Distinctive higher-order chromatin structure at mammalian centromeres

Proc Natl Acad Sci U S A. 2001 Oct 9;98(21):11949-54. doi: 10.1073/pnas.211322798.


The structure of the higher-order chromatin fiber has not been defined in detail. We have used a novel approach based on sucrose gradient centrifugation to compare the conformation of centromeric satellite DNA-containing higher-order chromatin fibers with bulk chromatin fibers obtained from the same mouse fibroblast cells. Our data show that chromatin fibers derived from the centromeric domain of a chromosome exist in a more condensed structure than bulk chromatin whereas pericentromeric chromatin fibers have an intermediate conformation. From the standpoint of current models, our data are interpreted to suggest that satellite chromatin adopts a regular helical conformation compatible with the canonical 30-nm chromatin fiber whereas bulk chromatin fibers appear less regularly folded and are perhaps intermittently interrupted by deformations. This distinctive conformation of the higher-order chromatin fiber in the centromeric domain of the mammalian chromosome could play a role in the formation of heterochromatin and in the determination of centromere identity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3 Cells
  • Animals
  • Centrifugation, Density Gradient
  • Centromere / chemistry*
  • Chromatin / chemistry*
  • DNA, Satellite / chemistry*
  • Humans
  • Mammals
  • Mice
  • Protein Folding
  • Time Factors
  • Tumor Cells, Cultured


  • Chromatin
  • DNA, Satellite