scholarly journals Characterization of an E1A-CBP Interaction Defines a Novel Transcriptional Adapter Motif (TRAM) in CBP/p300

1999 ◽  
Vol 73 (5) ◽  
pp. 3574-3581 ◽  
Author(s):  
Mark J. O’Connor ◽  
Holger Zimmermann ◽  
Søren Nielsen ◽  
Hans-Ulrich Bernard ◽  
Tony Kouzarides
Keyword(s):  
Transcription Factors ◽  
Cell Fate ◽  
Transcriptional Activation ◽  
Molecular Model ◽  
P53 Protein ◽  
Small Region ◽  
Adenovirus E1a ◽  
Cellular Transcription

ABSTRACT The adenovirus E1A protein subverts cellular processes to induce mitotic activity in quiescent cells. Important targets of E1A include members of the transcriptional adapter family containing CBP/p300. Competition for CBP/p300 binding by various cellular transcription factors has been suggested as a means of integrating different signalling pathways and may also represent a potential mechanism by which E1A manipulates cell fate. Here we describe the characterization of the interaction between E1A and the C/H3 region of CBP. We define a novel conserved 12-residue transcriptional adapter motif (TRAM) within CBP/p300 that represents the binding site for both E1A and numerous cellular transcription factors. We also identify a sequence (FPESLIL) within adenovirus E1A that is required to bind the CBP TRAM. Furthermore, an E1A peptide containing the FPESLIL sequence is capable of preventing the interaction between CBP and TRAM-binding transcription factors, such as p53, E2F, and TFIIB, thus providing a molecular model for E1A action. As an in vivo demonstration of this model, we used a small region of CBP containing a functional TRAM that can bind to the p53 protein. The CBP TRAM binds p53 sequences targeted by the cellular regulator MDM2, and we demonstrate that an MDM2-p53 interaction can be disrupted by the CBP TRAM, leading to stabilization of cellular p53 levels and the activation of p53-dependent transcription. Transcriptional activation of p53 by the CBP TRAM is abolished by wild-type E1A but not by a CBP-binding-deficient E1A mutant.

Transactivation by the adenovirus E1A gene

1988 ◽  
Vol 66 (6) ◽  
pp. 578-583 ◽  
Author(s):  
Joseph R. Nevins ◽  
Pradip Raychaudhuri ◽  
Amy S. Yee ◽  
Robert J. Rooney ◽  
Imre Kovesdi ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Transcription Factors ◽  
Dna Binding ◽  
Gene Product ◽  
Transcriptional Activation ◽  
Viral Gene ◽  
Product Analysis ◽  
Adenovirus E1a ◽  
E1a Gene

The 289aa product of the adenovirus E1A gene mediates the transcriptional activation of the set of early viral genes as well as several cellular genes. The E1A protein is not a DNA binding protein but, rather, acts indirectly to achieve the activation. The process of viral gene activation involves the use of cellular transcription factors, and in at least one case, in vivo assays have demonstrated a stimulation of stable promoter complex formation as a function of the E1A gene product. Analysis of transcription factors in nuclear extracts has identified a cellular factor, termed E2F, with specificity for the viral E2 promoter. The concentration of this factor increases as a result of the action of E1A. This increase in DNA binding activity does not require protein synthesis, thus indicating an E1A-mediated modification of a pre-existing factor. The E2F factor has been purified to homogeneity and is a polypeptide of 54 000 molecular weight. Analysis of an additional viral promoter, the E4 promoter, has identified a protein that interacts with sequences critical for transcription. This factor, termed E4F, is also increased as a function of the E1A product. The E4F factor has also been purified to homogeneity and has a molecular weight of 50 000. Therefore, the coordinate control of transcription by the E1A gene product involves the activation of multiple promoter specific factors.

Subnuclear compartmentalization of sequence-specific transcription factors and regulation of eukaryotic gene expression

2005 ◽  
Vol 83 (4) ◽  
pp. 535-547 ◽  
Author(s):  
Gareth N Corry ◽  
D Alan Underhill
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Transcription Factors ◽  
Transcriptional Activation ◽  
Current Knowledge ◽  
Nuclear Architecture ◽  
Subnuclear Localization ◽  
Modular Structures

