Saccharomyces cerevisiae
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ABSTRACT:
PROVIDER: PRJNA296115 | ENA |
REPOSITORIES: ENA
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Project description:Nuclear RNA degradation pathways are highly conserved across eukaryotes and play important roles in RNA quality control. Key substrates for exosomal degradation include aberrant functional RNAs and cryptic unstable transcripts (CUTs). It has recently been reported that the nuclear exosome is inactivated during meiosis in budding yeast through degradation of the subunit Rrp6, leading to the stabilisation of a subset of meiotic unstable transcripts (MUTs) of unknown function. We have analysed the activity of the nuclear exosome during meiosis by deletion of TRF4, which encodes a key component of the exosome targeting complex TRAMP. We find that TRAMP mutants produce high levels of CUTs during meiosis which are undetectable in wild-type cells, suggesting that the nuclear exosome remains functional, and we further show that the meiotic exosome complex still contains Rrp6. Indeed Rrp6 over-expression is insufficient to suppress MUT transcripts, showing that the reduced amount of Rrp6 in meiotic cells does not directly cause MUT accumulation. Lack of TRAMP activity stabilises ~1600 CUTs in meiotic cells, which occupy 40% of the binding capacity of the nuclear cap binding complex (CBC). CBC mutants display defects in the formation of meiotic double strand breaks (DSBs), and we see similar defects in TRAMP mutants, suggesting that a key function of the nuclear exosome is to prevent saturation of the CBC complex by CUTs. Together, our results show that the nuclear exosome remains active in meiosis and has an important role in facilitating meiotic recombination.
2015-05-15 | PXD001239 | Pride
Project description:Nuclear RNA degradation pathways are highly conserved across eukaryotes and play important roles in RNA quality control. Key substrates for exosomal degradation include aberrant functional RNAs and cryptic unstable transcripts (CUTs). It has recently been reported that the nuclear exosome is inactivated during meiosis in budding yeast through degradation of the subunit Rrp6, leading to the stabilisation of a subset of meiotic unstable transcripts (MUTs) of unknown function. We have analysed the activity of the nuclear exosome during meiosis by deletion of TRF4, which encodes a key component of the exosome targeting complex TRAMP. We find that TRAMP mutants produce high levels of CUTs during meiosis which are undetectable in wild-type cells, suggesting that the nuclear exosome remains functional, and we further show that the meiotic exosome complex still contains Rrp6. Indeed Rrp6 over-expression is insufficient to suppress MUT transcripts, showing that the reduced amount of Rrp6 in meiotic cells does not directly cause MUT accumulation. Lack of TRAMP activity stabilises ~1600 CUTs in meiotic cells, which occupy 40% of the binding capacity of the nuclear cap binding complex (CBC). CBC mutants display defects in the formation of meiotic double strand breaks (DSBs), and we see similar defects in TRAMP mutants, suggesting that a key function of the nuclear exosome is to prevent saturation of the CBC complex by CUTs. Together, our results show that the nuclear exosome remains active in meiosis and has an important role in facilitating meiotic recombination.
2015-05-15 | PXD001223 | Pride
Project description:We studied the differences in RNA accumulation profiles of an rrp6-null mutant and compared it to RNA accumulation in rrp6 catalytic mutants as well as dis3 mutants using RNA-Seq. Rrp6 and Dis3 are exosome exoncleases, therefore this study was used to determine their target RNAs We examined 3' end RNA processing changes by RNA-Seq in wild type, rrp6Δ and rrp6-cat mutants. Libraries were made by 3' adapter ligation
2015-12-01 | GSE74411 | GEO
Project description:The Saccharomyces cerevisiae TRAMP4 and TRAMP5 complexes, which consist of the poly(A) polymerase Trf4 or Trf5, respectively, the zinc knuckle proteins Air1 or Air2, and the RNA helicase Mtr4, play a critical role in nuclear RNA surveillance. Although it is known to enhance the nuclease activity of the exosome, relatively little is known about the exact mechanism and specificity of TRAMP. To better define the specificities of the TRAMP complexes, we used phenotypic analysis and RNA deep-sequencing technology to measure differences in global RNA polyadenylation in air mutants, revealing specific requirements for each Air protein in the regulation of the levels of non-coding and coding RNAs. These findings reveal differential functions for Air proteins in eukaryotic RNA metabolism and indicate that they control the substrate specificity of the RNA exosome. Poly(A)+ RNA from WT, rrp6-M-NM-^T, air1-M-NM-^T rrp6-M-NM-^T and air2-M-NM-^T rrp6-M-NM-^T was sequenced using ABI SOLiD platform, in duplicate.
