Abstract
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.
Original language | English |
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Pages (from-to) | 11949-54 |
Number of pages | 6 |
Journal | Proceedings of the National Academy of Sciences (PNAS) |
Volume | 98 |
Issue number | 21 |
DOIs | |
Publication status | Published - 9 Oct 2001 |
Keywords
- 3T3 Cells
- Animals
- Centrifugation, Density Gradient
- Centromere/chemistry
- Chromatin/chemistry
- DNA, Satellite/chemistry
- Humans
- Mammals
- Mice
- Protein Folding
- Time Factors
- Tumor Cells, Cultured