Ash1 and Tup1 Dependent Repression of the Saccharomyces cerevisiae HO promoter Requires Activator-Dependent Nucleosome Eviction
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA664211 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Transcriptional regulation of the Saccharomyces cerevisiae HO gene is highly complex, requiring a balance of multiple activating and repressing factors to ensure that only a few transcripts are produced in mother cells within a narrow window of the cell cycle. Here, we show that the Ash1 repressor associates with two DNA sequences that are usually concealed within nucleosomes in the HO promoter and recruits the Tup1 corepressor and the Rpd3 histone deacetylase, both of which are required for full repression in daughters. Genome-wide ChIP identified greater than 200 additional sites of co-localization of these factors, primarily within large, intergenic regions from which they could regulate adjacent genes. Most Ash1 binding sites are in nucleosome depleted regions (NDRs), while a small number overlap nucleosomes, similar to HO. We demonstrate that Ash1 binding to the HO promoter does not occur in the absence of the Swi5 transcription factor, which recruits coactivators that evict nucleosomes, including the nucleosomes obscuring the Ash1 binding sites. In the absence of Swi5, artificial nucleosome depletion allowed Ash1 to bind, demonstrating that nucleosomes are inhibitory to Ash1 binding. The location of binding sites within nucleosomes may therefore be a mechanism for limiting repressive activity to periods of nucleosome eviction that are otherwise associated with activation of the promoter. Our results illustrate that activation and repression can be intricately connected, and events set in motion by an activator may also ensure the appropriate level of repression and reset the promoter for the next activation cycle.
2020-12-01 | GSE158180 | GEO
Project description:Transcriptional regulation of the Saccharomyces cerevisiae HO gene is highly complex, requiring a balance of multiple activating and repressing factors to ensure that only a few transcripts are produced in mother cells within a narrow window of the cell cycle. Here, we show that the Ash1 repressor associates with two DNA sequences that are usually concealed within nucleosomes in the HO promoter and recruits the Tup1 corepressor and the Rpd3 histone deacetylase, both of which are required for full repression in daughters. Genome-wide ChIP identified greater than 200 additional sites of co-localization of these factors, primarily within large, intergenic regions from which they could regulate adjacent genes. Most Ash1 binding sites are in nucleosome depleted regions (NDRs), while a small number overlap nucleosomes, similar to HO. We demonstrate that Ash1 binding to the HO promoter does not occur in the absence of the Swi5 transcription factor, which recruits coactivators that evict nucleosomes, including the nucleosomes obscuring the Ash1 binding sites. In the absence of Swi5, artificial nucleosome depletion allowed Ash1 to bind, demonstrating that nucleosomes are inhibitory to Ash1 binding. The location of binding sites within nucleosomes may therefore be a mechanism for limiting repressive activity to periods of nucleosome eviction that are otherwise associated with activation of the promoter. Our results illustrate that activation and repression can be intricately connected, and events set in motion by an activator may also ensure the appropriate level of repression and reset the promoter for the next activation cycle.
| S-EPMC7806131 | biostudies-literature
Project description:Heme Oxygenase-1 (HO-1) is expressed in many cancers and influences the growth, survivall and metastasis of tumors, however, the molecular mechanisms remains largely unknown. To identify a common mechanism of action of HO-1 in cancer, we studied the global effect of HO-1 on the transcriptome of multiple tumors. Genome-wide expression profiling of HO-1 expressing versus HO-1 silenced cancer cells and a further data mining analysis of the preexisting expression database of 190 human tumors of 14 cancer types led us to identify 14 genes, the expression of which correlated firmly and universally with that of HO-1 (P < 0.001). These genes included regulators of cell plasticity and extracellular matrix remodeling (MMP2, ADAM8, TGFβ1, BGN, COL21A1, PXDN), signaling (CRIP2, MICB), amino acid transport and glycosylation (SLC7A1 and ST3GAL2), estrogen and phospholipid biosynthesis (AGPAT2 and HSD17B1), protein stabilization (IFI30) and phosphorylation (ALPPL2). PXDN, one of the genes being co-expressed with HO-1, was selected for further analysis. Immunofluorescence and western blotting confirmed positive correlation of PXDN with HO-1 levels in BeWo cancer cells as well as co-localization in invasive extravillous trophoblast cells of first trimester placenta. Loss of HO-1 in BeWo cells correlated with reduced cell adhesion to Collagen type I, Fibronectin and Laminin. The adhesion-promoting effects of HO-1 were dependent on PXDN expression, as loss of PXDN in HO-1 expressing BeWo cells led to reduced cell attachment to Laminin and Fibronectin coated wells.
