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

Abstract

The chromatin-associated enzyme poly(ADP-Rib) polymerase catalyzes the posttranslational modifications of histones. Antibody to poly(ADP ribose) [poly(ADP-Rib)] was coupled to Sepharose, and the resulting immunoadsorbant was used to fractionate, specifically, oligonucleosomes derived from [human cervical carcinoma HeLa] cells pulse labeled for the acetylation modificatoins 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. Certain histone molecules might be mutually poly(ADP-ribosylated) and acetylated, and this phenomenon was further explored at the protein level in another study.