Differential roles for MBD2 and MBD3 at methylated CpG islands, active promoters and binding to exon sequences

Nucleic Acids Res. 2013 Mar 1;41(5):3010-21. doi: 10.1093/nar/gkt035. Epub 2013 Jan 29.

Abstract

The heterogeneous collection of nucleosome remodelling and deacetylation (NuRD) complexes can be grouped into the MBD2- or MBD3-containing complexes MBD2-NuRD and MBD3-NuRD. MBD2 is known to bind to methylated CpG sequences in vitro in contrast to MBD3. Although functional differences have been described, a direct comparison of MBD2 and MBD3 in respect to genome-wide binding and function has been lacking. Here, we show that MBD2-NuRD, in contrast to MBD3-NuRD, converts open chromatin with euchromatic histone modifications into tightly compacted chromatin with repressive histone marks. Genome-wide, a strong enrichment for MBD2 at methylated CpG sequences is found, whereas CpGs bound by MBD3 are devoid of methylation. MBD2-bound genes are generally lower expressed as compared with MBD3-bound genes. When depleting cells for MBD2, the MBD2-bound genes increase their activity, whereas MBD2 plus MBD3-bound genes reduce their activity. Most strikingly, MBD3 is enriched at active promoters, whereas MBD2 is bound at methylated promoters and enriched at exon sequences of active genes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Binding Sites
  • Cell Line
  • CpG Islands*
  • DNA Methylation
  • DNA-Binding Proteins / metabolism
  • DNA-Binding Proteins / physiology*
  • Epigenesis, Genetic
  • Euchromatin / metabolism
  • Exons*
  • Genome, Human
  • Humans
  • Promoter Regions, Genetic*
  • Protein Binding
  • Protein Isoforms / metabolism
  • Protein Isoforms / physiology
  • Protein Transport
  • Rats
  • Transcription Initiation Site

Substances

  • DNA-Binding Proteins
  • Euchromatin
  • MBD2 protein, human
  • MBD3 protein, human
  • Protein Isoforms