title: Dermo-1, a multifunctional basic helix-loop-helix protein, represses MyoD transactivation via the HLH domain, MEF2 interaction, and chromatin deacetylation.
abstract: Dermo-1 is a multifunctional basic helix-loop-helix (bHLH) transcription factor that has been shown to be a potent negative regulator for gene transcription and apoptosis. To understand the molecular mechanisms that mediate the function of Dermo-1, we generated a series of Dermo-1 mutants and used a MyoD-mediated transcriptional activation model to characterize the roles of its N-terminal, bHLH, and C-terminal structural domains in transcriptional repression. Both the C-terminal and HLH domains of Dermo-1 were essential for its repression of MyoD-mediated transactivation. Dermo-1 repressed, in a dose-dependent fashion, the transactivation activity of myocyte enhancer factor 2 (MEF2), a protein known to cooperate with MyoD in activating E-box-dependent gene expression. Both the N- and C-terminal domains of Dermo-1, but not the bHLH domain, were required for the inhibition of MEF2, suggesting that Dermo-1 inhibits both MyoD- and MEF2-dependent transactivation but through different mechanisms. Dermo-1 interacted directly with MEF2 and selectively repressed the MEF2 transactivation domain. An overall increase of histone acetylation induced by trichostatin A treatment reduced Dermo-1 transcriptional repression activity, suggesting that histone deacetylation is involved in Dermo-1-mediated transcriptional repression. Together, these results suggest that MEF2 is an important target in Dermo-1-mediated transcriptional repression and provide initial evidence of the involvement of histone acetylation in Dermo-1 transcriptional repression.
authors.affiliation: Department of Internal Medicine and the Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
authors.forename: Xue Q
authors.initials: XQ
authors.lastname: Gong
authors.forename: Li
authors.initials: L
authors.lastname: Li
mesh_terms: D000107:Acetylation; D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D002843:Chromatin / Q000378:metabolism*; D018076:DNA, Complementary / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D006655:Histone Deacetylases; D006657:Histones / Q000378:metabolism; D006877:Hydroxamic Acids / Q000494:pharmacology; D008156:Luciferases / Q000378:metabolism; D064326:MEF2 Transcription Factors; D051379:Mice; D008954:Models, Biological; D008969:Molecular Sequence Data; D009154:Mutation; D017570:MyoD Protein / Q000737:chemistry*; D018006:Myogenic Regulatory Factors; D017354:Point Mutation; D011233:Precipitin Tests; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012097:Repressor Proteins; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000737:chemistry* / Q000378:metabolism*; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014162:Transfection; D051879:Twist-Related Protein 1
chemical_list: D002843:Chromatin; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D006657:Histones; D006877:Hydroxamic Acids; D064326:MEF2 Transcription Factors; D017570:MyoD Protein; D018006:Myogenic Regulatory Factors; D012097:Repressor Proteins; D014157:Transcription Factors; D051879:Twist-Related Protein 1; C096852:Twist2 protein, mouse; C012589:trichostatin A; D008156:Luciferases; D006655:Histone Deacetylases