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GSE18488
Saccharomyces cerevisiae
14 Downloadable Samples
Affymetrix Yeast Genome 2.0 Array (yeast2)
Description
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.
Publication Title
Thiamine biosynthesis in Saccharomyces cerevisiae is regulated by the NAD+-dependent histone deacetylase Hst1.
Sample Metadata Fields
No sample metadata fields
View Samples- Saccharomyces cerevisiae
- 10 Downloadable Samples
- Affymetrix Yeast Genome 2.0 Array (yeast2)
Description
The 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.
Publication Title
Functional genomic analysis reveals overlapping and distinct features of chronologically long-lived yeast populations.
Sample Metadata Fields
No sample metadata fields
View Samples- Homo sapiens
- 525 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Mutations in CCAAT/enhancer binding protein alpha (CEBPA) are seen in 5-14% of acute myeloid leukemia (AML) and have been associated with a favorable clinical outcome. Most AMLs with CEBPA mutations simultaneously carry two mutations (CEBPAdouble-mut), usually biallelic, while single heterozygous mutations (CEBPAsingle-mut) are less frequently seen. Using denaturing high performance liquid chromatography and nucleotide sequencing we identified among a cohort of 598 newly diagnosed AMLs a subset of 41 CEBPA mutant cases, i.e. 28 CEBPAdouble-mut and 13 CEBPAsingle-mut cases. CEBPAdouble-mut associated with a unique gene expression profile as well as favorable overall and event-free survival, retained in multivariable analysis that included cytogenetic risk, FLT3-ITD and NPM1 mutation, white blood cell count and age. In contrast, CEBPAsingle-mut AMLs did not express a discriminating signature and could not be distinguished from wild type cases as regards clinical outcome. These results demonstrate significant underlying heterogeneity within CEBPA mutation positive AML with prognostic relevance.
Publication Title
Double CEBPA mutations, but not single CEBPA mutations, define a subgroup of acute myeloid leukemia with a distinctive gene expression profile that is uniquely associated with a favorable outcome.
Sample Metadata Fields
Sex, Age, Specimen part, Disease, Disease stage
View Samples- Homo sapiens
- 537 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
The pretreatment karyotype of leukemic blasts is currently the key determinant in therapy decision-making in acute myeloid leukemia (AML). However, approximately fifty percent of AML patients, often carrying a normal karyotype, are currently unclassifiable based these established methods. Gene expression profiling has proven to be valuable for risk stratification of AML.
Publication Title
Prediction of molecular subtypes in acute myeloid leukemia based on gene expression profiling.
Sample Metadata Fields
Sex, Age, Specimen part, Disease, Disease stage
View Samples- Hordeum vulgare
- 35 Downloadable Samples
- Affymetrix Barley Genome Array (barley1)
Description
Drought tolerance is a key trait for increasing and stabilizing barley productivity in dry areas worldwide. Identification of the genes responsible for drought tolerance in barley (Hordeum vulgare L.) will facilitate understanding of the molecular mechanisms of drought tolerance, and also genetic improvement of barley through marker-assisted selection or gene transformation. To monitor the changes in gene expression at transcription levels in barley leaves during the reproductive stage under drought conditions, the 22K Affymetrix Barley 1 microarray was used to screen two drought-tolerant barley genotypes, Martin and Hordeum spontaneum 41-1 (HS41-1), and one drought-sensitive genotype Moroc9-75. Seventeen genes were expressed exclusively in the two drought-tolerant genotypes under drought stress, and their encoded proteins may play significant roles in enhancing drought tolerance through controlling stomatal closure via carbon metabolism (NADP malic enzyme (NADP-ME) and pyruvate dehydrogenase (PDH), synthesizing the osmoprotectant glycine-betaine (C-4 sterol methyl oxidase (CSMO), generating protectants against reactive-oxygen-species scavenging (aldehyde dehydrogenase (ALDH), ascorbate-dependant oxidoreductase (ADOR), and stabilizing membranes and proteins (heat-shock protein 17.8 (HSP17.8) and dehydrin 3 (DHN3). Moreover, 17 genes were abundantly expressed in Martin and HS41-1 compared with Moroc9-75 under both drought and control conditions. These genes were likely constitutively expressed in drought-tolerant genotypes. Among them, 7 known annotated genes might enhance drought tolerance through signaling (such as calcium-dependent protein kinase (CDPK) and membrane steroid binding protein (MSBP), anti-senescence (G2 pea dark accumulated protein GDA2) and detoxification (glutathione S-transferase (GST) pathways. In addition, 18 genes, including those encoding l-pyrroline-5-carboxylate synthetase (P5CS), protein phosphatase 2C-like protein (PP2C) and several chaperones, were differentially expressed in all genotypes under drought; thus, they were more likely general drought-responsive genes in barley. These results could provide new insights into further understanding of drought-tolerance mechanisms in barley.
Publication Title
Differentially expressed genes between drought-tolerant and drought-sensitive barley genotypes in response to drought stress during the reproductive stage.
