ICLIP of components of the TREX complex
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE113896 | GEO | 2019/05/01
REPOSITORIES: GEO
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Project description:During gene expression, RNA export factors are mainly known for driving nucleocytoplasmic transport. While early studies suggested that the Exon Junction Complex (EJC) may provide a binding platform for them, subsequent work proposed that they are only recruited by the Cap-Binding Complex (CBC) to the 5’ end of RNAs, as part of the TREX complex. Using iCLIP, we show that the export receptor Nxf1 and two TREX subunits, Alyref and Chtop, are actually recruited to the whole mRNA co-transcriptionally via splicing but before 3’-end processing. Consequently, Alyref can alter splicing decisions and Chtop regulates alternative polyadenylation. Surprisingly, we observe that eIF4A3 stimulates Alyref deposition on single exon or spliced RNAs close to EJC sites. Additional experiments suggest that Alyref is recruited to the 5’-end of RNAs by CBC before binding RNAs near EJCs. Our study reveals mechanical insights into the co-transcriptional recruitment of mRNA export factors and how this shapes the human transcriptome.
2019-05-10 | GSE130992 | GEO
Project description:During gene expression, RNA export factors are mainly known for driving nucleocytoplasmic transport. While early studies suggested that the Exon Junction Complex (EJC) may provide a binding platform for them, subsequent work proposed that they are only recruited by the Cap-Binding Complex (CBC) to the 5’ end of RNAs, as part of the TREX complex. Using iCLIP, we show that the export receptor Nxf1 and two TREX subunits, Alyref and Chtop, are actually recruited to the whole mRNA co-transcriptionally via splicing but before 3’-end processing. Consequently, Alyref can alter splicing decisions and Chtop regulates alternative polyadenylation. Surprisingly, we observe that eIF4A3 stimulates Alyref deposition on single exon or spliced RNAs close to EJC sites. Additional experiments suggest that Alyref is recruited to the 5’-end of RNAs by CBC before binding RNAs near EJCs. Our study reveals mechanical insights into the co-transcriptional recruitment of mRNA export factors and how this shapes the human transcriptome.
2019-05-01 | GSE113952 | GEO
Project description:The TREX complex (TREX) plays key roles in nuclear export of mRNAs. However, little is known about its transcriptome-wide binding targets. We used individual cross-linking and immunoprecipitation (iCLIP) to identify the binding sites of ALYREF, an mRNA export adaptor in TREX, in human cells. As expected, iCLIP reads are mainly mapped to exons of mRNAs. Globally, ALYREF binding shows two apparent enrichments on the mRNA, one is near the 5’ end and the other is very close to the 3’ end. In addition, numerous middle exons harbor ALYREF binding sites. CBP80 and PABPN1 mainly affect ALYREF binding at the 5’ and the 3’ region, respectively. Interestingly, we found that the 3’ processing factor CstF64 directly interacts with ALYREF and is required for the overall binding of ALYREF on the mRNA. Sequence analysis led to the identification of multiple
2017-05-19 | GSE99069 | GEO
Project description:Dynamic RNA-protein interactions govern the co-transcriptional packaging of RNA polymerase II (RNAPII)-derived transcripts. Yet, our current understanding of this process in vivo primarily stems from steady state analysis. To remedy this, we here conduct temporal-iCLIP (tiCLIP), combining RNAPII transcriptional synchronisation with UV cross-linking of RNA-protein complexes at serial timepoints. We apply tiCLIP to the RNA export adaptor, ALYREF; a component of the Nuclear Exosome Targeting (NEXT) complex, RBM7; and the nuclear cap binding complex (CBC). Regardless of function, all tested factors interact with nascent RNA as it exits RNAPII. Moreover, we demonstrate that the two transesterification steps of pre-mRNA splicing temporally separate ALYREF and RBM7 binding to splicing intermediates, and that exon-exon junction density drives RNA 5’end binding of ALYREF. Finally, we identify underappreciated steps in snoRNA 3’end processing performed by RBM7. Altogether, our data provide an unprecedented temporal view of RNA-protein interactions during the early phases of transcription.
