scholarly journals Identification of distal silencing elements in the murine interferon-A11 gene promoter

1996 ◽  
Vol 317 (3) ◽  
pp. 697-706 ◽  
Author(s):  
Pascal ROFFET ◽  
Sébastien LOPEZ ◽  
Sébastien NAVARRO ◽  
Marie-Thérèse BANDU ◽  
Colette COULOMBEL ◽  
...  
Keyword(s):  
Transcriptional Response ◽  
Gene Promoter ◽  
Inhibitory Effect ◽  
Transient Transfection Assay ◽  
Nuclear Extracts ◽  
Nuclear Factors ◽  
Multigenic Family ◽  
Responsive Element ◽  
Related Proteins ◽  
Distal Promoter

The murine interferon-A11 (Mu IFN-A11) gene is a member of the IFN-A multigenic family. In mouse L929 cells, the weak response of the gene's promoter to viral induction is due to a combination of both a point mutation in the virus responsive element (VRE) and the presence of negatively regulating sequences surrounding the VRE. In the distal part of the promoter, the negatively acting E1E2 sequence was delimited. This sequence displays an inhibitory effect in either orientation or position on the inducibility of a virus-responsive heterologous promoter. It selectively represses VRE-dependent transcription but is not able to reduce the transcriptional activity of a VRE-lacking promoter. In a transient transfection assay, an E1E2-containing DNA competitor was able to derepress the native Mu IFN-A11 promoter. Specific nuclear factors bind to this sequence; thus the binding of trans-regulators participates in the repression of the Mu IFN-A11 gene. The E1E2 sequence contains an IFN regulatory factor (IRF)-binding site. Recombinant IRF2 binds this sequence and anti-IRF2 antibodies supershift a major complex formed with nuclear extracts. The protein composing the complex is 50 kDa in size, indicating the presence of IRF2 or antigenically related proteins in the complex. The Mu IFN-A11 gene is the first example within the murine IFN-A family, in which a distal promoter element has been identified that can negatively modulate the transcriptional response to viral induction.

scholarly journals A zinc-dependent DNA-binding activity co-operates with cAMP-responsive-element-binding protein to activate the human thyroglobulin enhancer

1997 ◽  
Vol 323 (2) ◽  
pp. 349-357 ◽  
Author(s):  
Véronique BERG ◽  
Gilbert VASSART ◽  
Daniel CHRISTOPHE
Keyword(s):  
Dna Binding ◽  
Transcriptional Activation ◽  
Binding Protein ◽  
Binding Activity ◽  
Band Shift ◽  
Transient Transfection Assay ◽  
Dna Binding Activity ◽  
Nuclear Extracts ◽  
Element Binding Protein ◽  
Responsive Element

Footprinting experiments involving the human thyroglobulin gene enhancer and thyroid nuclear extracts revealed a protected region called X2, containing an incomplete cAMP-responsive element (CRE). Band-shift experiments identified two binding activities recognizing the X2 element: a CRE-binding protein (CREB)/activating transcription factor (ATF) relative that binds the half CRE motif and a second factor that interacts with a G-rich motif located just upstream from the CRE. The first factor appears to be CREB itself, as indicated by the supershifting when using an antibody directed against CREB, and the second DNA-binding activity involved was shown to be zinc-dependent and exhibited an apparent molecular mass of 42–44 kDa in South-Western blotting experiments. This factor may represent a novel entity, which we named CAF, for ‘CREB Associated Factor’. Three copies of X2 sequence conferred a strong cAMP-dependent transcriptional activation to a heterologous promoter in transient transfection assay in cAMP-stimulated primary thyrocytes and HeLa cells. Transfection experiments of constructs containing the X2 element mutated in either the CRE or the G-rich site showed that both motifs were required for this transcription activating function. Moreover, the combination of several individual X2 elements mutated in either the CRE or the G-rich motif did not exhibit full transcriptional activity. This suggests that, in the context of the X2 element, CREB requires a close interaction with CAF to achieve both basal and cAMP-dependent transcriptional activation.

scholarly journals CCAAT/Enhancer-Binding Protein-α Is a Component of the Growth Hormone-Regulated Network of Liver Transcription Factors*

Endocrinology ◽  
2000 ◽  
Vol 141 (5) ◽  
pp. 1686-1692 ◽  
Author(s):  
Mojgan Rastegar ◽  
Guy G. Rousseau ◽  
Frédéric P. Lemaigre
Keyword(s):  
Transcription Factors ◽  
Binding Protein ◽  
Gene Promoter ◽  
Dna Interaction ◽  
Inhibitory Effect ◽  
Nuclear Extracts ◽  
Gene Coding ◽  
Enhancer Binding Protein ◽  
Ccaat Enhancer Binding Protein ◽  
Hypophysectomized Rats

