Back to Search
Start Over
Chromosomes without a 30-nm chromatin fiber
- Source :
- Nucleus; September 2012, Vol. 3 Issue: 5 p404-410, 7p
- Publication Year :
- 2012
-
Abstract
- How is a long strand of genomic DNA packaged into a mitotic chromosome or nucleus? The nucleosome fiber (beads-on-a-string), in which DNA is wrapped around core histones, has long been assumed to be folded into a 30-nm chromatin fiber, and a further helically folded larger fiber. However, when frozen hydrated human mitotic cells were observed using cryoelectron microscopy, no higher-order structures that included 30-nm chromatin fibers were found. To investigate the bulk structure of mitotic chromosomes further, we performed small-angle X-ray scattering (SAXS), which can detect periodic structures in noncrystalline materials in solution. The results were striking: no structural feature larger than 11 nm was detected, even at a chromosome-diameter scale (~1 μm). We also found a similar scattering pattern in interphase nuclei of HeLa cells in the range up to ~275 nm. Our findings suggest a common structural feature in interphase and mitotic chromatins: compact and irregular folding of nucleosome fibers occurs without a 30-nm chromatin structure.
Details
- Language :
- English
- ISSN :
- 19491034 and 19491042
- Volume :
- 3
- Issue :
- 5
- Database :
- Supplemental Index
- Journal :
- Nucleus
- Publication Type :
- Periodical
- Accession number :
- ejs52500260
- Full Text :
- https://doi.org/10.4161/nucl.21222