2012-11-14 | E-GEOD-42231 | biostudies-arrayexpress
Project description:Abstract: Quality control requires discrimination between functional and aberrant species to selectively target substrates for destruction. Nuclear RNA quality control in Saccharomyces cerevisiae includes the TRAMP complex that marks RNA for decay via polyadenylation and helicase-dependent 3′ to 5′ degradation by the RNA exosome. Using reconstitution biochemistry we show that polyadenylation and helicase activities of TRAMP cooperate with processive and distributive exoribonuclease activities of the nuclear RNA exosome to selectively target and degrade an unmodified tRNA while leaving native tRNA intact. Inactivation of the distributive exoribonuclease activity of Rrp6 results in loss of substrate discrimination, leading to degradation of all RNAs. These data suggest that the activities of the Mtr4 helicase and Rrp6 exoribonuclease endow the TRAMP-RNA exosome complex with the ability to protect stable RNA while degrading defective RNA species. Rrp6 and its 3′-5′ exonuclease activity have previously been shown to contribute to quality control and processing of various types of nuclear RNAs. Our sequencing analysis further confirms that Rrp6 contributes to this process.
2021-03-18 | GSE160368 | GEO
Project description:Nuclear 3’ to 5’ nuclease RNA exosome plays a key role in quality control and processing of multiple protein-coding and non-coding transcripts made by RNA polymerase II. A mechanistic understanding of exosome function remains a challenge given the large number of RNA species and intervening RNA processing factors. Here we analysed changes in the poly(A)+ RNA proteins interactome provoked by mutations in three distinct subunits of the nuclear RNA exosome. Our data demonstrate a functional connection between Rrp6 and Mtl1 in controlling processing and levels of multiple protein-coding and non-coding transcripts. Furthermore, we show that exosome mutants accumulate components of U1 and U2 snRNPs and show depletion of NTC components from RNA suggesting that the stage prior to the activation of the spliceosome represents a critical quality control step. We have also identified potential new RNA binding factors involved in exosome regulation, including a zinc-finger protein called Mub1 that controls levels of selected transcripts encoding for proteins implicated in stress response. Collectively, our data have provided a global view of RNA metabolism alterations in exosome deficient cells and revealed RNA binding proteins that may act as novel exosome cofactors.
2020-04-17 | GSE148799 | GEO
Project description:Nuclear 3’ to 5’ nuclease RNA exosome plays a key role in quality control and processing of multiple protein-coding and non-coding transcripts made by RNA polymerase II. A mechanistic understanding of exosome function remains a challenge given the large number of RNA species and intervening RNA processing factors. Here we analysed changes in the poly(A)+ RNA proteins interactome provoked by mutations in three distinct subunits of the nuclear RNA exosome. Our data demonstrate a functional connection between Rrp6 and Mtl1 in controlling processing and levels of multiple protein-coding and non-coding transcripts. Furthermore, we show that exosome mutants accumulate components of U1 and U2 snRNPs and show depletion of NTC components from RNA suggesting that the stage prior to the activation of the spliceosome represents a critical quality control step. We have also identified potential new RNA binding factors involved in exosome regulation, including a zinc-finger protein called Mub1 that controls levels of selected transcripts encoding for proteins implicated in stress response. Collectively, our data have provided a global view of RNA metabolism alterations in exosome deficient cells and revealed RNA binding proteins that may act as novel exosome cofactors.
