scholarly journals Cubitus interruptus Requires DrosophilaCREB-Binding Protein To Activate wingless Expression in theDrosophila Embryo

2000 ◽  
Vol 20 (5) ◽  
pp. 1616-1625 ◽  
Author(s):  
Yang Chen ◽  
R. H. Goodman ◽  
Sarah M. Smolik
Keyword(s):  
Transcriptional Activation ◽  
Target Genes ◽  
Binding Protein ◽  
Point Mutations ◽  
Creb Binding Protein ◽  
Wild Type ◽  
Interaction Domain ◽  
Cubitus Interruptus

ABSTRACT CREB-binding protein (CBP) serves as a transcriptional coactivator in multiple signal transduction pathways. The Drosophilahomologue of CBP, dCBP, interacts with the transcription factors Cubitus interruptus (CI), MAD, and Dorsal (DL) and functions as a coactivator in several signaling pathways during Drosophiladevelopment, including the hedgehog (hh),decapentaplegic (dpp), and Tollpathways. Although dCBP is required for the expression of thehh target genes, wingless (wg) andpatched (ptc) in vivo, and potentiatesci-mediated transcriptional activation in vitro, it is not known that ci absolutely requires dCBP for its activity. We used a yeast genetic screen to identify several ci point mutations that disrupt CI-dCBP interactions. These mutant proteins are unable to transactivate a reporter gene regulated by cibinding sites and have a lower dCBP-stimulated activity than wild-type CI. When expressed exogenously in embryos, the CI point mutants cannot activate endogenous wg expression. Furthermore, a CI mutant protein that lacks the entire dCBP interaction domain functions as a negative competitor for wild-type CI activity, and the expression of dCBP antisense RNAs can suppress CI transactivation in Kc cells. Taken together, our data suggest that dCBP function is necessary forci-mediated transactivation of wg duringDrosophila embryogenesis.

scholarly journals Interdependent Recruitment of SAGA and Srb Mediator by Transcriptional Activator Gcn4p

2005 ◽  
Vol 25 (9) ◽  
pp. 3461-3474 ◽  
Author(s):  
Hongfang Qiu ◽  
Cuihua Hu ◽  
Fan Zhang ◽  
Gwo Jiunn Hwang ◽  
Mark J. Swanson ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Target Genes ◽  
Wild Type ◽  
General Transcription Factors ◽  
Tata Element ◽  
High Level ◽  
Target Promoters ◽  
Activation Sequence

ABSTRACT Transcriptional activation by Gcn4p is enhanced by the coactivators SWI/SNF, SAGA, and Srb mediator, which stimulate recruitment of TATA binding protein (TBP) and polymerase II to target promoters. We show that wild-type recruitment of SAGA by Gcn4p is dependent on mediator but independent of SWI/SNF function at three different promoters. Recruitment of mediator is also independent of SWI/SNF but is enhanced by SAGA at a subset of Gcn4p target genes. Recruitment of all three coactivators to ARG1 is independent of the TATA element and preinitiation complex formation, whereas efficient recruitment of the general transcription factors requires the TATA box. We propose an activation pathway involving interdependent recruitment of SAGA and Srb mediator to the upstream activation sequence, enabling SWI/SNF recruitment and the binding of TBP and other general factors to the promoter. We also found that high-level recruitment of Tra1p and other SAGA subunits is independent of the Ada2p/Ada3p/Gcn5p histone acetyltransferase module but requires Spt3p in addition to subunits required for SAGA integrity. Thus, while Tra1p can bind directly to Gcn4p in vitro, it requires other SAGA subunits for efficient recruitment in vivo.

scholarly journals The N-Terminal Domain of p73 Interacts with the CH1 Domain of p300/CREB Binding Protein and Mediates Transcriptional Activation and Apoptosis

2000 ◽  
Vol 20 (4) ◽  
pp. 1299-1310 ◽  
Author(s):  
Xiaoya Zeng ◽  
Xiaorong Li ◽  
Ashley Miller ◽  
Zhimin Yuan ◽  
Wuchao Yuan ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Binding Protein ◽  
Small Cell Lung Carcinoma ◽  
Creb Binding Protein ◽  
Cell Lung Carcinoma ◽  
Cell Extracts ◽  
N Terminus ◽  
Mcf 7

