Tetrameric Structure of Centromeric Nucleosomes in Interphase Drosophila Cells

Centromeres, the specialized chromatin structures that are responsible for equal segregation of chromosomes at mitosis, are epigenetically maintained by a centromere-specific histone H3 variant (CenH3). However, the mechanistic basis for centromere maintenance is unknown. We investigated biochemical...

Full description

Bibliographic Details
Main Authors:	Dalal, Yamini, Wang, Hongda, Lindsay, Stuart, Henikoff, Steven
Format:	Online
Language:	English
Published:	Public Library of Science 2007
Online Access:	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1933458/

id	pubmed-1933458
recordtype	oai_dc
spelling	pubmed-19334582007-08-14 Tetrameric Structure of Centromeric Nucleosomes in Interphase Drosophila Cells Dalal, Yamini Wang, Hongda Lindsay, Stuart Henikoff, Steven Research Article Centromeres, the specialized chromatin structures that are responsible for equal segregation of chromosomes at mitosis, are epigenetically maintained by a centromere-specific histone H3 variant (CenH3). However, the mechanistic basis for centromere maintenance is unknown. We investigated biochemical properties of CenH3 nucleosomes from Drosophila melanogaster cells. Cross-linking of CenH3 nucleosomes identifies heterotypic tetramers containing one copy of CenH3, H2A, H2B, and H4 each. Interphase CenH3 particles display a stable association of approximately 120 DNA base pairs. Purified centromeric nucleosomal arrays have typical “beads-on-a-string” appearance by electron microscopy but appear to resist condensation under physiological conditions. Atomic force microscopy reveals that native CenH3-containing nucleosomes are only half as high as canonical octameric nucleosomes are, confirming that the tetrameric structure detected by cross-linking comprises the entire interphase nucleosome particle. This demonstration of stable half-nucleosomes in vivo provides a possible basis for the instability of centromeric nucleosomes that are deposited in euchromatic regions, which might help maintain centromere identity. Public Library of Science 2007-08 2007-07-31 /pmc/articles/PMC1933458/ /pubmed/17676993 http://dx.doi.org/10.1371/journal.pbio.0050218 Text en © 2007 Dalal et al. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
repository_type	Open Access Journal
institution_category	Foreign Institution
institution	US National Center for Biotechnology Information
building	NCBI PubMed
collection	Online Access
language	English
format	Online
author	Dalal, Yamini Wang, Hongda Lindsay, Stuart Henikoff, Steven
spellingShingle	Dalal, Yamini Wang, Hongda Lindsay, Stuart Henikoff, Steven Tetrameric Structure of Centromeric Nucleosomes in Interphase Drosophila Cells
author_facet	Dalal, Yamini Wang, Hongda Lindsay, Stuart Henikoff, Steven
author_sort	Dalal, Yamini
title	Tetrameric Structure of Centromeric Nucleosomes in Interphase Drosophila Cells
title_short	Tetrameric Structure of Centromeric Nucleosomes in Interphase Drosophila Cells
title_full	Tetrameric Structure of Centromeric Nucleosomes in Interphase Drosophila Cells
title_fullStr	Tetrameric Structure of Centromeric Nucleosomes in Interphase Drosophila Cells
title_full_unstemmed	Tetrameric Structure of Centromeric Nucleosomes in Interphase Drosophila Cells
title_sort	tetrameric structure of centromeric nucleosomes in interphase drosophila cells
description	Centromeres, the specialized chromatin structures that are responsible for equal segregation of chromosomes at mitosis, are epigenetically maintained by a centromere-specific histone H3 variant (CenH3). However, the mechanistic basis for centromere maintenance is unknown. We investigated biochemical properties of CenH3 nucleosomes from Drosophila melanogaster cells. Cross-linking of CenH3 nucleosomes identifies heterotypic tetramers containing one copy of CenH3, H2A, H2B, and H4 each. Interphase CenH3 particles display a stable association of approximately 120 DNA base pairs. Purified centromeric nucleosomal arrays have typical “beads-on-a-string” appearance by electron microscopy but appear to resist condensation under physiological conditions. Atomic force microscopy reveals that native CenH3-containing nucleosomes are only half as high as canonical octameric nucleosomes are, confirming that the tetrameric structure detected by cross-linking comprises the entire interphase nucleosome particle. This demonstration of stable half-nucleosomes in vivo provides a possible basis for the instability of centromeric nucleosomes that are deposited in euchromatic regions, which might help maintain centromere identity.
publisher	Public Library of Science
publishDate	2007
url	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1933458/
_version_	1611398642376114176

Tetrameric Structure of Centromeric Nucleosomes in Interphase Drosophila Cells

Similar Items