A Midzone-Based Ruler Adjusts Chromosome Compaction to Anaphase Spindle Length

Abstract

Partitioning of chromatids during mitosis requires that chromosome compaction and spindle length scale appropriately with each other. However, it is not clear whether chromosome condensation and spindle elongation are linked. Here, we find that yeast cells could cope with a 45% increase in the length of their longest chromosome arm by increasing its condensation. The spindle midzone, aurora/Ipl1 activity, and Ser10 of histone H3 mediated this response. Thus, the anaphase spindle may function as a ruler to adapt the condensation of chromatids, promoting their segregation regardless of chromosome or spindle length.

A Cascade of Histone Modifications Induces Chromatin Condensation in Mitosis

“…This may indicate that in this organism, different recruitment mechanisms exist between centromeres and chromosome arms. Unlike in most other organisms (21)(22)(23), mutation of H3 S10 does not cause obvious growth defects in yeast (24), but it impairs the ability of fitting the condensation state of chromosomes to spindle length through "adaptive hypercondensation" (4). Because budding yeast chromosomes are short, this process is probably not essential for chromosome segregation during most mitoses.…”

“…Phosphorylation of histone H3 Ser 10 (H3 S10) by the kinase Aurora B-an event that correlates with mitosis in all organisms (3)-drives hypercondensation of an artificially elongated chromosome during anaphase of budding yeast (4), which suggests that histone tail modifications may influence chromosome condensation. In vitro, the flexible N-terminal domains of the core histones mediate the condensation of arrays of nucleosome core particles upon addition of Mg 2+ ions.…”

The Epigenetic Pathways to Ribosomal DNA Silencing

“…This kinase also phosphorylates condensin during postmetaphase chromosome assembly maturation. The aurora B kinase is associated with mitosis in all eukaryotes and, in particular, drives the hypercondensation of an artificially elongated chromosome during anaphase in budding yeast, suggesting that changes in the histone modification pattern affect chromosome condensation (39).…”

A high-sensitivity phospho-switch triggered by Cdk1 governs chromosome morphogenesis during cell division

“…Chief among those is the condensin complex, a pentameric ATPase that binds to chromatin and alters its configuration and/or association status with distant chromatin regions (Bazile et al 2010;Baxter and Aragon 2012;Hirano 2012). Other factors, such as cell cycle kinases and histone-modifying enzymes, have also been proposed as possible regulators of chromosome condensation during mitosis (Morishita et al 2001;St-Pierre et al 2009;Abe et al 2011;Neurohr et al 2011;Wilkins et al 2014). Although it is clear that these enzymes impact chromatin compaction at specific genomic locations and/or during specific stages of mitosis, it is remarkable that Ó 2015 Robellet et al This article is distributed exclusively by Cold Spring Harbor Laboratory Press for the first six months after the full-issue publication date (see http://genesdev.cshlp.org/site/misc/terms.xhtml).…”