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Transcription FactorsTranscription, GeneticGATA4 Transcription FactorGATA6 Transcription FactorGATA2 Transcription FactorDNA-Binding ProteinsPromoter Regions, GeneticGATA3 Transcription FactorGATA Transcription FactorsGATA1 Transcription FactorSp1 Transcription FactorGene Expression RegulationMolecular Sequence DataBase SequenceBinding SitesTranscriptional ActivationGATA5 Transcription FactorTrans-ActivatorsBasic Helix-Loop-Helix Transcription FactorsRNA, MessengerProtein BindingNuclear ProteinsTranscription Factor AP-1Gene Expression Regulation, DevelopmentalRepressor ProteinsHomeodomain ProteinsCell LineForkhead Transcription FactorsSignal TransductionAmino Acid SequenceDNAMutationBasic-Leucine Zipper Transcription FactorsCell DifferentiationTranscription Factor AP-2Cell NucleusTransfectionGenes, ReporterChromatin ImmunoprecipitationKruppel-Like Transcription FactorsTranscription Factors, TFIIZinc FingersCells, CulturedYY1 Transcription FactorHeLa CellsSTAT3 Transcription FactorTranscription Factor TFIIDNFATC Transcription FactorsEnhancer Elements, GeneticReverse Transcriptase Polymerase Chain ReactionActivating Transcription Factor 3Electrophoretic Mobility Shift AssayTranscription Initiation SiteSp3 Transcription FactorNF-kappa BPaired Box Transcription FactorsRegulatory Sequences, Nucleic AcidGene Expression ProfilingActivating Transcription Factor 2Transcription Factor TFIIBCloning, MolecularRecombinant Fusion ProteinsE2F1 Transcription FactorRNA Polymerase IIMEF2 Transcription FactorsBasic Helix-Loop-Helix Leucine Zipper Transcription FactorsPlasmidsGene ExpressionGene Expression Regulation, FungalLuciferasesErythroid-Specific DNA-Binding FactorsTCF Transcription FactorsProtein Structure, TertiaryMicrophthalmia-Associated Transcription FactorCell Line, TumorSTAT1 Transcription FactorChromatinActivating Transcription FactorsOligonucleotide Array Sequence AnalysisHelix-Loop-Helix MotifsPhosphorylationTranscription Factor RelAE2F Transcription FactorsSaccharomyces cerevisiaeModels, BiologicalMice, KnockoutSequence Homology, Amino AcidSaccharomyces cerevisiae ProteinsMice, TransgenicProto-Oncogene ProteinsGene Expression Regulation, PlantActivating Transcription Factor 4Transcription Factor 7-Like 1 ProteinActivating Transcription Factor 1Cyclic AMP Response Element-Binding ProteinBlotting, WesternDown-RegulationTATA BoxTranscription Factor TFIIIAModels, Genetic

Context-dependent transcriptional cooperation mediated by cardiac transcription factors Csx/Nkx-2.5 and GATA-4. (1/561)

Although the cardiac homeobox gene Csx/Nkx-2.5 is essential for normal heart development, little is known about its regulatory mechanisms. In a search for the downstream target genes of Csx/Nkx-2. 5, we found that the atrial natriuretic peptide (ANP) gene promoter was strongly transactivated by Csx/Nkx-2.5. Deletion and mutational analyses of the ANP promoter revealed that the Csx/Nkx-2.5-binding element (NKE2) located at -240 was required for high level transactivation by Csx/Nkx-2.5. We also found that Csx/Nkx-2.5 and GATA-4 displayed synergistic transcriptional activation of the ANP promoter, and in contrast to previous reports (Durocher, D., Charron, F., Warren, R., Schwartz, R. J., and Nemer, M. (1997) EMBO J. 16, 5687-5696; Lee, Y., Shioi, T., Kasahara, H., Jobe, S. M., Wiese, R. J., Markham, B., and Izumo, S (1998) Mol. Cell. Biol. 18, 3120-3129), this synergism was dependent on binding of Csx/Nkx-2.5 to NKE2, but not on GATA-4-DNA interactions. Although GATA-4 also potentiated the Csx/Nkx-2.5-induced transactivation of the artificial promoter that contains multimerized Csx/Nkx-2.5-binding sites, Csx/Nkx-2.5 reduced the GATA-4-induced transactivation of the GATA-4-dependent promoters. These findings indicate that the cooperative transcriptional regulation mediated by Csx/Nkx-2.5 and GATA-4 is promoter context-dependent and suggest that the complex cis-trans interactions may fine-tune gene expression in cardiac myocytes.  (+info)

Characterization of the murine A1 adenosine receptor promoter, potent regulation by GATA-4 and Nkx2.5. (2/561)

