Molecular Cell
Volume 28, Issue 6, 28 December 2007, Pages 1029-1044
Journal home page for Molecular Cell

Article
A NASP (N1/N2)-Related Protein, Sim3, Binds CENP-A and Is Required for Its Deposition at Fission Yeast Centromeres

https://doi.org/10.1016/j.molcel.2007.10.010Get rights and content
Under a Creative Commons license
open access

Summary

A defining feature of centromeres is the presence of the histone H3 variant CENP-ACnp1. It is not known how CENP-ACnp1 is specifically delivered to, and assembled into, centromeric chromatin. Through a screen for factors involved in kinetochore integrity in fission yeast, we identified Sim3. Sim3 is homologous to known histone binding proteins NASPHuman and N1/N2Xenopus and aligns with Hif1S. cerevisiae, defining the SHNi-TPR family. Sim3 is distributed throughout the nucleoplasm, yet it associates with CENP-ACnp1 and also binds H3. Cells defective in Sim3 function have reduced levels of CENP-ACnp1 at centromeres (and increased H3) and display chromosome segregation defects. Sim3 is required to allow newly synthesized CENP-ACnp1 to accumulate at centromeres in S and G2 phase-arrested cells in a replication-independent mechanism. We propose that one function of Sim3 is to act as an escort that hands off CENP-ACnp1 to chromatin assembly factors, allowing its incorporation into centromeric chromatin.

DNA

Cited by (0)

5

Present address: Department of Chromatin Dynamics, Institut Curie, Section de Recherche, UMR 218-Pavillon Pasteur, 26 rue d'Ulm, 75248 Paris Cedex 05, France.

6

Present address: INSERM U740, Faculté de Médecine, 10 avenue de Verdun, 75010 Paris, France.