Minor intron splicing efficiency increases with the development of lethal prostate cancer
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ABSTRACT:
PROVIDER: EGAS00001005546 | EGA |
REPOSITORIES: EGA
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Project description:Minor intron-containing genes (MIGs) are crucial cell cycle regulators and are essential for cell survival. Thus, we explored whether MIGs play a role in cancer progression and cancer therapy resistance. Here we show that MIG-expression segregates sensitive and resistant prostate cancer cells from each other and them from benign tissue. Moreover, the rate of minor intron splicing, a crucial regulatory node for MIG-expression, was more efficient in patients with advanced prostate cancer. We show that the increased minor spliceosome (MiS) activity is downstream of the androgen receptor signaling axis in both therapy sensitive and insensitive prostate cancer types. The increased MiS activity was in line with the elevated expression of U6atac snRNA, a crucial MiS component. We propose the expression of U6atac as a potential point of vulnerability in cancer. MIGs are uniquely susceptible to the MiS, so we used siRNA against U6atac, which like protein-coding transcripts, is downregulated. Inhibition of MiS was sufficient to lower the tumor burden significantly in therapy-resistant (prostate) cancer cells and PCa patient-derived organoids. KD cells displayed elevated minor intron retention and alternative splicing across minor introns of MIGs which enriched for MAPK activity, DNA repair and cell cycle regulation. Importantly, these findings were confirmed by MassSpec analysis. Collectively our study nominates the MiS as a driver of highly proliferative, rapidly dividing (prostate) cancer cells that bears strong potential as a therapeutic target for many different cancer types.
2023-06-08 | PXD026949 | Pride
Project description:Bulk RNAseq data of scrambled and siRNA-mediated knock-down of the minor spliceosome snRNA U6atac in androgen-sensitive LNCaP cells (L), androgen-insensitive C4-2 (C) and 22Rv1 (R) cells and in patient derived neuroendocrine organoids PM154 (P).
| EGAD00001008034 | EGA
Project description:Mutations in the minor spliceosome components such as RNU4atac, a small nuclear RNA (snRNA), are linked to primary microcephaly. We have reported that in the conditional knockout (cKO) mice for Rnu11, a minor spliceosome snRNA, minor intron splicing defect in minor intron-containing genes (MIGs) regulating cell cycle resulted in cell cycle defect with a concomitant increase in yH2aX+ cells and P53-mediated apoptosis. Trp53 ablation in the Rnu11 cKO mice did not prevent microcephaly. Although RNAseq analysis of the double knockout (dKO) pallium reflected transcriptomic shift towards the control from the cKO. We found elevated minor intron retention and alternative splicing across minor introns in the dKO. Disruption of these minor intron-containing genes (MIGs) resulted in cell cycle defect that was detected earlier and was more severe in the dKO, but with delayed detection of yH2aX+ DNA damage. Thus, P53 might also play a role in causing DNA damage in the developing pallium. In all, our findings further refine our understanding of the role of the minor spliceosome in cortical development and identify MIGs underpinning microcephaly in minor spliceosome-related disease.
2021-09-30 | GSE168366 | GEO
Project description:scRNAseq data of scrambled and siRNA-mediated knock-down (96h) of the minor spliceosome snRNA U6atac in androgen-sensitive LNCaP cells and in patient derived neuroendocrine organoids (PM154). Three replicates for each cell line.
| EGAD00001007996 | EGA
Project description:Mutations in minor spliceosome components are linked to diseases such as Roifman syndrome, Lowry-Wood syndrome, and early-onset cerebellar ataxia (EOCA). Here we report that besides increased minor intron retention, Roifman syndrome and EOCA can also be characterized by elevated alternative splicing (AS) around minor introns. Consistent with the idea that the assembly/activity of the minor spliceosome informs AS in minor intron-containing genes (MIGs), inhibition of all minor spliceosome snRNAs led to upregulated AS. Notably, alternatively spliced MIG isoforms were bound to polysomes in the U11-null dorsal telencephalon, which suggested that aberrant MIG protein expression could contribute to disease pathogenesis. In agreement, expression of an aberrant isoform of the MIG Dctn3 by in utero electroporation, affected radial glial cell divisions. Finally, we show that AS around minor introns is executed by the major spliceosome and is regulated by U11-59K of the minor spliceosome, which forms exon-bridging interactions with proteins of the major spliceosome. Overall, we extend the exon-definition model to MIGs and postulate that disruptions of exon-bridging interactions might contribute to disease severity and pathogenesis.
2021-05-01 | GSE151141 | GEO
Project description:Mutations in minor spliceosome components are linked to diseases such as Roifman syndrome, Lowry-Wood syndrome, and early-onset cerebellar ataxia (EOCA). Here we report that besides increased minor intron retention, Roifman syndrome and EOCA can also be characterized by elevated alternative splicing (AS) around minor introns. Consistent with the idea that the assembly/activity of the minor spliceosome informs AS in minor intron-containing genes (MIGs), inhibition of all minor spliceosome snRNAs led to upregulated AS. Notably, alternatively spliced MIG isoforms were bound to polysomes in the U11-null dorsal telencephalon, which suggested that aberrant MIG protein expression could contribute to disease pathogenesis. In agreement, expression of an aberrant isoform of the MIG Dctn3 by in utero electroporation, affected radial glial cell divisions. Finally, we show that AS around minor introns is executed by the major spliceosome and is regulated by U11-59K of the minor spliceosome, which forms exon-bridging interactions with proteins of the major spliceosome. Overall, we extend the exon-definition model to MIGs and postulate that disruptions of exon-bridging interactions might contribute to disease severity and pathogenesis.
