Homo sapiens
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PROVIDER: PRJNA307593 | ENA |
REPOSITORIES: ENA
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Project description:Only a small number of genes are known direct targets of the zinc-responsive transcription factor MTF1; therefore, the aim of this study was to gain a more complete understanding of the MTF-1 regulated zinc-responsive component of the transcriptome. A targeted siRNA was used to deplete MTF1 expression in the human intestinal cell line Caco-2. We predicted that the response to zinc of direct MTF1 target genes would be abrogated by MTF1 knockdown. Surprisingly, a greater number of genes were regulated by zinc following MFT1 knockdown, and most genes that responded to zinc under both control and MTF1-depleted conditions had an augmented response in the latter condition. Exceptions were the zinc effluxer ZnT1 and a suite of metallothionein genes, suggesting that responses of other genes to zinc are usually buffered by increases in these proteins. We propose that MTF1 heads a hierarchy of zinc sensors, and through controlling the expression of a raft of metallothioneins and other key proteins involved in controlling intracellular zinc levels (e.g. ZnT1) alters zinc buffering capacity and total cellular zinc content. We tested and validated this model by overexpressing metallothionein and observing the predicted curtailment in response of the zinc-repressed SLC30A5 (ZnT5) promoter. The model provides the framework for an integrated understanding of cellular zinc homeostasis. Because MTs can bind metals other than zinc, this framework links with overall cellular metal homeostasis. Gene expression profiling by Illumina BeadArray of the effects of ZNF658 gene knockdown by siRNA. 2 different siRNAs were used, with appropriate non-targetting controls. All experiments were carried out in triplicate.
2016-02-24 | E-GEOD-76510 | biostudies-arrayexpress
Project description:Only a small number of genes are known direct targets of the zinc-responsive transcription factor MTF1; therefore, the aim of this study was to gain a more complete understanding of the MTF-1 regulated zinc-responsive component of the transcriptome. A targeted siRNA was used to deplete MTF1 expression in the human intestinal cell line Caco-2. We predicted that the response to zinc of direct MTF1 target genes would be abrogated by MTF1 knockdown. Surprisingly, a greater number of genes were regulated by zinc following MFT1 knockdown, and most genes that responded to zinc under both control and MTF1-depleted conditions had an augmented response in the latter condition. Exceptions were the zinc effluxer ZnT1 and a suite of metallothionein genes, suggesting that responses of other genes to zinc are usually buffered by increases in these proteins. We propose that MTF1 heads a hierarchy of zinc sensors, and through controlling the expression of a raft of metallothioneins and other key proteins involved in controlling intracellular zinc levels (e.g. ZnT1) alters zinc buffering capacity and total cellular zinc content. We tested and validated this model by overexpressing metallothionein and observing the predicted curtailment in response of the zinc-repressed SLC30A5 (ZnT5) promoter. The model provides the framework for an integrated understanding of cellular zinc homeostasis. Because MTs can bind metals other than zinc, this framework links with overall cellular metal homeostasis.
2016-02-24 | GSE76510 | GEO
Project description:BACKGROUND: The zinc homeostasis system in Escherichia coli is one of the most intensively studied prokaryotic zinc homeostasis systems. Its underlying regulatory machine consists of repression on zinc influx through ZnuABC by Zur (Zn2+ uptake regulator) and activation on zinc efflux via ZntA by ZntR (a zinc-responsive regulator). Although these transcriptional regulations seem to be well characterized, and there is an abundance of detailed in vitro experimental data available, as yet there is no mathematical model to help interpret these data. To our knowledge, the work described here is the first attempt to use a mathematical model to simulate these regulatory relations and to help explain the in vitro experimental data. RESULTS: We develop a unified mathematical model consisting of 14 reactions to simulate the in vitro transcriptional response of the zinc homeostasis system in E. coli. Firstly, we simulate the in vitro Zur-DNA interaction by using two of these reactions, which are expressed as 4 ordinary differential equations (ODEs). By imposing the conservation restraints and solving the relevant steady state equations, we find that the simulated sigmoidal curve matches the corresponding experimental data. Secondly, by numerically solving the ODEs for simulating the Zur and ZntR run-off transcription experiments, and depicting the simulated concentrations of zntA and znuC transcripts as a function of free zinc concentration, we find that the simulated curves fit the corresponding in vitro experimental data. Moreover, we also perform simulations, after taking into consideration the competitive effects of ZntR with the zinc buffer, and depict the simulated concentration of zntA transcripts as a function of the total ZntR concentration, both in the presence and absence of Zn(II). The obtained simulation results are in general agreement with the corresponding experimental data. CONCLUSION: Simulation results show that our model can quantitatively reproduce the results of several of the in vitro experiments conducted by Outten CE and her colleagues. Our model provides a detailed insight into the dynamics of the regulatory system and also provides a general framework for simulating in vitro metal-binding and transcription experiments and interpreting the relevant experimental data.