ABSTRACT The newly identified p53 homolog p73 mimics the transcriptional function of p53. We have investigated the regulation of p73's transcriptional activity by p300/CREB binding protein (CBP). p73-p300 complexes were identified in HeLa cell extracts by cofractionation and coimmunoprecipitation assays. The p73-p300 interaction was confirmed in vitro by glutathione S-transferase–protein association assays and in vivo by coimmunoprecipitating the overexpressed p300 and p73 in human p53-free small-cell lung carcinoma H1299 or osteosarcoma Saos-2 cells. The N terminus but not the N-terminal truncation of p73 bound to the CH1 domain (amino acids [aa] 350 to 450) of p300/CBP. Accordingly, this p73 N-terminal deletion was unable to activate transcription or to induce apoptosis. Overexpression of either p300 or CBP stimulated transcription mediated by p73 but not its N-terminally deleted mutant in vivo. The N-terminal fragment from aa 19 to 597, but not the truncated fragment from aa 242 to 1700 of p300, reduced p73-mediated transcription markedly. p73-dependent transcription or apoptosis was partially impaired in either p300- or CBP-deficient human breast carcinoma MCF-7 or H1299 cells, suggesting that both coactivators mediate transcription by p73 in cells. These results demonstrate that the N terminus of p73 directly interacts with the N-terminal CH1 domain of p300/CBP to activate transcription.

scholarly journals A yeast ARS-binding protein activates transcription synergistically in combination with other weak activating factors.

1990 ◽  
Vol 10 (3) ◽  
pp. 887-897 ◽  
Author(s):  
A R Buchman ◽  
R D Kornberg
Keyword(s):  
Dna Sequences ◽  
Transcriptional Activation ◽  
Binding Sites ◽  
Essential Gene ◽  
Specific Binding ◽  
Binding Protein ◽  
Point Mutations ◽  
Yeast Genes

ABFI (ARS-binding protein I) is a yeast protein that binds specific DNA sequences associated with several autonomously replicating sequences (ARSs). ABFI also binds sequences located in promoter regions of some yeast genes, including DED1, an essential gene of unknown function that is transcribed constitutively at a high level. ABFI was purified by specific binding to the DED1 upstream activating sequence (UAS) and was found to recognize related sequences at several other promoters, at an ARS (ARS1), and at a transcriptional silencer (HMR E). All ABFI-binding sites, regardless of origin, provided weak UAS function in vivo when examined in test plasmids. UAS function was abolished by point mutations that reduced ABFI binding in vitro. Analysis of the DED1 promoter showed that two ABFI-binding sites combine synergistically with an adjacent T-rich sequence to form a strong constitutive activator. The DED1 T-rich element acted synergistically with all other ABFI-binding sites and with binding sites for other multifunctional yeast activators. An examination of the properties of sequences surrounding ARS1 left open the possibility that ABFI enhances the initiation of DNA replication at ARS1 by transcriptional activation.

scholarly journals PCAF Interacts with Tax and Stimulates Tax Transactivation in a Histone Acetyltransferase-Independent Manner

1999 ◽  
Vol 19 (12) ◽  
pp. 8136-8145 ◽  
Author(s):  
Hua Jiang ◽  
Hanxin Lu ◽  
R. Louis Schiltz ◽  
Cynthia A. Pise-Masison ◽  
Vasily V. Ogryzko ◽  
...  
Keyword(s):  
Transcriptional Activation ◽  
Histone Acetyltransferase ◽  
Point Mutations ◽  
Creb Binding Protein ◽  
Independent Manner ◽  
Cell Leukemia Virus Type ◽  
Knock Out ◽  
Human T Cell

