scholarly journals Hypoxia acts through multiple signaling pathways to induce metallothionein transactivation by the metal-responsive transcription factor-1 (MTF-1)

2011 ◽  
Vol 89 (6) ◽  
pp. 562-577 ◽  
Author(s):  
Annie Dubé ◽  
Jean-François Harrisson ◽  
Geneviève Saint-Gelais ◽  
Carl Séguin
Keyword(s):  
Transcription Factor ◽  
Hypoxia Inducible Factor ◽  
Direct Interaction ◽  
Regulatory Elements ◽  
Binding Activity ◽  
Pi3k Inhibitors ◽  
Dna Binding Activity ◽  
Transport Chain ◽  
Genes Encoding ◽  
Transcription Factor 1

Metal-responsive transcription factor-1 (MTF-1) is essential for the induction of genes encoding metallothionein by metals and hypoxia. Here, we studied the mechanism controlling the activation of MTF-1 by hypoxia. Hypoxia activation of Mt gene transcription is dependent on the presence of metal regulatory elements (MREs) in the promoter of Mt genes. We showed that MREa and MREd are the main elements controlling mouse Mt-1 gene induction by hypoxia. Transfection experiments in Mtf-1-null cells showed that MTF-1 is essential for induction by hypoxia. Chromatin immunoprecipitation analysis showed that MTF-1 DNA-binding activity was strongly enhanced in the presence of zinc but not by hypoxia. Notably, hypoxia inducible factor- (HIF) 1α was recruited to the Mt-1 promoter in response to hypoxia but not to zinc. MTF-1 activation was inhibited by PKC, JNK, and PI3K inhibitors and by the electron transport chain inhibitors rotenone and myxothiazol, but not by the antioxidant N-acetylcysteine. We showed that prolyl-hydroxylase inhibitors can activate MTF-1, but this activation requires the presence of HIF-1α. Finally, HIF-dependent transcription is enhanced in the presence of MTF-1 and induction of an MRE promoter is stimulated by HIF-1α, thus indicating cooperation between these 2 factors. However, coimmunoprecipitation experiments did not suggest direct interaction between MTF-1 and HIF-1α.

Characterization of the mouse metal-regulatory-element-binding proteins, metal element protein-1 and metal regulatory transcription factor-1

2001 ◽  
Vol 353 (3) ◽  
pp. 591-601 ◽  
Author(s):  
Olivier LAROCHELLE ◽  
Gale STEWART ◽  
Pierre MOFFATT ◽  
Véronique TREMBLAY ◽  
Carl SÉGUIN
Keyword(s):  
Transcription Factor ◽  
Dna Binding ◽  
Binding Activity ◽  
Dependent Manner ◽  
Rnase Protection ◽  
Dna Binding Activity ◽  
Cell Extracts ◽  
Metal Element ◽  
Transcription Factor 1

Metal activation of metallothionein gene transcription depends mainly on the presence of regulatory DNA sequences termed metal-regulatory elements (MREs) and involves MRE-binding transcription factor-1 (MTF-1) interacting with the MREs in a Zn2+-dependent manner. We previously identified and characterized a nuclear protein, termed metal element protein-1 (MEP-1), specifically binding with high affinity to MRE elements. The precise relationship between MTF-1 and MEP-1 was unclear, and to determine whether MEP-1 and MTF-1 were distinct protein species, we performed DNA binding analyses to characterize the binding properties of both proteins. Electrophoretic mobility-shift assays showed that MTF-1, produced in COS cells, produces a slower-migrating band compared with that obtained with purified MEP-1. Using an anti-MTF-1 antibody, we showed that both the MTF-1–MRE and the MEP-1–MRE complexes are supershifted by an anti-MTF-1 antibody, thus demonstrating that MEP-1 is antigenically related to MTF-1. RNase protection analyses carried out with RNA prepared from different tissues and cell lines failed to reveal the presence of MTF-1 splicing variants. This indicates that MEP-1 may be a proteolytic fragment of MTF-1. MTF-1 DNA-binding activity was rapidly activated in vivo by Zn2+ ions but not by Cd2+, UV irradiation or PMA, and occurred on ice as well as at 21°C. In control and Zn2+-treated cell extracts, DNA-binding activity was not enhanced in vitro following the addition of exogenous Zn2+ or a preincubation at 37°C. However, recombinant MTF-1 produced in vitro required Zn2+ activation for DNA binding. Interestingly, treatment of nuclear extracts with calf intestine phosphatase completely abrogated MTF-1 DNA-binding activity, thus suggesting that phosphorylation is involved in the regulation of MTF-1 activity.

scholarly journals Reversible activation of mouse metal response element-binding transcription factor 1 DNA binding involves zinc interaction with the zinc finger domain.

