Vgl-4, a Novel Member of the Vestigial-like Family of Transcription Cofactors, Regulates α1-Adrenergic Activation of Gene Expression in Cardiac Myocytes

Abstract

Cardiac and skeletal muscle genes are regulated by the transcriptional enhancer factor (TEF-1) family of transcription factors. In skeletal muscle, TEF-1 factors interact with a skeletal muscle-specific cofactor called Vestigial-like 2 (Vgl-2) that is related to the Drosophila protein Vestigial. Here, we characterize Vgl-4, the only member of the Vestigial-like family expressed in the heart. Unlike other members of the Vgl family that have a single TEF-1 interaction domain called the tondu (TDU) motif, Vgl-4 has two TDU motifs in its carboxyl-terminal domain. Like other Vgl factors, Vgl-4 physically interacts with TEF-1 in an immunoprecipitation assay. Vgl-4 functionally interacts with TEF-1 and also with myocyte enhancer factor 2 in a mammalian two-hybrid assay. Overexpression of Vgl-4 in cardiac myocytes interfered with the basal expression and α1-adrenergic receptor-dependent activation of a TEF-1-dependent skeletal α-actin promoter. In cardiac myocytes cultured in serum and in serum-free medium, a myc-tagged Vgl-4 protein was located in the nucleus and cytoplasm but was exported from the nucleus when cells were treated with α1-adrenergic receptor agonist. A chimeric nuclear-retained Vgl-4 protein inhibited α1-adrenergic receptor-dependent activation. In contrast, deletion of the TDU motifs of Vgl-4 prevented Vgl-4 nuclear localization, relieved Vgl-4 interference of basal activity, and enhanced α1-adrenergic up-regulation of the skeletal α-actin promoter. Nuclear export of Vgl-4 is dependent on the nuclear exportin CRM-1. These results suggest that Vgl-4 modulates the activity of TEF-1 factors and counteracts α1-adrenergic activation of gene expression in cardiac myocytes. Cardiac and skeletal muscle genes are regulated by the transcriptional enhancer factor (TEF-1) family of transcription factors. In skeletal muscle, TEF-1 factors interact with a skeletal muscle-specific cofactor called Vestigial-like 2 (Vgl-2) that is related to the Drosophila protein Vestigial. Here, we characterize Vgl-4, the only member of the Vestigial-like family expressed in the heart. Unlike other members of the Vgl family that have a single TEF-1 interaction domain called the tondu (TDU) motif, Vgl-4 has two TDU motifs in its carboxyl-terminal domain. Like other Vgl factors, Vgl-4 physically interacts with TEF-1 in an immunoprecipitation assay. Vgl-4 functionally interacts with TEF-1 and also with myocyte enhancer factor 2 in a mammalian two-hybrid assay. Overexpression of Vgl-4 in cardiac myocytes interfered with the basal expression and α1-adrenergic receptor-dependent activation of a TEF-1-dependent skeletal α-actin promoter. In cardiac myocytes cultured in serum and in serum-free medium, a myc-tagged Vgl-4 protein was located in the nucleus and cytoplasm but was exported from the nucleus when cells were treated with α1-adrenergic receptor agonist. A chimeric nuclear-retained Vgl-4 protein inhibited α1-adrenergic receptor-dependent activation. In contrast, deletion of the TDU motifs of Vgl-4 prevented Vgl-4 nuclear localization, relieved Vgl-4 interference of basal activity, and enhanced α1-adrenergic up-regulation of the skeletal α-actin promoter. Nuclear export of Vgl-4 is dependent on the nuclear exportin CRM-1. These results suggest that Vgl-4 modulates the activity of TEF-1 factors and counteracts α1-adrenergic activation of gene expression in cardiac myocytes. Differentiation of cardiac and skeletal muscle from pluripotent embryonic stem cells requires the selective activation of a limited number of transcription factors that drive the expression of many genes that confer the tissue-specific phenotype. The transcriptional enhancer factor-1 (TEF-1) 1The abbreviations