Stepwise unfolding supports a subunit model for vertebrate kinetochores

Proc Natl Acad Sci U S A. 2017 Mar 21;114(12):3133-3138. doi: 10.1073/pnas.1614145114. Epub 2017 Mar 6.


During cell division, interactions between microtubules and chromosomes are mediated by the kinetochore, a proteinaceous structure located at the primary constriction of chromosomes. In addition to the centromere histone centromere protein A (CENP-A), 15 other members of the constitutive centromere associated network (CCAN) participate in the formation of a chromatin-associated scaffold that supports kinetochore structure. We performed a targeted screen analyzing unfolded centrochromatin from CENP-depleted chromosomes. Our results revealed that CENP-C and CENP-S are critical for the stable folding of mitotic kinetochore chromatin. Multipeak fitting algorithms revealed the presence of an organized pattern of centrochromatin packing consistent with arrangement of CENP-A-containing nucleosomes into up to five chromatin "subunits"-each containing roughly 20-30 nucleosomes. These subunits could be either layers of a boustrophedon or small loops of centromeric chromatin.

Keywords: CENP-A; boustrophedon; centrochromatin; centromere; kinetochore.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Centromere / chemistry
  • Centromere Protein A / chemistry
  • Centromere Protein A / genetics
  • Centromere Protein A / metabolism
  • Chickens
  • Chromatin / chemistry
  • Fluorescent Antibody Technique
  • Gene Expression
  • Gene Knockdown Techniques
  • Kinetochores / chemistry*
  • Kinetochores / metabolism
  • Microscopy, Fluorescence
  • Mitosis
  • Models, Molecular*
  • Mutation
  • Protein Conformation*
  • Protein Subunits / chemistry*
  • Protein Unfolding*
  • Recombinant Fusion Proteins
  • Vertebrates


  • Centromere Protein A
  • Chromatin
  • Protein Subunits
  • Recombinant Fusion Proteins