The Transcription Factors GATA4 and dHAND Physically Interact to Synergistically Activate Cardiac Gene Expression through a p300-dependent Mechanism

Background: Protein arginine methyltransferase 5 (PRMT5) is a type II protein arginine methyltransferase that catalyzes the symmetrical dimethylation of arginine residues within target proteins. Results: PRMT5 interacts with and methylates GATA4 in cardiomyocytes. Conclusion: PRMT5 suppresses hypertrophic responses in cardiomyocytes by attenuating GATA4 transcriptional activity. Significance: Targeting PRMT5 may represent a novel therapeutic strategy for preventing cardiac hypertrophy and heart failure.

Section: Discussionmentioning

confidence: 99%

Inhibition of Cardiomyocyte Hypertrophy by Protein Arginine Methyltransferase 5

Chen

Sun

2014

“…Recently, it was proposed that a larger enhanceosome complex mediates the cardiac-specific expression, where several transcription factors like GATA4, SRF, MEF-2, NFAT, and HAND2, interact with each other through indirect mechanisms that involve transcriptional scaffolding molecules. The co-activator p300/CBP has been proposed as one of the molecules involved in the formation of the cardiacspecific enhanceosome (29,36,37).…”

Section: Discussionmentioning

confidence: 99%

Transcriptional Analysis of the Human Cardiac Calsequestrin Gene in Cardiac and Skeletal Myocytes

Reyes-Juárez

Juárez-Rubí

Rodrı́guez

et al. 2007

Calsequestrin is the main calcium-binding protein inside the sarcoplasmic reticulum of striated muscle. In mammals, the cardiac calsequestrin gene (casq2) mainly expresses in cardiac muscle and to a minor extent in slow-twitch skeletal muscle and it is not expressed in non-muscle tissues. This work is the first study on the transcriptional regulation of the casq2 gene in cardiac and skeletal muscle cells. The sequence of the casq2 genes proximal promoter (180 bp) of mammals and avians is highly conserved and contains one TATA box, one CArG box, one E-box, and one myocyte enhancer factor 2 (MEF-2) site. We cloned the human casq2 gene 5 -regulatory region into a luciferase reporter expression vector. By functional assays we showed that a construct containing the first 288 bp of promoter was up-regulated during myogenic differentiation of Sol8 cells and had higher transcriptional activity compared with longer constructs. In neonatal rat cardiac myocytes, the larger construct containing 3.2 kb showed the highest transcriptional activity, demonstrating that the first 288 bp are sufficient to confer muscle specificity, whereas distal sequences may act as a cardiacspecific enhancer. Electrophoretic mobility shift assay studies demonstrated that the proximal MEF-2 and CArG box sequences were capable of binding MEF-2 and serum response factor, respectively, whereas the E-box did not show binding properties. Functional studies demonstrated that site-directed mutagenesis of the proximal MEF-2 and CArG box sites significantly decreased the transcription of the gene in cardiac and skeletal muscle cells, indicating that they are important to drive cardiac and skeletal musclespecific transcription of the casq2 gene.

“…MyoD-E12 associates with myocyte enhancer factor-2A, a member of the MADS family, to activate myogenesis, but only one of these factors (either myocyte enhancer factor-2A or the MyoD-E12 complex) needs to interact with the DNA to activate transcription (3). dHAND has been shown to associate with the bHLH proteins E12 (6) and eHAND (18) and GATA4 and p300 (19); and the cardiospecific enhancer adenylosuccinate synthetase was the first target gene for dHAND (20). However, all of these studies demonstrated the dependence of dHAND binding to E-boxes within the promoter region to activate gene expression.…”

mentioning

confidence: 90%

“…6B), we believe that dHAND and Arix directly interact at the DBH promoter region to cooperatively activate transcription. Recently, dHAND has been shown to make direct contacts with the HD protein Nkx2.5 (26) and GATA4 and p300 (19); and together, these factors are able to activate transcription of the atrial naturetic peptide promoter. However, the interaction between GATA4 and dHAND does not alter either the magnitude or the pattern of DNA binding of either protein (19).…”

Section: Dhand Interacts Independent Of Dna Bindingmentioning

confidence: 99%

“…Recently, dHAND has been shown to make direct contacts with the HD protein Nkx2.5 (26) and GATA4 and p300 (19); and together, these factors are able to activate transcription of the atrial naturetic peptide promoter. However, the interaction between GATA4 and dHAND does not alter either the magnitude or the pattern of DNA binding of either protein (19). The conclusions from that study suggest that contact with the coactivator p300 is needed for the cooperative interaction between dHAND and GATA4.…”

Section: Dhand Interacts Independent Of Dna Bindingmentioning

confidence: 99%

See 1 more Smart Citation

The Interaction between dHAND and Arix at the Dopamine β-Hydroxylase Promoter Region Is Independent of Direct dHAND Binding to DNA

Rychlik

Gerbasi

Lewis

2003

Dopamine ␤-hydroxylase (DBH) catalyzes the production of norepinephrine, and its expression defines the noradrenergic phenotype. Transcription factors dHAND, a basic helix-loop-helix protein, and Arix/ Phox2a, a homeoprotein, have been demonstrated to play a role in the differentiation and maintenance of catecholaminergic neurons. Three Arix regulatory sites have been identified in the DBH promoter proximal region, but there is no such evidence for dHAND. Cotransfection with a DBH promoter-luciferase reporter construct plus dHAND or dHAND-E12 expression plasmids did not alter luciferase activity, whereas transfection with Arix resulted in a 2.5-fold stimulation of luciferase activity. However, a 5.5-fold increase was observed when Arix and dHAND were combined, and an 8-fold level of expression was observed when Arix was transfected with a dHAND mutant lacking the basic DNAbinding domain. When the homeodomain sites in the DBH promoter proximal region were mutated, all activity was lost, demonstrating dependence upon Arix-DNA interaction for transcriptional activation. In electrophoretic mobility shift assays, the addition of dHAND decreased the amount of Arix needed to elicit a mobility shift with the DBH homeodomain sites, and the dHAND basic mutant potentiated Arix binding in a manner similar to wild-type dHAND. The dHAND-Arix complex was dissociated upon the addition of an unlabeled competitor containing a homeodomain, but not upon the addition of a competitor containing E-boxes. Arix coprecipitated with antisera directed against recombinant dHAND, demonstrating direct protein-protein interactions. These results indicate that the activation of the DBH promoter by Arix is potentiated by dHAND via a mechanism independent of a direct interaction of dHAND with DNA.Cell-specific transcription is accomplished by the precise and transient interactions of numerous and complex molecular factors. Basic helix-loop-helix (bHLH) 1 proteins are transcription factors that play an important role in the development and differentiation of specific cell types such as neurons (1), appendages (2), and myocytes (3, 4). These bHLH proteins have been shown to bind to defined consensus sites, E-boxes (CANNTG), through the basic domain and require dimerization partners (via helices) to activate transcription. These proteins have been divided into several classes based on structure, function, and tissue specificity. Class I bHLH proteins (E12 and E47) are expressed ubiquitously in all tissues and can function as homodimers, but prefer to form heterodimers with other bHLH proteins (5). Class II proteins (dHAND, NeuroD, and MyoD) are expressed in specific tissues and are believed to be functionally active when complexed with a class I protein (5, 6). dHAND/HAND2 (deciduum, heart, autonomic nervous system, and neural crest cell derivatives) is a 30-kDa member of the class II bHLH protein family (7,8) and has been detected in Xenopus, zebrafish, chicks, mice, and humans (9). dHAND is required for cardiac (7), vascular (10), and craniofacial...