used are: TEF-1, transcriptional enhancer factor-1; Vgl, Vestigial-like; TDU, tondu; MEF2, myocyte enhancer factor 2.1The abbreviations used are: TEF-1, transcriptional enhancer factor-1; Vgl, Vestigial-like; TDU, tondu; MEF2, myocyte enhancer factor 2. family of transcription factors is required for muscle-specific gene activation. TEF-1 was identified from the characterization of the cardiac troponin T promoter. Cardiac troponin T is expressed in fetal skeletal muscle and in cardiac muscle. Mutation analysis of the cardiac troponin T promoter showed that the MCAT element (originally defined as a muscle-specific cytidine-adenosine-thymidine sequence, 5′-CATTCCT-3′) is required for high levels of promoter activity in cardiac and skeletal muscle cells (1Mar J.H. Ordahl C.P. Proc. Natl. Acad. Sci. U. S. A. 1988; 85: 6404-6408Crossref PubMed Scopus (113) Google Scholar, 2Mar J.H. Ordahl C.P. Mol. Cell. Biol. 1990; 10: 4271-4283Crossref PubMed Scopus (148) Google Scholar). Similar MCAT elements have been characterized in a large number of skeletal and cardiac muscle-specific promoters (3Larkin S.B. Farrance I.K.G. Ordahl C.P. Mol. Cell. Biol. 1996; 16: 3742-3755Crossref PubMed Scopus (72) Google Scholar). The transcription factor that binds to this element was identified as the SV40 enhancer-binding factor TEF-1 (4Farrance I.K. Mar J.H. Ordahl C.P. J. Biol. Chem. 1992; 267: 17234-17240Abstract Full Text PDF PubMed Google Scholar). TEF-1 is expressed in many tissues (5Stewart A.F.R. Richard III, C.W. Suzow J. Stephan D. Weremowicz S. Morton C.C. Adra C.N. Genomics. 1996; 37: 68-76Crossref PubMed Scopus (35) Google Scholar), and TEF-1 has also been implicated in placenta-specific enhancer function (6Jiang S.-W. Eberhardt N.L. J. Biol. Chem. 1994; 269: 10384-10392Abstract Full Text PDF PubMed Google Scholar, 7Jacquemin P. Oury C. Belayew A. Martial J.A. DNA Cell Biol. 1994; 13: 1037-1045Crossref PubMed Scopus (15) Google Scholar). Thus, the mechanism whereby TEF-1 confers tissue specificity to an MCAT-bearing promoter has been ascribed to the interaction of TEF-1 with tissue-specific cofactors. For example, both the human placental lactogen promoter (6Jiang S.-W. Eberhardt N.L. J. Biol. Chem. 1994; 269: 10384-10392Abstract Full Text PDF PubMed Google Scholar, 7Jacquemin P. Oury C. Belayew A. Martial J.A. DNA Cell Biol. 1994; 13: 1037-1045Crossref PubMed Scopus (15) Google Scholar) and the β-myosin heavy chain promoter (8Tsika R.W. McCarthy J. Karasseva N. Ou Y. Tsika G.L. Am. J. Physiol. Cell Physiol. 2002; 283: C1761-C1775Crossref PubMed Scopus (12) Google Scholar, 9Huey K.A. Haddad F. Qin A.X. Baldwin K.M. Am. J. Physiol. Cell Physiol. 2003; 284: C738-C748Crossref PubMed Scopus (25) Google Scholar) contain MCAT elements and are TEF-1-dependent for their specific expression in placenta and muscle, respectively. Thus, placenta- and muscle-specific TEF-1 cofactors must confer tissue-specific activity of TEF-1-dependent promoters. Studies in Drosophila have identified an important role for a cofactor of the TEF-1 homologue scalloped during wing and flight muscle differentiation (10Bate M. Rushton E. C. R. Acad. Sci. (Paris). 1993; 316: 1047-1061PubMed Google Scholar, 11Sudarsan V. Anant S. Guptan P. VijayRaghavan K. Skaer H. Dev. Cell. 2001; 1: 829-839Abstract Full Text Full Text PDF PubMed Scopus (71) Google Scholar). This cofactor, called Vestigial, is critical for the development and patterning of the wing: loss of Vestigial results in a failure of wing development, and ectopic expression of Vestigial in tissues of the eyes, legs, and antennae leads to the development of ectopic wing tissue (12Kim J. Sebring A. Esch J.J. Kraus M.E. Vorwerk K. Magee J. Carroll S.B. Nature. 