Poly(ADP-ribosyl)ation of polynucleosomes causes relaxation of chromatin structure

G G Poirier , G De Murcia (1) , J Jongstra-Bilen , C Niedergang , P Mandel

1 IBMC - Institut de biologie moléculaire et cellulaire

When rat pancreatic polynucleosomes were poly(ADP-ribosyl)ated with purified calf thymus poly(ADP-ribose) polymerase and examined by electron microscopy, a relaxation of their native zigzag structure was observed. At high ionic strengths control nucleosomes condensed into 250-A-thick fibers, but poly(ADP-ribosyl)ated polynucleosomes did not; they showed a close resemblance to chromatin depleted of histone H1. The relaxed state of poly(ADP-ribosyl)ated polynucleosomes was also confirmed by sedimentation velocity analysis. Histone H1 was found to be the major histone acceptor of poly(ADP-ribose). Poly(ADP-ribose) linked to histone H1 did not seem to cause its dissociation from the chromatin, but it impaired significantly its effect on chromatin condensation.

Domaines: Biochimie, Biologie Moléculaire; Biologie structurale [q-bio.BM]

G G Poirier, G De Murcia, J Jongstra-Bilen, C Niedergang, P Mandel. Poly(ADP-ribosyl)ation of polynucleosomes causes relaxation of chromatin structure. Proceedings of the National Academy of Sciences of the United States of America, 1982, 79 (11), pp.3423-7. ⟨10.1073/pnas.79.11.3423⟩. ⟨hal-02371437⟩