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Updated: Jul 5, 2026

Visualization of DNA Replication in the Vertebrate Model System DT40 using the DNA Fiber Technique
Published on: October 27, 2011
Nucleosome arrays reveal the two-start organization of the chromatin fiber
Benedetta Dorigo1, Thomas Schalch, Alexandra Kulangara
1Eidgenössische Technische Hochschule (ETH) Zürich, Institute for Molecular Biology and Biophysics, ETH-Hönggerberg, CH-8093 Zürich, Switzerland.
Abstract:
Chromatin folding determines the accessibility of DNA constituting eukaryotic genomes and consequently is profoundly important in the mechanisms of nuclear processes such as gene regulation. Nucleosome arrays compact to form a 30-nanometer chromatin fiber of hitherto disputed structure. Two competing classes of models have been proposed in which nucleosomes are either arranged linearly in a one-start higher order helix or zigzag back and forth in a two-start helix. We analyzed compacted nucleosome arrays stabilized by introduction of disulfide cross-links and show that the chromatin fiber comprises two stacks of nucleosomes in accord with the two-start model.
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