Mechanisms of mammalian zinc-regulated gene expression

2008 ◽  
Vol 36 (6) ◽  
pp. 1262-1266 ◽  
Author(s):  
Kelly A. Jackson ◽  
Ruth A. Valentine ◽  
Lisa J. Coneyworth ◽  
John C. Mathers ◽  
Dianne Ford
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Transcriptional Repression ◽  
Mammalian Cells ◽  
Gene Promoter ◽  
Mrna Levels ◽  
Promoter Regions ◽  
Mrna Stabilization ◽  
Transcriptional Regulatory ◽  
Regulated Gene Expression

Mechanisms through which gene expression is regulated by zinc are central to cellular zinc homoeostasis. In this context, evidence for the involvement of zinc dyshomoeostasis in the aetiology of diseases, including Type 2 diabetes, Alzheimer's disease and cancer, highlights the importance of zinc-regulated gene expression. Mechanisms elucidated in bacteria and yeast provide examples of different possible modes of zinc-sensitive gene regulation, involving the zinc-regulated binding of transcriptional activators and repressors to gene promoter regions. A mammalian transcriptional regulatory mechanism that mediates zinc-induced transcriptional up-regulation, involving the transcription factor MTF1 (metal-response element-binding transcription factor 1), has been studied extensively. Gene responses in the opposite direction (reduced mRNA levels in response to increased zinc availability) have been observed in mammalian cells, but a specific transcriptional regulatory process responsible for such a response has yet to be identified. Examples of single zinc-sensitive transcription factors regulating gene expression in opposite directions are emerging. Although zinc-induced transcriptional repression by MTF1 is a possible explanation in some specific instances, such a mechanism cannot account for repression by zinc of all mammalian genes that show this mode of regulation, indicating the existence of as yet uncharacterized mechanisms of zinc-regulated transcription in mammalian cells. In addition, recent findings reveal a role for effects of zinc on mRNA stability in the regulation of specific zinc transporters. Our studies on the regulation of the human gene SLC30A5 (solute carrier 30A5), which codes for the zinc transporter ZnT5, have revealed that this gene provides a model system by which to study both zinc-induced transcriptional down-regulation and zinc-regulated mRNA stabilization.

scholarly journals MON-711 Induction of Apolipoprotein A1 Gene Expression by the Rare Sugar Allulose

2020 ◽  
Vol 4 (Supplement_1) ◽  
Author(s):  
Shrina Parekh
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Promoter Activity ◽  
Gene Promoter ◽  
Apolipoprotein A1 ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Rare Sugar ◽  
Transcription Factor Sp1 ◽  
I Gene

Abstract Apolipoprotein A-I (apo A-I) is the primary protein component of high-density lipoprotein (HDL) and has many well documented properties which promote cardiovascular health. However, clinical trials designed to increase HDL levels by preventing its catabolism have failed in their primary endpoints in decreasing the risk of cardiovascular disease. Alternative strategies to increase de-novo apo A-I production may be more attractive. We recently demonstrated that the rare sugar allulose decreases oxidative stress and endoplasmic reticulum stress in both endothelial cells and hepatocytes. During these studies we demonstrated that allulose also induces apo A-I secretion by HepG2 cells. Apo A-I, albumin, and SP1 levels were measured by Western blot. Apo A-I and glyceraldehyde-3-phosphate (GAPDH) mRNA levels were measured by quantitative real-time polymerase chain reaction. The effect of allulose on apo A-I promoter activity was measured using transient transfection assays with several plasmids containing various segments and mutations in the apo A-I gene promoter. Apo A-I protein and mRNA levels in cells treated with allulose increased more than two-fold in a dose-dependent manner. These changes were due to the ability of allulose to induce apo A-I gene promoter activity. Using a series of deletion constructs, an allulose-response element was identified in the apo A-I gene promoter which was previously shown to confer induction of apo A-I gene expression by insulin and epidermal growth factor (EGF), the insulin response core element (IRCE). Mutation of the IRCE decreased the ability of allulose and insulin to induce apo A-I promoter activity. Allulose treatment also increased expression of the transcription factor SP1, which had been shown previously be essential for the effects of insulin and EGF on apo A-I promoter activity. In conclusion, allulose increased apo A-I gene expression in HepG2 hepatocytes. This effect was mediated by the IRCE in the apo A-I gene promoter and the transcription factor SP1. The rare sugar allulose may have novel anti-atherogenic properties, in part, by increasing HDL levels.

