Splicing defects in RNA export receptor mutants
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ABSTRACT:
ORGANISM(S): Saccharomyces cerevisiae
PROVIDER: GSE93307 | GEO | 2018/01/01
SECONDARY ACCESSION(S): PRJNA360580
REPOSITORIES: GEO
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Project description:SF3B1 mutations are the most frequent spliceosomal alterations across cancers, yet no successful therapy exists to target this pathway. Previous findings from a phase 2 clinical trial of the XPO1 inhibitor selinexor in patients with high-risk myelodysplastic neoplasms (MDS) relapsed or refractory to hypomethylating agents (HMA) revealed increased activity in patients with SF3B1 mutations. XPO1 (Exportin-1) is responsible for the export of over 200 proteins, but also plays a role in the transport of multiple RNA species, including small nuclear RNAs (snRNAs), ribosomal RNAs (rRNAs), and select messenger RNAs (mRNAs) out of the nucleus. We therefore hypothesized that XPO1 inhibition perturbs RNA export and may preferentially affect SF3B1 mutants via altered splicing, given the role of XPO1 in exporting snRNAs, which form the catalytic portion of the spliceosome. To evaluate the mechanism underlying preferentially sensitivity of SF3B1-mutants to XPO1 inhibition, we performed nuclear and cytoplasmic fraction followed by RNA sequencing before and after XPO1 inhibition in SF3B1 wildtype and SF3B1 K666N cells (subcellular RNA-seq). Whole transcriptomic analysis of subcellular RNA-seq data revealed more nuclear retention of global RNA transcripts after XPO1 inhibition in the SF3B1 mutant cell line. Similarly, we performed subcellular RNA-seq for small RNAs and found snRNAs to be increased in the nucleus after XPO1 inhibition in the SF3B1 mutant cells. We then performed total cellular RNA sequencing to understand the effect of XPO1 inhibition on global RNA expression and RNA splicing. Differential gene expression analysis identified that XPO1 inhibition had the greatest effect on cell cycle in SF3B1 wildtype cells but in SF3B1-mutant cells differentiation pathways were more significantly affected. Alternative splicing analysis showed increased 3’ alternative splicing events in SF3B1 mutant after XPO1 inhibition. These results signify the mechanistic basis for preferential sensitivity of SF3B1 mutant cells to nuclear export inhibition arises through nuclear retention of spliceosomal snRNAs and select mRNAs that result in perturbation of differentiation pathways.
2024-08-05 | GSE255179 | GEO
Project description:The essential process of pre-mRNA splicing must occur with high fidelity and efficiency for proper gene expression. The spliceosome employs DExD/H box helicases to promote on-pathway interactions while simultaneously minimizing errors. Prp8 and Snu114, an EF2-like GTPase, regulate the activity of the Brr2 helicase, promoting RNA unwinding by Brr2 at appro-priate points in the splicing cycle and repressing it at others. Mutations linked to Retinitis Pig-mentosa (RP), a disease that causes blindness in humans, map to the Brr2 regulatory region of Prp8. Previous In vitro studies of homologous mutations in Saccharomyces cerevisiae show that Prp8-RP mutants cause defects in spliceosome activation. Here we show a subset of RP muta-tions in Prp8 also cause defects in the transition between the 1st and 2nd catalytic steps of splic-ing. Though Prp8-RP mutants do not cause defects in splicing fidelity, they result in an overall decrease in splicing efficiency. Furthermore, genetic analyses link Snu114 GTP/GDP occupancy to Prp8-dependent regulation of Brr2. Our results implicate the transition between the 1st and 2nd catalytic steps as a critical place in the splicing cycle where Prp8-RP mutants influence splic-ing efficiency. The location of the Prp8-RP mutants, at the “hinge” that links the Prp8 Jab1-MPN regulatory “tail” to the globular portion of the domain, suggests that these Prp8-RP mutants inhibit regulated movement of the Prp8 Jab1/MPN domain into the Brr2 RNA binding channel to transiently inhibit Brr2 activity. Therefore, in Prp8-linked RP, disease likely results not only from defects in spliceosome assembly and activation, but also because of defects in splicing ca-talysis. paper to be submitted
