During organogenesis, PAX6 is required for establishment of various progenitor subtypes within the central nervous system, eye and pancreas. PAX6 expression is maintained in a variety of cell types within each organ, although its role in each lineage and how it acquires cell-specific activity remain elusive. Herein, we aimed to determine the roles and the hierarchical organization of the PAX6-dependent gene regulatory network during the differentiation of the retinal pigmented epithelium (RPE). Somatic mutagenesis of Pax6 in the differentiating RPE revealed that PAX6 functions in a feed-forward regulatory loop with MITF during onset of melanogenesis. PAX6 both controls the expression of an RPE isoform of Mitf and synergizes with MITF to activate expression of genes involved in pigment biogenesis. This study exemplifies how one kernel gene pivotal in organ formation accomplishes a lineage-specific role during terminal differentiation of a single lineage.
PAX6 regulates melanogenesis in the retinal pigmented epithelium through feed-forward regulatory interactions with MITF.
Specimen part
View SamplesHuman ESCs are pluripotent cells that have the capacity of self renewal for a prolonged period in vitro, and can differentiate into derivatives of all three primary germ layers: endoderm, mesoderm and ectoderm. Human ESCs are responsive to a wide range of factors in vitro that can direct their differentiation into specific cell types. We analyzed the effect of nicotinamide (NIC) on differentiation of hESCs in vitro. CEL file for GSM424319 is unavailable.
Directed differentiation of human embryonic stem cells into functional retinal pigment epithelium cells.
Specimen part, Treatment
View SamplesGene expression analysis identified 27 of these 744 p300 and pol II associated genes as significantly increased (p 0.05) within the first hour following mitogen stimulation
Dynamic bookmarking of primary response genes by p300 and RNA polymerase II complexes.
No sample metadata fields
View SamplesSoyfoods have been drawn the interrest in the roles that reducing risk of cardiovascular disease. Among various components, isoflavones have been come to the attention as beneficial soy ingredients. To evaluate the effectiveness of isoflavone content in dietary soybean (Glycine max) on modulating lipid metabolism, hepatic gene expressions involved in lipid metabolism were analyzed in rats. An isoflavone-rich cultivar (Yukipirika) and a conventional cultivar (Fukuyutaka) were employed. A principal component analysis (PCA) of microarray data was used to summarize characteristics of the experimental groups. As a result, the characteristics of the diets were largely explained by the first principal component (PC1). Soybean content in the diets distinctly separated in PC1. In contrast, isoflavone content had little effect on the mRNA expression.
Effects of soy protein and isoflavone on hepatic fatty acid synthesis and oxidation and mRNA expression of uncoupling proteins and peroxisome proliferator-activated receptor gamma in adipose tissues of rats.
Age, Specimen part
View SamplesEffects of soy isoflavones, genistein and daidzein, on the hepatic gene expression profile and indices for lipid metabolism were compared in rats.
A comparative analysis of genistein and daidzein in affecting lipid metabolism in rat liver.
Sex, Specimen part
View SamplesThe impact of sesamin, episesamin and sesamolin (sesame lignans) on hepatic gene expression profiles was compared with a DNA microarray. Male Sprague-Dawley rats were fed experimental diets containing 0.2% sesamin, episesamin or sesamolin, and a control diet free of lignans for 15 d. Compared to a lignan-free diet, a diet containing sesamin, episesamin and sesamolin caused 1.5- and 2-fold changes in the expression of 128 and 40, 526 and 152, and 516 and 140 genes, respectively. The lignans modified not only the mRNA levels of many enzymes involved in hepatic fatty acid oxidation, but also those of proteins involved in the transportation of fatty acids into hepatocytes and their organelles, and regulate hepatic concentrations of carnitine, CoA and malonyl-CoA. It is apparent that sesame lignans stimulate hepatic fatty acid oxidation by affecting the gene expression of various proteins regulating hepatic fatty acid metabolism. We also observed that lignans modified the gene expression of various proteins involved in hepatic lipogenesis, cholesterogenesis and glucose metabolism. The changes were generally greater with episesamin and sesamolin than with sesamin. In terms of the amounts accumulated in serum and the liver, the lignans ranked in the order sesamolin, episesamin and sesamin. The differences in bio-availability among these lignans appear to be important to their divergent physiological activities.
Comparative study of sesame lignans (sesamin, episesamin and sesamolin) affecting gene expression profile and fatty acid oxidation in rat liver.
