Mitotic entry is accompanyed by the expression of a cluster of so called mitotic genes, whose activation is critical for mitosis in human and yeast cells. We found a link between the transcription machinery and cell cycle control network at mitosis in fission yeast, involving the Cdk8 kinase dependent phosphorylation of the fork head transcription factor Fkh2. We have generated a non-phosphorylatable fkh2 mutant (fkh2-S2A) also.
Cyclin-dependent kinase 8 regulates mitotic commitment in fission yeast.
No sample metadata fields
View SamplesThe multiprotein Mediator complex is an important regulator of RNA polymerase II-dependent genes in eukaryotic cell. In contrast to the situation in many other eukaryotes, the conserved Med15 protein is not a stable component of Mediator isolated from fission yeast. We now demonstrate that Med15 exists in a protein complex together with Hrp1, an ATP-dependent chromatin remodeling protein. The Med15/Hrp1 subcomplex is not a component of the core Mediator complex, but can interact with the repressive L-Mediator conformation. Deletion of MED15 and HRP1 cause similar effects on global steady-state levels of mRNA, but only MED15 is required for galactose-dependent activation of the inv1 gene. Hrp1 has been found in complex with other proteins and genome-wide analysis demonstrates that Med15 only associates with a distinct subset of Hrp1-bound gene promoters. Global analysis reveals that Hrp1-binding normally is associated with increased histone H3 density, but at promoters also bound by Med15, histone H3 density is instead increased. Our findings reveal that Med15 functions as a separate entity in fission yeast and indicate that the function and organization of the Mediator complex may differ significantly between eukaryotes.
A chromatin-remodeling protein is a component of fission yeast mediator.
No sample metadata fields
View SamplesThe activation of the transcription factor NF-E2-related factor 2 (Nrf2) maintains cellular homeostasis in response to oxidative stress by the regulation of multiple cytoprotective genes. Without stressors the activity of Nrf2 is inhibited by its interaction with the kelch-like ECH-associated protein 1 (Keap1). Here, we describe RA839, a small molecule that binds non-covalently to the Nrf2-interacting kelch domain of Keap1 with a Kd of approximately 6 M, as demonstrated by X-ray co-crystallization and isothermal titration calorimetry. Whole-genome DNA arrays showed that at 10 M RA839 significantly regulated 105 genes in bone marrow-derived macrophages. Canonical pathway mapping of these genes revealed an activation of pathways linked with Nrf2 signalling. These pathways were also activated after the activation of Nrf2 by the silencing of Keap1 expression. RA839 regulated only two genes in Nrf2 knockout macrophages. Similar to the activation of Nrf2 by either silencing of Keap1 expression or by the reactive compound CDDO-Me, RA839 prevented the induction of both inducible nitric oxide synthase expression and nitric oxide release in response to lipopolysaccharides in macrophages. In mice RA839 acutely induced Nrf2-target gene expression in liver. RA839 is a selective inhibitor of the Keap1/Nrf2 interaction and a useful tool compound to study the biology of Nrf2.
Characterization of RA839, a Noncovalent Small Molecule Binder to Keap1 and Selective Activator of Nrf2 Signaling.
Specimen part, Treatment
View SamplesUncontrolled Transforming growth factor-beta (TGF) signaling promotes aggressive metastatic properties in late-stage breast cancers. However, how TGF-mediated cues are directed to induce late-stage tumorigenic events is poorly understood, particularly given that TGF has clear tumor suppressing activity in other contexts. Here we demonstrate that the transcriptional regulators TAZ and YAP (TAZ/YAP), key effectors of the Hippo pathway, are necessary to promote and maintain TGF-induced tumorigenic phenotypes in breast cancer cells. Interactions between TAZ/YAP, TGF-activated SMAD2/3, and TEAD transcription factors reveal convergent roles for these factors in the nucleus. Genome-wide expression analyses indicate that TAZ/YAP, TEADs and TGF-induced signals coordinate a specific pro-tumorigenic transcriptional program. Importantly, genes cooperatively regulated by TAZ/YAP, TEAD, and TGF, such as the novel targets NEGR1 and UCA1, are necessary for maintaining tumorigenic activity in metastatic breast cancer cells. Nuclear TAZ/YAP also cooperate with TGF signaling to promote phenotypic and transcriptional changes in non-tumorigenic cells to overcome TGF repressive effects. Our work thus identifies crosstalk between nuclear TAZ/YAP and TGF signaling in breast cancer cells, revealing novel insight into late-stage disease-driving mechanisms.
The transcriptional regulators TAZ and YAP direct transforming growth factor β-induced tumorigenic phenotypes in breast cancer cells.
Cell line, Treatment
View SamplesOur study identified long term salt stress treatment to induce symptoms similar to developmental senescence. In order to identify possible crosstalk components shared between developmental and salt-triggered senescence.
Salt stress and senescence: identification of cross-talk regulatory components.
Age, Specimen part, Treatment
View SamplesMethylated DNA binding protein 2 (MBD2) has been shown to bind specific methylated promoters and suppress transcription. Here we systematically investigate MBD2 suppression by overexpressing MBD2 in MCF-10A cells and generating gene expression profiles of overexpressing cells and normal MCF-10A cells.
Methylated DNA binding domain protein 2 (MBD2) coordinately silences gene expression through activation of the microRNA hsa-mir-496 promoter in breast cancer cell line.
Cell line, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Definition of the landscape of promoter DNA hypomethylation in liver cancer.
Specimen part, Cell line, Subject
View SamplesSex differences in rat adrenal cortex are manifested as larger adrenal volume of cortex and higher corticosterone secretion by females compared with males. The molecular bases of these sex related differences are poorly understood.
Transcriptome Profile of Rat Adrenal Evoked by Gonadectomy and Testosterone or Estradiol Replacement.
Sex, Age, Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
A common promoter hypomethylation signature in invasive breast, liver and prostate cancer cell lines reveals novel targets involved in cancer invasiveness.
Sex, Disease, Disease stage, Cell line
View SamplesExtensive loss of DNA methylation is a hallmark of cancer. The role of hypomethylation in altering gene expression in cancer cells has been poorly understood. Hepatic cellular carcinoma (HCC) is one of the most common human cancers. We use HCC as a model to investigate hypomethylation in cancer by a combination of methylated DNA immunoprecipitation and hybridization with comprehensive promoter arrays. We identify approximately 2,800 promoters that are hypomethylated in tumor samples. The hypomethylated promoters appear in clusters across the genome suggesting a high-level organization behind the epigenomic changes in cancer. The genes whose promoters are demethylated are mainly involved in cell growth, cell adhesion and communication, signal transduction, mobility and invasion; functions that are essential for cancer progression and metastasis. Previous studies suggested that MBD2 was involved in demethylation of uPA and MMP2 genes in human breast and prostate cancer cell lines. We extend these results here showing that whereas MBD2 depletion in normal liver cells has little or no effect, its depletion in the human hepatocellular carcinoma cell line HepG2 and the adenocarcinoma cell line SkHep1 results in suppression of cell growth, anchorage-independent growth and invasiveness, as well as an increase in promoter methylation and silencing of several of the genes that are hypomethylated in tumors. Our studies establish for the first time the rules governing hypomethylation of promoters in liver cancer and define the potential functional role of hypomethylation in cancer.
Definition of the landscape of promoter DNA hypomethylation in liver cancer.
Specimen part, Subject
View Samples