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Mol Biol Cell. 2018 Mar 15;29(6):751-762. doi: 10.1091/mbc.E17-10-0596. Epub 2018 Jan 17.

Constitutive centromere-associated network contacts confer differential stability on CENP-A nucleosomes in vitro and in the cell.

Author information

1
Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305.
2
Department of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, CO 80309.
3
National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027.
4
Department of Chemistry and Biochemistry, University of Colorado Boulder, Boulder, CO 80309 astraigh@stanford.edu Karolin.Luger@Colorado.edu.
5
Institute for Genome Architecture and Function, Colorado State University, Fort Collins, CO 80523.
6
Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO 80309.
7
Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305 astraigh@stanford.edu Karolin.Luger@Colorado.edu.

Abstract

Eukaryotic centromeres are defined by the presence of nucleosomes containing the histone H3 variant, centromere protein A (CENP-A). Once incorporated at centromeres, CENP-A nucleosomes are remarkably stable, exhibiting no detectable loss or exchange over many cell cycles. It is currently unclear whether this stability is an intrinsic property of CENP-A containing chromatin or whether it arises from proteins that specifically associate with CENP-A chromatin. Two proteins, CENP-C and CENP-N, are known to bind CENP-A human nucleosomes directly. Here we test the hypothesis that CENP-C or CENP-N stabilize CENP-A nucleosomes in vitro and in living cells. We show that CENP-N stabilizes CENP-A nucleosomes alone and additively with CENP-C in vitro. However, removal of CENP-C and CENP-N from cells, or mutating CENP-A so that it no longer interacts with CENP-C or CENP-N, had no effect on centromeric CENP-A stability in vivo. Thus, the stability of CENP-A nucleosomes in chromatin does not arise solely from its interactions with CENP-C or CENP-N.

PMID:
29343552
PMCID:
PMC6003232
DOI:
10.1091/mbc.E17-10-0596
[Indexed for MEDLINE]
Free PMC Article

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