Adenosine acts via A1 adenosine receptors (A1ARs) in the heart and brain to potently influence mammalian physiology. A1ARs are expressed very early in embryonic development, and A1ARs are among the earliest expressed G protein coupled receptors in the heart and brain. To understand the biologic basis of A1AR expression, a genomic fragment containing the murine A1AR promoter was cloned. Reporter assay studies using DDT1 MF2 cells that express A1ARs revealed that 500 base pairs of the proximal A1AR promoter contained essential elements for A1AR gene expression. Transgenic mice with A1AR proximal promoter coupled with the beta-galactosidase reporter gene had heavy labeling of the brain and atria, consistent with normal patterns of A1AR expression. Within the proximal A1AR promoter, putative binding sites for cardiac transcription factors GATA and Nkx2.5 were identified. Co-expression studies revealed that GATA-4 and Nkx2.5 could individually drive A1AR promoter activity and act synergistically to activate A1AR expression. These observations suggest that embryonic A1AR expression involves activation of the A1AR promoter by GATA-4 and Nkx2.5.  (+info)

Cooperative interaction between GATA-4 and GATA-6 regulates myocardial gene expression. (3/561)

Two members of the GATA family of transcription factors, GATA-4 and GATA-6, are expressed in the developing and postnatal myocardium and are equally potent transactivators of several cardiac promoters. However, several in vitro and in vivo lines of evidence suggest distinct roles for the two factors in the heart. Since identification of the endogenous downstream targets of GATA factors would greatly help to elucidate their exact functions, we have developed an adenovirus-mediated antisense strategy to specifically inhibit GATA-4 and GATA-6 protein production in postnatal cardiomyocytes. Expression of several endogenous cardiac genes was significantly down-regulated in cells lacking GATA-4 or GATA-6, indicating that these factors are required for the maintenance of the cardiac genetic program. Interestingly, transcription of some genes like the alpha- and beta-myosin heavy-chain (alpha- and beta-MHC) genes was preferentially regulated by GATA-4 due, in part, to higher affinity of GATA-4 for their promoter GATA element. However, transcription of several other genes, including the atrial natriuretic factor and B-type natriuretic peptide (ANF and BNP) genes, was similarly down-regulated in cardiomyocytes lacking one or both GATA factors, suggesting that GATA-4 and GATA-6 could act through the same transcriptional pathway. Consistent with this, GATA-4 and GATA-6 were found to colocalize in postnatal cardiomyocytes and to interact functionally and physically to provide cooperative activation of the ANF and BNP promoters. The results identify for the first time bona fide in vivo targets for GATA-4 and GATA-6 in the myocardium. The data also show that GATA factors act in concert to regulate distinct subsets of genes, suggesting that combinatorial interactions among GATA factors may differentially control various cellular processes.  (+info)

FOG-2, a heart- and brain-enriched cofactor for GATA transcription factors. (4/561)

Members of the GATA family of zinc finger transcription factors have been shown to play important roles in the control of gene expression in a variety of cell types. GATA-1, -2, and -3 are expressed primarily in hematopoietic cell lineages and are required for proliferation and differentiation of multiple hematopoietic cell types, whereas GATA-4, -5, and -6 are expressed in the heart, where they activate cardiac muscle structural genes. Friend of GATA-1 (FOG) is a multitype zinc finger protein that interacts with GATA-1 and serves as a cofactor for GATA-1-mediated transcription. FOG is coexpressed with GATA-1 in developing erythroid and megakaryocyte cell lineages and cooperates with GATA-1 to control erythropoiesis. We describe a novel FOG-related factor, FOG-2, that is expressed predominantly in the developing and adult heart, brain, and testis. FOG-2 interacts with GATA factors, and interaction of GATA-4 and FOG-2 results in either synergistic activation or repression of GATA-dependent cardiac promoters, depending on the specific promoter and the cell type in which they are tested. The properties of FOG-2 suggest its involvement in the control of cardiac and neural gene expression by GATA transcription factors.  (+info)

Retinoic acid-regulated expression of fibroblast growth factor 3 requires the interaction between a novel transcription factor and GATA-4. (5/561)

fgf-3 shows a complex spatial-temporal pattern of transcription during mouse development, and the gene product appears to be an important intercellular signaling molecule. Here we show that the major enhancer, which is obligatory for transcription, is composed of three elements with different properties. Both functional analyses in undifferentiated and differentiated F9 cells and characterization of DNA-protein complexes in vitro have identified the sequence motifs GTGACT(C), ATTGT, and GATA as the key transcription factor binding sites. The GTGACT(C) motif, while not essential, is required for full enhancer activity. However, binding at ATTGT is crucial for transcriptional activity and is required for cooperative binding at the proximal GATA site. The GATA binding site mediates the retinoic acid/dibutyryl cyclic AMP stimulation of transcription and correlates with the binding of Gata-4 which is induced by retinoic acid in differentiating F9 cells. The ATTGT and GATA motifs are inactive when placed separately on a minimal thymidine kinase (TK) promoter, but together they act as a strong retinoic acid-regulated enhancer. In undifferentiated F9 cells, gata-4 expression stimulates the fgf-3 promoter, whereas in differentiated F9 cells already expressing gata-4, no further increase in promoter activity was observed.  (+info)

