In eukaryotes, regulation of mRNA translation enables a fast, localized and finely tuned expression of gene products. Within the translation process, the first stage of translation initiation is most rigorously modulated by the actions of eukaryotic initiation factors (eIFs) and their associated proteins. These 11 eIFs catalyze the joining of the tRNA, mRNA and rRNA into a functional translation complex. Their activity is influenced by a wide variety of extra- and intracellular signals, ranging from global, such as hormone signaling and unfolded proteins, to specific, such as single amino acid imbalance and iron deficiency. Their action is correspondingly comprehensive, in increasing or decreasing recruitment and translation of most cellular mRNAs, and specialized, in targeting translation of mRNAs with regulatory features such as a 5 terminal oligopyrimidine tract (TOP), upstream open reading frames (uORFs), or an internal ribosomal entry site (IRES). In mammals, two major pathways are linked to targeted mRNA translation. The target of rapamycin (TOR) kinase induces translation of TOP and perhaps other subsets of mRNAs, whereas a family of eIF2 kinases does so with mRNAs containing uORFs or an IRES. TOR targets translation of mRNAs that code for proteins involved in translation, an action compatible with its widely accepted role in regulating cellular growth. The four members of the eIF2 kinase family increase translation of mRNAs coding for stress response proteins such as transcription factors and chaperones. Though all four kinases act on one main substrate, eIF2, published literature demonstrates both common and unique effects by each kinase in response to its specific activating stress. This suggests that the activated eIF2 kinases regulate the translation of both a global and a specific set of mRNAs. Up to now, few studies have attempted to test such a hypothesis; none has been done in mammals.
eIF2alpha kinases GCN2 and PERK modulate transcription and translation of distinct sets of mRNAs in mouse liver.
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View Samplesto study the proliferation of PERK knockout mice islets.
PERK EIF2AK3 control of pancreatic beta cell differentiation and proliferation is required for postnatal glucose homeostasis.
Sex
View SamplesAs a first step towards identifying the target genes of EGFR activity in glioma cells, genome-wide expression analyses were performed using the Affymetrix GeneChip Human Genome U133A array.
Guanylate binding protein 1 is a novel effector of EGFR-driven invasion in glioblastoma.
Cell line, Treatment
View SamplesThe analysis of several mammalian genomes has revealed between 20,000 to 30,000 genes in each genome, a number that may seem hard to reconcile with the large number of cell types and complex functions of these organisms. The solution to this paradox partly lies in the large array of transcripts that each gene can potentially generate through usage of alternative promoters and the variable levels of transcripts that each gene produces in different tissues and cell types. Thus, in order to understand the mechanisms that control diverse patterns of gene expression in mammals, it is necessary to accurately define the active promoters and monitor their cell or tissue-dependent activity. Previous high throughput strategies for assaying tissue-specific gene expression have primarily relied on measurements of steady-state transcript levels by microarrays or tag sequencing. Here, we employ a new experimental strategy to identify and characterize tissue specific promoters by integrating genome-wide maps of RNA polymerase II (Pol II) binding, chromatin modifications and gene expression profiles. We applied this strategy to mouse embryonic stem cells (mES), and adult brain, heart, kidney, and liver. Our results delineated 24,363 Pol II binding sites throughout the genome, 91% of which correspond to 5 end annotation based on known transcripts and cap-analysis of gene expression (CAGE) and can be regarded as promoters. A majority of these experimentally defined promoters are active in all tissues, while only 4,396 can be characterized as tissue-specific using a quantitative measure of Pol II occupancy. In general, Pol II occupancy at these tissue specific promoters is correlated with the presence of active histone modification marks. However, a set of mES- specific promoters display persistent levels of H3K4me3 in non-ES tissues despite undetectable Pol II binding and transcript. Broadly, our results expand the knowledge of tissue-specific mammalian genes and provide a resource for understanding the transcriptional programs in mammalian development and differentiation.
Genome-wide mapping and analysis of active promoters in mouse embryonic stem cells and adult organs.
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View SamplesWe have developed a nonheuristic genome topography scan (GTS) algorithm to characterize the patterns of genomic alterations in human glioblastoma (GBM), identifying frequent p18INK4C and p16INK4A codeletion. Functional reconstitution of p18INK4C in GBM cells null for both p16INK4A and p18INK4C resulted in impaired cell-cycle progression and tumorigenic potential. Conversely, RNAi-mediated depletion of p18INK4C in p16INK4A-deficient primary astrocytes or established GBM cells enhanced tumorigenicity in vitro and in vivo. Furthermore, acute suppression of p16INK4A in primary astrocytes induced a concomitant increase in p18INK4C. Together, these findings uncover a feedback regulatory circuit in the astrocytic lineage and demonstrate a bona fide tumor suppressor role for p18INK4C in human GBM wherein it functions cooperatively with other INK4 family members to constrain inappropriate proliferation.
Feedback circuit among INK4 tumor suppressors constrains human glioblastoma development.
No sample metadata fields
View SamplesWe have developed a nonheuristic genome topography scan (GTS) algorithm to characterize the patterns of genomic alterations in human glioblastoma (GBM), identifying frequent p18INK4C and p16INK4A codeletion. Functional reconstitution of p18INK4C in GBM cells null for both p16INK4A and p18INK4C resulted in impaired cell-cycle progression and tumorigenic potential. Conversely, RNAi-mediated depletion of p18INK4C in p16INK4A-deficient primary astrocytes or established GBM cells enhanced tumorigenicity in vitro and in vivo. Furthermore, acute suppression of p16INK4A in primary astrocytes induced a concomitant increase in p18INK4C. Together, these findings uncover a feedback regulatory circuit in the astrocytic lineage and demonstrate a bona fide tumor suppressor role for p18INK4C in human GBM wherein it functions cooperatively with other INK4 family members to constrain inappropriate proliferation.