2023-01-13 | GSE202980 | GEO
Project description:The nuclear cap-binding complex (CBC) stimulates multiple steps in several RNA maturation pathways, but how it functions in humans is incompletely understood. For small capped RNAs like pre-snRNAs, the CBC recruits PHAX. Here, we identify the CBCAP complex, composed of CBC, Ars2 and PHAX, and show that both CBCAP and CBC-Ars2 complexes can be reconstituted from recombinant proteins. Ars2 stimulates PHAX binding to the CBC as well as snRNAs 3'-end processing, hereby coupling maturation with export. In vivo, CBC and Ars2 bind similar capped non-coding and coding RNAs, and stimulate their 3’-end processing. Strongest effects are displayed for cap-proximal polyadenylation sites, thereby favoring premature transcription termination. Ars2 functions in part through the mRNA 3’-end cleavage factor CLP1, which binds RNA Polymerase II through PCF11. Ars2 is thus a major CBC effector that stimulates functional and cryptic 3'-end processing sites.
2013-11-08 | GSE52131 | GEO
Project description:The nuclear cap-binding complex (CBC) stimulates multiple steps in several RNA maturation pathways, but how it functions in humans is incompletely understood. For small capped RNAs like pre-snRNAs, the CBC recruits PHAX. Here, we identify the CBCAP complex, composed of CBC, Ars2 and PHAX, and show that both CBCAP and CBC-Ars2 complexes can be reconstituted from recombinant proteins. Ars2 stimulates PHAX binding to the CBC as well as snRNAs 3'-end processing, hereby coupling maturation with export. In vivo, CBC and Ars2 bind similar capped non-coding and coding RNAs, and stimulate their 3M-bM-^@M-^Y-end processing. Strongest effects are displayed for cap-proximal polyadenylation sites, thereby favoring premature transcription termination. Ars2 functions in part through the mRNA 3M-bM-^@M-^Y-end cleavage factor CLP1, which binds RNA Polymerase II through PCF11. Ars2 is thus a major CBC effector that stimulates functional and cryptic 3'-end processing sites. In total 12 samples; 4 control IP, 2 Flag- Ars2 IP and 2 Flag-CBP20 IP; 2 control FFL siRNA and 2 siRNA Ars2
2013-11-08 | E-GEOD-52131 | biostudies-arrayexpress
Project description:mRNA export is central to gene regulation and expression. In trypanosomes, transcription is polycistronic, all mRNAs are processed by trans-splicing and export is mediated by non-canonical mechanisms. We have described several conserved mRNA export pathway components in Trypanosoma cruzi, including orthologs of Sub2, a component of the TREX complex, and eIF4AIII, a core component of the exon junction complex (EJC). Few orthologs of proteins involved in mRNA export in higher eukaryotes are detectable in trypanosome genomes and examples of mechanistic divergence well known. To uncover additional components of the trypanosome mRNA maturation and export system we undertook an unbiased search for protein interactors of TcSub2 and TceIF4AIII. Significant overlap between TcSub2 and TceIF4AIII interacting protein cohorts suggests that both proteins associate with similar machinery. We confirmed several interactions with conserved core components of the EJC and multiple additional complexes, together with identification of proteins specific to trypanosomatids. The highly interactive super-interactome uncovered here, capable of supporting RNA processing from splicing through to nuclear export and cytoplasmic events, highlights kinetoplastid-specific and conserved components creating an amalgam to support the unique mRNA maturation mechanisms in trypanosomes.