1996; 382: 133-138Crossref PubMed Scopus (395) Google Scholar, 13Halder G. Polaczyk P. Kraus M.E. Hudson A. Kim J. Laughon A. Carroll S. Genes Dev. 1998; 12: 3900-3909Crossref PubMed Scopus (185) Google Scholar). Binding of Vestigial switches the DNA target selectivity of the Scalloped protein (14Halder G. Carroll S.B. Development (Camb.). 2001; 128: 3295-3305PubMed Google Scholar) and activates many wing and flight muscle-specific genes. These studies suggest that Vestigial acts as a selector protein controlling tissue-specific gene activation during organogenesis. We and others have identified mammalian homologues of Vestigial (14Halder G. Carroll S.B. Development (Camb.). 2001; 128: 3295-3305PubMed Google Scholar, 15Vaudin P. Delanoue R. Davidson I. Silber J. Zider A. Development (Camb.). 1999; 126: 4807-4816Crossref PubMed Google Scholar, 16Maeda T. Chapman D.L. Stewart A.F.R. J. Biol. Chem. 2002; 277: 48889-48898Abstract Full Text Full Text PDF PubMed Scopus (118) Google Scholar, 17Mielcarek M. Günther S. Kruger M. Braun T. Mech. Dev. 2002; 119: S269-S274Crossref PubMed Scopus (25) Google Scholar). The first human homologue of Vestigial was named Tondu (the French word for “shaved”), perhaps because it could partially rescue the wing phenotype caused by a null mutation in Drosophila Vestigial (15Vaudin P. Delanoue R. Davidson I. Silber J. Zider A. Development (Camb.). 1999; 126: 4807-4816Crossref PubMed Google Scholar). In a Northern blot of fetal human tissues, Tondu was found to be expressed in the kidney and lung, but not in the brain or the heart (15Vaudin P. Delanoue R. Davidson I. Silber J. Zider A. Development (Camb.). 1999; 126: 4807-4816Crossref PubMed Google Scholar). Tondu was shown to physically and functionally interact with TEF-1 through a conserved sequence called the tondu (TDU) motif. We also identified this factor but named it Vestigial-like (Vgl)-1. Northern blot analysis of adult human tissues showed that it is expressed almost exclusively in the placenta (16Maeda T. Chapman D.L. Stewart A.F.R. J. Biol. Chem. 2002; 277: 48889-48898Abstract Full Text Full Text PDF PubMed Scopus (118) Google Scholar). We identified two other genes that bear a TDU motif and called them Vgl-2 and Vgl-3, although these proteins have little homology outside the TDU motif. Vgl-3 was also found to be placenta-specific. Thus, Vgl-1 and Vgl-3 likely contribute to the placenta-specific activity of TEF-1. In the adult, Vgl-2 was detected only in skeletal muscle. Vgl-2 is expressed in the myogenic cell line C2C12, and Vgl-2 mRNA levels increase during muscle differentiation. Using a mammalian two-hybrid assay, we found that Vgl-2 also interacts with TEF-1 factors through its TDU motif. In addition, we found that Vgl-2 uses the TDU motif to interact with the transcription factor myocyte enhancer factor (MEF) 2 (16Maeda T. Chapman D.L. Stewart A.F.R. J. Biol. Chem. 2002; 277: 48889-48898Abstract Full Text Full Text PDF PubMed Scopus (118) Google Scholar). Interestingly, Vgl-2 activated a TEF-1-dependent promoter and a MEF2-dependent promoter in myotubes, but not in myoblasts. By in situ hybridization in fetal mice, Vgl-2 mRNA appeared in early muscle precursors together with the myogenic differentiation factor myogenin (16Maeda T. Chapman D.L. Stewart A.F.R. J. Biol. Chem. 2002; 277: 48889-48898Abstract Full Text Full Text PDF PubMed Scopus (118) Google Scholar). Co-expression of Vgl-2 with MyoD, another myogenic differentiation factor, enhanced MyoD-induced muscle differentiation of 10T½ cells with a 7-fold increase in myosin heavy chain expression (16Maeda T. Chapman D.L. Stewart A.F.R. J. Biol. Chem. 2002; 277: 48889-48898Abstract Full Text Full Text PDF PubMed Scopus (118) Google Scholar). From these functional properties, because Vgl-2 is skeletal muscle-specific and is expressed at the onset of skeletal muscle differentiation in the somitic myotome, Vgl-2 likely accounts for the skeletal muscle-specific function ascribed to TEF-1. However, a similar tissue-restricted