Widespread EJC footprints in the RNA degradome mark mRNA degradation before steady-state translation
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ABSTRACT:
PROVIDER: PRJNA484887 | ENA |
REPOSITORIES: ENA
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Project description:Exon junction complexes (EJCs) are deposited to mRNAs during splicing and displaced from mRNAs by ribosomes in the pioneer round of translation. The understanding of EJC-bound mRNA degradation before steady-state translation has been limited to nonsense-mediated mRNA decay (NMD) due to a lack of suitable methodologies. Here, we show that RNA degradome data of Arabidopsis, rice, worm and human cells all exhibit a predominant accumulation of 5′ monophosphate (5′P) ends in the canonical EJC region. Inhibition of 5′-3′ exoribonuclease activity and overexpression of an EJC disassembly factor in Arabidopsis reduced the 5′P ends accumulating in the EJC region, supporting the notion that these 5′P ends are in vivo EJC footprints. Hundreds of Arabidopsis NMD targets possess evident EJC footprints, validating their degradation during the pioneer round of translation. In addition to premature termination codons, plant microRNAs can also direct the degradation of EJC-bound mRNAs. However, the production of EJC footprints from NMD but not microRNA targets is dependent on an NMD factor, SMG7. Together, our finding demonstrating in vivo EJC footprinting unravels the composition of the RNA degradome, and provides a new avenue for studying NMD and other mechanisms, such as microRNAs, targeting EJC-bound mRNAs for degradation before steady-state translation.
2020-02-02 | GSE118215 | GEO
Project description:To uncover exon junction complex (EJC) deposition sites on cellular mRNAs, RNA footprints of EJC immuo-purified from HEK293 cells were deep sequenced. The analysis of these data revealed that major “canonical” EJC occupancy site in vivo lies 24 nucleotides upstream of exon junctions (-24 position) and that the majority of exon junctions carry an EJC. Unexpectedly, we find that many sites further upstream of -24 position are also enriched in these EJC footprints. These "non-canonical" sites are binding sites of EJC-interacting proteins with a subset being occupied by SR proteins. Thus, an EJC-SR protein nexus exists within spliced mRNPs and is revealed here. Deep sequencing based profiling of EJC RNA footprints obtained by tandem RNA immunoprecipitation (RIPiT) of RNase I digested RNA:protein complexes.
2012-10-18 | E-GEOD-41154 | biostudies-arrayexpress
Project description:To uncover exon junction complex (EJC) deposition sites on cellular mRNAs, RNA footprints of EJC immuo-purified from HEK293 cells were deep sequenced. The analysis of these data revealed that major “canonical” EJC occupancy site in vivo lies 24 nucleotides upstream of exon junctions (-24 position) and that the majority of exon junctions carry an EJC. Unexpectedly, we find that many sites further upstream of -24 position are also enriched in these EJC footprints. These "non-canonical" sites are binding sites of EJC-interacting proteins with a subset being occupied by SR proteins. Thus, an EJC-SR protein nexus exists within spliced mRNPs and is revealed here.
2012-10-18 | GSE41154 | GEO
Project description:EJC ipaRt: Transcriptome-wide definition of stable EJC RNA interactions in cytoplasm of adult flies
| PRJEB26421 | ENA
Project description:In metazoans, mRNA quality is tightly monitored from transcription to translation. A key role lies with the exon junction complex (EJC) that is placed upstream of the exon-exon junction after splicing. The EJC inner core is composed of Magoh, Y14, eIF4AIII and BTZ and the outer core of proteins involved in mRNA splicing (CWC22), export (Yra1), translation (PYM) and non-sense mediated decay (NMD, UPF1/2/3). The protozoan parasite Trypanosoma brucei encodes only two genes with introns, but all mRNAs are processed by trans-splicing. The presence of the three core EJC proteins and a potential BTZ homologue (Rbp25) in trypanosomes has been suggested as an adaptation of the EJC function to mark trans-spliced mRNAs. Here we explore the interactome of Magoh, Y14, eIF4AIII in T. brucei by TurboID proximity labelling.
