CTCF mediates methylation-sensitive enhancer-blocking activity at the H19/Igf2 locus

Nature. 2000 May 25;405(6785):486-9. doi: 10.1038/35013106.


The Insulin-like growth factor 2 (Igf2) and H19 genes are imprinted, resulting in silencing of the maternal and paternal alleles, respectively. This event is dependent upon an imprinted-control region two kilobases upstream of H19 (refs 1, 2). On the paternal chromosome this element is methylated and required for the silencing of H19 (refs 2-4). On the maternal chromosome the region is unmethylated and required for silencing of the Igf2 gene 90 kilobases upstream. We have proposed that the unmethylated imprinted-control region acts as a chromatin boundary that blocks the interaction of Igf2 with enhancers that lie 3' of H19 (refs 5, 6). This enhancer-blocking activity would then be lost when the region was methylated, thereby allowing expression of Igf2 paternally. Here we show, using transgenic mice and tissue culture, that the unmethylated imprinted-control regions from mouse and human H19 exhibit enhancer-blocking activity. Furthermore, we show that CTCF, a zinc finger protein implicated in vertebrate boundary function, binds to several sites in the unmethylated imprinted-control region that are essential for enhancer blocking. Consistent with our model, CTCF binding is abolished by DNA methylation. This is the first example, to our knowledge, of a regulated chromatin boundary in vertebrates.

Publication types

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

MeSH terms

  • Animals
  • CCCTC-Binding Factor
  • Cell Line
  • DNA / metabolism
  • DNA Methylation*
  • DNA-Binding Proteins / physiology*
  • Enhancer Elements, Genetic*
  • Gene Expression Regulation*
  • Genomic Imprinting
  • Humans
  • Insulin-Like Growth Factor II / genetics*
  • Mice
  • Mice, Transgenic
  • Muscle Proteins / genetics*
  • Protein Binding
  • RNA, Long Noncoding
  • RNA, Untranslated*
  • Regulatory Sequences, Nucleic Acid
  • Repressor Proteins*
  • Transcription Factors / physiology*
  • Zinc Fingers


  • CCCTC-Binding Factor
  • CTCF protein, human
  • Ctcf protein, mouse
  • DNA-Binding Proteins
  • H19 long non-coding RNA
  • Muscle Proteins
  • RNA, Long Noncoding
  • RNA, Untranslated
  • Repressor Proteins
  • Transcription Factors
  • Insulin-Like Growth Factor II
  • DNA