member of the Vestigial-like family of cofactors had not been identified in the heart. Differentiation of cardiac muscle progenitor cells involves the selective activation of the GATA4 and Nkx2.5 transcription factors in pluripotent mesoderm (18Komuro I. Izumo S. Proc. Natl. Acad. Sci. U. S. A. 1993; 90: 8145-8149Crossref PubMed Scopus (462) Google Scholar, 19Kuo C.T. Morrisey E.E. Anandappa R. Sigrist K. Lu M.M. Parmacek M.S. Soudais C. Leiden J.M. Genes Dev. 1997; 11: 1048-1060Crossref PubMed Scopus (868) Google Scholar, 20Sepulveda J.L. Belaguli N. V. M. Mol. Cell. Biol. 1998; PubMed Scopus Google Scholar). However, because mutation of TEF-1 in the promoters of genes a loss of tissue specificity J.H. Ordahl C.P. Mol. Cell. Biol. 1990; 10: 4271-4283Crossref PubMed Scopus (148) Google Scholar), and because of TEF-1 expression cardiac development and an embryonic phenotype P. Genes Dev. 1994; PubMed Scopus Google Scholar), these studies a role for TEF-1 factors in cardiac In the adult, cardiac myocytes to by cell cardiac myocytes are to be as the α1-adrenergic receptor the expression of a number of genes expressed in the fetal heart K. Farrance I.K. J. Biol. Chem. 1993; Full Text PDF PubMed Google Scholar, K. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar) and also partially specific of the cell members of the family of transcription factors D. K.A. G. J. Biol. Chem. 2003; Full Text Full Text PDF PubMed Scopus Google Scholar) and J. C.C. R. J. S. 2002; PubMed Scopus Google Scholar). Thus, myocytes through the of the cell but to a TEF-1 factors have been implicated in the activation of fetal genes in to K. Farrance I.K. J. Biol. Chem. 1993; Full Text PDF PubMed Google Scholar, K. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, Farrance I.K. J. Mol. Cell. 2003; Full Text Full Text PDF PubMed Scopus Google Scholar, A.F.R. Suzow J. T. T. 1998; PubMed Scopus Google Scholar, T. C. Suzow Stewart A.F.R. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, T. Farrance I.K. Stewart A.F.R. J. Biol. Chem. 2002; 277: Full Text Full Text PDF PubMed Scopus Google Scholar). cardiac myocytes could be to and the cell this an to and of adult stem cells could also a of tissue D. M. F. S. H. M. E. K. A. J. P. Cell. 2003; Full Text Full Text PDF PubMed Scopus Google Scholar). In the we characterized Vgl-4, a member of the Vgl family of TEF-1 cofactors. Vgl-4 was identified as a expressed in an adult human stem cell line T. N. A. K. N. DNA 2 PubMed Scopus Google Scholar). Vgl-4 is the only Vgl member expressed in the heart. Unlike other members of the Vestigial Vgl-4 has two TDU that Vgl-4 a TEF-1 and transcription factors. two-hybrid analysis showed that Vgl-4 interacts with and TEF-1. Overexpression of Vgl-4 in in cardiac myocytes a skeletal α-actin promoter and interfered with its α1-adrenergic Vgl-4 to the cytoplasm with α1-adrenergic that it is of a phenotype. the functional role of Vgl-4 in cardiac development to be its interaction with and of cardiac and skeletal muscle transcription factors a of cardiac muscle differentiation. and human and Vgl-4 were from The human Vgl-4 was from the and by and used for Northern blot analysis of gene expression with a Northern blot The was the human expression a myc-tagged Vgl-4 the Vgl-4 in the expression was by a with and a The was to a to the From the an myc-tagged Vgl-4 was the expression to the A chimeric the domain of TEF-1 the domain and nuclear to the sequence was by an of TEF-1 to a of an A expression the TDU motifs was by and a of the from For the mammalian two-hybrid the was The the sequence for the domain to the human TEF-1 and the sequence to the have been (16Maeda T. Chapman D.L. Stewart A.F.R. J. Biol. Chem. 2002; 277: 48889-48898Abstract Full Text Full Text PDF PubMed Scopus (118) Google Scholar). The the activation domain of the was with and A of the human Vgl-4 