Project description:This SuperSeries is composed of the following subset Series: GSE25170: MYC drives resistance to PI3K/mTOR targeted inhibition (Sty SNP array) GSE25172: MYC drives resistance to PI3K/mTOR targeted inhibition (gene expression) Refer to individual Series
Project description:This work explores the therapeutic potential for the translation initiation factor eIF4E in multiple myeloma (MM). We show that targeting eIF4E is deleterious to MM cells and causes reduction of targets with established importance to the disease progression. We demonstrate that eIF4E inhibition may be achieved by treating the MM cells with the already clinically employed anti-viral drug Ribavirin. Results indicate that tetraspanin overexpression in MM cell lines increased global protein synthesis; CD81N1/CD82N1 also caused a decrease in peIF4E, its regulators and targets; direct inhibition of eIF4E (siRNA, Ribavirin) deleteriously affected MM cell lines; and Ribavirin attenuated viability and induced death of primary BM MM cells. Multiple Myeloma cell lines RPMI 8226 and CAG were each transiently transfected with purified plasmids of tetraspanins: pEGFP-N1 (N1, control), CD81N1-eGFP (81N1) or CD82N1-eGFP (82N1) (Clontech). Transfected cells were separated by Sorter Flow Cytometer 24 hours after transfection. Total RNA was extracted from sorted transfected cells with the Qiagen kit. Three separate experiments were analyzed by Whole Genome Affymetrix microarray chips (N1, 81N1, 82N1 in each cell line).
Project description:This work explores the therapeutic potential for the translation initiation factor eIF4E in multiple myeloma (MM). We show that targeting eIF4E is deleterious to MM cells and causes reduction of targets with established importance to the disease progression. We demonstrate that eIF4E inhibition may be achieved by treating the MM cells with the already clinically employed anti-viral drug Ribavirin. Results indicate that tetraspanin overexpression in MM cell lines increased global protein synthesis; CD81N1/CD82N1 also caused a decrease in peIF4E, its regulators and targets; direct inhibition of eIF4E (siRNA, Ribavirin) deleteriously affected MM cell lines; and Ribavirin attenuated viability and induced death of primary BM MM cells. Overall design: Multiple Myeloma cell lines RPMI 8226 and CAG were each transiently transfected with purified plasmids of tetraspanins: pEGFP-N1 (N1, control), CD81N1-eGFP (81N1) or CD82N1-eGFP (82N1) (Clontech). Transfected cells were separated by Sorter Flow Cytometer 24 hours after transfection. Total RNA was extracted from sorted transfected cells with the Qiagen kit. Three separate experiments were analyzed by Whole Genome Affymetrix microarray chips (N1, 81N1, 82N1 in each cell line).
Project description:Autophagy is an essential catabolic process responsible for recycling of intracellular material and preserving cellular fidelity. Key to the autophagy pathway is the ubiquitin-like conjugation system mediating lipidation of Atg8 proteins and their anchoring to autophagosomal membranes. While regulation of autophagy has been characterized at the level of transcription, protein interactions and post-translational modifications, its translational regulation remains elusive. Here we describe a novel regulatory axis of autophagy at the translational level, guided by the conserved eukaryotic translation factor eIF5A. Identified from a high-throughput screen, we find that eIF5A is required for lipidation of LC3B and its paralogs and promotes autophagosome formation. This feature is evolutionarily conserved and results from the translation of the E2-like ATG3 protein. Mechanistically, we identify an amino acid motif in ATG3 causing eIF5A-dependency for its efficient translation. Our study identifies a key regulatory mechanism of autophagosome formation and demonstrates the impact of translation in the regulation autophagy.
Project description:Firczuk2013 - Eukaryotic mRNA translation machinery
This is a model of Saccharomyces cerevisiae
mRNA translation which includes the initiation, elongation and termination phases. The model is for 20 condon mRNAs. The building of a multi-factor complex in initiation and also the different processes in elongation and termination are modelled in detail. The model takes into account that ribosomes cover more than one codon of mRNA so that the movement of ribosomes are effectively blocked by other ribosomes several codons downstream. It is assumed that 15 codons are occupied by each ribosome. This blocking effect is considered in reaction R18 in initiation and also reaction R26, the reaction where translocation of ribosomes takes place in elongation. The kinetic functions of these two reactions are based on MacDonald et al. 1968 and Heinrich & Rapaport 1980. All other kinetic functions follow mass-action kinetics. The concentrations of transfer RNA species (Met-tRNA, aa-tRNA and tRNA in the model) are kept constant, while the other species' concentrations can change in the course of the simulation. The model describes the translation of a short mRNA with 20 codons. Therefore, all reactions in the elongation cycle (R22, R23, R25, R26, R28 and R29) and the corresponding species are replicated accordingly to model the species with ribosomes bound at different positions. In summary, the model contains 165 different species and 141 reactions.
The value of the 56 rate constant parameters were estimated by fitting the model against a series of experimental data consisting of modulation of the various translation factors (Figures 2, 3 and S3). Overall the parameter estimation was carried out over 212 different data points (steady states).
