Nucleosome arrays reveal the two-start organization of the chromatin fiber.
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.
Dorigo
Benedetta
B
Eidgenössische Technische Hochschule (ETH) Zürich, Institute for Molecular Biology and Biophysics, ETH-Hönggerberg, CH-8093 Zürich, Switzerland.
Schalch
Thomas
T
Kulangara
Alexandra
A
Duda
Sylwia
S
Schroeder
Rasmus R
RR
Richmond
Timothy J
TJ
D000818:Animals; D002843:Chromatin / Q000737:chemistry* / Q000648:ultrastructure; D004247:DNA / Q000737:chemistry / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D006657:Histones / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008854:Microscopy, Electron; D008954:Models, Biological; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000737:chemistry; D009154:Mutation; D009707:Nucleosomes / Q000737:chemistry* / Q000648:ultrastructure; D017510:Protein Folding; D014982:Xenopus laevis
D002843:Chromatin; D006657:Histones; D046912:Multiprotein Complexes; D009707:Nucleosomes; D004247:DNA