Global analysis of the nuclear processing of unspliced U12-type introns by the exosome
ABSTRACT: we analyzed globally the effect of exosome processing on the nuclear pre-mRNA transcripts by inactivating either the RRP41 or DIS3 subunit of the exosome. Using SOLiD RNA sequencing technology, we report 30-120 million mapped cellular compartment specific reads per sample allowing the detection of unspliced pre-mRNAs. We show that RRP41 and DIS3 knockdowns stabilize an overlapping set of U12-type introns. Studying the global effect of the exosome (Rrp41 or Dis3 subunit) knockdown comparing to the control sample.
Project description:The recently proposed exozyme hypothesis posits that subunits of the RNA processing exosome assemble into structurally distinct protein complexes that function in disparate cellular compartments and RNA metabolic pathways. Here, in a genetic test of this hypothesis, we examine the role of Dis3 -- an essential polypeptide with endo- and 3' to 5' exo-ribonuclease activity -- in cell cycle progression. We present several lines of evidence that perturbation of DIS3 affects microtubule (MT) localization and structure in Saccharomyces cerevisiae. Cells with a DIS3 mutation: (i) accumulate anaphase and pre-anaphase mitotic spindles; (ii) exhibit spindles that are mis-oriented and displaced from the bud neck; (iii) harbor elongated spindle-associated astral MTs; (iv) have an increased G1 astral MT length and number; and (v) are hypersensitive to MT poisons. Mutations in the core exosome genes RRP4 and MTR3 and the exosome cofactor gene MTR4 -- but not other exosome subunit gene mutants -- also elicit MT phenotypes. RNA deep sequencing analysis (RNA-seq) shows broad changes in the levels of cell cycle- and microtubule-related transcripts in mutant strains. Collectively, the different mitotic phenotypes and distinct sets of mRNAs affected by the exosome subunit and cofactor mutants studied here suggest that Dis3 has a core exosome-independent role(s) in cell cycle progression. These observations are consistent with the predictions of the exozyme hypothesis and also suggest an evolutionarily conserved role for Dis3 in linking RNA metabolism, MTs, and mitotic progression. RNA-seq analysis of total RNA harvested from WT, mtr3-1, mtr4-1, and Dis3^mtr (rrp44-1/mtr17-1) Saccharomyces cerevisiae strains after a temperature shift.
Project description:Somatic mutations affecting DIS3, the catalytic component of the RNA exosome, have been found in up to 18% of patients affected by the hematological cancer multiple myeloma. Here we show that DIS3 targets and degrades the pluripotency factor LIN28B. In cancer cells, DIS3 inactivation leads to enhanced LIN28B expression, thus disrupting the let-7 miRNAs tumor suppressor network and ultimately increasing protein levels of crucial oncogenes such as MYC and RAS. DIS3 represents the catalytic component of the exosome. The exosome is required for cell viability and targets several RNA species, including pre-mRNAs, pre-tRNAs, pre-rRNAs, snRNAs and snoRNAs. To gain insight on the macular wiring underlying DIS3 activity in mammalian cells, we comprehensively evaluated expression profiles, including miRNAs, in various cell lines, upon DIS3 knockdown. This series of microarray experiments contains the miRNA expression profiles of independent replicates of RPMI-8226, KMS12-BM multiple myeloma cell lines and HEK-293T cells, knocked-down with a scrambled or hDIS3 sh4 and collected 72 hours after infection. 500 nanograms of total RNA were processed using the FlashTag labeling kit, which uses a tailing reaction followed by ligation of the biotinylated signal molecule to the target RNA sample. The labelled RNA was then hybridized to Affymetrix GeneChip® microRNA arrays v1.0, following the Affymetrix manufacturer's instructions.