1997 ◽  
Vol 17 (5) ◽  
pp. 2781-2789 ◽  
Author(s):  
T P Dalton ◽  
D Bittel ◽  
G K Andrews
Keyword(s):  
Transcription Factor ◽  
Dna Binding ◽  
Binding Capacity ◽  
Binding Activity ◽  
Response Element ◽  
Dna Binding Activity ◽  
Cell Extracts ◽  
Free Zinc ◽  
Transcription Factor 1

The DNA-binding activity of the Zn finger protein metal response element-binding transcription factor 1 (MTF-1) was rapidly induced both in vivo in mouse Hepa cells, canine MDCK, and human HeLa cells after incubation in medium containing zinc and in vitro in whole-cell extracts to which zinc was added. Acquisition of DNA-binding capacity in the presence of free zinc was temperature and time dependent and did not occur at 4 degrees C. In contrast, activated MTF-1 binding to the metal response element occurred at 4 degrees C. After Zn activation, mouse MTF-1 binding activity was more sensitive to EDTA and was stabilized by DNA binding relative to the Zn finger transcription factor Sp1. After dilution of nuclear or whole-cell extracts from Zn-treated cells and incubation at 37 degrees C, mouse MTF-1 DNA-binding activity was no longer detected but could be completely reconstituted by the subsequent readdition of zinc. In vitro-synthesized, recombinant mouse MTF-1 displayed a similar, reversible temperature- and Zn-dependent activation of DNA-binding activity. Analysis of deletion mutants of recombinant MTF-1 suggests that the Zn finger domain is important for the Zn-dependent activation of DNA-binding capacity. Thus, mouse MTF-1 functions as a reversibly activated sensor of free zinc pools in the cell.

Expression and characterization of SUMO-conjugated metal-responsive transcription factor 1: SIM-dependent cross-interaction and distinct DNA binding activity

2013 ◽  
Vol 153 (4) ◽  
pp. 361-369 ◽  
Author(s):  
Chang-Yi Lin ◽  
Ya-Chuan Liu ◽  
Meng-Chieh Lin ◽  
Thao Thi Nguyen ◽  
Ming F. Tam ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Dna Binding ◽  
Binding Activity ◽  
Dna Binding Activity ◽  
Transcription Factor 1

PTEN interacts with metal-responsive transcription factor 1 and stimulates its transcriptional activity

2011 ◽  
Vol 441 (1) ◽  
pp. 367-377 ◽  
Author(s):  
Meng-Chieh Lin ◽  
Ya-Chuan Liu ◽  
Ming F. Tam ◽  
Yu-Ju Lu ◽  
Ya-Ting Hsieh ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Nuclear Translocation ◽  
Cadmium Toxicity ◽  
Binding Activity ◽  
Dependent Manner ◽  
Dna Binding Activity ◽  
Expression Of Genes ◽  
Zinc Addition ◽  
Phosphoinositide 3 Kinase ◽  
Transcription Factor 1

MTF-1 (metal-responsive transcription factor 1) is an essential mammalian protein for embryonic development and modulates the expression of genes involving in zinc homoeostasis and responding to oxidative stress. We report in the present paper that PTEN (phosphatase and tensin homologue deleted on chromosome 10) associates with MTF-1 in the cells. These two proteins interact via the acidic domain of MTF-1 and the phosphatase/C2 domain of PTEN. Depletion of PTEN reduced MT (metallothionein) gene expression and increased cellular sensitivity to cadmium toxicity. PTEN did not alter the nuclear translocation, protein stability or DNA-binding activity of MTF-1. Zinc increased MTF-1–PTEN interaction in a dose-dependent manner. The interaction elevated within 2 h of zinc addition and declined afterwards in the cells. The enhanced binding activity occurred mainly in the cytoplasm and reduced after translocating the MTF-1 into the nucleus. Blocking signalling through the PI3K (phosphoinositide 3-kinase) pathway did not alter the zinc-induced MT expression. Analysis of enzymatically inactive PTEN mutants demonstrated that protein but not lipid phosphatase activity of PTEN was involved in the regulation of MTF-1 activity. The same regulatory role of PTEN was also noted in the regulation of ZnT1 (zinc transporter 1), another target gene of MTF-1.

