scholarly journals A Transcription Factor Cascade Involving Fep1 and the CCAAT-Binding Factor Php4 Regulates Gene Expression in Response to Iron Deficiency in the Fission Yeast Schizosaccharomyces pombe

2006 ◽  
Vol 5 (11) ◽  
pp. 1866-1881 ◽  
Author(s):  
Alexandre Mercier ◽  
Benoit Pelletier ◽  
Simon Labbé
Keyword(s):  
Schizosaccharomyces Pombe ◽  
Transcriptional Activation ◽  
Tricarboxylic Acid Cycle ◽  
Site Directed Mutagenesis ◽  
Regulatory Subunit ◽  
Regulatory Sequence ◽  
Mrna Levels ◽  
Rnase Protection ◽  
Iron Storage ◽  
Binding Factor

ABSTRACT We have identified genes encoding candidate proteins involved in iron storage (pcl1 + ), the tricarboxylic acid cycle (sdh4 + ), and iron-sulfur cluster assembly (isa1 + ) that are negatively regulated in response to iron deprivation. Promoter deletion and site-directed mutagenesis permitted identification of a new cis-regulatory element in the promoter region of the pcl1 + gene. This cis-acting regulatory sequence containing the pentanucleotide sequence CCAAT is responsible for transcriptional repression of pcl1 + under low iron supply conditions. In Schizosaccharomyces pombe, the CCAAT-binding factor is a heteromeric DNA-binding complex that contains three subunits, designated Php2, Php3, and Php5. Inactivation of the php2 + locus negatively affects the transcriptional competency of pcl1 + . A fourth subunit, designated Php4, is not essential for the transcriptional activation of target genes under basal and iron-replete conditions. We demonstrate that, in response to iron-limiting conditions, Php4 is required for down-regulation of pcl1 + , sdh4 + , and isa1 + mRNA levels. In vivo RNase protection studies reveal that the expression of php4 + is negatively regulated by iron and that this regulated expression requires a functional fep1 + gene. The results of these studies reveal that Fep1 represses php4 + expression in response to iron. In contrast, when iron is scarce, Fep1 becomes inactive and php4 + is expressed to act as a regulatory subunit of the CCAAT-binding factor that is required to block pcl1 + , sdh4 + , and isa1 + gene transcription.

scholarly journals Transcriptional Regulation of the Copper Transporter Mfc1 in Meiotic Cells

2013 ◽  
Vol 12 (4) ◽  
pp. 575-590 ◽  
Author(s):  
Jude Beaudoin ◽  
Raphaël Ioannoni ◽  
Stéphane Mailloux ◽  
Samuel Plante ◽  
Simon Labbé
Keyword(s):  
Transcriptional Activation ◽  
Regulatory Element ◽  
Specific Protein ◽  
Copper Transport ◽  
Site Directed Mutagenesis ◽  
Regulatory Sequence ◽  
Transcriptional Level ◽  
Binding Studies ◽  
Copper Transporter ◽  
Content Type

ABSTRACT Mfc1 is a meiosis-specific protein that mediates copper transport during the meiotic program in Schizosaccharomyces pombe . Although the mfc1 + gene is induced at the transcriptional level in response to copper deprivation, the molecular determinants that are required for its copper starvation-dependent induction are unknown. Promoter deletion and site-directed mutagenesis have allowed identification of a new cis -regulatory element in the promoter region of the mfc1 + gene. This cis -acting regulatory sequence containing the sequence TCGGCG is responsible for transcriptional activation of mfc1 + under low-copper conditions. The TCGGCG sequence contains a CGG triplet known to serve as a binding site for members of the Zn (2) Cys (6) binuclear cluster transcriptional regulator family. In agreement with this fact, one member of this group of regulators, denoted Mca1, was found to be required for maximum induction of mfc1 + gene expression. Analysis of Mca1 cellular distribution during meiosis revealed that it colocalizes with both chromosomes and sister chromatids during early, middle, and late phases of the meiotic program. Cells lacking Mca1 exhibited a meiotic arrest at metaphase I under low-copper conditions. Binding studies revealed that the N-terminal 150-residue segment of Mca1 expressed as a fusion protein in Escherichia coli specifically interacts with the TCGGCG sequence of the mfc1 + promoter. Taken together, these results identify the cis -regulatory TCGGCG sequence and the transcription factor Mca1 as critical components for activation of the meiotic copper transport mfc1 + gene in response to copper starvation.