To date, the majority of the research regarding eukaryotic transcription factors has focused on characterizing their function primarily through in vitro methods. These studies have revealed that transcription factors are essentially modular structures, containing separate regions that participate in such activities as DNA binding, protein–protein interaction, and transcriptional activation or repression. To fully comprehend the behavior of a given transcription factor, however, these domains must be analyzed in the context of the entire protein, and in certain cases the context of a multiprotein complex. Furthermore, it must be appreciated that transcription factors function in the nucleus, where they must contend with a variety of factors, including the nuclear architecture, chromatin domains, chromosome territories, and cell-cycle-associated processes. Recent examinations of transcription factors in the nucleus have clarified the behavior of these proteins in vivo and have increased our understanding of how gene expression is regulated in eukaryotes. Here, we review the current knowledge regarding sequence-specific transcription factor compartmentalization within the nucleus and discuss its impact on the regulation of such processes as activation or repression of gene expression and interaction with coregulatory factors.Key words: transcription, subnuclear localization, chromatin, gene expression, nuclear architecture.

scholarly journals RAE-1 ligands for the NKG2D receptor are regulated by E2F transcription factors, which control cell cycle entry

2012 ◽  
Vol 209 (13) ◽  
pp. 2409-2422 ◽  
Author(s):  
Heiyoun Jung ◽  
Benjamin Hsiung ◽  
Kathleen Pestal ◽  
Emily Procyk ◽  
David H. Raulet
Keyword(s):  
Cell Cycle ◽  
Transcription Factors ◽  
Stress Responses ◽  
Transcriptional Activation ◽  
Posttranscriptional Regulation ◽  
Cellular Proliferation ◽  
Control Cell ◽  
T Cell Subsets ◽  
Cell Cycle Entry

The NKG2D stimulatory receptor expressed by natural killer cells and T cell subsets recognizes cell surface ligands that are induced on transformed and infected cells and facilitate immune rejection of tumor cells. We demonstrate that expression of retinoic acid early inducible gene 1 (RAE-1) family NKG2D ligands in cancer cell lines and proliferating normal cells is coupled directly to cell cycle regulation. Raet1 genes are directly transcriptionally activated by E2F family transcription factors, which play a central role in regulating cell cycle entry. Induction of RAE-1 occurred in primary cell cultures, embryonic brain cells in vivo, and cells in healing skin wounds and, accordingly, wound healing was delayed in mice lacking NKG2D. Transcriptional activation by E2Fs is likely coordinated with posttranscriptional regulation by other stress responses. These findings suggest that cellular proliferation, as occurs in cancer cells but also other pathological conditions, is a key signal tied to immune reactions mediated by NKG2D-bearing lymphocytes.

scholarly journals Targeting of p38 Mitogen-Activated Protein Kinases to MEF2 Transcription Factors

1999 ◽  
Vol 19 (6) ◽  
pp. 4028-4038 ◽  
Author(s):  
Shen-Hsi Yang ◽  
Alex Galanis ◽  
Andrew D. Sharrocks
Keyword(s):  
Transcription Factors ◽  
Transcriptional Activation ◽  
Cellular Response ◽  
Map Kinases ◽  
Biological Response ◽  
Extracellular Signals ◽  
Extracellular Signal ◽  
Mitogen Activated Protein

ABSTRACT Mitogen-activated protein (MAP) kinase-mediated signalling to the nucleus is an important event in the conversion of extracellular signals into a cellular response. However, the existence of multiple MAP kinases which phosphorylate similar phosphoacceptor motifs poses a problem in maintaining substrate specificity and hence the correct biological response. Both the extracellular signal-regulated kinase (ERK) and c-Jun NH2-terminal kinase (JNK) subfamilies of MAP kinases use a second specificity determinant and require docking to their transcription factor substrates to achieve maximal substrate activation. In this study, we demonstrate that among the different MAP kinases, the MADS-box transcription factors MEF2A and MEF2C are preferentially phosphorylated and activated by the p38 subfamily members p38α and p38β2. The efficiency of phosphorylation in vitro and transcriptional activation in vivo of MEF2A and MEF2C by these p38 subtypes requires the presence of a kinase docking domain (D-domain). Furthermore, the D-domain from MEF2A is sufficient to confer p38 responsiveness on different transcription factors, and reciprocal effects are observed upon the introduction of alternative D-domains into MEF2A. These results therefore contribute to our understanding of signalling to MEF2 transcription factors and demonstrate that the requirement for substrate binding by MAP kinases is an important facet of three different subclasses of MAP kinases (ERK, JNK, and p38).

scholarly journals Activating Signal Cointegrator 2 Belongs to a Novel Steady-State Complex That Contains a Subset of Trithorax Group Proteins

