Title:	Human centromeric CENP-A chromatin is a homotypic, octameric nucleosome at all cell cycle points
Authors:	Nechemia-Arbely, Yael Soni, G.V. +11 Co-authors
Issue Date:	Feb-2017
Publisher:	The Rockefeller University Press
Citation:	The Journal of Cell Biology, 2017, Vol.216, p 607
Abstract:	Chromatin assembled with centromere protein A (CENP-A) is the epigenetic mark of centromere identity. Using new reference models, we now identify sites of CENP-A and histone H3.1 binding within the megabase, α-satellite repeat–containing centromeres of 23 human chromosomes. The overwhelming majority (97%) of α-satellite DNA is found to be assembled with histone H3.1–containing nucleosomes with wrapped DNA termini. In both G1 and G2 cell cycle phases, the 2–4% of α-satellite assembled with CENP-A protects DNA lengths centered on 133 bp, consistent with octameric nucleosomes with DNA unwrapping at entry and exit. CENP-A chromatin is shown to contain equimolar amounts of CENP-A and histones H2A, H2B, and H4, with no H3. Solid-state nanopore analyses show it to be nucleosomal in size. Thus, in contrast to models for hemisomes that briefly transition to octameric nucleosomes at specific cell cycle points or heterotypic nucleosomes containing both CENP-A and histone H3, human CENP-A chromatin complexes are octameric nucleosomes with two molecules of CENP-A at all cell cycle phases.
Description:	Open Access
URI:	http://hdl.handle.net/2289/6723
ISSN:	1540-8140
Alternative Location:	http://dx.doi.org/10.1083/jcb.201608083
Copyright:	2017 Nechemia-Arbely et al & The Rockefeller University Press
Appears in Collections:	Research Papers (SCM)

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