2024-03-25 | PXD050946 | Pride
Project description:Signaling pathways are controlled by a vast array of post-translational mechanisms. By contrast, little is known regarding the mechanisms that regulate the expression of their core components. We conducted an RNAi screen in Drosophila for factors modulating RAS/MAPK signaling and identified the Exon Junction Complex (EJC) as a novel key element of this pathway. The EJC binds the exon-exon junctions of mRNAs, and thus far, has been linked exclusively to post-splicing events. Here, we report that the EJC is required for proper splicing of mapk transcripts by a mechanism that apparently controls exon definition. Moreover, whole transcriptome and RT-PCR analyses of EJC-depleted cells revealed that the splicing of long intron-containing genes, which includes mapk, is sensitive to EJC activity. These results identify a role for the EJC in the splicing of a subset of transcripts and suggest that RAS/MAPK signaling depends on the regulation of MAPK levels by the EJC.
2010-10-20 | GSE24012 | GEO
Project description:Signaling pathways are controlled by a vast array of post-translational mechanisms. By contrast, little is known regarding the mechanisms that regulate the expression of their core components. We conducted an RNAi screen in Drosophila for factors modulating RAS/MAPK signaling and identified the Exon Junction Complex (EJC) as a novel key element of this pathway. The EJC binds the exon-exon junctions of mRNAs, and thus far, has been linked exclusively to post-splicing events. Here, we report that the EJC is required for proper splicing of mapk transcripts by a mechanism that apparently controls exon definition. Moreover, whole transcriptome and RT-PCR analyses of EJC-depleted cells revealed that the splicing of long intron-containing genes, which includes mapk, is sensitive to EJC activity. These results identify a role for the EJC in the splicing of a subset of transcripts and suggest that RAS/MAPK signaling depends on the regulation of MAPK levels by the EJC. Transcriptome sequencing (RNA-Seq) of Drosophila S2 cells to monitor the effect of EJC depletion on the cellular mRNA expression profile. Each treatment (dsRNA knockdown of MAGO (CG9401), dsRNA knockdown of eIF4AIII (CG7483)) was done in biological duplicate and each sample was sequenced separately on a quad slide on the SOLiD 3.0 platform. The reference samples were treated with a dsRNA targeted to GFP.
2010-10-19 | E-GEOD-24012 | biostudies-arrayexpress
Project description:This study used Drosophila melanogaster S2 cells treated with siRNA against the EJC components mago or eIF4A3, or a non-targeting control siRNA (three samples per condition). mRNA-seq libraries were prepared from the samples and the data was used to examine 'RS-exons' - exons which reconstitute a 5' splice site when they are spliced to the upstream exon. In contrast to mammalian cells, RS-exons are not recursively spliced out from Drosophila transcripts after perturbation of the EJC.
2018-10-15 | E-MTAB-7271 | biostudies-arrayexpress
Project description:Tracking of dCas9-methyltransferase footprints
| PRJNA347354 | ENA
Project description:Promoter-proximal pausing of RNA polymerase II (Pol II) is a widespread transcriptional regulatory step across metazoans. Here we find that the nuclear exon junction complex (pre-EJC) is a critical and conserved regulator of this process. Depletion of pre-EJC subunits leads to a global decrease in Pol II pausing and to premature entry into elongation. This effect occurs, at least in part, via non-canonical recruitment of pre-EJC components at promoters. Failure to recruit the pre-EJC at promoters results in increased binding of the positive transcription elongation complex (P-TEFb) and in enhanced Pol II release. Notably, restoring pausing is sufficient to rescue exon skipping and the photoreceptor differentiation defect associated with depletion of pre-EJC components in vivo. We propose that the pre-EJC serves as an early transcriptional checkpoint to prevent premature entry into elongation, ensuring proper recruitment of RNA processing components that are necessary for exon definition.
2019-01-22 | GSE106907 | GEO