Sir2 is an NAD+-dependent histone deacetylase, and is the founding member of a large, phylogentically conserved, family of such deacetylases called the Sirtuins. The budding yeast, Saccharomyces cerevisiae, harbors 4 paralogs of Sir2, known as Hst1, Hst2, Hst3, and Hst4. Reducing the intracellular NAD+ concentration is inhibitory for the Sirtuins, and raising the intracellular nicotinamide (NAM) concentration is inhibitory. Microarray gene expression analysis was used to identify novel classes of yeast genes whose expression is altered when either NAD+ concentration is reduced or NAM is elevated. A subset of genes involved in thiamine biosynthesis was identified as being upregulated when Sir2 or Hst1 was inactivated.
Thiamine biosynthesis in Saccharomyces cerevisiae is regulated by the NAD+-dependent histone deacetylase Hst1.
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View SamplesThe chronological lifespan (CLS) of Saccharomyces cerevisiae is defined as the number days that non-dividing cells remain viable, typically in stationary phase cultures or in water. CLS is extended by restricting glucose in the starting cultures, and is considered a form of caloric restriction (CR). Through a previous genetic screen our lab determined that deleting components of the de novo purine biosynthesis pathway also significantly increased CLS. Significant similarities in gene expression profiles between calorie restricted WT cells and a non-restricted ade4 mutant suggested the possibility of common gene expression biomarkers of all chronologically long lived cells that could also provide insights into general mechanisms of lifespan extension. We have identified additional growth conditions that extend CLS of WT cells, including supplementation of the media with isonicotinamide (INAM), a known sirtuin activator, or by supplementation with a concentrate collected from the expired media of a calorie restricted yeast culture, presumably due to an as yet unidentified longevity factor. Using these varied methods to extend CLS, we compared gene expression profiles in the aging cells (at day 8) to identify functionally relevant biomarkers of longevity. Nineteen genes were differentially regulated in all 4 of the long-lived populations relative to wild type. Of these 19 genes, viable haploid deletion mutants were available for 16 of them, and 12 were found to have a significant impact on CLS.
Functional genomic analysis reveals overlapping and distinct features of chronologically long-lived yeast populations.
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Epigenetic coordination of signaling pathways during the epithelial-mesenchymal transition.
Cell line
View SamplesA new site of methylation was identified on histone H3 K42 in Saccharomyces cerevisiae. Mutations were engineered at this site to mimic either a constitutively modified state, K42L, or a constitutively unmodified state, K42Q in addition to an alanine substitution. K42A. The effects of these mutations on global transcription was monitored in yeast cells whose sole source of histone H3 was from a plasmid expressing these mutant proteins, and compared to that of an isogenic strain expressing the wild-type histone H3 protein from the same plasmid.
An evolutionarily 'young' lysine residue in histone H3 attenuates transcriptional output in Saccharomyces cerevisiae.
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View SamplesTGFbeta/TNFalpha treated spheroid A549 cultures are a model of the epithelial-mesenchymal transition (EMT). These experiments capture the changes in global gene expression that result from cells being induced to undergo EMT (3D control vs 3D treated), but also the differences in gene expression when A549 is grown in spheroid cultures (2D control vs 3D untreated). EMT is efficiently induced only in the spheroid culture model.
Epigenetic coordination of signaling pathways during the epithelial-mesenchymal transition.
Cell line
View SamplesThe estrogen receptor is the master transcriptional regulator of breast cancer phenotype and the archetype of a molecular therapeutic target. We mapped all estrogen receptor and RNA polymerase II binding sites on a genome-wide scale, identifying the authentic cis binding sites and target genes, in breast cancer cells. Combining this unique resource with gene expression data demonstrates distinct temporal mechanisms of estrogen-mediated gene regulation,particularly in the case of estrogen-suppressed genes. Furthermore, this resource has allowed the identification of cis-regulatory sites in previously unexplored regions of the genome and the cooperating transcription factors underlying estrogen signaling in breast cancer.
Genome-wide analysis of estrogen receptor binding sites.
No sample metadata fields
View SamplesAnalysis of genes and pathways related to psychomotor retardation symptoms in patients with major depressive disorder. Results indicate that psychomotor slowing is associated with enrichment of inflammatory and metabolic pathways in unmedicated patients with depression.
Protein and gene markers of metabolic dysfunction and inflammation together associate with functional connectivity in reward and motor circuits in depression.
Sex, Age, Specimen part, Race, Subject
View SamplesThe cleavage of sphingoid base phosphates by sphingosine-1-phosphate (S1P) lyase to produce phosphoethanolamine and a fatty aldehyde is the final degradative step in the sphingolipid metabolic pathway. We have studied mice with an inactive S1P lyase gene and have found that, in addition to the expected increase of sphingoid base phosphates, other sphingolipids (including sphingosine, ceramide, and sphingomyelin) were substantially elevated in the serum and /or liver of these mice. This latter increase is consistent with a reutilization of the sphingosine backbone for sphingolipid synthesis due to its inability to exit the sphingolipid metabolic pathway. Furthermore, the S1P lyase deficiency resulted in changes in the levels of serum and liver lipids not directly within the sphingolipid pathway, including phospholipids, triacyglycerol, diacylglycerol, and cholesterol. Even though lipids in serum and lipid storage were elevated in liver, adiposity was reduced in the S1P lyase-deficient mice. Microarray analysis of lipid metabolism genes in liver showed that the S1P lyase deficiency caused widespread changes in their expression pattern. These results demonstrate that S1P lyase is a key regulator of the levels of multiple sphingolipid substrates and reveal functional links between the sphingolipid metabolic pathway and other lipid metabolic pathways that may be mediated by shared lipid substrates and changes in gene expression programs. The disturbance of lipid homeostasis by altered sphingolipid levels may be relevant to metabolic diseases.
Sphingosine 1-phosphate lyase deficiency disrupts lipid homeostasis in liver.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Age-associated changes in basal NF-κB function in human CD4+ T lymphocytes via dysregulation of PI3 kinase.
Sex, Age, Specimen part, Treatment
View SamplesImmune impairment and high circulating level of pro-inflammatory cytokines are landmarks of human aging. However, the molecular basis of immune dysregulation and the source of inflammatory markers remain unclear. Here we demonstrate that in the absence of overt cell stimulation, gene expression mediated by the transcription factor NF-B is higher in purified and rested human CD4+ T lymphocytes from older compared to younger individuals. This increase of NF-B -associated transcription includes transcripts for pro-inflammatory cytokines such as IL-1 and chemokines such as CCL2 and CXCL10. We demonstrate that NF-B up-regulation is cell-intrinsic and mediated in part by phosphatidylinositol 3-kinase (PI3K) activity induced in response to metabolic activity, which can be moderated by rapamycin treatment. Our observations provide direct evidence that dysregulated basal NF-B activity may contribute to the mild pro-inflammatory state of aging.
Age-associated changes in basal NF-κB function in human CD4+ T lymphocytes via dysregulation of PI3 kinase.
Sex, Age, Specimen part, Treatment
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