SELECTIVE USE OF H4 ACETYLATION SITES IN THE YEAST SACCHAROMYCES-CEREVISIAE

The acetylation of specific lysine residues in the histone H4 may play a role in regulating various genes in the yeast Saccharomyces cerevis iae [Grunstein (1990) Annu. Rev. Cell Biol. 6, 643-678]. The detailed consideration of this possibility has been hampered by the lack of inf ormation on the frequency with which different H4 lysine residues are acetylated in yeast. In this paper, we use Western blotting from acid/ urea/Triton gels and immunostaining with antisera specific for H4 mole cules acetylated at particular lysine residues to show that 70-80% of H4 molecules in S. cerevisiae contain one or more acetylated lysines, and that lysines-5, -8, -12 and -16 are acetylated in an ordered, non- random fashion. The monoacetylated isoform (H4Ac1) is acetylated predo minantly at lysine-16 (rarely at lysine-12), H4Ac2 is acetylated at ly sine-16 and at either lysine-12 or at -8, while lysine-5 is acetylated frequently only in H4Ac3 and in H4Ac4.