Sex, Specimen part
View SamplesWhile it is clear that T cell derived IFN has to act on tumor stroma cells for rejection of solid tumors, it is not clear which tumor stroma cells are targets. We studied how IFN affects gene expression in tumor blood vessels in vivo. To study the effect on endothelial cells, we either used a model of ectopic IFN (MCA313 tumors) or IFN-GFP fusion protein (J558L tumors) expression in tumors, or we used T cell derived IFN in large vascularized 16.113 tumours. Tumors were grown in mice that were expressing the IFN receptor ubiquitously (J558L tumors + IFN-GFP treatment and 16.113 tumors + T cell treatment) or in some experiments the IFN-receptor was expressed exclusively in endothelial cells (MCA313 tumor + IFN treatment).
Tumour ischaemia by interferon-γ resembles physiological blood vessel regression.
Sex, Specimen part, Time
View SamplesClassic ‘position effect’ experiments repositioned genes to the telomere to demonstrate that the epigenetic landscape can dramatically alter gene expression. Here we show that systematic gene knockout collections provide an exceptional resource for interrogating position effects, not only at the telomere but at every single genetic locus. Because deleted genes are replaced by the same reporter gene, interrogation of this reporter provides a sensitive probe into many different chromatin environments while controlling for genetic context. Using this approach we find that, whereas replacement of yeast genes with the kanMX marker does not perturb the chromatin landscape, differences due to gene position account for more than 35% of marker gene activity. We observe chromatin influences different from those reported previously, including an antagonistic interaction between histone H3 lysine 36 trimethylation (H3K36me3) and the Rap1 transcriptional activation site in kanMX that is mediated through a Set2-Rpd3-dependent pathway. This interaction explains why some yeast genes have been resistant to deletion and allows successful generation of these deletion strains using a modified transformation procedure. These findings demonstrate that chromatin regulation is not governed by a uniform ‘histone code’, but by specific interactions between chromatin and genetic factors. Overall design: Data included are RNA-Seq data for 4 heterzygous diploid yeast strains and diploid wild-type. Therea re three replicates for each heterzygous strain, and six replicates for wild-type.
Decoupling epigenetic and genetic effects through systematic analysis of gene position.
Subject
View SamplesThe circadian clock generates daily rhythms in mammalian liver processes, such as glucose and lipid homeostasis, xenobiotic metabolism, and regeneration. The mechanisms governing these rhythms are not well understood, particularly the distinct contributions of the cell-autonomous clock and central pacemaker to rhythmic liver physiology. Through microarray expression profiling in MMH-D3 hepatocytes, we identified over 1,000 transcripts that exhibit circadian oscillations, demonstrating that many rhythms can be driven by the cell-autonomous clock and that MMH-D3 is a valid circadian model system. The genes represented by these circadian transcripts displayed both co-phasic and anti-phasic organization within a protein-protein interaction network, suggesting the existence of competition for binding sites or partners by genes of disparate transcriptional phases. Multiple pathways displayed enrichment in MMH-D3 circadian transcripts, including the polyamine synthesis module of the glutathione metabolic pathway. The polyamine synthesis module, which is highly associated with cell proliferation and whose products are required for initiation of liver regeneration, includes enzymes whose transcripts exhibit circadian oscillations, such as ornithine decarboxylase (Odc1) and spermidine synthase (Srm). Metabolic profiling revealed that the enzymatic product of SRM, spermidine, cycles as well. Thus, the cell-autonomous hepatocyte clock can drive a significant amount of transcriptional rhythms and orchestrate physiologically relevant modules such as polyamine synthesis.
Cell-autonomous circadian clock of hepatocytes drives rhythms in transcription and polyamine synthesis.
Specimen part, Cell line
View SamplesHIV-associated dementia (HAD) is a syndrome occurring in HIV-infected patients with advanced disease that likely develops as a result of macrophage and microglial activation as well as other immune events triggered by virus in the central nervous system. The most relevant experimental model of HAD, rhesus macaques exhibiting SIV encephalitis (SIVE), closely reproduces the human disease and has been successfully used to advance our understanding of mechanisms underlying HAD. In this study we integrate gene expression data from uninfected and SIV-infected hippocampus with a human protein interaction network and discover modules of genes whose expression patterns distinguish these two states, to facilitate identification of neuronal genes that may contribute to SIVE/HIV cognitive deficits. Using this approach we identify several downregulated candidate genes and select one, EGR1, a key molecule in hippocampus-related learning and memory, for further study. We show that EGR1 is downregulated in SIV-infected hippocampus and that it can be downregulated in differentiated human neuroblastoma cells by treatment with CCL8, a product of activated microglia. Integration of expression data with protein interaction data to discover discriminatory modules of interacting proteins can be usefully employed to prioritize differentially expressed genes for further study. Investigation of EGR1, selected in this manner, indicates that its downregulation in SIVE may occur as a consequence of the host response to infection, leading to deficits in cognition.
An integrated systems analysis implicates EGR1 downregulation in simian immunodeficiency virus encephalitis-induced neural dysfunction.
Sex
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