2016-07-21 | GSE75081 | GEO
Project description:The essential process of pre-mRNA splicing must occur with high fidelity and efficiency for proper gene expression. The spliceosome employs DExD/H box helicases to promote on-pathway interactions while simultaneously minimizing errors. Prp8 and Snu114, an EF2-like GTPase, regulate the activity of the Brr2 helicase, promoting RNA unwinding by Brr2 at appro-priate points in the splicing cycle and repressing it at others. Mutations linked to Retinitis Pig-mentosa (RP), a disease that causes blindness in humans, map to the Brr2 regulatory region of Prp8. Previous In vitro studies of homologous mutations in Saccharomyces cerevisiae show that Prp8-RP mutants cause defects in spliceosome activation. Here we show a subset of RP muta-tions in Prp8 also cause defects in the transition between the 1st and 2nd catalytic steps of splic-ing. Though Prp8-RP mutants do not cause defects in splicing fidelity, they result in an overall decrease in splicing efficiency. Furthermore, genetic analyses link Snu114 GTP/GDP occupancy to Prp8-dependent regulation of Brr2. Our results implicate the transition between the 1st and 2nd catalytic steps as a critical place in the splicing cycle where Prp8-RP mutants influence splic-ing efficiency. The location of the Prp8-RP mutants, at the â??hingeâ?? that links the Prp8 Jab1-MPN regulatory â??tailâ?? to the globular portion of the domain, suggests that these Prp8-RP mutants inhibit regulated movement of the Prp8 Jab1/MPN domain into the Brr2 RNA binding channel to transiently inhibit Brr2 activity. Therefore, in Prp8-linked RP, disease likely results not only from defects in spliceosome assembly and activation, but also because of defects in splicing ca-talysis. paper to be submitted Two channel microarrays were used. RNA isolated from wt yeast grown simultaneously to the mutant was used as a reference. This reference was used in one of the channels for each hybridization and used in the statistical analysis to obtain an average expression-profile for each mutant relative to the wt. Three independent cultures were hybridized on two separate microarrays. For the first hybridization the Cy5 (red) labeled cRNA from the mutant is hybridized together with the Cy3 (green) labeled cRNA from the common reference. For the replicate hybridization, the labels are swapped. Each gene is represented twice on the microarray, resulting in four measurements per mutant. Strains, both WT and mutant, were grown at 37C until mid-log phase, OD600 of approximately 0.7. The mutated PRP8 gene is present on HIS marked CEN plasmid, and the corresponding genomic copy of PRP8 deleted. Strains labeled as wildtype also have the relevant genomic PRP8 deleted, but complemented with wildtype PRP8 on CEN plasmid.
2016-07-21 | E-GEOD-75081 | biostudies-arrayexpress
Project description:Three shuttling SR-like proteins exist in Saccharomyces cerevisiae, Npl3, Gbp2 and Hrb1, that are involved in the nuclear export of mRNAs. In a screen for genes that regulate the export of Gbp2, we identified novel mutants of the splicing factors PRP8 and PRP17 that lead to severe mislocalization defects for Gbp2 and Hrb1, but not Npl3. Microarray and qRT-PCR analyses show that Gbp2 and Hrb1 preferentially bind to transcripts derived from intron-containing genes. Moreover, in contrast to Npl3, Gbp2 and Hrb1 show genetic and physical interactions with late splicing factors such as Prp17 and Prp43. Further, RNA co-immunoprecipitation experiments reveal that, unlike Npl3, association of Gbp2 and Hrb1 with the mRNA requires splicing, and this in turn is required for their Mex67 recruitment. We propose a model in which Gbp2 and Hrb1 are attached to the mRNAs at late stages of splicing to promote the subsequent export of spliced mRNAs. keyword: RIP-chip RNA-IP of endogenously expressed 3-fold C-terminal myc-tagged Gbp2 and Hrb1 in S288C background cells was each performed once in cells grown to a density of 4x10^7 cells/ml and hybridized against a total (input) RNA reference.
