The CREB family of transcription factors stimulates cellular gene expression following phosphorylation at a conserved serine (Ser133 in CREB1) in response to cAMP and other extracellular signals. In order to characterize CREB target genes in various tissues, we give a cAMP agonist, forskolin (FSK), to cell lines or primary cultures and monitor the gene expression. To eliminate CREB-independent effects of FSK on cellular gene expression, we employed a dominant negative form of CREB called A-CREB, which dimerizes selectively with and blocks the DNA binding activity of CREB but not other bZIP family members. Therefore, genes that are induced by cAMP and the induction was blocked by A-CREB treatment likely represents CREB target genes.
Genome-wide analysis of cAMP-response element binding protein occupancy, phosphorylation, and target gene activation in human tissues.
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View SamplesModels for tumorigenesis can be made by transforming normal cells with defined genetic elements. This allows us to determine that adrenocortical tumor development and progression follows a multistep model. Morever, we demonstrated that the order of genetic events has a great consequence on the phenotype of the resultant tumor. We performed transcriptomic analysis using cDNA microarrays to identify the molecular signature that might explain the distinctive in vivo phenotypes observed in response to both orders of the mutational events.
Acquisition order of Ras and p53 gene alterations defines distinct adrenocortical tumor phenotypes.
Specimen part
View SamplesTo identify proteins regulated by glucose through changes in their rate of protein synthesis, translational profiling of MIN6 cells acutely incubated at either low or high glucose concentration was performed (i.e. microarray analysis was performed on mRNAs associated with polysomes, as an increase in the association of mRNA with polysomes is indicative of an increase in the rate of initiation step of translation and hence an increase in protein expression) (Johannes et al., 1999; Mikulits et al., 2000).
Distinct glucose-dependent stress responses revealed by translational profiling in pancreatic beta-cells.
Specimen part, Cell line, Compound, Time
View SamplesOverexpression of ecotropic viral integration site 1 (EVI1) is associated with aggressive disease in acute myeloid leukemia (AML). Despite of its clinical importance, little is known about the mechanism through which EVI1 confers resistance to antileukemic drugs. Here, we show that a human myeloid cell line constitutively overexpressing EVI1 after infection with a retroviral vector (U937_EVI1) was partially resistant to etoposide and daunorubicin as compared to empty vector infected control cells (U937_vec). Similarly, inducible expression of EVI1 in HL-60 cells decreased their sensitivity to daunorubicin. Gene expression microarray analyses of U937_EVI1 and U937_vec cells cultured in the absence or presence of etoposide showed that 77 and 419 genes were regulated by EVI1 and etoposide, respectively. Notably, mRNA levels of 26 of these genes were altered by both stimuli, indicating that EVI1 regulated genes were strongly enriched among etoposide regulated genes and vice versa. One of the genes that were induced by both EVI1 and etoposide was CDKN1A/p21/WAF, which in addition to its function as a cell cycle regulator plays an important role in conferring chemotherapy resistance in various tumor types. Indeed, overexpression of CDKN1A in U937 cells mimicked the phenotype of EVI1 overexpression, similarly conferring partial resistance to antileukemic drugs.
EVI1 inhibits apoptosis induced by antileukemic drugs via upregulation of CDKN1A/p21/WAF in human myeloid cells.
Cell line, Treatment
View SamplesWhile prion infections have been extensively characterized in the laboratory mouse, little is known regarding the molecular responses to prions in other rodents. To explore these responses and make comparisons, we generated a prion disease in the laboratory rat by successive passage of mouse RML prions. Here we describe the accumulation of prions and associated pathology in the rat and describe the transcriptional impact throughout prion disease. Comparative transcriptional profiling between laboratory mice and rats suggests that similar molecular processes are unfolding in response to prion infection. At the level of individual transcripts, however, variability exists between mice and rats and many genes deregulated in mouse scrapie are not affected in rats. Notwithstanding these differences, many transcriptome responses are conserved between mice and rats infected with scrapie. Our findings highlight the usefulness of comparative approaches to understanding neurodegeneration and prion diseases in particular.
