TACC3 mediates the association of MBD2 with histone acetyltransferases and relieves transcriptional repression of methylated promoters

Nucleic Acids Res. 2006 Jan 12;34(1):364-72. doi: 10.1093/nar/gkj400. Print 2006.

Abstract

We have recently reported that a novel MBD2 interactor (MBDin) has the capacity to reactivate transcription from MBD2-repressed methylated promoters even in the absence of demethylation events. Here we show that another unrelated protein, TACC3, displays a similar activity on methylated genes. In addition the data reported here provide possible molecular mechanisms for the observed phenomenon. Immunoprecipitation experiments showed that MBD2/TACC3 form a complex in vivo with the histone acetyltransferase pCAF. MBD2 could also associate with HDAC2, a component of MeCP1 repression complex. However, we found that the complexes formed by MBD2 with TACC3/pCAF and with HDAC2 were mutually exclusive. Moreover, HAT enzymatic assays demonstrated that HAT activity associates with MBD2 in vivo and that such association significantly increased when TACC3 was over-expressed. Overall our findings suggest that TACC3 can be recruited by MBD2 on methylated promoters and is able to reactivate transcription possibly by favoring the formation of an HAT-containing MBD2 complex and, thus, switching the repression potential of MBD2 in activation even prior to eventual demethylation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Nucleus / enzymology
  • Centrosome / chemistry
  • DNA Methylation*
  • DNA-Binding Proteins / analysis
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Gene Silencing
  • Histone Acetyltransferases / metabolism*
  • Humans
  • Immunoprecipitation
  • Microtubule-Associated Proteins / physiology*
  • Promoter Regions, Genetic
  • Sequence Deletion
  • Transcription, Genetic
  • Transcriptional Activation*
  • Two-Hybrid System Techniques

Substances

  • DNA-Binding Proteins
  • MBD2 protein
  • Microtubule-Associated Proteins
  • TACC3 protein, human
  • Histone Acetyltransferases