Abstract GH regulates gene expression by modulating the concentration or activity of transcription factors. To identify transcription factors that mediate the effects of GH in liver we analyzed the promoter of the gene coding for hepatocyte nuclear factor-6 (HNF-6), whose expression in liver is stimulated by GH. In protein-DNA interaction studies and in transfection experiments, we found that the liver-enriched transcription factor CCAAT/enhancer-binding protein-α (C/EBPα) binds to the hnf6 gene and inhibits its expression. This inhibitory effect involved an N-terminal subdomain of C/EBPα and two sites in the hnf6 gene promoter. Using liver nuclear extracts from GH-treated hypophysectomized rats, we found that GH induces a rapid, transient decrease in the amount of C/EBPα protein. This GH-induced change is concomitant with the transient stimulatory effect of GH on the hnf6 gene. Stimulation of the hnf6 gene by GH therefore involves lifting of the repression exerted by C/EBPα in addition to the known GH-induced stimulatory effects of STAT5 (signal transducer and activator of transcription-5) and HNF-4 on that gene. Our data provide further evidence that GH controls a network of liver transcription factors and show that C/EBPα participates in this process.

scholarly journals Mechanical Sensing Element PDLIM5 Promotes Osteogenesis of Human Fibroblasts by Affecting the Activity of Microfilaments

Biomolecules ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 759
Author(s):  
Xiaolan Huang ◽  
Rongmei Qu ◽  
Yan Peng ◽  
Yuchao Yang ◽  
Tingyu Fan ◽  
...  
Keyword(s):  
Osteogenic Differentiation ◽  
Morphological Changes ◽  
Human Fibroblasts ◽  
Inhibitory Effect ◽  
Induction Medium ◽  
Sensing Element ◽  
Differentiation Potential ◽  
Osteogenic Induction Medium ◽  
Osteogenic Induction ◽  
Related Proteins

Human skin fibroblasts (HSFs) approximate the multidirectional differentiation potential of mesenchymal stem cells, so they are often used in differentiation, cell cultures, and injury repair. They are an important seed source in the field of bone tissue engineering. However, there are a few studies describing the mechanism of osteogenic differentiation of HSFs. Here, osteogenic induction medium was used to induce fibroblasts to differentiate into osteoblasts, and the role of the mechanical sensitive element PDLIM5 in microfilament-mediated osteogenic differentiation of human fibroblasts was evaluated. The depolymerization of microfilaments inhibited the expression of osteogenesis-related proteins and alkaline phosphatase activity of HSFs, while the polymerization of microfilaments enhanced the osteogenic differentiation of HSFs. The evaluation of potential protein molecules affecting changes in microfilaments showed that during the osteogenic differentiation of HSFs, the expression of PDLIM5 increased with increasing induction time, and decreased under the state of microfilament depolymerization. Lentivirus-mediated PDLIM5 knockdown by shRNA weakened the osteogenic differentiation ability of HSFs and inhibited the expression and morphological changes of microfilament protein. The inhibitory effect of knocking down PDLIM5 on HSF osteogenic differentiation was reversed by a microfilament stabilizer. Taken together, these data suggest that PDLIM5 can mediate the osteogenic differentiation of fibroblasts by affecting the formation and polymerization of microfilaments.

scholarly journals Identification of a TPA-responsive element mediating preferential transactivation of the galanin gene promoter in chromaffin cells.

1994 ◽  
Vol 269 (9) ◽  
pp. 6823-6831
Author(s):  
Y. Anouar ◽  
L. MacArthur ◽  
J. Cohen ◽  
A.L. Iacangelo ◽  
L.E. Eiden
Keyword(s):  
Chromaffin Cells ◽  
Gene Promoter ◽  
Responsive Element

scholarly journals Intestinal Apolipoprotein A-IV Gene Transcription Is Controlled by Two Hormone-Responsive Elements: A Role for Hepatic Nuclear Factor-4 Isoforms

2005 ◽  
Vol 19 (9) ◽  
pp. 2320-2334 ◽  
Author(s):  
Amena Archer ◽  
Dominique Sauvaget ◽  
Valérie Chauffeton ◽  
Pierre-Etienne Bouchet ◽  
Jean Chambaz ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transgenic Mice ◽  
Distal Region ◽  
Proximal Region ◽  
Dominant Negative ◽  
Specific Expression ◽  
Nuclear Factors ◽  
Dominant Negative Form ◽  
Responsive Element ◽  
Hormone Responsive Element