Transcriptomic responses to prion disease in rats.
Specimen part, Disease
View SamplesHIV Tg rats exhibit pulmonary hypertension and pulmonary artery remodeling. In an effort to begin to understand cell signaling pathways which are altered in lungs from HIV transgenic rats, we used microarray analysis.
Human immunodeficiency virus transgenic rats exhibit pulmonary hypertension.
Sex, Age, Specimen part
View SamplesMuscle tissue was longitudinally characterized histologically for electron transport function by staining 1mm of quadriceps muscle at 70 micron intervals for the activities of two complexes in the mitochondrial electron transport chain, Cytochrome C Oxidase and Succinate Dehydrogenase. Unstained serial cryosections were prepared for Laser Capture Microdissection. Target cells from the serial sections were isolated and pooled for RNA extraction, amplification and hybridization on Affymetrix microarrays. We selected homogeneous populations of muscle fibers for expression profiling based upon the presence/absence of electron transport dysfunction caused by the somatic accumulation of mitochondrial DNA deletion mutations.
Mitochondrial biogenesis drives a vicious cycle of metabolic insufficiency and mitochondrial DNA deletion mutation accumulation in aged rat skeletal muscle fibers.
Age, Specimen part
View SamplesPurpose: Next-generation sequencing (NGS) has revolutionized systems-based analysis of cellular pathways. The goals of this study was to obtain the trasncriptome of DGCR8_KO mESCs to compare it with the transcriptome of WT mESCs (deposit separately). Overall design: mRNA profiles of DGCR8_KO mouse embryonic stem cells were generated by deep sequencing, in duplicate, using Illumina HiSeq2000.
Noncanonical function of DGCR8 controls mESC exit from pluripotency.
Specimen part, Cell line, Subject
View SamplesThe mitochondrial respiratory chain is composed of lipoprotein complexes imbedded in the inner mitochondrial membrane. This chain of enzymes transfers electrons from NADH and FADH2, provided from divers metabolic pathways, to oxygen. It couples the transfer of electrons to the translocation of protons across the membrane. Several clinical syndromes have been associated with respiratory dysfunction caused by mitochondrial or nuclear mutations. A number of mutations in the mitochondrial genes encoding for cytochrome b (CYTB) and cytochrome oxidase (COX 1, 2 and 3) have been linked with diseases. We are using yeast mutants to characterize the deleterious effect of mutations reported in patients on the assembly and catalytic properties of the affected enzymes, and to study the impact of mutations in nuclear genes, such as OXA1, encoding for factors required for the assembly of the respiratory complexes. In this work, we monitored the effects of the mutations causing respiratory defect on the whole genome expression. We compared the change in gene expression in rho0 cells (with a complete deletion of the mitochondrial genome, and by consequence without respiratory chain), in cells with either a single defective enzyme or several, and in cells after prolonged treatment with the bc1 inhibitors myxothiazol or antimycin. The impact of the mutations on the respiratory function ranged from mild to severe. The expression of approx. 350 genes was changed in at least one mutant. Cluster analysis was performed using the Cluster program (Eisen, 1998, PNAS 95:14863). Four groups of genes were studied in more details: Group A, the most repressed genes; Group B, the most over-expressed genes; Group C, genes more repressed in rho0 and Doxa1 cells; and Group D, genes more over-expressed in Doxa1.
Multiple defects in the respiratory chain lead to the repression of genes encoding components of the respiratory chain and TCA cycle enzymes.
Compound
View SamplesTo validate the suitability of two commonly used colorectal cancer cell lines, DLD1 and SW480, as model systems to study colorectal carcinogenesis, we treated these cell lines with -catenin siRNA and identified -catenin target genes using DNA microarrays. The list of identified target genes was compared to previously published -catenin target genes found in the PubMed and the GEO databases.
Comprehensive analysis of β-catenin target genes in colorectal carcinoma cell lines with deregulated Wnt/β-catenin signaling.
Cell line, Treatment
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