2020-10-09 | BIOMD0000000966 | BioModels
Project description:Zinc is an essential divalent trace metal for living cells. Intracellular zinc homeostasis is critical to the pathogenicity and virulence of bacteria, however the strategies of zinc homeostasis maintain in Streptococcus mutans, an important causative pathogen of dental caries, is unknown. In this study, we examined the function of an ABC transporter AdcCBA and its transcription factor AdcR in S. mutans. Using RNA-Seq analysis, LacZ-reporter studies and gel mobility shift assay, we showed that a MarR family transcription factor AdcR directly regulates the activity of promoters of adcRCB and adcA in response to the concentration of zinc in their environmental niches. Deletion of adcR increases the sensitivity of S. mutans to excessive zinc supply. Taken together, our finding suggests that Adc regulon, consists of a zinc uptake transporter AdcCBA and a zinc-responsive repressor AdcR, plays a prominent role in the maintenance of intracellular zinc homeostasis of S. mutans.
2021-07-01 | GSE165796 | GEO
Project description:Thioneins are cysteine-rich, evolutionary conserved apoproteins that regulate divalent metal homeostasis by virtue of their metal-chelation properties resulting in the ligand-bound metallothionein state. Previous studies have demonstrated a transient upregulation (102- 103-fold) of a cluster of metallothionein genes as part of a transcriptional response to a class of histone demethylase tool compounds targeting human Fe2+ dependent ketoglutarate oxygenases KDM6A (UTX) and KDM6B (JmjD3). Exposure of multiple myeloma cells to the prototypic bioactive KDM6 inhibitor GSK-J4 induces apoptotic cell death and transcriptomic profiles that are dominated by metal and metabolic stress response signatures. We here investigate the hypothesis that the metal-chelating property of GSK-J4 provides the means for transport and intracellular release of Zn2+ leading to a metallothionein transcriptomic response signature. Live cell imaging upon myeloma cell exposure to GSK-J4 shows a transient increase of intracellular free Zn2+ concentrations upon KDM6 inhibitor treatment consistent with a model of inhibitor mediated metal transport. Comparison of KDM6 inhibitor and ZnSO4 treatments in the presence or absence of metal chelators show that both treatment conditions induce different transcription factor repertoires with an overlapping MTF1 transcriptional regulation responsible for metallothionein and metal ion transport regulation.
2022-09-16 | GSE213292 | GEO
Project description:Thioneins are cysteine-rich, evolutionary conserved apoproteins that regulate divalent metal homeostasis by virtue of their metal-chelation properties resulting in the ligand-bound metallothionein state. Previous studies have demonstrated a transient upregulation (102- 103-fold) of a cluster of metallothionein genes as part of a transcriptional response to a class of histone demethylase tool compounds targeting human Fe2+ dependent ketoglutarate oxygenases KDM6A (UTX) and KDM6B (JmjD3). Exposure of multiple myeloma cells to the prototypic bioactive KDM6 inhibitor GSK-J4 induces apoptotic cell death and transcriptomic profiles that are dominated by metal and metabolic stress response signatures. We here investigate the hypothesis that the metal-chelating property of GSK-J4 provides the means for transport and intracellular release of Zn2+ leading to a metallothionein transcriptomic response signature. Live cell imaging upon myeloma cell exposure to GSK-J4 shows a transient increase of intracellular free Zn2+ concentrations upon KDM6 inhibitor treatment consistent with a model of inhibitor mediated metal transport. Comparison of KDM6 inhibitor and ZnSO4 treatments in the presence or absence of metal chelators show that both treatment conditions induce different transcription factor repertoires with an overlapping MTF1 transcriptional regulation responsible for metallothionein and metal ion transport regulation.
