Transcription factor occupancy can mediate active turnover of DNA methylation at regulatory regions

PLoS Genet. 2013;9(12):e1003994. doi: 10.1371/journal.pgen.1003994. Epub 2013 Dec 19.

Abstract

Distal regulatory elements, including enhancers, play a critical role in regulating gene activity. Transcription factor binding to these elements correlates with Low Methylated Regions (LMRs) in a process that is poorly understood. Here we ask whether and how actual occupancy of DNA-binding factors is linked to DNA methylation at the level of individual molecules. Using CTCF as an example, we observe that frequency of binding correlates with the likelihood of a demethylated state and sites of low occupancy display heterogeneous DNA methylation within the CTCF motif. In line with a dynamic model of binding and DNA methylation turnover, we find that 5-hydroxymethylcytosine (5hmC), formed as an intermediate state of active demethylation, is enriched at LMRs in stem and somatic cells. Moreover, a significant fraction of changes in 5hmC during differentiation occurs at these regions, suggesting that transcription factor activity could be a key driver for active demethylation. Since deletion of CTCF is lethal for embryonic stem cells, we used genetic deletion of REST as another DNA-binding factor implicated in LMR formation to test this hypothesis. The absence of REST leads to a decrease of hydroxymethylation and a concomitant increase of DNA methylation at its binding sites. These data support a model where DNA-binding factors can mediate turnover of DNA methylation as an integral part of maintenance and reprogramming of regulatory regions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 5-Methylcytosine / analogs & derivatives
  • Animals
  • Binding Sites
  • CCCTC-Binding Factor
  • Cell Differentiation
  • CpG Islands / genetics
  • Cytosine / analogs & derivatives
  • Cytosine / pharmacology
  • DNA Methylation / genetics*
  • DNA-Binding Proteins / genetics*
  • Embryonic Stem Cells
  • Gene Expression Regulation / drug effects
  • Genome
  • Mice
  • Promoter Regions, Genetic*
  • Regulatory Sequences, Nucleic Acid / genetics
  • Repressor Proteins / genetics*
  • Transcription Factors / genetics
  • Transcription, Genetic*

Substances

  • CCCTC-Binding Factor
  • Ctcf protein, mouse
  • DNA-Binding Proteins
  • RE1-silencing transcription factor
  • Repressor Proteins
  • Transcription Factors
  • 5-hydroxymethylcytosine
  • 5-Methylcytosine
  • Cytosine

Grants and funding

AF is supported by a predoctoral fellowship from the Marie Curie training network “Nuc4D”, RM is supported by an EMBO long-term postdoctoral fellowship. Research in the laboratory of DS is supported by the Novartis Research Foundation, the European Union (NoE “EpiGeneSys” FP7-HEALTH-2010-257082 and the “Blueprint” consortium FP7-282510), the European Research Council (EpiGePlas), the SNF Sinergia program and the Swiss initiative in Systems Biology (RTD Cell Plasticity). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.