ABSTRACT Recent studies have shown that the p300/CREB binding protein (CBP)-associated factor (PCAF) is involved in transcriptional activation. PCAF activity has been shown strongly associated with histone acetyltransferase (HAT) activity. In this report, we present evidence for a HAT-independent transcription function that is activated in the presence of the human T-cell leukemia virus type 1 (HTLV-1) Tax protein. In vitro and in vivo GST-Tax pull-down and coimmunoprecipitation experiments demonstrate that there is a direct interaction between Tax and PCAF, independent of p300/CBP. PCAF can be recruited to the HTLV-1 Tax responsive element in the presence of Tax, and PCAF cooperates with Tax in vivo to activate transcription from the HTLV-1 LTR over 10-fold. Point mutations at Tax amino acid 318 (TaxS318A) or 319 to 320 (Tax M47), which have decreased or no activity on the HTLV-1 promoter, are defective for PCAF binding. Strikingly, the ability of PCAF to stimulate Tax transactivation is not solely dependent on the PCAF HAT domain. Two independent PCAF HAT mutants, which knock out acetyltransferase enzyme activity, activate Tax transactivation to approximately the same level as wild-type PCAF. In contrast, p300 stimulation of Tax transactivation is HAT dependent. These studies provide experimental evidence that PCAF contains a coactivator transcription function independent of the HAT activity on the viral long terminal repeat.

scholarly journals WBP-2, a WW domain binding protein, interacts with the thyroid-specific transcription factor Pax8

2004 ◽  
Vol 377 (3) ◽  
pp. 553-560 ◽  
Author(s):  
Roberto NITSCH ◽  
Tina DI PALMA ◽  
Anna MASCIA ◽  
Mariastella ZANNINI
Keyword(s):  
Protein Interaction ◽  
Transcriptional Activation ◽  
Binding Protein ◽  
Interaction Domain ◽  
Ww Domain ◽  
Transcriptional Activation Domain ◽  
Culture Cells ◽  
C Terminus

The Pax gene family encodes transcription factors that are essential in organogenesis and in the differentiation of various organs in higher eukaryotes. Pax proteins have a DNA binding domain at the N-terminus, and a transcriptional activation domain at the C-terminus. How these domains interact with the transcriptional machinery of the cell is still unclear. In the present paper, we describe the identification by means of immunological screening of the WW domain binding protein WBP-2 as a biochemical interactor of Pax8 (a WW domain is a protein-interaction domain containing two conserved tryptophan residues). Pax8 is required for the morphogenesis of the thyroid gland and for the maintenance of the thyroid differentiated cellular phenotype. WBP-2 was identified originally as a WW domain binding protein, and its function is still unknown. WBP-2 binds to Pax8 in vitro in pulldown assays, and in vivo in tissue culture cells in co-immunoprecipitation assays. Interestingly, Pax8 does not contain a WW domain. Our results point to the identification of a new protein-interacting domain that is present in the C-terminal portion of Pax8 and that is required for protein–protein interaction with WBP-2. Our results demonstrate that WBP-2 is not a transcriptional co-activator of Pax8, but rather behaves as an adaptor molecule, as suggested in other studies.

scholarly journals Transcriptional Regulation of the MDR1 Gene by Histone Acetyltransferase and Deacetylase Is Mediated by NF-Y

1998 ◽  
Vol 18 (7) ◽  
pp. 4377-4384 ◽  
Author(s):  
Shengkan Jin ◽  
Kathleen W. Scotto
Keyword(s):  
Transcriptional Activation ◽  
Histone Acetyltransferase ◽  
Binding Protein ◽  
Trichostatin A ◽  
Present Report ◽  
Dominant Negative ◽  
Creb Binding Protein ◽  
Wild Type ◽  
Ccaat Box

ABSTRACT Recent studies have shown that the histone-modifying enzymes histone acetyltransferase (HAT) and histone deacetylase (HDAC) are involved in transcriptional activation and repression, respectively. However, little is known about the endogenous genes that are regulated by these enzymes or how specificity is achieved. In the present report, we demonstrate that HAT and HDAC activities modulate transcription of the P-glycoprotein-encoding gene, MDR1. Incubation of human colon carcinoma SW620 cells in 100-ng/ml trichostatin A (TSA), a specific HDAC inhibitor, increased the steady-state level ofMDR1 mRNA 20-fold. Furthermore, TSA treatment of cells transfected with a wild-type MDR1 promoter/luciferase construct resulted in a 10- to 15-fold induction of promoter activity. Deletion and point mutation analysis determined that an inverted CCAAT box was essential for this activation. Consistent with this observation, overexpression of p300/CREB binding protein-associated factor (P/CAF), a transcriptional coactivator with intrinsic HAT activity, activated the wild-type MDR1 promoter but not a promoter containing a mutation in the CCAAT box; deletion of the P/CAF HAT domain abolished activation. Gel shift and supershift analyses identified NF-Y as the CCAAT-box binding protein in these cells, and cotransfection of a dominant negative NF-Y expression vector decreased the activation of the MDR1promoter by TSA. Moreover, NF-YA and P/CAF were shown to interact in vitro. This is the first report of a natural promoter that is modulated by HAT and HDAC activities in which the transcription factor mediating this regulation has been identified.

