Identification of the post-translational modifications present in centromeric chromatin

Aaron O. Bailey, Tanya Panchenko, Jeffrey Shabanowitz, Stephanie M. Lehman, Dina L. Bai, Donald F. Hunt, Ben E. Black, Daniel R. Foltz*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

33 Scopus citations

Abstract

The centromere is the locus on the chromosome that acts as the essential connection point between the chromosome and the mitotic spindle. A histone H3 variant, CENP-A, defines the location of the centromere, but centromeric chromatin consists of a mixture of both CENP-A-containing and H3-containing nucleosomes. We report a surprisingly uniform pattern of primarily monomethylation on lysine 20 of histone H4 present in short polynucleosomes mixtures of CENP-A and H3 nucleosomes isolated from functional centromeres. Canonical H3 is not a component of CENP-A-containing nucleosomes at centromeres, so the H3 we copurify from these preparations comes exclusively from adjacent nucleosomes. We find that CENP-A-proximal H3 nucleosomes are not uniformly modified but contain a complex set of PTMs. Dually modified K9me2-K27me2 H3 nucleosomes are observed at the centromere. Side-chain acetylation of both histone H3 and histone H4 is low at the centromere. Prior to assembly at centromeres, newly expressed CENP-A is sequestered for a large portion of the cell cycle (late S-phase, G2, and most of mitosis) in a complex that contains its partner, H4, and its chaperone, HJURP. In contrast to chromatin associated centromeric histone H4, we show that prenucleosomal CENP-A-associated histone H4 lacks K20 methylation and contains side-chain and α-amino acetylation. We show HJURP displays a complex set of serine phosphorylation that may potentially regulate the deposition of CENP-A. Taken together, our findings provide key information regarding some of the key components of functional centromeric chromatin.

Original languageEnglish (US)
Pages (from-to)918-931
Number of pages14
JournalMolecular and Cellular Proteomics
Volume15
Issue number3
DOIs
StatePublished - Mar 2016

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biochemistry
  • Molecular Biology

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