2003 ◽  
Vol 23 (1) ◽  
pp. 140-149 ◽  
Author(s):  
Young-Hwa Goo ◽  
Young Chang Sohn ◽  
Dae-Hwan Kim ◽  
Seung-Whan Kim ◽  
Min-Jung Kang ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Steady State ◽  
Nuclear Receptors ◽  
Transcriptional Activation ◽  
Retinoic Acid Receptor ◽  
Dependent Manner ◽  
Trithorax Group ◽  
Trithorax Group Proteins

ABSTRACT Many transcription coactivators interact with nuclear receptors in a ligand- and C-terminal transactivation function (AF2)-dependent manner. These include activating signal cointegrator 2 (ASC-2), a recently isolated transcriptional coactivator molecule, which is amplified in human cancers and stimulates transactivation by nuclear receptors and numerous other transcription factors. In this report, we show that ASC-2 belongs to a steady-state complex of approximately 2 MDa (ASC-2 complex [ASCOM]) in HeLa nuclei. ASCOM contains retinoblastoma-binding protein RBQ-3, α/β-tubulins, and trithorax group proteins ALR-1, ALR-2, HALR, and ASH2. In particular, ALR-1/2 and HALR contain a highly conserved 130- to 140-amino-acid motif termed the SET domain, which was recently implicated in histone H3 lysine-specific methylation activities. Indeed, recombinant ALR-1, HALR, and immunopurified ASCOM exhibit very weak but specific H3-lysine 4 methylation activities in vitro, and transactivation by retinoic acid receptor appears to involve ligand-dependent recruitment of ASCOM and subsequent transient H3-lysine 4 methylation of the promoter region in vivo. Thus, ASCOM may represent a distinct coactivator complex of nuclear receptors. Further characterization of ASCOM will lead to a better understanding of how nuclear receptors and other transcription factors mediate transcriptional activation.

scholarly journals Molecular Characterization of HOXA2 and HOXA3 Binding Properties

2021 ◽  
Vol 9 (4) ◽  
pp. 55
Author(s):  
Joshua Mallen ◽  
Manisha Kalsan ◽  
Peyman Zarrineh ◽  
Laure Bridoux ◽  
Shandar Ahmad ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Molecular Characterization ◽  
Sequence Motif ◽  
Body Parts ◽  
Binding Affinities ◽  
Binding Properties ◽  
Functional Consequences

The highly conserved HOX homeodomain (HD) transcription factors (TFs) establish the identity of different body parts along the antero–posterior axis of bilaterian animals. Segment diversification and the morphogenesis of different structures is achieved by generating precise patterns of HOX expression along the antero–posterior axis and by the ability of different HOX TFs to instruct unique and specific transcriptional programs. However, HOX binding properties in vitro, characterised by the recognition of similar AT-rich binding sequences, do not account for the ability of different HOX to instruct segment-specific transcriptional programs. To address this problem, we previously compared HOXA2 and HOXA3 binding in vivo. Here, we explore if sequence motif enrichments observed in vivo are explained by binding affinities in vitro. Unexpectedly, we found that the highest enriched motif in HOXA2 peaks was not recognised by HOXA2 in vitro, highlighting the importance of investigating HOX binding in its physiological context. We also report the ability of HOXA2 and HOXA3 to heterodimerise, which may have functional consequences for the HOX patterning function in vivo.

Abstract 356: Krueppel-Like Factor 15 Regulates Wnt/β-Catenin Transcription and Controls Cardiac Progenitor Cell Fate in the Postnatal Heart

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Claudia Noack ◽  
Maria P Zafiriou ◽  
Anke Renger ◽  
Hans J Schaeffer ◽  
Martin W Bergmann ◽  
...  
Keyword(s):  
Cell Fate ◽  
Transcriptional Activation ◽  
Progenitor Cell ◽  
Cellular Localization ◽  
Target Genes ◽  
Critical Role ◽  
Isolated Cells ◽  
Cardiac Progenitor Cell

