Med26 is a subunit of the Human Mediator complex. The Mediator complex is an evolutionarily conserved coregulatory complex that interacts with RNA polymerase II to regulate gene expression. In metazoa, Mediator is composed of some 30 distinct subunits. Mediator exists in multiple, functionally distinct forms that share a common core of subunits and can be distinguished by the presence or absence of a kinase module composed of Med12, Med13, Cdk8, and Cyclin C. In higher eukaryotes, a subset of Mediator complexes is associated with an additional subunit, Med26. This Med26-containing Mediator copurifies from cells with little or no kinase module, but near-stoichiometric Pol II. Evidence suggests that Med26-containing Mediator plays a key role in transcriptional activation however, the mechanism(s) by which Med26 contributes to this process are not known. To identify Med26 target genes, we used Affymetrix U133A plus 2.0 expression arrays to analyze mRNA expression in 293T cells from which Med26 had been depleted by transient transfection by each of three different siRNAs.
Human mediator subunit MED26 functions as a docking site for transcription elongation factors.
Specimen part, Cell line
View SamplesGene expression data from 21 triple negative breast cancer samples treated with cisplatin & bevacizumab in the neoadjuvant setting as part of a clinical trial.
Overexpression of BLM promotes DNA damage and increased sensitivity to platinum salts in triple-negative breast and serous ovarian cancers.
Specimen part
View SamplesOligodendrocytes are cells from the central nervous system that can be grouped into precursors, myelin-forming, and non-myelinating perineuronal. The function of perineuronal oligodendrocytes is unknown; it was suggested that they can ensheath denuded axons. We tested this hypothesis. Using cell-specific tags, microarray technology and bioinformatics tools to identify gene expression differences between these subpopulations allowed us to capture the genetic signature of perineuronal oligodendrocytes. Here we report that perineuronal oligodendrocytes are configured for a dual role. As perineuronal, they integrate a repertoire of transcripts designed to create a cell with its own physiological agenda. But they maintain a reservoir of untranslated transcripts encoding the major myelin proteins for we speculate a pathological eventuality. We posit that the signature molecules PDGFR-, cytokine PDGF-CC, and the transcription factor Pea3 used among others - to define the non-myelinating phenotype, may be critical for mounting a myelinating programme during demyelination. Harnessing this capability is of therapeutic value for diseases such as multiple sclerosis. This is the first molecular characterization of perineuronal oligodendrocytes.
The genetic signature of perineuronal oligodendrocytes reveals their unique phenotype.
No sample metadata fields
View SamplesPrimary diffuse large B cell lymphomas of different immune-privileged sites (IP-DLBCL) share many clinical and biological features, such as a relatively poor prognosis, preferential dissemination to other immune-privileged sites and deletion of the HLA region, which suggests that IP-DLBCL represents a separate entity. To further investigate the nature of IP-DLBCL, we investigated site-specific genomic aberrations in 16 testicular, 9 central nervous system (CNS) and 15 nodal DLBCL using array-CGH. We also determined minimal common regions of gain and loss. Using robust algorithms, the array-CGH data were combined with gene expression data to explore pathways deregulated by chromosomal aberrations.
Genomic alterations and gene expression in primary diffuse large B-cell lymphomas of immune-privileged sites: the importance of apoptosis and immunomodulatory pathways.
Specimen part
View SamplesSamples collected from human subjects in clinical trials possess a level of complexity, arising from multiple cell types, that can obfuscate the analysis of data derived from them. Blood, for example, contains many different cell types that are derived from a distinct lineage and carry out a different immunological purpose. Failure to identify, quantify, and incorporate sources of heterogeneity into an analysis can have widespread and detrimental effects on subsequent statistical studies.
Optimal deconvolution of transcriptional profiling data using quadratic programming with application to complex clinical blood samples.
