Histone modifications in the yeast S. Cerevisiae.

The content of the acetylated histone species associated with the highly transcriptionally active chromatin of yeast was examined. We found yeast chromatin to contain very high levels of the acetylated species for histones H3, H4 and possibly the H2B variants, H2B-1 and H2B-2. Sixty-three percent of the histone H4 species was represented by the di-, tri- and tetra-acetylated forms. These results make yeast chromatin among the most highly acetylated of any chromatins reported thus far. In addition, the results are consistent with the idea that hyperacetylation of histones allows chromatin to be transcribed at an increased rate.