Relationship between histone H1 poly(adenosine diphosphate ribosylation) and histone H1 phosphorylation using anti-poly(adenosine diphosphate ribose) antibody.

The chromatin-associated enzyme poly(ADP-Rib) polymerase catalyzes the posttranslational modification of histones. Antibody to poly(ADP-Rib) has been coupled to Sepharose, and the resultant immunoadsorbent was used to fractionate, specifically, histone H1 subpopulations undergoing this nuclear protein modification. When this method of separation was used, it was additionally observed that poly-(ADP-ribosylated) H1 species were highly accessible to in vitro phosphorylation by nuclear protein kinase. Phosphorylated H1 molecules were retained by the anti-poly(ADP-Rib)-Sepharose column due to the presence of endogenous poly-(ADP-Rib) components. Degradation of the latter moieties on phosphorylated H1 reversed their adsorption to the column.