Feedback circuit among INK4 tumor suppressors constrains human glioblastoma development.
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View SamplesImproving outcomes in multiple myeloma will not only involve development of new therapies, but better use of existing treatments. We performed RNA sequencing (RNA-Seq) on samples from newly diagnosed patients enrolled into the phase II PADIMAC study. Using an empirical Bayes approach and synthetic annealing, we developed and trained a seven-gene signature to predict treatment outcome. We tested the signature on independent cohorts treated with bortezomib- and lenalidomide-based therapies. The signature was capable of distinguishing which patients would respond better to which regimen. In the CoMMpass dataset, patients who were treated correctly according to the signature had a better progression-free and overall survival than those who were not. Indeed, the outcome for these correctly treated patients was non-inferior to those treated with combined bortezomib, lenalidomide, and dexamethasone (VRD). PADIMAC: Bortezomib, Adriamycin and Dexamethasone (PAD) therapy for previously untreated patients with multiple myeloma: Impact of minimal residual disease (MRD) in patients with deferred ASCT (autologous stem cell transplant) Overall design: RNA-Seq data from 44 patients enrolled into the PADIMAC study who provided RNA with an RNA Integrity score of 6 or greater. Thirteen out of forty-four patients had at least a very good partial remission sustained for at least a year without progression and were labelled as "bortezomib-good".
RNA-seq of newly diagnosed patients in the PADIMAC study leads to a bortezomib/lenalidomide decision signature.
Age, Specimen part, Subject
View SamplesIn vitro differentiation of embryonic stem cells (ESC) provides models that reproduce in vivo development and cells for therapy. Whether the epigenetic signatures that are crucial for brain development and function and that are sensitive to in vitro culture are similar between native brain tissues and their artificial counterpart generated from ESC is largely unknown. Here, using RNA-seq we have compared the parental origin-dependent expression of imprinted genes (IGs), a model of epigenetic regulation, in cerebral cortex generated either in vivo, or from ESCs using in vitro corticogenesis, a model that reproduces the landmarks of in vivo corticogenesis. For a majority of IGs, the expressed parental alleles were the same for in vivo and in vitro cortex. In most cases, this choice was already set in ESCs and faithfully maintained during the 3 weeks of in vitro corticogenesis. Confirming these findings, methylation, which selects the parental allele to be transcribed, was also largely equivalent between the 2 types of cortex and ESCs. Our results thus indicate that the allele specific expression of imprinted transcripts, a model of epigenetic regulation resulting from a differential methylation of parental genomes, is mostly mimicked in cortical cells derived from ESC. Overall design: We have crossed two strains of mice (B6 and JF1) that display more than 12 million of SNPs (Takada et al., Genome Res. 2013 Aug;23(8):1329-38. doi: 10.1101/gr.156497.113). We have then analyzed allele specific expression transcriptome-wide using RNA-seq on hybrid F1 cortex generated either in vivo or in vitro from ESCs. In addition, we have used 2 different developmental stages of in vivo cortex (E13.5, P0) and three stages in vitro (undiffererentiated ESC, and differentiated into cortex for 12 and 21 days) to measure the dynamics of parental expression. Please note that [1] the same raw data files were used to generate the ''*allele-specific_sense_read_bases_by_gene_withoutContamination.txt'' processed data files. [2] The samples associated with each file are indicated in the file column header (as their GSM accession numbers). [3] The readme.txt file contains the data processing steps, file description.
In Vitro Corticogenesis from Embryonic Stem Cells Recapitulates the In Vivo Epigenetic Control of Imprinted Gene Expression.
No sample metadata fields
View SamplesToxin A and B from Clostridium difficile are the primary virulence factors in Clostridium difficile disease. The changes in gene transcription of human colon epithelial cells were investigated in vitro in order to better understand the many effects of both toxins.
Systems analysis of the transcriptional response of human ileocecal epithelial cells to Clostridium difficile toxins and effects on cell cycle control.
Cell line
View SamplesThe response of human neutrophils to the emerging pathogen Mycobacterium abscessus has not been described. However, M. abscessus infections are frequently associated with neutrophil-rich abscesses. To better understand the reponse of neutrophils to M. abscessus we performed gene expression analysis using Affymetrix HG-U133A Plus 2.0 microarrays. Human neutrophils from healthy donors were stimulated with isogenic rough and smooth morphotypes of M. abscessus. Staphylococcus aureus was used as a control. Gene expression was compared to neutrophils left unstimulated. Neutrophils from four individual donors were isolated on separate days and stimulated with freshly prepared bacteria. Neutrophils (stimulated and control) were left for 2 hours before total RNA was isolated, and biotinylated cRNA was prepared by standard methods. Analysis indicates that M. abscessus morphotypes induce a limited number of genes, when compared to S. aureus, which are enriched in genes for cytokines and chemokines, including neutrophil-specific chemokines. These data suggest that neutrophils have a limited response to M. abscessus, which may contribute to neutrophil-rich abscess formation.overall_design = Human neutrophils from healthy donors were exposed to rough Mab (ATCC 19977T), smooth Mab (ATCC 19977T) and S. aureus (CF clinical strain) for two hours; control cells were exposed to saline.
Mycobacterium abscessus induces a limited pattern of neutrophil activation that promotes pathogen survival.
Specimen part, Disease, Treatment
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