CTCF physically links cohesin to chromatin.

Publication Type:

Journal Article

Source:

Proceedings of the National Academy of Sciences of the United States of America, Volume 105, Issue 24, p.8309-14 (2008)

Keywords:

2008, 3T3 Cells, Alleles, Amino Acid Sequence, Animals, Cell Cycle Proteins, centromere, chromatin, Chromatin Immunoprecipitation, Chromosomal Proteins, Non-Histone, Chromosomes, Human, DNA-Binding Proteins, Genomic Imprinting, GENOMICS, Human Biology Division, Humans, Insulator Elements, Insulin-Like Growth Factor II, Jurkat Cells, mass spectrometry, MICE, Molecular Sequence Data, Nuclear Proteins, PROTEOMICS, Repressor Proteins

Abstract:

Cohesin is required to prevent premature dissociation of sister chromatids after DNA replication. Although its role in chromatid cohesion is well established, the functional significance of cohesin's association with interphase chromatin is not clear. Using a quantitative proteomics approach, we show that the STAG1 (Scc3/SA1) subunit of cohesin interacts with the CCTC-binding factor CTCF bound to the c-myc insulator element. Both allele-specific binding of CTCF and Scc3/SA1 at the imprinted IGF2/H19 gene locus and our analyses of human DM1 alleles containing base substitutions at CTCF-binding motifs indicate that cohesin recruitment to chromosomal sites depends on the presence of CTCF. A large-scale genomic survey using ChIP-Chip demonstrates that Scc3/SA1 binding strongly correlates with the CTCF-binding site distribution in chromosomal arms. However, some chromosomal sites interact exclusively with CTCF, whereas others interact with Scc3/SA1 only. Furthermore, immunofluorescence microscopy and ChIP-Chip experiments demonstrate that CTCF associates with both centromeres and chromosomal arms during metaphase. These results link cohesin to gene regulatory functions and suggest an essential role for CTCF during sister chromatid cohesion. These results have implications for the functional role of cohesin subunits in the pathogenesis of Cornelia de Lange syndrome and Roberts syndromes.