Mapping Polycomb-repressed domains in the bithorax complex using in vivo formaldehyde cross-linked chromatin

Cell. 1993 Dec 17;75(6):1187-98. doi: 10.1016/0092-8674(93)90328-n.


The Polycomb group (Pc-G) proteins are responsible for keeping developmental regulators, like homeotic genes, stably and inheritably repressed during Drosophila development. Several similarities to a protein class involved in heterochromatin formation suggest that the Pc-G exerts its function at the higher order chromatin level. Here we have mapped the distribution of the Pc protein in the homeotic bithorax complex (BX-C) of Drosophila tissue culture cells. We have elaborated a method, based on the in vivo formaldehyde cross-linking technique, that allows a substantial enrichment for Pc-interacting sites by immunoprecipitation of the cross-linked chromatin with anti-Pc antibodies. We find that the Pc protein quantitatively covers large regulatory regions of repressed BX-C genes. Conversely, we find that the Abdominal-B gene is active in these cells and the region devoid of any bound Pc protein.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Binding Sites
  • Blotting, Southern
  • Cells, Cultured
  • Chromatin / metabolism*
  • Chromatin / ultrastructure
  • Cloning, Molecular
  • Cross-Linking Reagents
  • DNA / isolation & purification
  • DNA / metabolism
  • Drosophila Proteins*
  • Drosophila melanogaster / genetics
  • Drosophila melanogaster / metabolism*
  • Formaldehyde
  • Genes, Homeobox
  • Heterochromatin / metabolism
  • Insect Hormones / metabolism
  • Molecular Sequence Data
  • Oligodeoxyribonucleotides
  • Polycomb Repressive Complex 1
  • Polymerase Chain Reaction
  • Proteins / genetics*
  • Proteins / metabolism*
  • Regulatory Sequences, Nucleic Acid
  • Restriction Mapping


  • Chromatin
  • Cross-Linking Reagents
  • Drosophila Proteins
  • Heterochromatin
  • Insect Hormones
  • Oligodeoxyribonucleotides
  • Pc protein, Drosophila
  • Proteins
  • Formaldehyde
  • DNA
  • Polycomb Repressive Complex 1