Abstract In the small intestine, the expression of the apolipoprotein (apo) C-III and A-IV genes is restricted to the enterocytes of the villi. We have previously shown that, in transgenic mice, specific expression of the human apo C-III requires a hormone-responsive element (HRE) located in the distal region of the human apoA-IV promoter. This HRE binds the hepatic nuclear factors (HNF)-4α and γ. Here, intraduodenal injections in mice and infections of human enterocytic Caco-2/TC7 cells with an adenovirus expressing a dominant-negative form of HNF-4α repress the expression of the apoA-IV gene, demonstrating that HNF-4 controls the apoA-IV gene expression in enterocytes. We show that HNF-4α and γ functionally interact with a second HRE present in the proximal region of the human apoA-IV promoter. New sets of transgenic mice expressing mutated forms of the promoter, combined with the human apo C-III enhancer, demonstrate that, whereas a single HRE is sufficient to reproduce the physiological cephalo-caudal gradient of apoA-IV gene expression, both HREs are required for expression that is restricted to villi. The combination of multiple HREs may specifically recruit regulatory complexes associating HNF-4 and either coactivators in villi or corepressors in crypts.

scholarly journals Image-Guided Neutron Capture Therapy Using the Gd-DO3A-BTA Complex as a New Combinatorial Treatment Approach

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Ki-Hye Jung ◽  
Ji-Ae Park ◽  
Jung Young Kim ◽  
Mi Hyun Kim ◽  
Seyoung Oh ◽  
...  
Keyword(s):  
Tumor Size ◽  
Neutron Capture ◽  
Inhibitory Effect ◽  
Accurate Information ◽  
Therapeutic Effects ◽  
Neutron Capture Therapy ◽  
Accumulation Time ◽  
Related Proteins ◽  
Treat Breast Cancer

Gadolinium-neutron capture therapy (Gd-NCT) is based on the nuclear capture reaction that occurs when 157Gd is irradiated with low energy thermal neutrons to primarily produce gamma photons. Herein, we investigated the effect of neutron capture therapy (NCT) using a small molecular gadolinium complex, Gd-DO3A-benzothiazole (Gd-DO3A-BTA), which could be a good candidate for use as an NCT drug due to its ability to enter the intracellular nuclei of tumor cells. Furthermore, MRI images of Gd-DO3A-BTA showed a clear signal enhancement in the tumor, and the images also played a key role in planning NCT by providing accurate information on the in vivo uptake time and duration of Gd-DO3A-BTA. We injected Gd-DO3A-BTA into MDA-MB-231 breast tumor-bearing mice and irradiated the tumors with cyclotron neutrons at the maximum accumulation time (postinjection 6 h); then, we observed the size of the growing tumor for 60 days. Gd-DO3A-BTA showed good therapeutic effects of chemo-Gd-NCT for the in vivo tumor models. Simultaneously, the Gd-DO3A-BTA groups ([Gd-DO3A-BTA(+), NCT(+)]) showed a significant reduction in tumor size (p<0.05), and the inhibitory effect on tumor growth was exhibited in the following order: [Gd-DO3A-BTA(+), NCT(+)] > [Gd-DO3A-BTA(+), NCT(−)] > [Gd-DO3A-BTA(−), NCT(+)] > [Gd-DO3A-BTA(−), NCT(−)]. On day 60, the [Gd-DO3A-BTA(+), NCT(+)] and [Gd-DO3A-BTA(−), NCT(−)] groups exhibited an approximately 4.5-fold difference in tumor size. Immunohistochemistry studies demonstrated that new combinational therapy with chemo-Gd-NCT could treat breast cancer by both the inhibition of tumor cell proliferation and induction of apoptosis-related proteins, with in vivo tumor monitoring by MRI.

scholarly journals Single-strand-DNA-binding factors specifically recognize the pyrimidine element in the chick α2(I) collagen gene promoter

1996 ◽  
Vol 314 (1) ◽  
pp. 293-296 ◽  
Author(s):  
Dashzeveg BAYARSAIHAN ◽  
Lewis N. LUKENS
Keyword(s):  
Dna Binding ◽  
Chick Embryo ◽  
Gene Promoter ◽  
Binding Activity ◽  
Dna Conformation ◽  
Collagen Gene ◽  
Nuclear Extracts ◽  
Binding Factor ◽  
Dna Binding Factors ◽  
Collagen Promoter

A pyrimidine element with mirror repeats centred at position -192 bp of the chick α2(I) collagen promoter interacts with sequence-specific DNA-binding factors. These factors bind to only the pyrimidine strand of this region and have no affinity for the complementary purine strand. Binding activity is also seen with the double-stranded form of this element, but with less affinity than to the single-stranded pyrimidine species. Southwestern blot analyses have shown that proteins of 80 and 134 kDa in chick embryo fibroblast nuclear extracts bind to the pyrimidine strand, whereas only a 134 kDa DNA-binding protein was found in chondrocyte nuclear extracts. The binding mechanism of these nuclear proteins with single-stranded DNA might be based on a non-B-DNA conformation of the pyrimidine element. The position of this binding site in the promoter region, its potential for adopting an unusual secondary structure and the presence of the 80 kDa binding factor in chick embryo fibroblasts, but not in chondrocytes, suggest a possible role for this factor in the expression of the α2(I) collagen gene.

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