scholarly journals Suppression of E1A-Mediated Transformation by the p50E4F Transcription Factor

1999 ◽  
Vol 19 (7) ◽  
pp. 4739-4749 ◽  
Author(s):  
Elma R. Fernandes ◽  
Robert J. Rooney
Keyword(s):  
Cell Death ◽  
Transcription Factor ◽  
Suppressive Effect ◽  
Culture Conditions ◽  
Binding Activity ◽  
Cellular Transcription Factor ◽  
Dna Binding Activity ◽  
3T3 Fibroblasts ◽  
Induced Apoptosis ◽  
Nih 3T3

ABSTRACT The adenovirus E1A gene can act as an oncogene or a tumor suppressor, with the latter effect generally arising from the induction of apoptosis or the repression of genes that provide oncogenic growth stimuli (e.g., HER-2/c-erbB2/neu) or increased metastatic invasiveness (e.g., metalloproteases). In this study, coexpression of E1A and p50E4F, a cellular transcription factor whose DNA binding activity is stimulated by E1A, suppressed colony formation by NIH 3T3 cells and transformation of primary rat embryo fibroblasts but had no observed effect in the absence of E1A. Domains in p50E4F required for stimulation of the adenovirus E4 promoter were required for the suppressive effect, indicating a transcriptional mechanism. In serum-containing media, retroviral expression of p50E4F in E1A13S/ras-transformed NIH 3T3 fibroblasts had little effect on subconfluent cultures but accelerated a decline in viability after the cultures reached confluence. Cell death occurred by both apoptosis and necrosis, with the predominance of each process determined by culture conditions. In serum-free media, p50E4F accelerated E1A-induced apoptosis. The results suggest that p50E4F sensitizes cells to signals or conditions that cause cell death.

Effects of Echinomycin on PCNA-Dependent Follicular Development in PMSG-Induced Sprague-Dawley Rats

2014 ◽  
Vol 998-999 ◽  
pp. 228-232
Author(s):  
Zheng Hong Zhang ◽  
Fan Wang ◽  
Yan Qing Wu ◽  
Zong Hao Tang ◽  
Qing Qiang Lin ◽  
...  
Keyword(s):  
Hypoxia Inducible Factor ◽  
Follicular Development ◽  
Antral Follicle ◽  
Binding Activity ◽  
Nuclear Antigen ◽  
Sprague Dawley ◽  
Dna Binding Activity ◽  
Molecule Inhibitor ◽  
Protein Expressions ◽  
Serum Gonadotropin

Echinomycin (Ech) is a small-molecule inhibitor of hypoxia-inducible factor-1 DNA-binding activity, which plays a crucial role in the regulation of ovarian functions in mammals. The present study was designed to test the hypothesis that hypoxia-inducible factor (HIF)-1alpha-mediated proliferation cell nuclear antigen (PCNA) expressions contributed to the follicular development in the rat ovary primed by pregnant mare serum gonadotropin (PMSG). Through the histological examination, the decrease of growing and antral follicle numbers was found after Ech treatment both in control and PMSG treated groups. And then PCNA mRNA and protein expressions were found to significantly increase in the ovaries treated with PMSG, and the similar changes were found in HIF-1alpha mRNA and protein expressions, indicating PMSG-induced follicular development may be through HIF-1alpha/PCNA signaling. Furthermore, PCNA expression was found to significantly decrease in the ovaries after Ech treatment, while HIF-1alpha mRNA and protein expression was no obviously changes. Further analysis found the changes of PCNA expression were consistent with HIF-1 activity in the ovaries, further suggesting the regulatory roles in the follicular development. Taken together, these results demonstrated this HIF-1alpha-mediated PCNA expression is one of the important mechanisms regulating the ovarian follicular development in mammals. Keywords: HIF-1alpha; PCNA; echinomycin; HIF prolyl hyodroxylase acitvity; follicular development

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