Nucleosomal Particles Open as the Histone Core Becomes Hyperacetylated

Abstract

Lymphoblastoid cells grown in the presence of the deacetylase inhibitor butyrate were used to isolate nucleosomal particles in a hyperacetylated state. During a non‐denaturing gel electrophoresis these particles revealed a heterogeneity which is only in part due to the presence of nonhistone proteins. Monomers that are free from histone H1 and high‐mobility‐group (HMG) proteins 14 and 17 yield a subfractionation according to the degree of core histone acetylation beyond a limiting value of 10 acetyl groups/particle. It is shown that hyperacetylation provides particles with low mobilities and a considerable conformational freedom in contrast to HMG protein 14 which locks them in a conformation that has a similar electrophoretic behaviour but is more defined. Copyright © 1983, Wiley Blackwell. All rights reserved