2021-05-01 | GSE151140 | GEO
Project description:Inactivation of the minor spliceosome has been linked to microcephalic osteodysplastic primordial dwarfism type 1 (MOPD1). To interrogate how minor intron splicing regulates cortical development, we employed Emx1-Cre to ablate Rnu11, which encodes the minor spliceosome-specific U11 small nuclear RNA (snRNA), in the developing cortex (pallium). Rnu11 cKO mice were born with microcephaly, caused by death of self-amplifying radial glial cells (RGCs). However, both intermediate progenitor cells (IPCs) and neurons were produced in the U11-null pallium. RNAseq of the pallium revealed elevated minor intron retention in the mutant, particularly in genes regulating cell cycle. Moreover, the only downregulated minor intron-containing gene (MIG) was Spc24, which regulates kinetochore assembly. These findings were consistent with the observation of fewer RGCs entering cytokinesis prior to RGC loss, underscoring the requirement of minor splicing for cell cycle progression in RGCs. Overall, we provide a potential explanation of how disruption of minor splicing might cause microcephaly in MOPD1.
2018-06-05 | GSE96616 | GEO
Project description:We identify RBM41 as a novel unique protein component of the minor spliceosome. RBM41 has no previously recognized cellular function but has been identified as a paralog of the U11/U12-65K protein, a known unique component of the minor spliceosome that functions during the early steps of minor intron recognition as a component of the U11/U12 di-snRNP. We show that both proteins use their highly similar C-terminal RRMs to bind to 3'-terminal stem-loops in U12 and U6atac snRNAs with comparable affinity. Our BioID data indicate that the unique N-terminal domain of RBM41 is necessary for its association with complexes containing DHX8, an RNA helicase, which in the major spliceosome drives the release of mature mRNA from the spliceosome. Consistently, we show that RBM41 associates with excised U12-type intron lariats, is present in the U12 mono-snRNP, and is enriched in Cajal bodies, together suggesting that RBM41 functions in the post-splicing steps of the minor spliceosome assembly/disassembly cycle. This contrasts with the U11/U12-65K protein, which uses the N-terminal region to interact with U11 snRNP during the intron recognition step. Finally, we show that while RBM41 knockout cells are viable, they show alterations in the splicing of U12-type introns, particularly differential U12-type 3' splice site usage. Together, our results highlight the role 3’-terminal stem-loop of U12 snRNA as a dynamic binding platform for the paralogous U11/U12-65K and RBM41 proteins, which function at distinct stages of minor spliceosome assembly/disassembly cycle.
2024-02-04 | GSE246283 | GEO
Project description:U12-type introns were originally recognized based on their highly conserved non-consensus AT-AC termini1,2, which are spliced by a separate minor spliceosome3,4. Padgett and Krainer groups later showed that terminal dinucleotides do not differentiate U12-type from U2-type introns, as there are U12-type introns with GT-AG termini and U2-type introns with AT-AC termini5,6. Rather, U12-type introns are recognized by their divergent and highly conserved 5’ splice site (5’ss) and branch point sequences, which both differ from the consensus sequences found in U2-type introns. To date, no functional differences have been ascribed to AT-AC or GT-AG subtypes of U12-type introns, nor have RNAseq analyses of minor spliceosome diseases reported any subtype specificity. Here, we describe a novel protein component of the minor spliceosome, encoded by the CENATAC locus, that is required for accurate splicing of AT-AC but not GT-AG type minor introns. CENATAC was initially identified in a subset of Mosaic Variegated Aneuploidy (MVA) patients with mutations in CENATAC, which lead to chromosome congression defects during mitosis. Earlier large-scale proteomic analyses tentatively classified CENATAC as a spliceosome component and phylogenetic analyses showed co-segregation of CENATAC with minor spliceosome components. Targeted depletion of CENATAC in HeLa cells, followed by RNAseq revealed global retention of AT-AC minor subtype introns with more than 60% showing statistically significant (up to 90%) intron retention (IR). Additionally, U12-type introns with 5’-AT, but divergent 3’-terminal dinucleotides also showed significant IR. We also detected cryptic U2-type splice site activation near affected AT-AC introns. In contrast, about 10% of GT-AG subtype introns responded to CENATAC depletion. Co-IP experiments revealed that CENATAC is not a U11/U12 di-snRNP component as expected for a specificity factor, but rather associates with the U4atac/U6atac.U5 tri-snRNP via interaction with PRPF3/4, suggesting a role for minor tri-snRNP in initial 5’ss recognition. CENATAC also interacts with TXNL4B, a paralog of TXNL4A in the major tri-snRNP. Finally, several genes encoding chromosome congression factors harbor U12 AT-AC-type introns that were highly retained in CENATAC depleted cells, potentially explaining the aneuploidy phenotype observed in MVA patients.
2021-04-19 | GSE143392 | GEO
Project description:Most metazoans contain two distinct pre-mRNA splicing machineries: the major spliceosome, which removes >99% of introns, and the minor spliceosome, which recognizes <1% of introns. Despite their rarity, minor introns are exquisitely conserved amongst species, suggesting important regulatory functions. However, physiologic roles for the minor spliceosome and the relevance of recurrent, leukemia-associated mutations affecting minor spliceosome components are not well understood. Here, we identify that mutational loss of the minor spliceosomal factor ZRSR2 enhances hematopoietic stem cell self-renewal via impaired minor intron splicing that converges on LZTR1, a regulator of Ras-related GTPases. LZTR1 minor intron retention is additionally observed in Noonan syndrome and diverse cancers. These data uncover minor intron recognition as a regulator of hematopoiesis and mechanistic links between ZRSR2 mutations, LZTR1, and leukemia.
2020-11-26 | GSE162136 | GEO