2013-08-30 | E-GEOD-20738 | biostudies-arrayexpress
Project description:The role of many splicing factors in pre-mRNA splicing and the involvement of these factors in the processing of specific transcripts have often been defined through the analysis of loss of function mutants in vivo. Here we show that inactivating the nonsense mediated mRNA decay (NMD) results in an enhancement of splicing phenotypes associated with several splicing factors mutations. Tiling microarrays showed that inactivation of the NMD factor Upf1p in the prp17Î and prp18Î mutant strains reveals a larger spectrum of splicing defects than what is observed in the single mutants, including new transcripts previously shown unaffected by Prp17p or Prp18p inactivation. In addition, inactivation of Upf1 in the prp22-1 mutant enhances the unspliced precursor accumulation phenotype of several specific transcripts and partially suppresses growth defects associated with the prp17Î or prp22-1 mutations. These results support the idea that RNA surveillance by NMD mutes some of the effects of splicing factors mutations and show that the roles of splicing factors and their transcripts specificity cannot be fully understood in vivo unless RNA degradation systems that degrade unspliced precursors are also inactivated. Three samples from the Prp17delta, Prp18delta, Prp17deltaUpf1delta and Prp18Upf1delta mutants were grown indepedently and analyzed by tiling arrays to understand the role of the NMD component Upf1 in minimizing the accumulation of unspliced RNAs generated by the Prp17delta and Prp18delta splicing mutations.
2010-05-16 | E-GEOD-18288 | biostudies-arrayexpress
Project description:We performed RNA-seq to determine the impact of XAB2 depletion on global splicing. The results show that XAB2 depletion using two different siRNAs led to a wide range of splicing defects, with more than 50% events were intron retention.
2019-09-23 | GSE130087 | GEO
Project description:Transcriptome-wide identification of splicing defects upon XAB2 knockdown
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Project description:The role of many splicing factors in pre-mRNA splicing and the involvement of these factors in the processing of specific transcripts have often been defined through the analysis of loss of function mutants in vivo. Here we show that inactivating the nonsense mediated mRNA decay (NMD) results in an enhancement of splicing phenotypes associated with several splicing factors mutations. Tiling microarrays showed that inactivation of the NMD factor Upf1p in the prp17Δ and prp18Δ mutant strains reveals a larger spectrum of splicing defects than what is observed in the single mutants, including new transcripts previously shown unaffected by Prp17p or Prp18p inactivation. In addition, inactivation of Upf1 in the prp22-1 mutant enhances the unspliced precursor accumulation phenotype of several specific transcripts and partially suppresses growth defects associated with the prp17Δ or prp22-1 mutations. These results support the idea that RNA surveillance by NMD mutes some of the effects of splicing factors mutations and show that the roles of splicing factors and their transcripts specificity cannot be fully understood in vivo unless RNA degradation systems that degrade unspliced precursors are also inactivated.
2009-12-31 | GSE18288 | GEO
Project description:Comparative analyses of Mex67 and Npl3 binding to mRNA at normal growth condition (25°C) and upon shift to heat stress (30 min, 42°C). Comparative analyses of mRNA binding of Mex67, Npl3 and no tag control at normal growth condition (25°C) and upon heat stress (30 min, 42°C) via RNA Co-IP experiments. Respective co-purified mRNAs were subjected to cDNA Microarray chips.
2016-06-14 | E-GEOD-83267 | biostudies-arrayexpress
Project description:Defects in the alternative splicing-dependent regulation of REST cause deafness
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