scholarly journals Challenges with Methods for Detecting and Studying the Transcription Factor Nuclear Factor Kappa B (NF-κB) in the Central Nervous System

Cells ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1335
Author(s):  
Marina Mostafizar ◽  
Claudia Cortes-Pérez ◽  
Wanda Snow ◽  
Jelena Djordjevic ◽  
Aida Adlimoghaddam ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Signaling Pathways ◽  
Quantitative Methods ◽  
Nuclear Factor Kappa B ◽  
Inflammatory Responses ◽  
Nuclear Factor ◽  
Nuclear Factor Kappa ◽  
Regulated Gene Expression ◽  
Transcription Factor Nuclear Factor

The transcription factor nuclear factor kappa B (NF-κB) is highly expressed in almost all types of cells. NF-κB is involved in many complex biological processes, in particular in immunity. The activation of the NF-κB signaling pathways is also associated with cancer, diabetes, neurological disorders and even memory. Hence, NF-κB is a central factor for understanding not only fundamental biological presence but also pathogenesis, and has been the subject of intense study in these contexts. Under healthy physiological conditions, the NF-κB pathway promotes synapse growth and synaptic plasticity in neurons, while in glia, NF-κB signaling can promote pro-inflammatory responses to injury. In addition, NF-κB promotes the maintenance and maturation of B cells regulating gene expression in a majority of diverse signaling pathways. Given this, the protein plays a predominant role in activating the mammalian immune system, where NF-κB-regulated gene expression targets processes of inflammation and host defense. Thus, an understanding of the methodological issues around its detection for localization, quantification, and mechanistic insights should have a broad interest across the molecular neuroscience community. In this review, we summarize the available methods for the proper detection and analysis of NF-κB among various brain tissues, cell types, and subcellular compartments, using both qualitative and quantitative methods. We also summarize the flexibility and performance of these experimental methods for the detection of the protein, accurate quantification in different samples, and the experimental challenges in this regard, as well as suggestions to overcome common challenges.

scholarly journals Repression of ESR1 through Actions of Estrogen Receptor Alpha and Sin3A at the Proximal Promoter

2009 ◽  
Vol 29 (18) ◽  
pp. 4949-4958 ◽  
Author(s):  
Stephanie J. Ellison-Zelski ◽  
Natalia M. Solodin ◽  
Elaine T. Alarid
Keyword(s):  
Gene Expression ◽  
Estrogen Receptor ◽  
Transcription Factor ◽  
Rna Polymerase Ii ◽  
Transcriptional Repression ◽  
Estrogen Receptor Alpha ◽  
Proximal Promoter ◽  
Receptor Alpha ◽  
Expression Of Genes ◽  
Activation Of Transcription

ABSTRACT Gene expression results from the coordinated actions of transcription factor proteins and coregulators. Estrogen receptor alpha (ERα) is a ligand-activated transcription factor that can both activate and repress the expression of genes. Activation of transcription by estrogen-bound ERα has been studied in detail, as has antagonist-induced repression, such as that which occurs by tamoxifen. How estrogen-bound ERα represses gene transcription remains unclear. In this report, we identify a new mechanism of estrogen-induced transcriptional repression by using the ERα gene, ESR1. Upon estrogen treatment, ERα is recruited to two sites on ESR1, one distal (ENH1) and the other at the proximal (A) promoter. Coactivator proteins, namely, p300 and AIB1, are found at both ERα-binding sites. However, recruitment of the Sin3A repressor, loss of RNA polymerase II, and changes in histone modifications occur only at the A promoter. Reduction of Sin3A expression by RNA interference specifically inhibits estrogen-induced repression of ESR1. Furthermore, an estrogen-responsive interaction between Sin3A and ERα is identified. These data support a model of repression wherein actions of ERα and Sin3A at the proximal promoter can overcome activating signals at distal or proximal sites and ultimately decrease gene expression.