Project description:To determine the global impact of the clbn mutation on gene expression and efficiency of U2- and U12-type splicing, we analyzed the transcriptome of 108hpf wt and clbn mutant larvae by microarrays and RNA sequencing. RNAseq data was used to characterize intron retention of U2-type and U12-type intron on a genome-wide scale to confirm that rnpc3 deficiency specifically impairs U12-type splicing. RNAseq and microarray data were combined to yield high-confidence lists of differentially expressed genes which show that impaired U12-type splicing has a wide-ranging effect on the developing transcriptome. RNAseq libraries prepared from 108 hours post-fertilization zebrafish larvae (approx. 60 embryos each, genotyped homozygous wildtype and homozygous clbns841 mutants, respectively)
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 Overall design: polyA selected RNA abundance measurements in wild type and exosome exonuclease mutants rrp6Δ, rrp6-cat, dis3-4 (ts mutant at 23°C and 30°C), rrp6-cat dis3-4 (ts mutant at 23°C and 30°C) double mutant using paired-end Illumina sequencing of stranded libraries 3' end adapter ligated total RNA from wild type, rrp6Δ and rrp6-cat mutants was used to make stranded RNA-Seq libraries and sequenced by paired-end Illumina sequencing
Project description:Human DIS3 is a nuclear, catalytic subunit of the exosome complex containing exonucleolytic and endonucleolytic active domains. To identify DIS3 targets genome-wide we conducted comprehensive transcriptomic analysis of HEK293 cells producing mutated DIS3 versions and Photoactivatable Ribonucleoside-Enhanced Crosslinking and Immunoprecipitation (PAR-CLIP) experiments. Pervasive transcription products like Promoter Upstream Transcripts (PROMPTs) accumulated robustly in catalytic DIS3 mutants, representing ~8% of PAR-CLIP reads. Importantly, RNAs originating from unannotated genomic regions increased ~2.5 times in double DIS3 mutants, covering ~70% of genome and allowing for discovery of thousands of novel transcripts. The first intron of many pre-mRNAs accumulated in DIS3 mutants indicating a widespread premature RNA polymerase II termination. The short form of NEAT1 lincRNA was overexpressed in DIS3 mutants, leading to increased number of paraspeckles. Moreover, there was a global deregulation of mRNAs in DIS3 double mutant. Finally, snoRNA precursors accumulated, which correlated with a strong PAR-CLIP signal indicating that DIS3 but not RRP6 is a main snoRNA processing enzyme. In aggregate, we demonstrate that DIS3 is a major nucleoplasmic activity responsible for shaping the human transcriptome. Overall design: RNA-seq experiments were performed in triplicates for DIS3 wild type (control), DIS3 PIN, DIS3 RNB domain mutants and DIS3 PIN RNB double mutant. RNA-seq samples from DIS3 wild type and DIS3 double mutant were additionally sequenced in deeper resolution, also in triplicates. DIS3 PAR-CLIP experiment was performed in duplicate. Pol II ChIP-seq experiment in WT and DIS3 PIN RNB double-mutants cells was performed in triplicates.
Project description:The RNA exosome is a multi-subunit complex essential for processing and degradation of many classes of RNA. Although many of the functions of the RNA exosome are well established, how the activity of this complex is regulated remains poorly understood. Here we report a comprehensive proteomic analysis of the RNA exosome complex from the fission yeast Schizosaccharomyces pombe and identified 39 post-translational modifications (PTMs), including phosphorylation, methylation, and acetylation. Interestingly, most of the modifications were identified in Dis3 and Rrp6, the catalytic subunits of the RNA exosome, as well as in the exosome-associated RNA helicase, Mtr4. Functional characterization of residues found to be modified in distinct exosome subunits revealed specific substitutions that affected cell growth and RNA exosome functions. Notably, phosphomimetic substitutions of phosphorylation sites Ser-809 and Tyr-814 in S. pombe Dis3 resulted in striking loss-of-function phenotype in vivo. Biochemical analysis of the Ser-809 and Tyr-814 phosphomimetic versions of Dis3 revealed proper assembly in vivo, but a marked decrease in degradation capacity in vitro. Given that Ser-809 and Tyr-814 are positioned in the vicinity of the catalytic centre of Dis3, our data suggest that site-specific phosphorylation of the RNA exosome represents a mechanism to control its activity in vivo.
