Sequential ADP‐ribosylation pattern of nucleosomal histones

Abstract

The pattern of nucleosomal histones poly(ADP-ribosy1)ation is changed under conditions which affect the poly(ADP-ribosy1)ation state of the enzyme. At low NAD concentrations the enzyme can poly(ADP-ribosy1)ate histones H1 and H1 O, H2A, A2A, and H2B. However at NAD concentrations above 10 yM the enzyme preferentially poly(ADP-ribosy1)ates histone H1 to a hyper ADP-ribosylated form. Furthermore we have observed hyper ADP-ribosylation of histone H2B at NAD concentrations of 10 yM suggesting that histone H2B can undergo the same type of ADP-ribosylation pattern as histone H1. Also at higher NAD concentrations an elongation of the polymer attached to the enzyme and other nuclear proteins takes place.There is growing evidence that poly(ADP-ribosy1)ation of nucleosomal proteins, which is a post-translational modification, might be related to the alteration of the chromatin structure during the cellular process of DNA repair and replication [l -31. The reaction is catalyzed by the nuclear enzyme poly(ADP4bose) polymerase [4 -61 which can act not only as a catalyst but also as the acceptor of the product of its own activity [7-91. Amongst the histone proteins, it has been shown that histones HI, H2B, A24 and to a lesser extent histones H3 and H2A could be poly(ADP-ribosy1)ated in nuclei as well as in nucleosomes [lo-121. Histone HI has been described to be the major histone acceptor in trout testis nuclei [13] and pancreatic nuclei and nucleosomes [14, 151 at NAD concentrations above 100 pM; whereas in rat liver and HeLa cells histones H1 and H2B have been shown to be the major histone protein acceptors of poly(ADP-ribose) [12,16].The biological role of the polymer has been ascribed to different nuclear events such as: DNA replication [17], DNA repair [18, 191, cell growth and differentiation [20, 211. Furthermore it has been shown that there is an increase in the poly(ADP-ribosy1)ation of histone HI during DNA repair in permeabilized cells [22]. Also studies in vivo have shown increased poly(ADP-ribosy1)ation of histone H1 and core histones [23] during DNA repair. Cell cycle studies have indicated increased poly(ADP-ribosy1)ation of histone H1 during S phase [24]. It has been suggested recently by Poirier et al. [25] that poly(ADP-ribosy1)ation of histone H1 could alter the chromatin structure and be one of the mechanisms by which such nuclear events could be facilitated [25]. Indeed, they observed an opening of the chromatin structure, that is a relaxation, following the poly(ADP-ribosy1)ation of histone H1 both upon the addition of exogenous poly(ADP-ribose) polymerase [25] or by the intrinsic enzymatic activity of the nucleosomes [26].Abbreviations. Poly(ADP-ribose), polymer of adenosine 5'-diphosphate ribose; LDS, lithium dodecyl sulfate; PAGE, polyacrylamide gel electrophoresis.Enzyme. Poly(ADP-ribose)polymerase (EC 2.4.99. -).In order to have a better understanding of the interaction between poly(ADP-ribose) polymerase and nucleosomal proteins during poly(ADP-ribosyl)ation, we have performed acceptor studies und...

Poly(ADP-Ribose) May Signal Changing Metabolic Conditions to the Chromatin of Mammalian Cells

“…However, results obtained with reconstituted in vitro systems involving purified poly-(ADP-ribose) polymerase and appropriate chromatin acceptors have clearly shown that the pattern of (ADP-ribosyl)ated proteins (16) and the complexity (17) and size (17,18) of the (ADP-ribose)n polymer depend directly on the NAD' concentration in the reaction mixture. Similarly, the size of (ADP-ribose)n polymers generated in polynucleosomes by endogenous poly(ADP-ribose) polymerase depends on the NAD' concentration (19,20).…”

Histone Phosphorylation and Pericentromeric Histone Modifications in Oocyte Meiosis

“…The histone amino termini exposed on the nucleosome surface can be post-translationally modified by acetylation, 1 phosphorylation, 2,3 methylation, 4 ADP-ribosylation 5 and ubiquitination. 6 All core histones contain phosphoacceptor sites in their N-terminal domains: 7 H2A and H4 are phosphorylated on serine 1, H2B on serine 14 /32, H3 on serine 10/28 and threonines 3/11.…”

Mechanisms of poly(ADP‐ribose) polymerase catalysis; mono‐ADP‐ribosylation of poly(ADP‐ribose) polymerase at nanomolar concentrations of NAD

“…[3]) and the histone adducts thus formed can be further elongated by poly(ADPribose) polymerase [7]. Mechanistic interpretation of the enzymology of poly-ADP-ribosylation and of important supramolecular events in chromatin that appear to coincide with shifts in protein patterns of ADP-ribosylation [8,9] depend on a more detailed understanding of the initial steps of ADPribosylation at the poly(ADP-ribose) polymerase level [lo]. Pursuing this question, the existence of an early product [l l] was indicated.…”