2011-02-15 | GSE20404 | GEO
Project description:Heme Oxygenase-1 (HO-1) is expressed in many cancers and influences the growth, survivall and metastasis of tumors, however, the molecular mechanisms remains largely unknown. To identify a common mechanism of action of HO-1 in cancer, we studied the global effect of HO-1 on the transcriptome of multiple tumors. Genome-wide expression profiling of HO-1 expressing versus HO-1 silenced cancer cells and a further data mining analysis of the preexisting expression database of 190 human tumors of 14 cancer types led us to identify 14 genes, the expression of which correlated firmly and universally with that of HO-1 (P < 0.001). These genes included regulators of cell plasticity and extracellular matrix remodeling (MMP2, ADAM8, TGFβ1, BGN, COL21A1, PXDN), signaling (CRIP2, MICB), amino acid transport and glycosylation (SLC7A1 and ST3GAL2), estrogen and phospholipid biosynthesis (AGPAT2 and HSD17B1), protein stabilization (IFI30) and phosphorylation (ALPPL2). PXDN, one of the genes being co-expressed with HO-1, was selected for further analysis. Immunofluorescence and western blotting confirmed positive correlation of PXDN with HO-1 levels in BeWo cancer cells as well as co-localization in invasive extravillous trophoblast cells of first trimester placenta. Loss of HO-1 in BeWo cells correlated with reduced cell adhesion to Collagen type I, Fibronectin and Laminin. The adhesion-promoting effects of HO-1 were dependent on PXDN expression, as loss of PXDN in HO-1 expressing BeWo cells led to reduced cell attachment to Laminin and Fibronectin coated wells. We used gene expression profiling to determine the genome-wide effect of HO-1 on the transcriptome of BeWo trophoblast cells. We specifically selected BeWo cells for our studies because these cells express HO-1 naturally. We knocked down endogenous HO-1 in BeWo cells using retroviral transduction with a micro-RNA adapted retroviral vector targeting human HO-1 sequence. RNA isolated from control (LMP) or miHO1 infected (miHO-1) cells was labeled and hybridized to human genome-wide gene level 1.0 ST arrays
2011-02-15 | E-GEOD-20404 | biostudies-arrayexpress
Project description:Excessive accumulation of white adipose tissue (WAT) is a hallmark of obesity. The expansion of WAT in obesity involves proliferation and differentiation of adipose precursors (APs), however, the underlying molecular mechanisms remain unclear. Here, we identify Heme Oxygenase-1 (HO-1) as selectively being upregulated in the AP fraction of WAT, upon high-fat diet (HFD) feeding. Specific conditional deletion of HO-1 in APs of Hmox1fl/fl-Pdgfra Cre mice enhanced HFD-dependent visceral AP proliferation and differentiation, upstream of Cebpα and PPARγ. Opposite effects on human preadipocyte proliferation and differentiation in vitro were observed following HO-1 overexpression. Mechanistically, HO-1 acts upstream of AKT2 via ROS thresholding in mitochondria. Deletion of HO-1 in APs is sufficient to lower blood glucose, insulin and free fatty acid levels as well as liver steatosis during obesity, an effect not seen when HO-1 was conditionally deleted at later stages of adipogenesis using AdipoQ-Cre. Together, our data identify HO-1 as a diet-induced regulator limiting visceral adipose tissue hyperplasia during obesity.