A yeast ARS-binding protein activates transcription synergistically in combination with other weak activating factors

1990 ◽  
Vol 10 (3) ◽  
pp. 887-897
Author(s):  
A R Buchman ◽  
R D Kornberg
Keyword(s):  
Dna Sequences ◽  
Transcriptional Activation ◽  
Binding Sites ◽  
Essential Gene ◽  
Specific Binding ◽  
Binding Protein ◽  
Point Mutations ◽  
Yeast Genes

ABFI (ARS-binding protein I) is a yeast protein that binds specific DNA sequences associated with several autonomously replicating sequences (ARSs). ABFI also binds sequences located in promoter regions of some yeast genes, including DED1, an essential gene of unknown function that is transcribed constitutively at a high level. ABFI was purified by specific binding to the DED1 upstream activating sequence (UAS) and was found to recognize related sequences at several other promoters, at an ARS (ARS1), and at a transcriptional silencer (HMR E). All ABFI-binding sites, regardless of origin, provided weak UAS function in vivo when examined in test plasmids. UAS function was abolished by point mutations that reduced ABFI binding in vitro. Analysis of the DED1 promoter showed that two ABFI-binding sites combine synergistically with an adjacent T-rich sequence to form a strong constitutive activator. The DED1 T-rich element acted synergistically with all other ABFI-binding sites and with binding sites for other multifunctional yeast activators. An examination of the properties of sequences surrounding ARS1 left open the possibility that ABFI enhances the initiation of DNA replication at ARS1 by transcriptional activation.

scholarly journals Direct methylation of FXR by Set7/9, a lysine methyltransferase, regulates the expression of FXR target genes

2012 ◽  
Vol 302 (9) ◽  
pp. G937-G947 ◽  
Author(s):  
Natarajan Balasubramaniyan ◽  
Meena Ananthanarayanan ◽  
Frederick J. Suchy
Keyword(s):  
Bile Acid ◽  
Transcriptional Activation ◽  
Target Genes ◽  
Farnesoid X Receptor ◽  
Mutant Form ◽  
Wild Type ◽  
Associated Proteins ◽  
Transcriptional Complex

The farnesoid X receptor (FXR) is a ligand (bile acid)-dependent nuclear receptor that regulates target genes involved in every aspect of bile acid homeostasis. Upon binding of ligand, FXR recruits an array of coactivators and associated proteins, some of which have intrinsic enzymatic activity that modify histones or even components of the transcriptional complex. In this study, we show chromatin occupancy by the Set7/9 methyltransferase at the FXR response element (FXRE) and direct methylation of FXR in vivo and in vitro at lysine 206. siRNA depletion of Set7/9 in the Huh-7 liver cell line decreased endogenous mRNAs of the FXR target genes, the short heterodimer partner (SHP) and bile salt export pump (BSEP). Mutation of the methylation site at K206 of FXR to an arginine prevented methylation by Set7/9. A pan-methyllysine antibody recognized the wild-type FXR but not the K206R mutant form. An electromobility shift assay showed that methylation by Set7/9 enhanced binding of FXR/retinoic X receptor-α to the FXRE. Interaction between hinge domain of FXR (containing K206) and Set7/9 was confirmed by coimmunoprecipitation, GST pull down, and mammalian two-hybrid experiments. Set7/9 overexpression in Huh-7 cells significantly enhanced transactivation of the SHP and BSEP promoters in a ligand-dependent fashion by wild-type FXR but not the K206R mutant FXR. A Set7/9 mutant deficient in methyltransferase activity was also not effective in increasing transactivation of the BSEP promoter. These studies demonstrate that posttranslational methylation of FXR by Set7/9 contributes to the transcriptional activation of FXR-target genes.

