Immunoaffinity fractionation of the poly(ADP-ribosyl)ated domains of chromatin.
Antibody to poly(ADP-ribose) has been covalently coupled to Sepharose and utilized to isolate selectively oligonucleosomes undergoing the poly(ADP-ribosyl)ation reaction from the bulk of chromatin. Approximately 12% of the unfractionated oligonucleosomes were bound to the immunoaffinity column and these represented essentially 100% of the original poly(ADP-ribosyl)ated nucleosomal species in the unfractionated chromatin. Poly(ADP-ribosyl)ated chromatin was not bound by preimmune IgG columns. KSCN eluted the modified nucleosomes in the form of nucleoprotein complexes. The eluted chromatin components were shown to contain poly(ADP-ribosyl)ated histones as well as automodified poly(ADP-ribose) polymerase. By using [3H]lysine- and [3H]arginine-labeled chromatin, it was shown that the poly-(ADP-ribosyl)ated histones, attached to stretches of oligonucleosomes bound to the column, had a 6-fold enrichment of the modification compared to histones of the unfractionated chromatin. This indicated that non-poly(ADP-ribosyl)ated nucleosomes, connected and proximal to the modified regions, were copurified by this procedure. This allowed characterization of the oligonucleosomal DNA around poly(ADP-ribosyl)ated chromatin domains to be compared with the unbound bulk chromatin. The data indicated that immunofractionated poly(ADP-ribosyl)ated oligonucleosomal DNA contained significant amounts of internal single-strand breaks compared with bulk chromatin. The bound nucleo-protein complexes were found to be enzymatically active for poly(ADP-ribose) polymerase after elution from the antibody column. In contrast, the unbound nucleosomes, representing 90% of the unfractionated chromatin, were totally inactive in the poly(ADP-ribosyl)ation reaction.
D002843:Chromatin / Q000032:analysis*; D002846:Chromatography, Affinity / Q000379:methods; D002868:Chromosomal Proteins, Non-Histone / Q000032:analysis; D006657:Histones / Q000032:analysis; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D009702:Nucleoside Diphosphate Sugars / Q000378:metabolism*; D011064:Poly Adenosine Diphosphate Ribose / Q000276:immunology / Q000378:metabolism*
D002843:Chromatin; D002868:Chromosomal Proteins, Non-Histone; D006657:Histones; D007074:Immunoglobulin G; D009702:Nucleoside Diphosphate Sugars; D011064:Poly Adenosine Diphosphate Ribose