains only the files resulting from the processing the RNA sequencing raw data. This avoids potential patient identifiability, but ensures the full reproducibility of the results described in the publication.
2013-12-27 | E-MTAB-2025 | biostudies-arrayexpress
Project description:Knockdown of mutant and/or wild-type SF3B1 in MEL202 cell line by Degron knock-in, followed by RNA-seq, to identify splicing events governed by mutant SF3B1. Control: parental MEL202 cell line. Experiments: mutant-SF3B1 knockdown; wildtype-SF3B1 knockdown; mutant SF3B1 knockout. Treatments: each of these four conditions plus and minus shld.
2015-03-11 | E-GEOD-66719 | 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. 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: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
Project description:Alternative splicing plays a critical role in generating transcriptome diversity, and aberrant splicing is frequently observed in cancer. Mutations in the splicing factor SF3B1 are particularly common in patients with chronic lymphocytic leukemia (CLL) and myelodysplastic syndromes (MDS), with different survival prognoses. We applied long-read sequencing for the investigation of the SF3B1 mutation effect on the transcriptome of MDS and CLL patients, as well as isogenic cell lines. Our results revealed that SF3B1 mutation effect was common across the different diseases and specifically altered the usage of 3’ alternative splice sites within short proximity to the canonical splice sites. Based on computational simulations, the most common K700E mutation led to destabilization of the SF3B1-mRNA binding. Furthermore, we combined the full isoform information with genome-wide SF3B1-RNA binding maps to predict the functional consequences of the aberrant splicing and gain mechanistic insights into the role of mutated SF3B1 in splicing.
2024-08-19 | GSE247658 | 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