Adenosine Diphosphate Ribosylation of Chicken‐Erythrocyte Histones H1, H5 and High‐Mobility‐Group Proteins by Purified Calf‐Thymus Poly(adenosinediphosphate‐ribose) Polymerase

Abstract

Poly(ADP‐ribosylation) of histones H1, H5 and non‐histone chromosomal high‐mobility‐group proteins HMG 1, 2, 14 and 17 from chicken erythrocytes by purified calf thymus poly(ADP‐ribose) polymerase was studied using acid/urea/Triton gel electrophoresis and autoradiography. With histone H1, besides ADP‐ribosylated H1 supporting short chains of polymer, the appearance of H1 ‘dimer’ was observed and this reaction was dependent on NAD concentration and incubation time. In addition, highly modified and/or aggregated species of histone H1 were observed. Histone H5 was slightly ADP‐ribosylated at low NAD concentrations. At higher NAD concentrations or after longer incubations the formation of H5 ‘dimer’ and of more modified forms of H5 could be observed. HMG 1 and HMG 2 were found to be ADP‐ribosylated, the reaction being dependent on NAD concentration and time. Here again some discrete intermediates appeared. HMG 14 and HMG 17 were only slightly ADP‐ribosylated under our experimental conditions. These results indicate that the purified DNA‐independent poly(ADP‐ribose) polymerase can catalyse the formation of H1 ‘dimer’ as in nuclei and nucleosomes and that H5 and HMG proteins can also be ADP‐ribosylated and produce well‐defined higher complexes. These modifications of nuclear proteins may provide a means of localized conformational changes of the chromatin structure in vivo. Copyright © 1982, Wiley Blackwell. All rights reserved