of the of Vgl-4 was to the to the The both and was by in an and to an in Vgl-4, the sequence for The was by a for of human Vgl-4 the at the The was by a for the the and the were at the of In and and were with and in to human TEF-1 and myc-tagged Vgl-4 of was also used to proteins for were with protein in and with was with TEF-1 and a and TEF-1 protein was with and with a were by the was and proteins were on a and cardiac myocytes were as P. J. PubMed Scopus Google Scholar), that in and was for were cultured at of a in with fetal serum and to the was with and the for 2 with medium, as (16Maeda T. Chapman D.L. Stewart A.F.R. J. Biol. Chem. 2002; 277: 48889-48898Abstract Full Text Full Text PDF PubMed Scopus (118) Google Scholar). cells were in serum-free for 2 and for the assay, as (16Maeda T. Chapman D.L. Stewart A.F.R. J. Biol. Chem. 2002; 277: 48889-48898Abstract Full Text Full Text PDF PubMed Scopus (118) Google Scholar). of the skeletal α-actin promoter were to basal activity when with expression and at By of the skeletal α-actin promoter to in the of TEF-1 transcription factors and the Vgl-4 cofactor were from the in the of expression at the in with fetal serum in were with of the and of the and expression For of cells and cardiac myocytes were and on were and in and in The myc-tagged protein was detected a and with heavy chain was Studies of with were with Vgl-4 was identified in the as a protein two TDU motifs A nuclear export and for interaction with the nuclear exportin the sequence M. Cell 2003; PubMed Scopus Google Scholar) was also identified in as a protein by a from a human stem cell line T. N. A. K. N. DNA 2 PubMed Scopus Google Scholar), Vgl-4 is the Vgl family of cofactors in that its expression is not tissue-restricted in the adult human Vgl-1 and Vgl-3 are and Vgl-2 is skeletal muscle-specific (16Maeda T. Chapman D.L. Stewart A.F.R. J. Biol. Chem. 2002; 277: 48889-48898Abstract Full Text Full Text PDF PubMed Scopus (118) Google Scholar), Vgl-4 is expressed in the and brain as as in other tissues at blot analysis of Vgl-4 expression in human A human Northern blot with was for Vgl-4 Vgl-4 expression was in the and of is the two TDU motifs from for other members of the Vgl family we Vgl-4 could also interact with TEF-1 interaction TEF-1 and Vgl-4 was by two-hybrid analysis in cells and interaction was by In addition, Vgl-1 and Vgl-2 (16Maeda T. Chapman D.L. Stewart A.F.R. J. Biol. Chem. 2002; 277: 48889-48898Abstract Full Text Full Text PDF PubMed Scopus (118) Google Scholar), Vgl-4 interacts with Interestingly, when the and the were both expressed with a interaction was with and the other Vgl-1 a single TDU motif, and when was with and enhanced interaction was not not that the of TDU motifs in Vgl-4 TEF-1 and to to Vgl-4 at the deletion of both TDU motifs in Vgl-4 Vgl-4 interaction with TEF-1 and with TEF-1 and with TDU motif was to interaction with TEF-1 or TDU motifs are required for Vgl-4 interaction with TEF-1 and Using the mammalian two-hybrid in an deletion of the TDU motifs in human Vgl-4 its interaction with TEF-1 and The motif with TEF-1 but not with In contrast, the motif not interact with TEF-1 but with the interaction Vgl-4 and TEF-1 modulates the transcriptional activity of TEF-1, we used the mammalian two-hybrid in cardiac myocytes Vgl-4 not the expression of the promoter with to the TEF-1 is a transcriptional of a in cardiac myocytes but not in cells as (16Maeda T. Chapman D.L. Stewart A.F.R. J. Biol. Chem. 2002; 277: 48889-48898Abstract Full Text Full Text PDF PubMed Scopus (118) Google Scholar). gene expression in the of but not in the of the domain Thus, α1-adrenergic TEF-1 transcriptional Vgl-4 and TEF-1 was also in cardiac myocytes with as it was in cells However, in the of Vgl-4, the α1-adrenergic of TEF-1 function was prevented with Vgl-4 modulates the α1-adrenergic of TEF-1 