scholarly journals Key Function for the CCAAT-Binding Factor Php4 To Regulate Gene Expression in Response to Iron Deficiency in Fission Yeast

2008 ◽  
Vol 7 (3) ◽  
pp. 493-508 ◽  
Author(s):  
Alexandre Mercier ◽  
Stephen Watt ◽  
Jürg Bähler ◽  
Simon Labbé
Keyword(s):  
Iron Deficiency ◽  
Fission Yeast ◽  
Tricarboxylic Acid Cycle ◽  
Transcriptional Level ◽  
Mrna Levels ◽  
Gata Factor ◽  
Iron Starvation ◽  
A Genome ◽  
Binding Factor ◽  
Genes Encoding

ABSTRACT The fission yeast Schizosaccharomyces pombe responds to the deprivation of iron by inducing the expression of the php4 + gene, which encodes a negative regulatory subunit of the heteromeric CCAAT-binding factor. Once formed, the Php2/3/4/5 transcription complex is required to inactivate a subset of genes encoding iron-using proteins. Here, we used a pan-S. pombe microarray to study the transcriptional response to iron starvation and identified 86 genes that exhibit php4 + -dependent changes on a genome-wide scale. One of these genes encodes the iron-responsive transcriptional repressor Fep1, whose mRNA levels were decreased after treatment with the permeant iron chelator 2,2′-dipyridyl. In addition, several genes encoding the components of iron-dependent biochemical pathways, including the tricarboxylic acid cycle, mitochondrial respiration, amino acid biosynthesis, and oxidative stress defense, were downregulated in response to iron deficiency. Furthermore, Php4 repressed transcription when brought to a promoter using a yeast DNA-binding domain, and iron deprivation was required for this repression. On the other hand, Php4 was constitutively active when glutathione levels were depleted within the cell. Based on these and previous results, we propose that iron-dependent inactivation of Php4 is regulated at two distinct levels: first, at the transcriptional level by the iron-responsive GATA factor Fep1 and second, at the posttranscriptional level by a mechanism yet to be identified, which inhibits Php4-mediated repressive function when iron is abundant.

Unloading induces transcriptional activation of the sarco(endo)plasmic reticulum Ca2+-ATPase 1 gene in muscle

1999 ◽  
Vol 276 (5) ◽  
pp. C1218-C1225 ◽  
Author(s):  
David G. Peters ◽  
Heather Mitchell-Felton ◽  
Susan C. Kandarian
Keyword(s):  
Transcriptional Activation ◽  
Mrna Levels ◽  
Rt Pcr ◽  
Rnase Protection ◽  
Control Of Gene Expression ◽  
Cis Acting ◽  
Plasmic Reticulum ◽  
Slow Twitch ◽  
Muscle Gene

Previous work showed that protein and mRNA levels of the “fast” isoform of the sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA1) are markedly increased in unloaded slow-twitch soleus muscles, suggesting pretranslational control of gene expression [L. M. Schulte, J. Navarro, and S. C. Kandarian. Am. J. Physiol. 264 ( Cell Physiol. 33): C1308–C1315, 1993]. However, because of the difficulty of measuring transcription rates from whole muscle, transcriptional activation of the SERCA1 gene with unloading has not been confirmed. Because SERCA1 pre-mRNA levels can reflect transcriptional activity, in the present study SERCA1 introns were sequenced to allow intron-directed RT-PCR measurement of SERCA1 pre-mRNA. These data were then compared with changes in SERCA1 mRNA expression in control and unloaded soleus muscles. After 2, 4, and 10 days of unloading, SERCA1 pre-mRNA and mRNA transcript levels increased significantly by two-, three-, and sevenfold, respectively ( P < 0.01). Parallel increases in SERCA1 pre-mRNA and mRNA suggest transcriptional activation of the endogenous SERCA1 gene by muscle unloading. SERCA2, the cardiac/slow-twitch skeletal muscle isoform, was not markedly increased by unloading, and RNase protection assays showed no change in alternative splicing of SERCA1 or SERCA2 primary transcripts. With use of in vivo plasmid injection, the activity of a reporter gene driven by 3.6 kb of the SERCA1 5′-flanking region increased fivefold in 7-day-unloaded soleus muscles. Comparison of the magnitude of transcriptional activation of endogenous and constructed SERCA1 genes by unloading confirms the fidelity of using intronic RT-PCR to examine muscle gene transcription rates and suggests that cis-acting elements sufficient for regulating unloading-induced transcriptional activation are contained in this promoter construct.

