A variable topology for the 30-nm chromatin fibre.
The structure of the 30-nm chromatin fibre is an important determinant of the regulation of eukaryotic transcription. A fundamental issue is whether the stacking of nucleosomes in this fibre is organized as a one-start or two-start helix. We argue that all recent experimental data are compatible with a two-start helix and propose that the topology of the fibre, but not the mode of stacking the nucleosomes, is dependent on the length of the linker DNA. This arrangement conserves nucleosome stacking and thus the external morphology of the fibre, and also ensures that the fibre adopts the highest available packing density.
Medical Research Council Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK.
Chenyi
C
Wu
Andrew
A
Bassett
Andrew
A
Travers
D000818:Animals; D002843:Chromatin / Q000737:chemistry / Q000378:metabolism*; D004247:DNA / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D008954:Models, Biological; D009690:Nucleic Acid Conformation; D009707:Nucleosomes / Q000737:chemistry / Q000378:metabolism
D002843:Chromatin; D009707:Nucleosomes; D004247:DNA