Dermo-1, a Multifunctional Basic Helix-Loop-Helix Protein, Represses MyoD Transactivation via the HLH Domain, MEF2 Interaction, and Chromatin Deacetylation*
- Xue Q. Gong and
- Li Li‡
- From the Department of Internal Medicine and the Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, Michigan 48201
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.
Footnotes
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↵* This work was supported by NHLBI, National Institutes of Health Grant HL58916-01A1 (to L. L.).The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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↵‡ To whom correspondence should be addressed: Program in Molecular and Cellular Cardiology, Dept. of Internal Medicine, Wayne State University, 421 E. Canfield Ave., No. 1107, Detroit, MI 48201. Tel.: 313-577-8749; Fax: 313-577-8615; E-mail: lili@med.wayne.edu.
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Published, JBC Papers in Press, January 23, 2002, DOI 10.1074/jbc.M110228200
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↵2 X. Q. Gong and L. Li, unpublished results.
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↵3 E. N. Olson, personal communication.
- Abbreviations:
- bHLH
-
basic helix-loop-helix
- MEF2
-
myocyte enhancer factor 2
- HDAC
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histone deacetylase
- NLS
-
nuclear localization signal
- tk
-
tyrosine kinase
- TSA
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trichostatin A
- DAB
-
3,3′-diaminobenzidine
- MCK
-
muscle creatine kinase
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- Received October 24, 2001.
- Revision received December 31, 2001.
- The American Society for Biochemistry and Molecular Biology, Inc.