scholarly journals REDD1 Is a Major Target of Testosterone Action in Preventing Dexamethasone-Induced Muscle Loss

Endocrinology ◽  
2009 ◽  
Vol 151 (3) ◽  
pp. 1050-1059 ◽  
Author(s):  
Yong Wu ◽  
Weidong Zhao ◽  
Jingbo Zhao ◽  
Yuanfei Zhang ◽  
Weiping Qin ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcriptional Activation ◽  
Cell Cycle Progression ◽  
Molecular Mechanisms ◽  
Muscle Development ◽  
Fold Increase ◽  
Regulatory Subunit ◽  
Mrna Levels ◽  
Igf I ◽  
Induced Changes

Glucocorticoids are a well-recognized and common cause of muscle atrophy that can be prevented by testosterone. However, the molecular mechanisms underlying such protection have not been described. Thus, the global effects of testosterone on dexamethasone-induced changes in gene expression were evaluated in rat gastrocnemius muscle using DNA microarrays. Gene expression was analyzed after 7-d administration of dexamethasone, dexamethasone plus testosterone, or vehicle. Dexamethasone changed expression of 876 probe sets by at least 2-fold. Among these, 474 probe sets were changed by at least 2-fold in the opposite direction in the dexamethasone plus testosterone group (genes in opposition). Major biological themes represented by genes in opposition included IGF-I signaling, myogenesis and muscle development, and cell cycle progression. Testosterone completely prevented the 22-fold increase in expression of the mammalian target of rapamycin (mTOR) inhibitor regulated in development and DNA damage responses 1 (REDD1), and attenuated dexamethasone induced increased expression of eIF4E binding protein 1, Forkhead box O1, and the p85 regulatory subunit of the IGF-I receptor but prevented decreased expression of IRS-1. Testosterone attenuated increases in REDD1 protein in skeletal muscle and L6 myoblasts and prevented dephosphorylation of p70S6 kinase at the mTOR-dependent site Thr389 in L6 myoblast cells. Effects of testosterone on REDD1 mRNA levels occurred within 1 h, required the androgen receptor, were blocked by bicalutamide, and were due to inhibition of transcriptional activation of REDD1 by dexamethasone. These data suggest that testosterone blocks dexamethasone-induced changes in expression of REDD1 and other genes that collectively would otherwise down-regulate mTOR activity and hence also down-regulate protein synthesis.

Copper-dependent ATP7B up-regulation drives the resistance of TMEM16A-overexpressing head-and-neck cancer models to platinum toxicity

2019 ◽  
Vol 476 (24) ◽  
pp. 3705-3719 ◽  
Author(s):  
Avani Vyas ◽  
Umamaheswar Duvvuri ◽  
Kirill Kiselyov
Keyword(s):  
Oxidative Stress ◽  
Head And Neck ◽  
Transcriptional Activation ◽  
Platinum Resistance ◽  
Mrna Levels ◽  
Strong Positive Correlation ◽  
Platinum Compounds ◽  
Copper Chelation ◽  
Novel Approach ◽  
Cancer Models

Platinum-containing drugs such as cisplatin and carboplatin are routinely used for the treatment of many solid tumors including squamous cell carcinoma of the head and neck (SCCHN). However, SCCHN resistance to platinum compounds is well documented. The resistance to platinum has been linked to the activity of divalent transporter ATP7B, which pumps platinum from the cytoplasm into lysosomes, decreasing its concentration in the cytoplasm. Several cancer models show increased expression of ATP7B; however, the reason for such an increase is not known. Here we show a strong positive correlation between mRNA levels of TMEM16A and ATP7B in human SCCHN tumors. TMEM16A overexpression and depletion in SCCHN cell lines caused parallel changes in the ATP7B mRNA levels. The ATP7B increase in TMEM16A-overexpressing cells was reversed by suppression of NADPH oxidase 2 (NOX2), by the antioxidant N-Acetyl-Cysteine (NAC) and by copper chelation using cuprizone and bathocuproine sulphonate (BCS). Pretreatment with either chelator significantly increased cisplatin's sensitivity, particularly in the context of TMEM16A overexpression. We propose that increased oxidative stress in TMEM16A-overexpressing cells liberates the chelated copper in the cytoplasm, leading to the transcriptional activation of ATP7B expression. This, in turn, decreases the efficacy of platinum compounds by promoting their vesicular sequestration. We think that such a new explanation of the mechanism of SCCHN tumors’ platinum resistance identifies novel approach to treating these tumors.

