Histone acetylation and deacetylation in senescent human diploid fibroblasts.

We measured the kinetics of histone H4 hyperacetylation and kinetics of deacetylation for all core histones in young and senescent human diploid fibroblast-like cells. Both cell populations contained a fraction of histone H4 characterized by very rapid acetylation and deacetylation. The kinetics of these reactions were similar in young and senescent cells. The distribution of acetylated species of core histones was also similar in young and senescent human diploid fibroblast-like cells. These results indicated that previously-reported alterations in chromatin template activity in senescent cells were due to a mechanism other than histone acetylation.