a myc-tagged Vgl-4 protein was expressed in cardiac myocytes by In cardiac myocytes cultured in fetal serum or in serum-free medium, was in the nucleus A and However, was exported to the and little in the of cultured cardiac myocytes Vgl-4 gene expression in cardiac the of Vgl-4 was on a TEF-1-dependent promoter Vgl-4 the basal activity of the promoter that Vgl-4 is a of TEF-1. The gene is by the α1-adrenergic to The of the skeletal α-actin promoter to was by TEF-1 by Vgl-4 or when Vgl-4 was with TEF-1 that Vgl-4 is exported from the nucleus of cardiac myocytes the of Vgl-4 to the α1-adrenergic activation of the skeletal α-actin promoter be enhanced it were to in the a nuclear could nuclear export of Vgl-4, a chimeric protein was the nuclear of TEF-1 to This chimeric is not exported from the nucleus of cardiac myocytes treated with and on the skeletal α-actin the chimeric protein that is to nuclear export the α1-adrenergic the other the carboxyl-terminal domain of Vgl-4 both TDU motifs caused of Vgl-4 and and the α1-adrenergic up-regulation of the skeletal α-actin promoter the mechanism that nuclear of Vgl-4 in cardiac myocytes requires the nuclear exportin as by the of a nuclear export cardiac myocytes treated with were also treated with the nuclear export of Vgl-4 in cardiac myocytes. In the we have identified Vgl-4 as a member of the Vgl family of transcription cofactors. Vgl-4 is expressed in tissues, with the expression in the by the kidney and brain This is the first member of the Vestigial family to be identified in the heart. Like other members of this by the TDU motif, Vgl-4 interacts with TEF-1 and in cultured Thus, Vgl-4 a of transcription factors and cofactors to interact with TEF-1. Vgl-4 two TDU motifs required for the interaction with TEF-1 and MEF2, as by the two-hybrid analysis and Vgl-4 an important function TEF-1 and in cardiac muscle. The of two TDU motifs in Vgl-4 is Vgl family members but is also in proteins of Drosophila and that are from Vestigial. However, the function of these other Vestigial-like factors is not Interestingly, the first and TDU motifs of the Drosophila protein are and are from other to the TDU motifs in Vgl-4, that these motifs are conserved and be functionally In of this and showed selective interaction with TEF-1 and MEF2, The of another protein in Drosophila TDU motifs to a of the Vgl TEF-1 a with other transcription factors the Ordahl C.P. Mol. Cell. Biol. 1999; PubMed Scopus Google Scholar), the serum factor M. P. Belaguli J. Biol. Chem. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar), and T. Stewart A.F.R. 2002; PubMed Scopus Google Scholar). transcriptional the proteins J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar), the protein A. H. Y. Genes Dev. 2001; PubMed Scopus Google Scholar), and Vgl-2 (16Maeda T. Chapman D.L. Stewart A.F.R. J. Biol. Chem. 2002; 277: 48889-48898Abstract Full Text Full Text PDF PubMed Scopus (118) Google Scholar) are to transcription from an promoter. Unlike Vgl-2 in skeletal muscle, Vgl-4 to be a of TEF-1-dependent gene expression in cardiac myocytes when on the TEF-1-dependent skeletal α-actin promoter and on the β-myosin heavy chain promoter not Vgl-4 interfered with the activity of a MEF2-dependent myosin chain promoter in cardiac myocytes not Vgl-4 interference with TEF-1-dependent promoter activity basal that Vgl-4 is a cofactor or that Vgl-4 a factor to TEF-1. Vgl-4 is a cofactor, its interaction with TEF-1 have skeletal α-actin promoter Vgl-4 a factor to TEF-1, Vgl-4 interaction with TEF-1 Vgl-4 to for to the factor with Vgl-4, the of the TEF-1 and increase the activity of the skeletal α-actin promoter. with the a Vgl-4 the TDU motifs the basal activity of the skeletal α-actin promoter The skeletal α-actin promoter is activated by α1-adrenergic and this requires TEF-1 transcription factors K. