Histone deacetylation in nuclei isolated from hepatoma tissue culture cells. Inhibition by sodium butyrate.

Nuclei from hepatoma tissue culture (HTC) cells were isolated by standard methods and incubated in media commonly used for nuclease digestions (DNAase I and micrococcal nuclease) and for in vitro RNA synthesis. During the incubation, histones can be deacetylated from both control cells and cells treated with 6 mM sodium butyrate to enhance the levels of histone acetylation. Deacetylation of histone is much more apparent in nuclei isolated from sodium butyrate-treated cells. Inclusion of 6 mM sodium butyrate in the incubation medium effectively inhibits the endogenous deacetylase activity acting on histones H3 and H4, whereas sodium acetate at the same concentration has very little inhibitory effect.