This model is described in the article:
An in vivo control map for the eukaryotic mRNA translation machinery
Helena Firczuk, Shichina Kannambath, Jürgen Pahle, Amy Claydon, Robert Beynon, John Duncan, Hans Westerhoff, Pedro Mendes and John EG McCarthy
Molecular Systems Biology. 9:635
Rate control analysis defines the in vivo control map governing yeast protein synthesis and generates an extensively parameterized digital model of the translation pathway. Among other non-intuitive outcomes, translation demonstrates a high degree of functional modularity and comprises a non-stoichiometric combination of proteins manifesting functional convergence on a shared maximal translation rate. In exponentially growing cells, polypeptide elongation (eEF1A, eEF2, and eEF3) exerts the strongest control. The two other strong control points are recruitment of mRNA and tRNAi to the 40S ribosomal subunit (eIF4F and eIF2) and termination (eRF1; Dbp5). In contrast, factors that are found to promote mRNA scanning efficiency on a longer than-average 5′untranslated region (eIF1, eIF1A, Ded1, eIF2B, eIF3, and eIF5) exceed the levels required for maximal control. This is expected to allow the cell to minimize scanning transition times, particularly for longer 5′UTRs. The analysis reveals these and other collective adaptations of control shared across the factors, as well as features that reflect functional modularity and system robustness. Remarkably, gene duplication is implicated in the fine control of cellular protein synthesis.
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Project description:Gene expression signatures were measured after treatment of cells with 50nM BEZ235. Affymetrix HG-U133AV2 expression arrays were performed according to the manufacturer's directions using RNA extracted by Qiagen RNeasy from engineered human cell-lines grown for 72h in the presence of 50nM BEZ235 Resulting expression signatures where derived based on phenotypic properties(resistance to BEZ235) of the cells (enriched vs GFP/HR).
Project description:Genomic copy-number changes were measured using 250K StyI SNP arrays after selection of cells to enrich for resistance to BEZ235. Affymetrix SNP arrays were performed according to the manufacturer's directions on DNA extracted using Qiagen DNeasy from engineered human cell-lines. Resulting alterations in copy numbers were calculated based on SNP intensities.
Project description:The identification of Lgr5 as an intestinal stem cell marker has made it possible to isolate and study primary intestinal stem cells. Transcriptional differences between intestinal stem cells can be explored by the use of the Lgr5-eGFP-ires-CreERT2 knock-in mouse. In this mouse model GFP expression is driven from the Lgr5 locus, leading to highest GFP levels in the Lgr5 positive cells. Yet, due to the stability of the GFP protein, it is distributed upon cell division to the daughter cells. Here we arbitrarily sorted crypt cells based on GFP expression into five fractions. The fraction with the lowest GFP level is named 1+, the fraction with the highest level 5+. We used cell fractions of intestines from Lgr5-EGFP-ires-CreERT2 mice, expressing GFP under the control of the Lgr5 promoter. RNA was isolated from five FACS sorted cell populations, with fraction 5+ expressing GFP at highest levels and 1+ expressing GFP at lowest levels. Differentially labelled cRNA from fractions 1+ to 4+ were hybridized against fraction 5+ on 4X44K Agilent Whole Mouse Genome dual colour Microarrays (G4122F) in dye swap experiments, resulting in eight individual arrays.
Project description:Via the deep-sequencing of Okazaki fragments from Saccharomyces cerevisiae, we report the first comprehensive documentation of genome-wide replication directionality in any eukaryote; this permits the systematic analysis of both replication initiation and termination. We conduct a genome-wide analysis of origin competence and efficiency, and conclude that the majority of origins are competent to fire in each cell cycle and generally do so with high efficiency. Additionally, the spatial resolution of our data allow us to determine that leading-strand initiation generally occurs within the nucleosome-free region at origins. Using a strain in which late origins can be induced to fire early, we show that replication termination is a largely passive phenomenon that does not rely on cis-acting sequences or replication fork pausing and that the replication profile is determined largely by the kinetics of origin firing, allowing us to reconstruct chromosome-wide timing profiles from an asynchronous culture. 5 samples are included. Two are replicate, paired-end, wild-type samples sequenced via Illumina methodology. The raw data for these two are also deposited in the GEO repository under accession numbers GSM835650 and GSM835651. Two replicate, single-end, Sld2, Sld3, Dbf4, Dpb11, Cdc45 and Sld7 (SSDDCS) overexpression via galactose induction experiments are reported sequenced via Ion Torrent methodology. One single-end, Sld2, Sld3, Dbf4, Dpb11, Cdc45 and Sld7 (SSDDCS) normal expression control via glucose media experiment is reported sequenced via Ion Torrent methodology.
Project description:Arabidopsis ecotype Col-0 expressing RPL18 fused to His & Flag epitopes (RPL18-HF) under 35S control was used to discern the effects of Turnip mosaic virus (TuMV) infection on host translation initiation. Plants were grown in LC-1 soil in 12 hour days and infected by TuMV-GFP or mock-inoculated just prior to sending up bolts. Samples were taken from rosette leaves 10 days after inoculation. Only tissue fluorescing GFP was selected from the virus-infected samples. Similar tissue was sampled from mock-infected leaves. FLAG antibody was used to isolate RPL18-HF. The RNA co-immunoprecipitated with RPL18-HF is fully translation-initiated. This translation-initiated RNA, also referred to as polysomal RNA, was isolated and compared to total RNA under both mock and TuMV-infected states to find TuMV-induced changes in host translation initiation. ****[PLEXdb(http://www.plexdb.org) has submitted this series at GEO on behalf of the original contributor, Jackson Moeller. The equivalent experiment is AT42 at PLEXdb.] pathogen infection: TuMV inoculated - RNA fraction: polysomal RNA(3-replications); pathogen infection: TuMV inoculated - RNA fraction: total RNA(3-replications); pathogen infection: mock inoculated - RNA fraction: polysomal RNA(3-replications); pathogen infection: mock inoculated - RNA fraction: total RNA(3-replications)