2022-02-07 | PXD028072 | Pride
Project description:THOC6 is the genetic basis of autosomal recessive THOC6 Intellectual Disability Syndrome (TIDS). THOC6 is critical for mammalian Transcription Export complex (TREX) tetramer formation, which is composed of four six-subunit THO monomers. The TREX tetramer facilitates mammalian RNA processing, in addition to the nuclear mRNA export functions of the TREX dimer conserved through yeast. Human and mouse TIDS model systems revealed novel THOC6-dependent, species-specific TREX tetramer functions. Germline biallelic Thoc6 loss-of-function (LOF) variants result in mouse embryonic lethality. Biallelic THOC6 LOF variants do not alter the expression of TREX dimer component proteins in human cells, but reduced binding affinity to ALYREF implicates impaired TREX tetramer formation. Defects in RNA nuclear export functions were not detected in biallelic THOC6 LOF human neural cells. Instead, mis-splicing was detected in human and mouse neural tissue, revealing novel THOC6-mediated TREX coordination of mRNA processing. We demonstrate that THOC6 is required for regulation of key signaling pathways in human corticogenesis that dictate the transition from proliferative to neurogenic divisions, developmental biology implicated in TIDS neuropathology.
2023-10-17 | GSE245121 | GEO
Project description:Through deep RNA-seq of human monocyte-derived macrophages, we identified RP11-184M15.1, a human macrophage-specific lincRNA, to be highly induced in the cytoplasm of IL-4-stimulated macrophage. Preliminary data showed that treatment of IL-4-stimulated THP1 human macrophages with RP11-184M15.1 small interfering RNA (siRNA) repressed apoptosis of resolving macrophages, as shown by decreased Annexin V+ macrophages, and reduced protein expression of cleaved PARP. Biotinylated RP11-184M15.1 pulldown coupled with mass spectrometry indicated an interaction between RP11-184M15.1 and zinc finger RNA-binding protein (ZFR). RIP corroborated the proposed interaction between RP11-184M15.1 and ZFR. RNAInter revealed mRNAs predicted to interact with ZFR, and some of those genes (e.g., ALYREF, CCNYL1) were also differentially expressed in RNA-seq data of control versus RP11-184M15.1 knockdown in IL-4-stimulated THP1 macrophages. qPCR validated that ALYREF and CCNYL1 expression are reduced with RP11-184M15.1 knockdown. In contrast, with ZFR siRNA, ALYREF and CCNYL1 mRNA expressions were elevated. Thus, a hypothesis to be further tested is that RP11-184M15.1 interacts with ZFR to regulate mRNA stability in IL-4-stimulated macrophages. Nuclear RNA export factor 1 (NXF1) was also validated by RIP to interact with RP11-184M15.1. NXF1 is a known interacting partner of ALYREF in the transcription-export (TREX) complex. With RP11-184M15.1 knockdown, the protein level of ALYREF decreased, and Ingenuity Pathway Analysis (IPA) of RNA-seq data of control versus RP11-184M15.1 knockdown revealed that THO complex subunit 5 homolog (THOC5), another component of the TREX complex, may be an upstream regulator. In addition, past studies have revealed that ALYREF and NXF1 are involved in nuclear export of inflammatory mRNAs and proinflammatory macrophage phenotype, respectively. With RP11-184M15.1 knockdown, there was decreased expression of inflammatory macrophage-associated genes. It may be possible that RP11-184M15.1 functions in mRNA export, along with NXF1 and ALYREF.
2022-11-23 | GSE218308 | GEO
Project description:The exon junction complex (EJC) deposited upstream of mRNA exon junctions shapes structure, composition and fate of spliced mRNA ribonucleoprotein particles (mRNPs). To achieve this, the EJC core nucleates assembly of a dynamic shell of peripheral proteins that function in diverse post-transcriptional processes. In this study we show that EJC exists in two mutually exclusive compositions characterized by peripheral proteins RNPS1 and CASC3. We identified transcriptome-wide binding sites of the two alternate EJCs via RNA:protein immunoprecipitation in tandem followed by deep sequencing (RIPiT-Seq). We show that RNPS1-EJC, which is an SR-rich mega-dalton sized RNP, is the major EJC form in the nucleus. After mRNP export to the cytoplasm and before translation, the EJC undergoes a remarkable compositional and structural remodeling into an SR- and RNPS1-devoid monomeric complex that contains CASC3. The CASC3-EJC is enriched on cytoplasmic RNAs and is the main EJC form that encounters ribosome and undergoes disassembly during translation.
2018-11-19 | GSE115977 | GEO