Repression of bone morphogenetic protein and activin-inducible transcription by Evi-1

J Biol Chem. 2005 Jun 24;280(25):24227-37. doi: 10.1074/jbc.M414305200. Epub 2005 Apr 22.

Abstract

Smads, key effectors of transforming growth factor (TGF)-beta, activin, and bone morphogenetic protein (BMP) signaling, regulate gene expression and interact with coactivators and corepressors that modulate Smad activity. The corepressor Evi-1 exerts its oncogenic effects by repressing TGF-beta/Smad3-mediated transcription, thereby blocking TGF-beta-induced growth arrest. Because Evi-1 interacts with the highly conserved MH2 domain of Smad3, we investigated the physical and functional interaction of Evi-1 with Smad1 and Smad2, downstream targets of BMP and activin signaling, respectively. Evi-1 interacted with and repressed the receptor-activated transcription through Smad1 and Smad2, similarly to Smad3. In addition, Evi-1 repressed BMP/Smad1- and activin/Smad2-mediated induction of endogenous Xenopus gene expression, suggesting a role of repression of BMP and activin signals by Evi-1 in vertebrate embryogenesis. Evi-1 also repressed the induction of endogenous Smad7 expression by TGF-beta family ligands. In the course of these studies, we observed Evi-1 repression of Smad transactivation even when Smad binding to DNA was kept constant. We therefore explored the mechanism of Evi-1 repression of TGF-beta family-inducible transcription. Evi-1 repression did not result from displacement of Smad binding to DNA or to CREB-binding protein but from the recruitment of Evi-1 by Smad3 and CREB-binding protein to DNA. Following TGF-beta stimulation, Evi-1 and the associated corepressor CtBP were recruited to the endogenous Smad7 promoter. Evi-1 recruitment to the promoter decreased TGF-beta-induced histone acetylation, coincident with its repression of Smad7 gene expression. In this way, Evi-1 acts as a general Smad corepressor to inhibit TGF-beta-, activin-, and BMP-inducible transcription.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acetylation
  • Activins / physiology*
  • Animals
  • Bone Morphogenetic Proteins / physiology*
  • CREB-Binding Protein
  • Cell Line
  • DNA / metabolism
  • DNA-Binding Proteins / metabolism
  • DNA-Binding Proteins / physiology*
  • Gene Expression Regulation, Developmental / physiology
  • Histones / metabolism
  • Humans
  • MDS1 and EVI1 Complex Locus Protein
  • Nuclear Proteins / physiology
  • Polymerase Chain Reaction
  • Promoter Regions, Genetic
  • Protein Binding
  • Proto-Oncogenes / physiology*
  • Smad3 Protein
  • Trans-Activators / physiology
  • Transcription Factors / metabolism
  • Transcription Factors / physiology*
  • Transcription, Genetic / physiology*
  • Transforming Growth Factor beta / physiology
  • Xenopus

Substances

  • Bone Morphogenetic Proteins
  • DNA-Binding Proteins
  • Histones
  • MDS1 and EVI1 Complex Locus Protein
  • MECOM protein, human
  • Nuclear Proteins
  • SMAD3 protein, human
  • Smad3 Protein
  • Trans-Activators
  • Transcription Factors
  • Transforming Growth Factor beta
  • Activins
  • DNA
  • CREB-Binding Protein
  • CREBBP protein, human