Sample Metadata Fields
Specimen part, Treatment
View Samples- Homo sapiens
- 94 Downloadable Samples
- Illumina HumanHT-12 V4.0 expression beadchip
Description
hTERT/cdk4 immortalized myogenic human cell lines represent an important tool for skeletal muscle research, being used as therapeutically-pertinent models of various neuromuscular disorders and in numerous fundamental studies of muscle cell function. However, the cell cycle is linked to other cellular processes such as integrin regulation, the PI3K/Akt pathway, and microtubule stability, raising the question as to whether transgenic modification of the cell cycle results in secondary effects that could undermine the validity of these cell models. Here we subjected healthy and disease lines to intensive transcriptomic analysis, comparing immortalized lines with their parent primary populations in both differentiated and undifferentiated states, and testing their myogenic character by comparison with non-myogenic (CD56-negative) cells. We found that immortalization has no measurable effect on the myogenic cascade or on any other cellular processes, and that it was protective against the systems level effects of senescence that are observed at higher division counts of primary cells.
Publication Title
Skeletal muscle characteristics are preserved in hTERT/cdk4 human myogenic cell lines.
Sample Metadata Fields
Specimen part, Disease, Disease stage
View Samples- Homo sapiens
- 71 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Acute Lymphoblastic Leukemia (ALL) in infants (<1 year) is characterized by a poor prognosis and a high incidence of MLL translocations. Several studies demonstrated the unique gene expression profile associated with MLL-rearranged ALL, but generally small cohorts were analyzed as uniform patient groups regardless of the type of MLL translocation, while the analysis of translocation-negative infant ALL remained unacknowledged.
Publication Title
Gene expression profiling-based dissection of MLL translocated and MLL germline acute lymphoblastic leukemia in infants.
Sample Metadata Fields
Sex, Age, Specimen part
View Samples- Homo sapiens
- 33 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Ficolled AML-M0 sample gene expression profiles on Affymetrix HGU133Plus2.0 GeneChips. Acute myeloid leukemia (AML) classified as FAB-M0 is defined as a subtype with minimally differentiated morphology. Here we investigated by gene expression (GEP) profiling whether AML-M0 cases should be considered as one or more unique molecular subgroups that discriminates them from other AML patients. By applying GEP and subsequent unsupervised analysis of 35 AML-M0 samples and 253 previously reported AML cases, we demonstrate that AML-M0 cases express a unique signature. Hematological transcription regulators such as CEBPA, CEBPD, PU.1 and ETV6 and the differentiation associated gene MPO appeared strongly down-regulated, in line with the very primitive state of this type of leukemia. Moreover, AML M0 cases appeared to have a strong positive correlation with a previously defined immature AML subgroup with adverse prognosis. AML-M0 leukemias frequently carry loss-of-function RUNX-1 mutation and unsupervised analyses revealed a striking distinction between cases with and without mutations. RUNX1 mutant AML-M0 samples showed a distinct up-regulation of B-cell-related genes, e.g. members of the B-cell receptor complex, transcriptions regulators RUNX3, ETS2, IRF8 or PRDM1 and major histocompatibility complex class II genes. Importantly, expression of one single gene, i.e. BLNK, enabled prediction of RUNX1 mutations in AML-M0 with high accuracy. We propose that RUNX1 mutations in this subgroup of AML cause lineage infidelity, leading to aberrant co-expression of myeloid and B-lymphoid genes in the same cells.
Publication Title
Gene expression profiling of minimally differentiated acute myeloid leukemia: M0 is a distinct entity subdivided by RUNX1 mutation status.
Sample Metadata Fields
Specimen part
View Samples- Homo sapiens
- 52 Downloadable Samples
- Affymetrix Human Genome U133A Array (hgu133a)
Description
Although the prognosis for childhood Acute Lymphoblastic Leukemia (ALL) in general has improved tremendously over the last decades, the survival chances for infants (<1 year of age) with ALL remains poor.
Publication Title
Association of high-level MCL-1 expression with in vitro and in vivo prednisone resistance in MLL-rearranged infant acute lymphoblastic leukemia.
Sample Metadata Fields
Sex, Specimen part, Disease
View Samples- Homo sapiens
- 25 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Acute Myeloid Leukemia (AML) is a heterogeneous disease from the molecular and biological standpoints, and even patients with a specific gene expression profile may present clinical and molecular heterogeneity. We studied the epigenetic profiles of a cohort of patients that shared a common gene expression profile but differed in that only half of them harbored mutations of the CEBPA locus, while the rest presented with silencing of this gene and co-expression of certain T cell markers. DNA methylation studies revealed that these two groups of patients could be readily segregated in an unsupervised fashion based on their DNA methylation profiles alone. Furthermore, CEBPA silencing was associated with the presence of an aberrant DNA hypermethylation signature, which was not present in the CEBPA mutant group. This aberrant hypermethylation occurred more frequently at sites within CpG islands. CEBPA silenced leukemias also displayed marked hypermethylation when compared with normal CD34+ hematopoietic cells, while CEBPA mutant cases showed only mild changes in DNA methylation when compared to these normal progenitors. Biologically, CEBPA silenced leukemias presented with a decreased response to myeloid growth factors in vitro.
Publication Title
Genome-wide epigenetic analysis delineates a biologically distinct immature acute leukemia with myeloid/T-lymphoid features.
Sample Metadata Fields
No sample metadata fields
View Samples