A relationship between nuclear poly(adenosine diphosphate ribosylation) and acetylation posttranslational modifications. 2. Histone studies.

In the accompanying paper [Malik, N., & Smulson, M. (1984) Biochemistry (preceding paper in this issue)], we report that certain acetylated domains of chromatin were selectively retained by an anti-poly(ADP-Rib) antibody column. In this paper, we describe investigations of this phenomenon at the molecular level of protein interactions. We observed that the majority of endogenously hyperacetylated histones have a high affinity toward the polymer antibody column. It is speculated that these proteins were bound to the column via endogenous poly(adenosine diphosphate ribose) [poly(ADP-Rib)] since the binding was reversed upon treatment of the histones with alkali prior to immunofractionation. In order to analyze the distribution of acetate and poly(ADP-Rib) on histone proteins, [3H]acetylated nuclei were incubated in vitro with [32P]NAD. Acetate was incorporated mainly into H3 and H4 while H1 was the major acceptor protein for poly(ADP-Rib). These results suggest that a correlation may exist in vivo between the two posttranslational modification processes and that identical histone molecules may be accessible to both modifications.