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Updated: Mar 14, 2026
Generation and Purification of Human INO80 Chromatin Remodeling Complexes and Subcomplexes
Published on: October 23, 2014
The proto-chromatosome: A fundamental subunit of chromatin?
Josefina Ocampo1, Feng Cui2, Victor B Zhurkin3
1a Division of Developmental Biology, Eunice Kennedy Shriver National Institute for Child Health and Human Development, National Institutes of Health , Bethesda , MD , USA.
Abstract:
Eukaryotic DNA is packaged into regularly spaced nucleosomes, resembling beads on a string. Each bead contains ∼147 bp wrapped around a core histone octamer. Linker histone (H1) binds to the linker DNA to drive chromatin folding. Micrococcal nuclease (MNase) digestion studies reveal 2 mono-nucleosomal intermediates: the core particle (∼147 bp) and the chromatosome (∼160 bp; a core particle with additional DNA protected by H1). We have recently developed an improved method for mapping nucleosomes, using exonuclease III to remove residual linker (MNase-Exo-seq). (1) We discovered 2 new intermediate particles corresponding to core particles with ∼7 bp of linker protruding from one side (∼154 bp) or both sides (∼161 bp), which are formed in the absence of H1. We propose that these "proto-chromatosomes" are stabilized by core histone-DNA contacts in the linker, ∼7 bp from the nucleosome boundaries. These contacts may determine the topography of the H1 binding site.
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