Mus musculus
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA362999 | ENA |
REPOSITORIES: ENA
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Project description:Transcription and translation are highly energy consuming processes and both are modulated by the intracellular energy status. Transcription start site (TSS) selection and alternative promoter (AP) usage contribute to the complexity of gene expression but little is known about their impact on translation in response to metabolic deficiencies. Here we performed TSS mapping of the translatome following energy stress. We assessed the contribution of cap-proximal TSS nucleotides and strikingly found dramatic effect on translation only upon stress. As eIF4E levels were reduced, we analyzed its binding to capped-RNAs with different initiating nucleotides and found differential affinity, the lowest being for 5’cytidine, in correlation with the translational response. In addition the number of differentially translated APs was highly elevated following energy stress, suggesting that AP usage is central to the stress response. These include novel glucose-starvation-induced downstream promoters for the translation regulators eIF4A and Pabp which are translationally-induced despite the general translational inhibition. The resultant eIF4A protein is N-terminally truncated and acts as eIF4A inhibitor. The induced Pabp isoform has shorter 5'UTR removing an auto-inhibitory element. These findings uncovered several levels of coordination of transcription and translation responses to energy stress.
2017-01-25 | GSE93981 | GEO
Project description:eIF4E, the major cap-binding protein, has long been considered limiting for translating the mammalian genome. However, the requirement for eIF4E dose at an organismal level remains unexplored. By generating an Eif4e haploinsufficient mouse, we surprisingly found that 50% reduction in eIF4E, while compatible with normal development and global protein synthesis, significantly impeded cellular transformation and tumorigenesis. Genome-wide translational profiling uncovered a translational program induced by oncogenic transformation and revealed a critical role for eIF4E dose specifically in translating a network of mRNAs enriched for a unique 5’UTR signature. In particular, we demonstrate that eIF4E dose is essential for translating mRNAs regulating reactive oxygen species (ROS) that fuel transformation and cancer cell survival in vivo. Therefore, mammalian cells have evolved surplus eIF4E levels that cancer cells hijack to drive a translational program supporting tumorigenesis Total cellular RNA and high MW polysome associated RNA were isolated from matched untransformed and transformed WT and Eif4e+/- MEFs for analysis on Affymetrix Mouse Gene 1.0 ST arrays. The difference in log2 RMA intensity between matched polysomal RNA and total RNA was taken to quantify translational efficiency (TE).
2015-07-01 | E-GEOD-68238 | biostudies-arrayexpress
Project description:Translational regulation plays a critical role in cell growth and proliferation, and its dysregulation results in cancer. Aberrant expression of the mRNA 5’cap-binding protein, eIF4E, has been implicated in cancer development and progression. eIF4E activity is promoted by phosphorylation. Here we show that “knock-in” mice in which eIF4E cannot be phosphorylated are resistant to tumorigenesis in a prostate cancer model. We identify multiple candidate genes involved in the resistance to oncogenic transformation. Importantly, phosphorylation of eIF4E is increased in hormone-refractory prostate cancer, the deadliest stage of the disease. Our results highlight eIF4E phosphorylation as a critical event in tumorigenesis. Comaparison of total RNA and polysomal RNA from mouse embryo fibroblasts derived from WT and eIF4E-KI (non phosphorylatable eIF4E) mice
2010-08-17 | E-GEOD-17451 | biostudies-arrayexpress
Project description:eIF4E, the major cap-binding protein, has long been considered limiting for translating the mammalian genome. However, the requirement for eIF4E dose at an organismal level remains unexplored. By generating an Eif4e haploinsufficient mouse, we surprisingly found that 50% reduction in eIF4E, while compatible with normal development and global protein synthesis, significantly impeded cellular transformation and tumorigenesis. Genome-wide translational profiling uncovered a translational program induced by oncogenic transformation and revealed a critical role for eIF4E dose specifically in translating a network of mRNAs enriched for a unique 5’UTR signature. In particular, we demonstrate that eIF4E dose is essential for translating mRNAs regulating reactive oxygen species (ROS) that fuel transformation and cancer cell survival in vivo. Therefore, mammalian cells have evolved surplus eIF4E levels that cancer cells hijack to drive a translational program supporting tumorigenesis