Wnt/β-catenin signaling controls adult heart remodeling partly by regulating cardiac progenitor cell (CPC) differentiation. We now identified and characterized a novel cardiac interaction of the transcription factor Krueppel-like factor 15 (KLF15) with the Wnt/β-catenin signaling on adult CPCs. In vitro mutation, reporter gene assays and co-localization studies revealed that KLF15 requires two distinct domains for nuclear localization and for repression of β-catenin-mediated transcription. KLF15 had no effect on β-catenin stability or cellular localization, but interacted with its co-factor TCF4, which is required for activation of β-catenin target gene expression. Moreover, increased TCF4 ubiquitination was induced by KLF15. In line with this finding we found KLF15 to interact with the Nemo-like kinase, which was shown to phosphorylate and target TCF4 for degradation. In vivo analyses of adult Klf15 functional knock-out (KO) vs. wild-type (WT) mice showed a cardiac β-catenin-mediated transcriptional activation and reduced TCF4 degradation along with cardiac dysfunction assessed by echocardiography (n=10). FACS analysis of the CPC enriched-population of KO vs. WT mice revealed a significant reduction of cardiogenic-committed precursors identified as Sca1+/αMHC+ (0.8±0.2% vs. 1.8±0.1%) and Tbx5+ (3.5±0.3% vs. 5.2±0.5%). In contrast, endothelial Sca1+/CD31+ cells were significantly higher in KO mice (11.3±0.4% vs. 8.6±0.4%; n≥9). In addition, Sca1+ isolated cells of Klf15 KO showed increased RNA expression of endothelial markers von Willebrand Factor, CD105, and Flk1 along with upregulation of β-catenin target genes. CPCs co-cultured on adult fibroblasts resulted in increased endothelial Flk1 cells and reduction of αMHC and Hand1 cardiogenic cells in KO vs. WT CPCs (n=9). Treating these co-cultures with Quercetin, an inhibitor of nuclear β-catenin, resulted in partial rescue of the observed phenotype. This study uncovers a critical role of KLF15 for the maintenance of cardiac tissue homeostasis. Via inhibition of β-catenin transcription, KLF15 controls cardiomyogenic cell fate similar to embryonic cardiogenesis. This knowledge may provide a tool for activation of endogenous CPCs in the postnatal heart.

Genetic analysis of laminin A reveals diverse functions during morphogenesis in Drosophila

Development ◽  
1993 ◽  
Vol 118 (2) ◽  
pp. 325-337 ◽  
Author(s):  
C. Henchcliffe ◽  
L. Garcia-Alonso ◽  
J. Tang ◽  
C.S. Goodman
Keyword(s):  
Cell Fate ◽  
Genetic Characterization ◽  
Complete Loss ◽  
Loss Of Function ◽  
Partial Loss ◽  
Multidomain Structure ◽  
A Subunit ◽  
Wing Structure

In order to dissect the functions of laminin A in vivo, we have undertaken a molecular and genetic characterization of the laminin A subunit (lamA) gene in Drosophila. Sequence analysis predicts a multidomain structure similar to mammalian homologs. We generated a series of complete and partial loss-of-function mutant alleles of the lamA gene; complete loss-of-function mutations lead to late embryonic lethality. Certain combinations of partial loss-of-function lamA alleles give rise to escaper adults, which have rough eyes associated with changes in cell fate and pattern, misshapen legs and defects in wing structure. These phenotypes suggest that laminin A has diverse functions during morphogenesis in Drosophila.

scholarly journals The in vivo impact of MsLAC1, a Miscanthus laccase isoform, on lignification and lignin composition contrasts with its in vitro substrate preference

2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Feng He ◽  
Katja Machemer-Noonan ◽  
Philippe Golfier ◽  
Faride Unda ◽  
Johanna Dechert ◽  
...  
Keyword(s):  
Cell Wall ◽  
Transcription Factors ◽  
Lignin Content ◽  
Lignin Biosynthesis ◽  
Lignin Composition ◽  
Xylem Fibers ◽  
Breeding Target

Abstract Background Understanding lignin biosynthesis and composition is of central importance for sustainable bioenergy and biomaterials production. Species of the genus Miscanthus have emerged as promising bioenergy crop due to their rapid growth and modest nutrient requirements. However, lignin polymerization in Miscanthus is poorly understood. It was previously shown that plant laccases are phenol oxidases that have multiple functions in plant, one of which is the polymerization of monolignols. Herein, we link a newly discovered Miscanthus laccase, MsLAC1, to cell wall lignification. Characterization of recombinant MsLAC1 and Arabidopsis transgenic plants expressing MsLAC1 were carried out to understand the function of MsLAC1 both in vitro and in vivo. Results Using a comprehensive suite of molecular, biochemical and histochemical analyses, we show that MsLAC1 localizes to cell walls and identify Miscanthus transcription factors capable of regulating MsLAC1 expression. In addition, MsLAC1 complements the Arabidopsis lac4–2 lac17 mutant and recombinant MsLAC1 is able to oxidize monolignol in vitro. Transgenic Arabidopsis plants over-expressing MsLAC1 show higher G-lignin content, although recombinant MsLAC1 seemed to prefer sinapyl alcohol as substrate. Conclusions In summary, our results suggest that MsLAC1 is regulated by secondary cell wall MYB transcription factors and is involved in lignification of xylem fibers. This report identifies MsLAC1 as a promising breeding target in Miscanthus for biofuel and biomaterial applications.

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