2020-06-15 | GSE149187 | GEO
Project description:We obtained Nab3, Nrd1, and RNA polymerase II occupancy profiles across the genome of S.cerevisiae in wild-type and rrp6∆ strains. This allowed us to determine the impact of defective nuclear exosome on NNS-dependent transcription termination.
2020-07-24 | GSE137881 | GEO
Project description:The RNA exosome complex functions in both the accurate processing and rapid degradation of many different classes of RNA. Functional and structural analyses indicate that RNA can either be threaded through the central channel of the exosome or more directly access the active sites of the ribonucleases Rrp44 and Rrp6, but it was unclear how many substrates follow each pathway in vivo. To address this we used UV crosslinking in growing cells to identify transcriptome-wide interactions of RNAs with the major nuclear exosome-cofactor Mtr4 and with individual exosome subunits (Rrp6, Csl4, Rrp41 and Rrp44) along the threaded RNA path. We performed comparative analyses on exosome complexes lacking the exonucleolytic activity of Rrp44, either carrying a mutation in the Rrp44 S1 RNA-binding domain, predicted to disfavor direct access to the Rrp44 exonuclease active site, or with multiple mutations in Rrp41, reported to block RNA passage through the central channel. Our analysis identified targets using preferentially channel-threading pathway such as mRNAs, 5S rRNA or scR1. Our results suggest as well that aborted tRNAs transcripts, released during transcription, would be rapidly degraded using this route. Alternatively, pre-tRNAs appears to access Rrp44 directly. Both routes seems to be involved for degradation or maturation of RNAPI transcripts. The Rrp41 mutations were found to block substrate passage to Rrp44 only for cytoplasmic mRNAs, apparently confirming the prediction of widening of the lumen in the nuclear, Rrp6-associated complex.
2017-03-20 | GSE90647 | GEO
Project description:Purpose: The exosome plays major roles in RNA processing and surveillance but the in vivo target range and substrate acquisition mechanisms remain unclear. We applied an in vivo cross-linking technique coupled with deep sequencing (CRAC) that captures transcriptome-wide interactions between individual yeast exosome subunits and their targets in a living cell. Methods: We apply CRAC to HTP-tagged proteins (HTP: His6 - TEV cleavage site - two copies of the z-domain of Protein A): Two nucleases (Rrp44, Rrp6) and two structural subunits (Rrp41, Csl4) of the yeast exosome. At least two independent experiments were performed in each case and analyzed separately. We performed CRAC on wild-type (WT) Rrp44 and two catalytic mutants, rrp44-endo (D91N, E120Q, D171N, D198N) and rrp44-exo (D551N). We further developed CRAC using cleavable proteins (split-CRAC) to compare endonuclease and exonuclease targets of Rrp44. Plasmids designed for split-CRAC contain a PreScission protease cleavage site (PP) inserted between aa 241 and 242 in the RRP44 ORF to allow in vitro cleavage of purified protein, and a His6 tag to select the respective cleaved fragment. Results: Analysis of wild-type Rrp44 and catalytic mutants showed that both the CUT and SUT classes of noncoding RNA, snoRNAs and, most prominently, pre-tRNAs and other Pol III transcripts are targeted for oligoadenylation and exosome degradation. Unspliced pre-mRNAs were also identified as targets for Rrp44 and Rrp6. CRAC performed using cleavable proteins (split-CRAC) revealed that Rrp44 endonuclease and exonuclease activities cooperate on most substrates. Mapping oligoadenylated reads suggests that the endonuclease activity may release stalled exosome substrates. Rrp6 was preferentially associated with structured targets, which frequently did not associate with the core exosome. This indicates that substrates can follow multiple pathways to the nucleases. Conclusion: Our study represents the first transcriptome-wide map of substrates for the yeast exosome nuclease complex. Identification of targets for individual exosome subunits in wild-type and mutant yeast cells.
2012-09-25 | E-GEOD-40046 | biostudies-arrayexpress