Human glucagon gene promoter sequences regulating tissue-specific versus nutrient-regulated gene expression

2002 ◽  
Vol 282 (1) ◽  
pp. R173-R183 ◽  
Author(s):  
Min Nian ◽  
Jun Gu ◽  
David M. Irwin ◽  
Daniel J. Drucker
Keyword(s):  
Gene Expression ◽  
Gene Promoter ◽  
Regulatory Sequences ◽  
Dependent Manner ◽  
Specific Expression ◽  
Tissue Specific ◽  
High Fiber ◽  
Fiber Diet ◽  
Regulated Gene Expression

The glucagon-like peptides (GLPs) are synthesized and secreted in a nutrient-dependent manner in rodents; however, the factors regulating human GLP-1 and GLP-2 biosynthesis remain unclear. To understand how nutrients regulate human proglucagon gene expression, we studied the expression of a human proglucagon promoter-growth hormone (GH) transgene in 1.6 human glucagon-GH transgenic mice. Fasting-refeeding significantly decreased and increased the levels of circulating mouse insulin and transgene-derived hGH ( P < 0.05 fasting vs. refeeding) and decreased and upregulated, respectively, the levels of endogenous mouse proglucagon RNA in the ileum but not in the jejunum or colon. High-fiber feeding significantly increased the levels of glucose-stimulated circulating hGH and upregulated levels of mouse intestinal proglucagon gene expression in the jejunum, ileum, and colon ( P < 0.05, 0 vs. 30% fiber diet). In contrast, neither fasting-refeeding nor a high-fiber diet upregulated the expression of the human proglucagon promoter-hGH transgene. These findings demonstrate that human proglucagon gene regulatory sequences specifying tissue-specific expression in gut endocrine cells are not sufficient for recognition of energy-derived signals regulating murine glucagon gene expression in enteroendocrine cells in vivo.

scholarly journals The TEA Transcription Factor Tec1 Confers Promoter-Specific Gene Regulation by Ste12-Dependent and -Independent Mechanisms

2010 ◽  
Vol 9 (4) ◽  
pp. 514-531 ◽  
Author(s):  
Barbara Heise ◽  
Julia van der Felden ◽  
Sandra Kern ◽  
Mario Malcher ◽  
Stefan Brückner ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Transcriptional Activation ◽  
Binding Sites ◽  
Target Genes ◽  
Specific Gene ◽  
Dependent Manner ◽  
A Genome ◽  
Regulated Gene Expression

ABSTRACT In Saccharomyces cerevisiae, the TEA transcription factor Tec1 is known to regulate target genes together with a second transcription factor, Ste12. Tec1-Ste12 complexes can activate transcription through Tec1 binding sites (TCSs), which can be further combined with Ste12 binding sites (PREs) for cooperative DNA binding. However, previous studies have hinted that Tec1 might regulate transcription also without Ste12. Here, we show that in vivo, physiological amounts of Tec1 are sufficient to stimulate TCS-mediated gene expression and transcription of the FLO11 gene in the absence of Ste12. In vitro, Tec1 is able to bind TCS elements with high affinity and specificity without Ste12. Furthermore, Tec1 contains a C-terminal transcriptional activation domain that confers Ste12-independent activation of TCS-regulated gene expression. On a genome-wide scale, we identified 302 Tec1 target genes that constitute two distinct classes. A first class of 254 genes is regulated by Tec1 in a Ste12-dependent manner and is enriched for genes that are bound by Tec1 and Ste12 in vivo. In contrast, a second class of 48 genes can be regulated by Tec1 independently of Ste12 and is enriched for genes that are bound by the stress transcription factors Yap6, Nrg1, Cin5, Skn7, Hsf1, and Msn4. Finally, we find that combinatorial control by Tec1-Ste12 complexes stabilizes Tec1 against degradation. Our study suggests that Tec1 is able to regulate TCS-mediated gene expression by Ste12-dependent and Ste12-independent mechanisms that enable promoter-specific transcriptional control.