Project description:The nuclear RNA exosome is an essential multi-subunit complex that controls RNA homeostasis. Congenital mutations in exosome genes are associated with neurodegenerative diseases. Here, we show that transient depletion of nuclear RNA exosome subunits in epithelial cells inhibits influenza virus replication. Similarly, viral biogenesis was suppressed in cells derived from mice with conditional ablation of the RNA exosome subunit Exosc3. Furthermore, patient-derived cells with a congenital EXOSC3 mutation were less susceptible to influenza virus infection. Using proteomics and next generation sequencing during infection, we show that the viral polymerase complex (PA, PB2, PB1) co-opts the nuclear RNA exosome complex and cellular RNAs en route to 3’ end degradation. Mechanistically, the nuclear RNA exosome coordinates the initial steps of viral transcription with RNAPII at host promoters. Exosome deficiency uncouples chromatin targeting of the viral polymerase complex and the formation of cellular:viral RNA hybrids, which are essential RNA intermediates that license transcription of antisense genomic viral RNAs. Overall, we discovered a critical nexus between an essential component of the influenza virus (polymerase) and an essential component of the cell (exosome), alteration of which leads to breakage of host-pathogen symmetry and a lose-lose scenario (viral impairment and neurodegeneration). Overall design: (1) Examination of influenza RNA levels in murine B cells conditionally ablated for the RNA exosome subunit Exosc3 (2) Examination of both host:viral chimeric mRNAs and the cellular transcriptome in human A549 cells transiently depleted for RNA exosome subunits DIS3 or EXOSC10; along with siRNA control (3) Examination of both host:viral chimeric mRNAs and the cellular transcriptome in human A549 cells transiently transfected with a plasmid encoding human DIS3 or an empty vector (EV) control
Project description:Cryptic unstable transcripts (CUTs) are rapidly degraded by the nuclear exosome, however, the way they are recognized and targeted to the exosome is not fully understood. The recently identified Schizosaccharomyces pombe MTREC complex has been shown to promote degradation of meiotic mRNAs and regulatory ncRNAs. Here, we report that the MTREC complex is also the major nuclear exosome targeting complex for CUTs and unspliced mRNAs. MTREC complex specifically binds to CUTs, meiotic mRNAs and unspliced mRNA transcripts and targets these RNAs for degradation by the nuclear exosome, while the TRAMP complex has only a minor role in this process. The MTREC complex physically interacts with the nuclear exosome and with various RNA-binding and -processing complexes, coupling RNA processing to the RNA degradation machinery. Our study reveals the central role of the evolutionarily conserved MTREC complex in RNA quality control, and in the recognition and elimination of aberrant, cryptic transcripts. RNA sequencing of WT and mutant S.pombe strains, processed data is normalized to median non-intron containing gene-expression, no replicates
Project description:To assay the effect of depletion of the RNA exosome on RNAs shorter than the standard length captured by RNA-seq (>200 nt), we created RNA-seq libraries using fragmented RNA and a linker-ligation-based protocol that does not deplete RNAs shorter than 200 nt. Note: these data relate to Figure 6E in Lubas, Andersen et al., Cell Reports 2014 (accepted) Overall design: These samples constitute RNA-seq libraries prepared to enrich for short RNA fragments such as snRNA and snoRNAs. Three different HeLa cell RNAi experiments were used to generate the RNA samples applied in the library construction: control transfected, hRRP40-depleted and triple-depleted of the known RNA exosome-associated ribonucleases (DIS3, DIS3L and hRRP6 knock-down). By these means the data offers reveal RNA exosome substrates via their up-regulation in the respective knock-downs NOTE: The 'Figure6E_RNAseq_DataTable_PlottedValues.txt' was generated from total 5 samples, with two additional published samples [SRP031620] and provided to better allow readers to fully replicate the analyses presented in the publication.
Project description:Abscisic acid (ABA) regulates plant development and adaptation to environmental conditions. The ABA biosynthesis pathway in plants has been thoroughly elucidated; however, very few transcription factors directly regulating the expression of ABA biosynthetic genes have been identified. Here we show that the tomato (Solanum lycopersicum) zinc finger transcription factor SlZFP2, which is mainly expressed in developing fruits and axillary buds, negatively regulates ABA biosynthesis. Overexpression of SlZFP2 resulted in multiple phenotypic changes, including more branches, early flowering, delayed fruit ripening, lighter seeds and faster seed germination, whereas gene silencing by RNA interference (RNAi) caused poor fruit set and inhibited seed germination. Gene expression analysis showed that SlZFP2 represses ABA biosynthesis mainly through downregulation of the ABA biosynthetic genes SITIENS (SIT), FLACCA (FLC) and aldehyde oxidase SlAO1. SlZFP2 delays the onset of ripening through suppression of the ripening regulator COLORLESS NON-RIPENING (CNR). Using bacterial one hybrid screening and a selected amplification and binding assay we identified the (A/T)(G/C)TT repeat as the core binding sequence of SlZFP2. We further identified a large number of tomato genes containing putative SlZFP2 binding sites in their promoter regions. Chromatin immunoprecipitation and electrophoretic mobility shift assays demonstrated that SIT, FLC and SlAO1 are direct targets of SlZFP2 through binding to their promoter regions. We propose that SlZFP2 represents a novel negative regulator for fine tuning ABA biosynthesis during fruit development and provides a potentially valuable tool for dissecting the role of ABA in fruit ripening.To gain further insight on transcriptome changes regulated by SlZFP2, we sequenced a representative SlZFP2 RNAi line in LA1589 background and its nontransgenic sibling (WT) on a Miseq platform. The RNAi line 207 showed defected fruit set and ABA biosynthesis were chosen for profiling gene expression via RNA sequencing. Its nontransgenic sibling was served as controls. Three biological replicates were conducted.