Sex, Specimen part
View Samplesaffy_xoo_rice - affy_xoo_rice - The Bacterial Leaf Blight disease of rice is due to Xanthomonas oryzae pv. oryzae. As for many pathogenic bacteria, it relies on a type 3 secretion system that is devoted to the injection of type 3 effectors into the eukaryotic host cell. These proteins are meant to suppress host basal defense responses and/or mimic some host regulatory function promoting bacterial survey in the plant. We are interested in the functional analysis of a subgroup of Xoo T3Es, that are specialized in host cell transcriptome remodelling. These effectors, therefore called TAL for Transcription Activator-Like proteins (also named AvrBs3/PthA-like), are often key virulence factors essential to Xoo pathogenicity such as the effector protein Talc of african Xoo strain BAI3. Our goal is to understand its function during disease development, by identifying rice host genes that are being directly up- or down-regulated by Talc. To that end, we aim at performing Affymetrix transcriptomic analysis, comparing leaf samples of a susceptible rice line inoculated with Xoo to leaves challenged with a Talc-deficient mutant and water-treated leaves. Highly induced genes are likely to be Talc primary targets and therefore potentially good susceptibility gene candidates.-The goal of the experiment is to identify the rice genes up- or down-regulated by the type III effector Talc from Xoo African strain BAI3, upon the inoculation of susceptible rice leaves 24 hours post-infection. To that end, the experimental design includes the inoculation of Nipponbare rice leaves with the virulent Xoo strain BAI3, that will be compared to Nipponbare rice leaves inoculated with a talc K.O. mutant strain and water.
Colonization of rice leaf blades by an African strain of Xanthomonas oryzae pv. oryzae depends on a new TAL effector that induces the rice nodulin-3 Os11N3 gene.
Specimen part
View SamplesMycosis fungoides (MF), the most common cutaneous T-cell lymphoma (CTCL), is a malignancy of mature, skin-homing T cells. Szary syndrome (Sz) is often considered to represent a leukemic phase of MF. In this study the pattern of numerical chromosomal alterations in MF tumor samples was defined using array-based CGH; simultaneously gene expression was analyzed using microarrays. Highly recurrent chromosomal alterations in MF include copy number gain of 7q36, 7q21-7q22 and loss of 5q13 and 9p21. This pattern characteristic of MF differs markedly from chromosomal alterations observed in Sz. Integration of data from array-based CGH and gene expression analysis yielded several candidate genes with potential relevance in the pathogenesis of MF. We confirmed that the FASTK and SKAP1 genes, residing in loci with recurrent gain, demonstrated increased expression. The RB1 and DLEU1 tumor suppressor genes showed diminished expression associated with loss. In addition, it was found that presence of chromosomal alterations on 9p21, 8q24 and 1q21-1q22 was associated with poor prognosis in patients with MF. This study provides novel insight into genetic alterations underlying MF. Furthermore, our analysis uncovered genomic differences between MF and Sz, which suggest that the molecular pathogenesis and therefore therapeutic requirements of these CTCLs may be distinct.
Oncogenomic analysis of mycosis fungoides reveals major differences with Sezary syndrome.
Specimen part
View SamplesGlioblastomas (GBMs) are divided into CpG Island Methylator Phenotype (CIMP) and non-CIMP tumors. Non-CIMP GBMs derive from cells with non-disjunction of chromosome (chr7) and chromosome 10 (chr10), resulting in chr7 gain and chr10 loss, while CIMP GBMs have mutations in isocitrate dehydrogenase 1 or 2 (IDH1/2). Gain of chr7 is largely driven by PDGFA, but other genes on chr7 are likely to contribute to fitness gains and aggressiveness of these GBMs. We computationally investigated genes on chr7 whose gene expression correlated with survival, identifying HOXA5 as a potential driver of proneural gliomagenesis. Using a combination of human GBM cells and mouse PDGF-driven gliomas, we showed that HOXA5 drives increased proliferation and radiation resistance in culture and in vivo. These phenotypes appear to be in part due to effects on p53 and other apoptosis-related genes.
Increased <i>HOXA5</i> expression provides a selective advantage for gain of whole chromosome 7 in IDH wild-type glioblastoma.
Disease
View SamplesThe vast majority of supratentorial ependymomas (ST-EPNs) have few mutations other than chromosomal rearrangements on chromosome 11, most generating a fusion between C11orf95 and RELA (CR). This CR fusion can transform stem cells ex vivo rendering them oncogenic and may possess NF-?B activity, which has been proposed to be a mechanism of oncogenesis. However, it is not known whether CR is sufficient for EPN formation in vivo, and from what cell type and location. We found that CR is sufficient to form tumors from cells in the ependymal zone in mice that show many molecular and histologic similarities to human ST-EPN. Furthermore, the activation of NF-?B by this fusion protein appears minimal and not related to its oncogenic activity Overall design: C11orf95-RELA is a potent oncogene for supratentorial ependymoma
A De Novo Mouse Model of C11orf95-RELA Fusion-Driven Ependymoma Identifies Driver Functions in Addition to NF-κB.
Specimen part, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
1q gain and CDT2 overexpression underlie an aggressive and highly proliferative form of Ewing sarcoma.
Sex, Age, Specimen part, Disease, Cell line
View Samples