A relationship between nuclear poly(adenosine diphosphate ribosylation) and acetylation posttranslational modifications. 1. Nucleosome studies.

The chromatin-associated enzyme poly(ADP-Rib) polymerase catalyzes the posttranslational modifications of histones. Antibody to poly(adenosine diphosphate ribose) [poly(ADP-Rib)] has been coupled to Sepharose, and the resulting immunoadsorbant was used to fractionate, specifically, oligonucleosomes derived from cells pulse labeled for the acetylation modifications of chromatin by incubation with [3H]acetate followed by treatment with sodium butyrate. Generally, about 50% of the histone H3 and H4 mass becomes acetylated under these conditions. Pulse-labeled acetylated regions of chromatin were selectively retained by the anti-poly(ADP-Rib)-Sepharose column due to the presence of endogenous poly(ADP-Rib) components. The data suggest that certain histone molecules might be mutally poly(ADP-ribosylated) and acetylated, and this phenomenon was further explored at the protein level in the accompanying paper [Wong, M., & Smulson, M. (1984) Biochemistry (following paper in this issue)].