PMID: 29269420
Authors:
Chittori S, Hong J, Saunders H, Feng H, Ghirlando R, Kelly AE, Bai Y, Subramaniam S
Title:
Structural mechanisms of centromeric nucleosome recognition by the kinetochore protein CENP-N.
Journal:
Science. 2017 Dec 21. pii: science.aar2781. doi: 10.1126/science.aar2781.
Abstract:
Accurate chromosome segregation requires the proper assembly of kinetochore proteins. A key step in this process is the recognition of the histone H3 variant CENP-A in the centromeric nucleosome by the kinetochore protein CENP-N. We report cryo-EM, biophysical, biochemical, and cell biological studies of the interaction between the CENP-A nucleosome and CENP-N. We show that human CENP-N confers binding specificity through interactions with the L1 loop of CENP-A, stabilized by electrostatic interactions with the nucleosomal DNA. Mutational analyses demonstrate analogous interactions in Xenopus, which is further supported by residue-swapping experiments involving the L1 loop of CENP-A. Our results are consistent with co-evolution of CENP-N and CENP-A, and establish the structural basis for recognition of the CENP-A nucleosome to enable kinetochore assembly and centromeric chromatin organization.