scholarly journals Molecular Basis of In Vivo Resistance to Sulfadoxine-Pyrimethamine in African Adult Patients Infected withPlasmodium falciparum Malaria Parasites

1998 ◽  
Vol 42 (7) ◽  
pp. 1811-1814 ◽  
Author(s):  
Leonardo K. Basco ◽  
Rachida Tahar ◽  
Pascal Ringwald
Keyword(s):  
Dihydrofolate Reductase ◽  
Point Mutations ◽  
Gene Mutations ◽  
Adult Patients ◽  
Wild Type ◽  
Dihydropteroate Synthase ◽  
Reductase Gene ◽  
Parasite Populations

ABSTRACT In vitro sulfadoxine and pyrimethamine resistance has been associated with point mutations in the dihydropteroate synthase and dihydrofolate reductase domains, respectively, but the in vivo relevance of these point mutations has not been well established. To analyze the correlation between genotype and phenotype, 10 Cameroonian adult patients were treated with sulfadoxine-pyrimethamine and followed up for 28 days. After losses to follow-up (n = 1) or elimination of DNA samples due to mixed parasite populations with pyrimethamine-sensitive and pyrimethamine-resistant profiles (n = 3), parasite genomic DNA from day 0 blood samples of six patients were analyzed by DNA sequencing. Three patients who were cured had isolates characterized by a wild-type or mutant dihydrofolate reductase gene (with one or two mutations) and a wild-type dihydropteroate synthase gene. Three other patients who failed to respond to sulfadoxine-pyrimethamine treatment carried isolates with triple dihydrofolate reductase gene mutations and either a wild-type or a mutant dihydropteroate synthase gene. Three dihydrofolate reductase gene codons (51, 59, and 108) may be reliable genetic markers that can accurately predict the clinical outcome of sulfadoxine-pyrimethamine treatment in Africa.

scholarly journals Extracellular Signal-Regulated Kinase Binds to TFII-I and Regulates Its Activation of the c-fosPromoter

2000 ◽  
Vol 20 (4) ◽  
pp. 1140-1148 ◽  
Author(s):  
Dae-Won Kim ◽  
Brent H. Cochran
Keyword(s):  
Map Kinase ◽  
Transcriptional Activation ◽  
Dominant Negative ◽  
Binding Motif ◽  
Dependent Manner ◽  
Consensus Map ◽  
Interaction Domain ◽  
Extracellular Signal

ABSTRACT We have previously shown that TFII-I enhances transcriptional activation of the c-fos promoter through interactions with upstream elements in a signal-dependent manner. Here we demonstrate that activated Ras and RhoA synergize with TFII-I for c-fospromoter activation, whereas dominant-negative Ras and RhoA inhibit these effects of TFII-I. The Mek1 inhibitor, PD98059 abrogates the enhancement of the c-fos promoter by TFII-I, indicating that TFII-I function is dependent on an active mitogen-activated protein (MAP) kinase pathway. Analysis of the TFII-I protein sequence revealed that TFII-I contains a consensus MAP kinase interaction domain (D box). Consistent with this, we have found that TFII-I forms an in vivo complex with extracellular signal-related kinase (ERK). Point mutations within the consensus MAP kinase binding motif of TFII-I inhibit its ability to bind ERK and its ability to enhance the c-fos promoter. Therefore, the D box of TFII-I is required for its activity on the c-fos promoter. Moreover, the interaction between TFII-I and ERK can be regulated. Serum stimulation enhances complex formation between TFII-I and ERK, and dominant-negative Ras abrogates this interaction. In addition, TFII-I can be phosphorylated in vitro by ERK and mutation of consensus MAP kinase substrate sites at serines 627 and 633 impairs the phosphorylation of TFII-I by ERK and its activity on the c-fos promoter. These results suggest that ERK regulates the activity of TFII-I by direct phosphorylation.

Sign in / Sign up

Export Citation Format

Share Document