Human centromeric CENP-A chromatin is a homotypic, octameric nucleosome at all cell cycle points

Yael Nechemia-Arbely, Daniele Fachinetti, Karen H. Miga, Nikolina Sekulic, Gautam V. Soni, Dong Hyun Kim, Adeline K. Wong, Ah Young Lee, Kristen Nguyen, Cees Dekker, Bing Ren, Ben E. Black, Don W. Cleveland

Research output: Contribution to journalArticleScientificpeer-review

42 Citations (Scopus)
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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.

Original languageEnglish
Pages (from-to)607-621
Number of pages15
JournalThe Journal of Cell Biology
Volume216
Issue number3
DOIs
Publication statusPublished - 6 Mar 2017

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