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, A.F.R. Suzow J. T. T. 1998; PubMed Scopus Google Scholar, T. C. Suzow Stewart A.F.R. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, T. Farrance I.K. Stewart A.F.R. J. Biol. Chem. 2002; 277: Full Text Full Text PDF PubMed Scopus Google Scholar). we a activation of the skeletal α-actin promoter by α1-adrenergic T. Farrance I.K. Stewart A.F.R. J. Biol. Chem. 2002; 277: Full Text Full Text PDF PubMed Scopus Google Scholar). Here, we found that the of during myocyte the to to not The of the skeletal α-actin promoter in the of expression the activity of TEF-1 transcription factors T. C. Suzow Stewart A.F.R. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, T. Farrance I.K. Stewart A.F.R. J. Biol. Chem. 2002; 277: Full Text Full Text PDF PubMed Scopus Google Scholar). with TEF-1 inhibited the to A.F.R. Suzow J. T. T. 1998; PubMed Scopus Google Scholar), that TEF-1 cofactors. Overexpression of Vgl-4 also the α1-adrenergic activation of the skeletal α-actin promoter Vgl-4 TEF-1 by two by a to TEF-1, as basal or by α1-adrenergic of TEF-1. The two-hybrid analysis of the of Vgl-4 basal and α1-adrenergic in cardiac myocytes of a promoter was activated by a protein basal and was activated in to α1-adrenergic The of to the in to α1-adrenergic was in the of a chimeric protein the activation domain of to Vgl-4 Thus, Vgl-4 with TEF-1 Nuclear of Vgl-1 on its interaction with TEF-1 because Vgl-4 interaction with TEF-1 by the TDU motifs caused of Vgl-4 Interestingly, Vgl-4 of the nucleus of cardiac myocytes treated with the α1-adrenergic that Vgl-4 is required to the α1-adrenergic nuclear of Vgl-4 in a chimeric a nuclear the α1-adrenergic of the skeletal α-actin promoter of a Vgl-4 the TDU motifs that is in the cytoplasm the α1-adrenergic of the skeletal α-actin promoter Overexpression of Vgl-4 likely the nuclear export and the of nuclear Vgl-4 could for the interference of the α1-adrenergic Vgl-4 a nuclear export a of the nuclear exportin M. Cell 2003; PubMed Scopus Google Scholar). studies that the nuclear export of Vgl-4 in cardiac myocytes A mechanism controlling nuclear of the cardiac transcription factor GATA4 in to has been C. K. Y. J. J. Biol. Chem. 2001; Full Text Full Text PDF PubMed Scopus Google Scholar). of interaction with GATA4 and its nuclear development, GATA4 the expression of the gene Nkx2.5 that cardiac myocyte differentiation III, E. M. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar). the nuclear export domain of Vgl-4 by the and nuclear export through a is to a fetal gene and to partially of the cell in a of cardiac myocyte K. Farrance I.K. J. Biol. Chem. 1993; Full Text PDF PubMed Google Scholar, K. J. Biol. Chem. Full Text Full Text PDF PubMed Scopus Google Scholar, D. K.A. G. J. Biol. Chem. 2003; Full Text Full Text PDF PubMed Scopus Google Scholar, J. C.C. R. J. S. 2002; PubMed Scopus Google Scholar). In this it is important to that the Drosophila Vestigial protein is required for cell in the wing C. Development (Camb.). 2002; Google Scholar, S. Zider A. P. Silber J. Dev. Genes 1998; PubMed Scopus Google Scholar), that members of the Vestigial family of transcription cofactors in the from to cell and differentiation. Thus, the nuclear of Vgl-4 a role in cardiac myocyte differentiation. we not the genes that are regulated by Vgl-4 through their interaction with TEF-1 factors, likely of this interaction is a in DNA specificity at muscle-specific promoters. In Vestigial interaction with Scalloped DNA specificity and activates many genes (14Halder G. Carroll S.B. Development (Camb.). 2001; 128: 3295-3305PubMed Google Scholar) and the differentiation of flight V. Anant S. Guptan P. VijayRaghavan K. Skaer H. Dev. Cell. 2001; 1: 829-839Abstract Full Text Full Text PDF PubMed Scopus (71) Google Scholar). Vgl-4 also TEF-1 target selectivity to be We are to for the of and