ADP-ribosylation of rye histones

Chromatin from etiolated rye seedlings synthesized protein-bound, acid-insoluble material from [3H]NAD, presumably poly(ADP-ribose). [3H]ADP-ribosylated histone fractions were isolated from crude chromatin and characterized by gel electrophoresis and exclusion chromatography. It was found that histone H2B was the main acceptor, that H2A and H1 were modified to a lesser extent, and that H3 and H4 were only slightly modified. The average chain length on purified histones was 2.5 units of polymer.