scholarly journals Architectural Epigenetics: Mitotic Retention of Mammalian Transcriptional Regulatory Information

2010 ◽  
Vol 30 (20) ◽  
pp. 4758-4766 ◽  
Author(s):  
Sayyed K. Zaidi ◽  
Daniel W. Young ◽  
Martin Montecino ◽  
Jane B. Lian ◽  
Janet L. Stein ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Transcription Factor ◽  
Epigenetic Mechanisms ◽  
Cellular Phenotype ◽  
Transcriptional Regulatory ◽  
Regulatory Information ◽  
Cellular Identity ◽  
Epigenetic Signatures ◽  
Transcription Factor Occupancy

ABSTRACT Epigenetic regulatory information must be retained during mammalian cell division to sustain phenotype-specific and physiologically responsive gene expression in the progeny cells. Histone modifications, DNA methylation, and RNA-mediated silencing are well-defined epigenetic mechanisms that control the cellular phenotype by regulating gene expression. Recent results suggest that the mitotic retention of nuclease hypersensitivity, selective histone marks, as well as the lineage-specific transcription factor occupancy of promoter elements contribute to the epigenetic control of sustained cellular identity in progeny cells. We propose that these mitotic epigenetic signatures collectively constitute architectural epigenetics, a novel and essential mechanism that conveys regulatory information to sustain the control of phenotype and proliferation in progeny cells by bookmarking genes for activation or suppression.

MGMT DNA repair gene promoter/enhancer haplotypes alter transcription factor binding and gene expression

2016 ◽  
Vol 39 (5) ◽  
pp. 435-447 ◽  
Author(s):  
Meixiang Xu ◽  
Courtney E. Cross ◽  
Jordan T. Speidel ◽  
Sherif Z. Abdel-Rahman
Keyword(s):  
Gene Expression ◽  
Dna Repair ◽  
Transcription Factor ◽  
Gene Promoter ◽  
Transcription Factor Binding ◽  
Repair Gene ◽  
Factor Binding ◽  
Dna Repair Gene

scholarly journals Posttranscriptional gene regulation by RNA-binding proteins during oxidative stress: implications for cellular senescence

2008 ◽  
Vol 389 (3) ◽  
pp. 243-255 ◽  
Author(s):  
Kotb Abdelmohsen ◽  
Yuki Kuwano ◽  
Hyeon Ho Kim ◽  
Myriam Gorospe
Keyword(s):  
Oxidative Stress ◽  
Gene Expression ◽  
Cellular Senescence ◽  
Mammalian Cells ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Expression Profiles ◽  
Expression Patterns ◽  
Oxidant Damage ◽  
Regulated Gene Expression

AbstractTo respond adequately to oxidative stress, mammalian cells elicit rapid and tightly controlled changes in gene expression patterns. Besides alterations in the subsets of transcribed genes, two posttranscriptional processes prominently influence the oxidant-triggered gene expression programs: mRNA turnover and translation. Here, we review recent progress in our knowledge of theturnover andtranslationregulatory (TTR) mRNA-bindingproteins (RBPs) that influence gene expression in response to oxidative damage. Specifically, we identify oxidant damage-regulated mRNAs that are targets of TTR-RBPs, we review the oxidant-triggered signaling pathways that govern TTR-RBP function, and we examine emerging evidence that TTR-RBP activity is altered with senescence and aging. Given the potent influence of TTR-RBPs upon oxidant-regulated gene expression profiles, we propose that the senescence-associated changes in TTR-RBPs directly contribute to the impaired responses to oxidant damage that characterize cellular senescence and advancing age.

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