2017-03-08 | GSE80147 | GEO
Project description:Excessive accumulation of white adipose tissue (WAT) is a hallmark of obesity. The expansion of WAT in obesity involves proliferation and differentiation of adipose precursors (APs), however, the underlying molecular mechanisms remain unclear. Here, we identify Heme Oxygenase-1 (HO-1) as selectively being upregulated in the AP fraction of WAT, upon high-fat diet (HFD) feeding. Specific conditional deletion of HO-1 in APs of Hmox1fl/fl-Pdgfra Cre mice enhanced HFD-dependent visceral AP proliferation and differentiation, upstream of Cebpα and PPARγ. Opposite effects on human preadipocyte proliferation and differentiation in vitro were observed following HO-1 overexpression. Mechanistically, HO-1 acts upstream of AKT2 via ROS thresholding in mitochondria. Deletion of HO-1 in APs is sufficient to lower blood glucose, insulin and free fatty acid levels as well as liver steatosis during obesity, an effect not seen when HO-1 was conditionally deleted at later stages of adipogenesis using AdipoQ-Cre. Together, our data identify HO-1 as a diet-induced regulator limiting visceral adipose tissue hyperplasia during obesity.
2017-03-08 | GSE80146 | GEO
Project description:Hydrogenobaculum sp. HO genome sequencing project
| PRJNA41741 | ENA
Project description:A major class of chemotherapeutics targets topoisomerase II for DNA double-strand breaks and cancer cell elimination. We compare four members of this class?the anthracyclines doxorubicin, daunorubicin and aclarubicin that does not induce DNA breaks?and a different compound, etoposide. We define a novel activity for anthracyclines: histone eviction from open chromosomal areas. Since histone variant H2AX is also evicted, DNA damage response is attenuated when compared to etoposide. Histone eviction also affects the epigenetic code and deregulates the transcriptome in cancer cells and organs such as the heart. Histone eviction by anthracyclines can drive apoptosis of topoisomerase-negative acute myeloid leukemia blasts in patients. Doxo- and daunorubicin combine the activities of two anti-cancer drugs: etoposide for DNA damage and aclarubicin for histone eviction. We define a novel mechanism of action of anti-cancer drugs doxo- and daunorubicin on chromatin biology with profound consequences on DNA damage responses, epigenetics, transcription, side effects and anti-cancer activities. Comparison of histone occupancy of cells or tissues treated with topoisomerase II inhibitors to un-treated ones by FAIRE-seq.
2013-06-04 | E-GEOD-33632 | biostudies-arrayexpress
Project description:Nrf2 antioxidant signaling is involved in liver protection, but this generalization overlooks conflicting studies indicating that Nrf2 effects are not necessarily hepatoprotective. The role of Nrf2/HO-1 in cholestatic liver injury (CLI) remains poorly defined. Here, we report that Nrf2/HO-1 activation exacerbates liver injury rather than exerts a protective effect in CLI. Inhibiting HO-1 or ameliorating bilirubin transport alleviates liver injury in CLI models. Nrf2 knockout confers hepatoprotection in CLI mice, whereas in non-CLI mice, Nrf2 knockout aggravates liver damage. In the CLI setting, oxidative stress activates Nrf2/HO-1, leads to bilirubin accumulation, and impairs mitochondrial function. High levels of bilirubin reciprocally upregulate the activation of Nrf2 and HO-1, while antioxidant and mitochondria-targeted SOD2 overexpression attenuate the toxicity of bilirubin. Additionally, the expression of Nrf2 and HO-1 is significantly elevated in serum of patients with CLI. These results reveal an unrecognized function of Nrf2 signaling in exacerbating liver injury in cholestatic disease.
2024-04-08 | GSE263093 | GEO
Project description:The aim was to determine the effect of heme oxygenase-1 (HO-1) overexpression on microRNA transcriptome in human non-small cell lung carcinoma cell line (NCI-H292). Since the cells of different HO-1 genotypes were used (cells are after retroviral transduction with empty vector with normal level of HO-1 or retroviral transduction with vector harboring HO-1), it is possible get the comprehensive answer which microRNAs are regulated by HO-1.
2013-04-27 | GSE37779 | GEO