CCAAT enhancer-binding protein beta and GATA-4 binding regions within the promoter of the steroidogenic acute regulatory protein (StAR) gene are required for transcription in rat ovarian cells. (6/561)

Steroidogenic acute regulatory protein (StAR) is a vital accessory protein required for biosynthesis of steroid hormones from cholesterol. The present study shows that in primary granulosa cells from prepubertal rat ovary, StAR transcript and protein are acutely induced by gonadotropin (FSH). To determine the sequence elements required for hormone inducibility of the StAR promoter, truncated regions of the -1002/+6 sequence of the mouse gene were ligated to pCAT-Basic plasmid and transfected by electroporation to freshly prepared cells. FSH inducibility determined over a 6-h incubation was 10-40-fold above basal levels of chloramphenicol acetyltransferase activity. These functional studies, supported by electrophoretic mobility shift assays indicated that two sites were sufficient for transcription of the StAR promoter constructs: a non-consensus binding sequence (-81/-72) for CCAAT enhancer-binding protein beta (C/EBPbeta) and a consensus motif for GATA-4 binding (-61/-66). Western analyses showed that GATA-4 is constitutively expressed in the granulosa cells, while all isoforms of C/EBPbeta were markedly inducible by FSH. Site-directed mutations of both binding sequences practically ablated both basal and hormone-driven chloramphenicol acetyltransferase activities to less than 5% of the parental -96/+6 construct. Unlike earlier notions, elimination of potential binding sites for steroidogenic factor-1, a well known tissue-specific transcription factor, did not impair StAR transcription. Consequently, we propose that C/EBPbeta and GATA-4 represent a novel combination of transcription factors capable of conferring an acute response to hormones upon their concomitant binding to the StAR promoter.  (+info)

Cardiac expression of the Na(+)/Ca(2+) exchanger NCX1 is GATA factor dependent. (7/561)

The cardiac sarcolemmal Na(+)/Ca(2+) exchanger plays a primary role in Ca(2+) efflux and is important in regulating intracellular Ca(2+) and beat-to-beat contractility. Of the three Na(+)/Ca(2+) exchanger genes cloned (NCX1, NCX2, and NCX3), only NCX1 is expressed in cardiac myocytes. NCX1 has alternative promoters for heart, kidney, and brain tissue-specific transcripts. Analysis of the cardiac NCX1 promoter (at -336 bp) identified a cardiac-specific minimum promoter (at -137) and two GATA sites (at -75 and -145). In this study, gel shift and supershift analyses identified GATA-4 in primary neonatal cardiac myocytes. Site-directed mutagenesis of the GATA-4 site at -75 abolishes binding and reduces activity of the minimum and full-length promoters by >90 and approximately 60%, respectively. Mutation of the GATA site at -145 reduces activity of the full-length promoter by approximately 30%. Mutation of an E-box at -175 does not alter promoter activity.  (+info)

Reciprocal changes in the expression of transcription factors GATA-4 and GATA-6 accompany adrenocortical tumorigenesis in mice and humans. (8/561)

While certain genetic changes are frequently found in adrenocortical carcinoma cells, the molecular basis of adrenocortical tumorigenesis remains poorly understood. Given that the transcription factors GATA-4 and GATA-6 have been implicated in gene expression and cellular differentiation in a variety of tissues, including endocrine organs such as testis, we have now examined their expression in the developing adrenal gland, as well as in adrenocortical cell lines and tumors from mice and humans. Northern blot analysis and in situ hybridization revealed abundant GATA-6 mRNA in the fetal and postnatal adrenal cortex of the mouse. In contrast, little or no GATA-4 expression was detected in adrenal tissue during normal development. In vivo stimulation with ACTH or suppression with dexamethasone did not affect the expression of GATA-4 or GATA-6 in the murine adrenal gland. To assess whether changes in the expression of GATA-4 or GATA-6 accompany adrenocortical tumorigenesis, we employed an established mouse model. When gonadectomized, inhibin alpha/SV40 T-antigen transgenic mice develop adrenocortical tumors in a gonadotropin-dependent fashion. In striking contrast to the normal adrenal glands, GATA-6 mRNA was absent from adrenocortical tumors or tumor-derived cell lines, while GATA-4 mRNA and protein were abundantly expressed in the tumors and tumor cell lines. Analogous results were obtained with human tissue samples; GATA-4 expression was detected in human adrenocortical carcinomas but not in normal tissue, adenomas, or pheochromocytomas. Taken together these results suggest different roles for GATA-4 and GATA-6 in the adrenal gland, and implicate GATA-4 in adrenal tumorigenesis. Immunohistochemical detection of GATA-4 may serve as a useful marker in the differential diagnosis of human adrenal tumors.  (+info)