Filters
Technology
Platform
GSE22809
Saccharomyces cerevisiae
12 Downloadable Samples
Affymetrix Yeast Genome 2.0 Array (yeast2)
Description
To investigate the role of DNA topoisomerases in transcription, we have studied global gene expression in Saccharomyces cerevisiae cells deficient for topoisomerases I and II and performed single-gene analyses to support our findings. The genome-wide studies show a general transcriptional down-regulation upon lack of the enzymes, which correlates with gene activity but not gene length. Furthermore, our data reveal a distinct subclass of genes with a strong requirement for topoisomerases. These genes are characterized by high transcriptional plasticity, chromatin regulation, TATA box presence, and enrichment of a nucleosome at a critical position in the promoter region, in line with a repressible/inducible mode of regulation. Single-gene studies with a range of genes belonging to this group demonstrate that topoisomerases play an important role during activation of these genes. Subsequent in-depth analysis of the inducible PHO5 gene reveals that topoisomerases are essential for binding of the Pho4p transcription factor to the PHO5 promoter, which is required for promoter nucleosome removal during activation. In contrast, topoisomerases are dispensable for constitutive transcription initiation and elongation of PHO5, as well as the nuclear entrance of Pho4p. Finally, we provide evidence that topoisomerases are required to maintain the PHO5 promoter in a superhelical state, which is competent for proper activation. In conclusion, our results reveal a hitherto unknown function of topoisomerases during transcriptional activation of genes with a repressible/inducible mode of regulation
Publication Title
DNA Topoisomerases maintain promoters in a state competent for transcriptional activation in Saccharomyces cerevisiae.
Sample Metadata Fields
No sample metadata fields
View Samples- Schizosaccharomyces pombe
- 6 Downloadable Samples
- Affymetrix Yeast Genome 2.0 Array (yeast2)
Description
The response to nitrogen starvation was studied in S. pombe. This experiment contains expression data from Affymetrix Yeast 2.0 arrays.
Publication Title
Nitrogen depletion in the fission yeast Schizosaccharomyces pombe causes nucleosome loss in both promoters and coding regions of activated genes.
Sample Metadata Fields
No sample metadata fields
View Samples- Homo sapiens
- 50 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Background & Aims: Genome-wide gene expression (GWGE) profiles of mucosal colonic biopsies have suggested the existence of a continuous inflammatory state in quiescent ulcerative colitis (UC). The aim of this study was to use DNA microarray-based GWGE profiling of mucosal colonic biopsies and isolated colonocytes from UC patients and controls in order to identify the cell types responsible for the continuous inflammatory state. Methods: Adjacent mucosal colonic biopsies were obtained endoscopically from the descending colon in patients with active UC (n=8), quiescent UC (n=9), and with irritable bowel syndrome (controls, n=10). After isolation of colonocytes and subsequent extraction of total RNA, GWGE data were acquired using Human Genome U133 Plus 2.0 GeneChip Array (Affymetrix, Santa Clara, CA). Data analysis was carried out by principal component analysis and projection to latent structure-discriminant analysis using the SIMCA-P11 software (Umetrics, Ume, Sweden). Results: A clear separation between active UC, quiescent UC and control biopsies were found, whereas the model for the colonocytes was unable to distinguish between quiescent UC and controls. The differentiation between quiescent UC and control biopsies was governed by unique profiles containing gene expressions with significant fold changes. These primarily belonged to the family of homeostatic chemokines revealing a plausible explanation to the abnormal regulated innate immune response seen in patients with UC. Conclusion: This study has demonstrated the presence of a continuous inflammatory state in quiescent UC, which seems to reflect an altered gene expression profile of lamina propria cells.
Publication Title
Genome-wide gene expression analysis of mucosal colonic biopsies and isolated colonocytes suggests a continuous inflammatory state in the lamina propria of patients with quiescent ulcerative colitis.
Sample Metadata Fields
No sample metadata fields
View Samples- Rattus norvegicus
- 29 Downloadable Samples
- Affymetrix Rat Gene 2.0 ST Array (ragene20st)
Description
Background: Extended hepatectomies may result in post-hepatectomy liver failure, a condition with a high mortality. The main purpose of the present study was to investigate and compare the gene expression profiles in rats subjected to increasing size of partial hepatectomy.
Publication Title
Gene Expression in the Liver Remnant Is Significantly Affected by the Size of Partial Hepatectomy: An Experimental Rat Study.
Sample Metadata Fields
Specimen part, Treatment
View Samples- Homo sapiens
- 48 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
This study characterizes the inflammatory processes in left-sided colitis, pancolitis, and UC-associated dysplasia at the transcriptional level in colonics biopsies in order to identify potential biomarkers and transcripts of importance for the carcinogenic behaviour of chronic inflammation
Publication Title
Transcriptional analysis of left-sided colitis, pancolitis, and ulcerative colitis-associated dysplasia.
Sample Metadata Fields
Specimen part, Disease, Disease stage
View Samples- Homo sapiens
- 26 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
The samples are a part of a study aiming at diagnosing ulcerative colitis from genome-wide gene expression analysis of the colonic mucosa. Colonic mucosal samples were collected as endoscopic pinch biopsies from ulcerative colitis patients and from control subjects. Samples with and without macroscopic signs of inflammation were collected from the patients.
Publication Title
Diagnosis of ulcerative colitis before onset of inflammation by multivariate modeling of genome-wide gene expression data.
Sample Metadata Fields
No sample metadata fields
View Samples- Homo sapiens
- 91 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
We used microarrays to assess gene expression in patients with ET, PV, and PMF compared to control subjects
Publication Title
Whole-blood transcriptional profiling of interferon-inducible genes identifies highly upregulated IFI27 in primary myelofibrosis.
Sample Metadata Fields
Specimen part, Disease
View Samples- Homo sapiens
- 58 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Microarrays were used to assess gene expression in patients with ET, PV, and PMF before and after treatment with IFNalpha2 in a paired design.
Publication Title
The impact of interferon-alpha2 on HLA genes in patients with polycythemia vera and related neoplasms.
Sample Metadata Fields
Specimen part, Disease, Disease stage, Treatment
View Samples- Homo sapiens
- 45 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Microarrays were used to assess gene expression in patients with ET, PV, and PMF before treatment with IFNalpha2.
Publication Title
Whole blood transcriptional profiling reveals deregulation of oxidative and antioxidative defence genes in myelofibrosis and related neoplasms. Potential implications of downregulation of Nrf2 for genomic instability and disease progression.
Sample Metadata Fields
Specimen part, Disease, Disease stage, Treatment
View Samples- Homo sapiens
- 58 Downloadable Samples
- Affymetrix Human Gene 1.0 ST Array (hugene10st)
Description
Glioblastoma (GBM) patient-derived orthotopic xenografts (PDOXs) were derived from organotypic spheroids obtained from patient tumor samples. To detect whether gene expression profiles of GBM patient tumors are retained in PDOXs, we performed genome-wide transcript analysis by human-specific microarrays . In parallel, we analyzed GBM cell cultures and corresponding intracranial xenografts from stem-like (NCH421k, NCH644) and adherent GBM cell lines (U87, U251). PDOXs show a better transcriptomic resemblance with patient tumors than other preclinical models. The major difference is largely explained by the depletion of human-derived non-malignant cells.
Publication Title
Patient-derived organoids and orthotopic xenografts of primary and recurrent gliomas represent relevant patient avatars for precision oncology.
Sample Metadata Fields
Specimen part, Disease
View Samples