A Cascade of Histone Modifications Induces Chromatin Condensation in Mitosis

Abstract

Chromosome Condensation The forces that shape the structure of the highly condensed metaphase chromosomes seen during cell division in eukaryotes are still largely unknown. In vitro evidence suggests that the amino-terminal tails of the histones—such as interaction of the histone H4 tail with H2A-H2B—play an important role in chromosome hypercondensation. Wilkins et al. (p. 77 ) used ultraviolet cross-linker amino acids in the histones of bakers' yeast to show that during early mitosis, phosphorylation of H3 threonine 3 by Haspin kinase recruits the chromosome passenger complex (CPC). The subsequent phosphorylation of H3 serine 10 by CPC allows the recruitment of the deacetylase Hst2p to nucleosomes. Hst2p drives the deacetylation of H4 lysine 16, facilitating the interaction between H4 and H2A-H2B in neighboring nucleosomes, promoting chromatin condensation.