scholarly journals Adipokines and Metabolic Regulators in Human and Experimental Pulmonary Arterial Hypertension

2021 ◽  
Vol 22 (3) ◽  
pp. 1435
Author(s):  
Aimilia Papathanasiou ◽  
Fotios Spyropoulos ◽  
Zoe Michael ◽  
Kyoung Joung ◽  
Despina Briana ◽  
...  
Keyword(s):  
Pulmonary Hypertension ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Tricarboxylic Acid Cycle ◽  
Fibroblast Growth Factor 21 ◽  
Mrna Levels ◽  
Rodent Models ◽  
Fatty Acid Binding ◽  
Metabolic Regulators ◽  
Circulating Levels

Pulmonary hypertension (PH) is associated with meta-inflammation related to obesity but the role of adipose tissue in PH pathogenesis is unknown. We hypothesized that adipose tissue-derived metabolic regulators are altered in human and experimental PH. We measured circulating levels of fatty acid binding protein 4 (FABP-4), fibroblast growth factor -21 (FGF-21), adiponectin, and the mRNA levels of FABP-4, FGF-21, and peroxisome proliferator-activated receptor γ (PPARγ) in lung tissue of patients with idiopathic PH and healthy controls. We also evaluated lung and adipose tissue expression of these mediators in the three most commonly used experimental rodent models of pulmonary hypertension. Circulating levels of FABP-4, FGF-21, and adiponectin were significantly elevated in PH patients compared to controls and the mRNA levels of these regulators and PPARγ were also significantly increased in human PH lungs and in the lungs of rats with experimental PH compared to controls. These findings were coupled with increased levels of adipose tissue mRNA of genes related to glucose uptake, glycolysis, tricarboxylic acid cycle, and fatty acid oxidation in experimental PH. Our results support that metabolic alterations in human PH are recapitulated in rodent models of the disease and suggest that adipose tissue may contribute to PH pathogenesis.

scholarly journals Cyclin-Dependent Kinase Regulatory Subunit 2 Indicated Poor Prognosis and Facilitated Aggressive Phenotype of Hepatocellular Carcinoma

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Jie Zhang ◽  
Qianqian Song ◽  
Jinxia Liu ◽  
Lina Lu ◽  
Yuqing Xu ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Poor Prognosis ◽  
Disease Free Survival ◽  
Normal Liver ◽  
Regulatory Subunit ◽  
Mrna Levels ◽  
Cyclin Dependent Kinase ◽  
Normal Tissues ◽  
Hcc Cells

Cyclin-dependent kinase regulatory subunit 2 (CKS2) is a member of the cell cycle-dependent protein kinase subunit family, which is implicated as an oncogene in various malignancies. However, the clinical significance, oncogenic functions, and related mechanisms of CKS2 in hepatocellular carcinoma (HCC) remain largely unclear. In the present study, expression features and prognostic value of CKS2 were evaluated in the bioinformatic databases and HCC tissues. The effects of CKS2 on the malignant phenotypes of HCC cells were explored in vitro. According to the analyses of three bioinformatic databases, mRNA levels of CKS2 were elevated in HCC tissues compared with the normal tissues. Immunohistochemical assays found that high CKS2 expression was closely associated with liver cirrhosis (P=0.019), poor differentiation (P=0.02), portal vein invasion (P<0.001), TNM stage (P=0.019), tumor metastasis (P=0.008), and recurrence (P=0.003). The multivariate regression analyses suggested that CKS2 was an independent prognostic factor for overall survival (HR=2.088, P=0.014) and disease-free survival (HR=2.511, P=0.002) of HCC patients. Moreover, the bioinformatic analyses indicated that CKS2 might be associated with the malignant phenotypes in HCC progression. In addition, in vitro assays showed that CKS2 expression was higher in HCC cell lines than in normal liver cells. Knockdown of CKS2 remarkably repressed the proliferation, colony formation (P=0.0003), chemoresistance, migration (P=0.0047), and invasion (P=0.0012) of HCC cells. Taken together, overexpression of CKS2 was significantly correlated with poor prognosis of HCC patients and the malignant phenotypes of HCC cells, suggesting that it was a novel prognostic biomarker and potential target of HCC.

scholarly journals Functional homology between the yeast regulatory proteins GAL4 and LAC9: LAC9-mediated transcriptional activation in Kluyveromyces lactis involves protein binding to a regulatory sequence homologous to the GAL4 protein-binding site.