2015-07-01 | GSE68238 | GEO
Project description:Virus infection may shut off host protein synthesis in order to achieve the replicative advantage over host cells. It is well known that human pathogenic viruses, particularly the picornaviruses, can block host protein synthesis by cleavage or inhibition of eukaryotic initiation factors (eIFs). In this study we found a novel mechanism that microRNA (miRNA) is involved in viral pathogenesis. Infection of enteroviruses can disturb the expression of host miRNAs, in which miR-141 is up-regulated and inhibits host protein synthesis by post-transcriptional repression of the target gene eIF4E, a key element for cap-dependent translation of host proteins. Knockdown of miR-141 by a specific siRNA, antagomiR-141, could restore host eIF4E expression, delay the occurrence of cytopathic effect (CPE), and impair virus propagation. We demonstrated that EV71 infection could increase early growth response 1 (EGR1) expression which induced miR-141 causing the eIF4E suppression; while silencing of EGR1 attenuated virus production. Our results suggest that enterovirus infection causes the EGR1-mediated upregulation of host miR-141, further lead to the translational switch from cap-dependent to cap-independent protein synthesis in the host cells, an environmental beneficial for viral propagation. This novel mechanism may highlight a new approach for future development of antiviral therapy. Enteroviruses in the Picornaviridae family are important human pathogens which can cause fatal diseases, including cardiopulmonary failure, aseptic meningitis, paralysis, myocarditis, and encephalomyelitis. Virus infection may induce shutoff of host protein synthesis, particularly in picornavirus, whose protein translation is cap-independent. It is known that poliovirus 2A protease cleaves eIF4G, a scaffold component of mammalian cell translational complex, leading to the shut down of host protein synthesis. Nevertheless, the cleavage of eIF4G may not be sufficient for the complete shutoff of host protein synthesis. Previous studies showed that cleavage of polyA-binding protein (PABP) by viral protease 3C and dephosphorylation of the translational repressor, eIF4E binding protein 1 (4E-BP1), also contribute to this process. The cap-binding protein, eIF4E, is the most crucial factor in determining whether cap-dependent or -independent translation takes place. The mechanism by which viral infection modulates host cell protein synthesis through interfering eIF4E expression is not yet known. miRNAs are a newly discovered class of small non-protein-coding RNAs that may act via endogenous RNA interference. Our understanding of its role in the dynamic interplay between virus and host components is quite limited. Since both virus infection and miRNAs could hinder cellular protein synthesis, whether miRNAs are involved during virus infection in shutting off host protein synthesis is still unknown. To address this issue, we analyze the altered gene and microRNA expression after EV71 infection. ***This submission represents the mRNA expression component of the study only***
2011-01-03 | E-GEOD-15323 | biostudies-arrayexpress
Project description:Translational regulation plays a critical role in cell growth and proliferation, and its dysregulation results in cancer. Aberrant expression of the mRNA 5’cap-binding protein, eIF4E, has been implicated in cancer development and progression. eIF4E activity is promoted by phosphorylation. Here we show that “knock-in” mice in which eIF4E cannot be phosphorylated are resistant to tumorigenesis in a prostate cancer model. We identify multiple candidate genes involved in the resistance to oncogenic transformation. Importantly, phosphorylation of eIF4E is increased in hormone-refractory prostate cancer, the deadliest stage of the disease. Our results highlight eIF4E phosphorylation as a critical event in tumorigenesis.
