Release of core DNA from nucleosomal core particles following (ADP-ribose)n-modification in vitro.

Isolated nucleosomal core particles from rat liver chromatin were ADP-ribosylated in vitro and the consequences of this modification on intranucleosomal DNA-protein interactions were studied by retention gel analysis. A separating force of 11 fN caused the complete release of 146 bp DNA fragments from ADP-ribosylated core particles, while the DNA of unmodified core particles remained protein-associated. We conclude that posttranslational (ADP-ribose)n-modification of chromatin proteins may reduce DNA-protein interactions at the nucleosomal level of chromatin organization.