1987 ◽  
Vol 7 (12) ◽  
pp. 4400-4406 ◽  
Author(s):  
K D Breunig ◽  
P Kuger
Keyword(s):  
Protein Binding ◽  
Binding Site ◽  
Transcriptional Activation ◽  
Kluyveromyces Lactis ◽  
Regulatory Protein ◽  
Binding Activity ◽  
Protein Binding Site ◽  
Regulatory Sequence ◽  
Functional Homology ◽  
Beta Galactosidase

As shown previously, the beta-galactosidase gene of Kluyveromyces lactis is transcriptionally regulated via an upstream activation site (UASL) which contains a sequence homologous to the GAL4 protein-binding site in Saccharomyces cerevisiae (M. Ruzzi, K.D. Breunig, A.G. Ficca, and C.P. Hollenberg, Mol. Cell. Biol. 7:991-997, 1987). Here we demonstrate that the region of homology specifically binds a K. lactis regulatory protein. The binding activity was detectable in protein extracts from wild-type cells enriched for DNA-binding proteins by heparin affinity chromatography. These extracts could be used directly for DNase I and exonuclease III protection experiments. A lac9 deletion strain, which fails to induce the beta-galactosidase gene, did not contain the binding factor. The homology of LAC9 protein with GAL4 (J.M. Salmeron and S. A. Johnston, Nucleic Acids Res. 14:7767-7781, 1986) strongly suggests that LAC9 protein binds directly to UASL and plays a role similar to that of GAL4 in regulating transcription.

Transcriptional Activation Domain of Human BTEB2, A GC Box-Binding Factor

1997 ◽  
Vol 121 (2) ◽  
pp. 389-396 ◽  
Author(s):  
S. Kojima ◽  
A. Kobayashi ◽  
O. Gotoh ◽  
Y. Ohkuma ◽  
Y. Fujii-Kuriyama ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Activation Domain ◽  
Transcriptional Activation Domain ◽  
Binding Factor ◽  
Gc Box

scholarly journals A nucleosome-positioning sequence is required for GCN4 to activate transcription in the absence of a TATA element.

1990 ◽  
Vol 10 (8) ◽  
pp. 4256-4265 ◽  
Author(s):  
C J Brandl ◽  
K Struhl
Keyword(s):  
Binding Site ◽  
Transcriptional Activation ◽  
Nucleosome Positioning ◽  
Alternative Mechanism ◽  
Tata Element ◽  
Binding Factor ◽  
Positioning Analysis ◽  
Binding Sequence

In the gal-his3 hybrid promoter his3-GG1, the yeast upstream activator protein GCN4 stimulates transcription when bound at the position normally occupied by the TATA element. This TATA-independent activation by GCN4 requires two additional elements in the gal enhancer region that are distinct from those involved in normal galactose induction. Both additional elements appear to be functionally distinct from a classical TATA element because they cannot be replaced by the TFIID-binding sequence TATAAA. One of these elements, termed Q, is essential for GCN4-activated transcription and contains the sequence GTCAC CCG, which overlaps (but is distinct from) a GAL4 binding site. Surprisingly, relatively small increases in the distance between Q and the GCN4 binding site significantly reduce the level of transcription. The Q element specifically interacts with a yeast protein (Q-binding protein [QBP]) that may be equivalent to Y, a protein that binds at a sequence that forms a constraint to nucleosome positioning. Analysis of various deletion mutants indicates that the sequence requirements for binding by QBP in vitro are indistinguishable from those necessary for Q activity in vivo, strongly suggesting that QBP is required for the function of this TATA-independent promoter. These results support the view that transcriptional activation can occur by an alternative mechanism in which the TATA-binding factor TFIID either is not required or is not directly bound to DNA. In addition, they suggest a potential role of nucleosome positioning for the activity of a promoter.

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