2010-08-17 | GSE17451 | GEO
Project description:The transformation of normal to malignant cells is accompanied by substantial changes in gene expression programs through diverse mechanisms. Here we examined the changes in the landscape of transcription start sites (TSSs) and alternative promoter (AP) usage and their impact on the translatome in TCL1-driven chronic lymphocytic leukemia (CLL). Our findings revealed a marked elevation of APs in CLL cells from Eµ-Tcl1 transgenic mice, which are particularly enriched with intragenic promoters that generate N-terminally truncated or modified proteins. Intragenic promoter activation is mediated by (i) loss of function of ‘closed chromatin’ epigenetic regulators due to the generation of inactive N-terminally modified isoforms or reduced expression; (ii) upregulation of transcription factors, including c-Myc, targeting the intragenic promoters and associated enhancers. Exogenous expression of Tcl1 in MEFs is sufficient to induce intragenic promoters of epigenetic regulators and promote c-Myc expression. We further found a dramatic translation downregulation of transcripts bearing CNY cap-proximal tri-nucleotides, reminiscent of cells undergoing metabolic stress. These findings uncovered the role of Tcl1 oncogenic function in altering promoter usage and mRNA translation in leukemogenesis.
2022-06-29 | GSE194265 | GEO
Project description:Background: Translation deregulation is an important mechanism that causes aberrant cell growth, proliferation and survival. eIF4E, the mRNA 5 prime cap–binding protein, plays a major role in translational control. To understand how eIF4E affects cellular proliferation and cell survival, we identified mRNA targets that are translationally responsive to eIF4E. Methodology/ principal findings: Microarray analysis of polysomal mRNA from an eIF4E-inducible NIH 3T3 cell line was performed. Induction of eIF4E expression resulted in increased translation of a defined set of mRNAs; many of the mRNAs are novel targets, including those that encode large- and small-subunit ribosomal proteins and cell growth–related factors. eIF4E overexpression also led to augmented translation of mRNAs encoding anti-apoptotic proteins, which conferred resistance to endoplasmic reticulum–mediated apoptosis. Conclusions/ significance: Our results shed new light on the mechanisms by which eIF4E prevents apoptosis and transforms cells. Downregulation of eIF4E and its downstream targets is a therapeutic option for the development of novel anti-cancer drugs. Keywords: time course
2007-04-21 | GSE6639 | GEO
Project description:The mRNA 5â² cap is normally essential for eukaryotic mRNA translation, stabilization and transport and both the cap and eIF4E are important elements of post-transcriptional gene regulation. To further our understanding of mRNA translation in the human malaria parasite Plasmodium falciparum, we have investigated the parasite translation initiation factor eIF4E and its interaction with 5â² capped mRNA. We have purified P. falciparum eIF4E as a recombinant protein and demonstrated that it has canonical mRNA 5â² cap binding activity. We used this protein to purify P. falciparum full-length 5â² capped mRNAs from total parasite RNA. Microarray analysis comparing total and eIF4E-purified 5â² capped mRNAs shows that a subset of 34 features were more than two-fold under-represented in the purified RNA sample, including 19 features representative of nuclear transcripts. The uncapped nuclear transcripts may represent a class of mRNAs targeted for storage and cap removal. Keywords: total RNA vs purified capped mRNA The microarray data were obtained from four hybridizations using RNA from two independent GST-PfeIF4E purifications from separate malaria cultures.
2010-06-10 | E-GEOD-6356 | biostudies-arrayexpress
Project description:Regulation of translation initiation is accomplished in diverse eukaryotes through proteins which bind to the mRNA cap-binding protein, eIF4E, and either prevent its association with eIF4G or form repressive mRNPs which exclude the translation machinery. Such mechanisms in plants, and even the presence of eIF4E-interacting proteins outside of eIF4G (and the plant-specific isoform eIFiso4G, which binds eIFiso4E) which operate in a gene regulatory manner are not known. Here we describe the Conserved Binding of eIF4E 1 (CBE1), a plant-specific protein with an evolutionarily conserved eIF4E binding motif. This protein binds eIF4E or eIFiso4E in vitro to form cap-binding complexes, and is found as a constituent of cap-binding complexes in vivo in an eIF4E-dependent manner. Mutants lacking CBE1 show dysregulation of cell cycle related transcripts, accumulating higher levels relative to wild-type plants of mRNAs encoding proteins involved in mitotic processes. These findings support CBE1 as a plant protein with the capability to form cap-binding complexes with the potential for gene regulatory activity.
2018-09-26 | GSE114363 | GEO