PC4 coactivates MyoD by relieving the histone deacetylase 4-mediated inhibition of myocyte enhancer factor 2C

Laura Micheli, Luca Leonardi, Filippo Conti, Pasquale Buanne, Nadia Canu, Maurizia Caruso, Felice Tirone

Research output: Contribution to journalArticle


Histone deacetylase 4 (HDAC4) negatively regulates skeletal myogenesis by associating with the myocyte enhancer factor 2 (MEF2) transcription factors. Our data indicate that the gene PC4 (interferon-related developmental regulator 1 [IFRD1], Tis7), which we have previously shown to be required for myoblast differentiation, is both induced by MyoD and potentiates the transcriptional activity of MyoD, thus revealing a positive regulatory loop between these molecules. Enhancement by PC4 of MyoD-dependent activation of muscle gene promoters occurs selectively through MEF2 binding sites. Furthermore, PC4 localizes in the nucleus of differentiating myoblasts, associates with MEF2C, and is able to counteract the HDAC4-mediated inhibition of MEF2C. This latter action can be explained by the observed ability of PC4 to dose dependency displace HDAC4 from MEF2C. Consistently, we have observed that (i) the region of PC4 that binds MEF2C is sufficient to counteract the inhibition by HDAC4; (ii) PC4, although able to bind HDAC4, does not inhibit the enzymatic activity of HDAC4; and (iii) PC4 overcomes the inhibition mediated by the amino-terminal domain of HDAC4, which associates with MEF2C but not with PC4. Together, our findings strongly suggest that PC4 acts as a coactivator of MyoD and MEF2C by removing the inhibitory effect of HDAC4, thus exerting a pivotal function during myogenesis.

Original languageEnglish
Pages (from-to)2242-2259
Number of pages18
JournalMolecular and Cellular Biology
Issue number6
Publication statusPublished - Mar 2005


ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cell Biology

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