Decoding the centromeric nucleosome through CENP-N

Elife. 2017 Dec 27;6:e33442. doi: 10.7554/eLife.33442.

Abstract

Centromere protein (CENP) A, a histone H3 variant, is a key epigenetic determinant of chromosome domains known as centromeres. Centromeres nucleate kinetochores, multi-subunit complexes that capture spindle microtubules to promote chromosome segregation during mitosis. Two kinetochore proteins, CENP-C and CENP-N, recognize CENP-A in the context of a rare CENP-A nucleosome. Here, we reveal the structural basis for the exquisite selectivity of CENP-N for centromeres. CENP-N uses charge and space complementarity to decode the L1 loop that is unique to CENP-A. It also engages in extensive interactions with a 15-base pair segment of the distorted nucleosomal DNA double helix, in a position predicted to exclude chromatin remodelling enzymes. Besides CENP-A, stable centromere recruitment of CENP-N requires a coincident interaction with a newly identified binding motif on nucleosome-bound CENP-C. Collectively, our studies clarify how CENP-N and CENP-C decode and stabilize the non-canonical CENP-A nucleosome to enforce epigenetic centromere specification and kinetochore assembly.

Keywords: CENP-A; CENP-C; CENP-N; biophysics; centromere; chromosomes; genes; human; kinetochore; mitosis; structural biology.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Centromere / chemistry
  • Centromere / metabolism*
  • Centromere Protein A / chemistry
  • Centromere Protein A / metabolism*
  • Chromosomal Proteins, Non-Histone / chemistry
  • Chromosomal Proteins, Non-Histone / metabolism*
  • Cryoelectron Microscopy
  • Crystallography, X-Ray
  • DNA / chemistry
  • DNA / metabolism*
  • Humans
  • Kinetochores / chemistry
  • Kinetochores / metabolism
  • Models, Molecular
  • Protein Binding
  • Protein Conformation

Substances

  • CENPN protein, human
  • Centromere Protein A
  • Chromosomal Proteins, Non-Histone
  • centromere protein C
  • DNA