2022-09-16 | GSE213291 | GEO
Project description:Identification of toxicants that underlie neurological diseases is a neglected area awaiting a valid strategy to identify such toxicants. We sought biomarkers that respond to known neurotoxicants in LUHMES immortalized neurons and evaluated these biomarkers for use in screening libraries of environmental toxicants. LUHMES immortalized human dopaminergic neurons were surveyed by RNA sequencing following challenge with Parkinsonian toxicants rotenone, 6-hydroxydopamine, MPP+, and ziram (zinc dimethyldithiocarbamate; Zn2+DDC2), as well as additional toxicants paraquat, MS275, and methylmercury. The metallothionein gene MT1G was the most dynamic gene expression response to all seven toxicants. Multiple toxicants also increased transcripts for SLC30A1 and SLC30A2 zinc secretion transporters, the SLC7A11 xCT cystine/glutamate antiporter important for glutathione synthesis, DNA damage Inducible Transcript 3 (DDIT3), and secreted growth factors FIBIN and CXCL12, whereas several toxicants decreased expression of the Apelin growth factor (APLN). These biomarker genes showed advantages in sensitivity by responding to many toxicants at sub-cytotoxic concentrations. Since several of these biomarker genes and prior neurological disease studies implicated disruption of metal distribution, we tested metal chelator thiram (dimethyldithiocarbamate, DDC), Zn2+DDC2, and several other metals and metal chelates for cytoxicity and induction of MT1G expression. Metals and chelators that caused dynamic increases in MT1G expression caused cytotoxicity, whereas Ni2+DDC2 caused MT1G increase, but no cytotoxicity. These results bolster prior work suggesting that neurons are characteristically sensitive to depletion of glutathione or to disruption of cellular metal distribution and provide biomarkers to search for such neurotoxicants in chemical libraries.
2020-08-11 | GSE150005 | GEO
Project description:Cells respond to changes in environment by shifting their gene expression profile to deal with the new conditions. The cellular response to changes in metal homeostasis is an important example of this. Transition metals such as iron, zinc, and copper are essential micronutrients but other metals such as cadmium are simply toxic. The cell must maintain metal concentrations in a window that supports efficient metabolic function but must also protect against the damaging effects of high concentrations of these metals. One way a cell regulates metal homeostasis is to control genes involved in metal mobilization and storage. Much of this regulation occurs at the level of transcription and the protein most responsible for this is the conserved metal responsive transcription factor, MTF-1. Interestingly, the nature of the changes in the gene expression profile depends on the type of exposure. The cell somehow senses the kind of metal challenge and responds appropriately. We have been using the Drosophila system to try to understand the mechanism of this metal discrimination. Using genome-wide mapping of MTF-1 binding under different metal stresses, we find that, surprisingly, MTF-1 chooses different DNA binding sites depending on the specific nature of the metal insult. We also find that the type of binding site chosen is an important component of the capability to induce the metal-specific transcription activation. Chromatin immunoprecipitation coupled with Drosophila genomic tiling arrays (ChIP-chip) was used to identify genomic regions directly bound by dMTF-1 in untreated and metal (Cu and Cd) challenged S2 cells. The dMTF-1 antibody was raised against amino acids 1-113 and 406-540 of MTF-1.
2012-09-01 | E-GEOD-40535 | biostudies-arrayexpress
Project description:Cells respond to changes in environment by shifting their gene expression profile to deal with the new conditions. The cellular response to changes in metal homeostasis is an important example of this. Transition metals such as iron, zinc, and copper are essential micronutrients but other metals such as cadmium are simply toxic. The cell must maintain metal concentrations in a window that supports efficient metabolic function but must also protect against the damaging effects of high concentrations of these metals. One way a cell regulates metal homeostasis is to control genes involved in metal mobilization and storage. Much of this regulation occurs at the level of transcription and the protein most responsible for this is the conserved metal responsive transcription factor, MTF-1. Interestingly, the nature of the changes in the gene expression profile depends on the type of exposure. The cell somehow senses the kind of metal challenge and responds appropriately. We have been using the Drosophila system to try to understand the mechanism of this metal discrimination. Using genome-wide mapping of MTF-1 binding under different metal stresses, we find that, surprisingly, MTF-1 chooses different DNA binding sites depending on the specific nature of the metal insult. We also find that the type of binding site chosen is an important component of the capability to induce the metal-specific transcription activation.
2012-09-01 | GSE40535 | GEO
Project description:Copper and MTF1: New roles for a classic metal sensing transcription factor in myogenesis
| PRJNA478204 | ENA