At least 60 ADP-ribosylated variant histones are present in nuclei from dimethylsulfate-treated and untreated cells.
The level of histone adenosine diphospho (ADP) ribosylation was studied in isolated nuclei from mouse myeloma cells in culture. The cells were treated with dimethylsulfate (DMS), a DNA-methylating agent, and histones were analyzed using two-dimensional gel electrophoresis. Seventeen or more bands probably representing mono-to heptadeca (ADP-ribosylated) histones could be visualized for each major variant histone. DMS treatment, by increasing the number of chromatin sites undergoing repair, greatly enhanced histone ADP-ribosylation. When histones were labeled in a cell lysate rather than in isolated nuclei, mono- and oligo(ADP-ribosylated) histone forms prevailed. The presence of approximately 87 ADP-ribosylated variant histone forms in cell lysates and of approximately 170 in isolated nuclei is shown for the first time in this work. Previous studies show multiple ADP-ribosylated forms for only histone H1. The theoretical number of variegated nucleosomes is thus much higher than previously thought, provided that histone-histone contacts are not disrupted at up to a certain level of histone ADP-ribosylation.
Boulikas
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Département de Biochimie, Faculté de Médecine, Université de Sherbrooke, Fleurimont, Québec, Canada.
D000246:Adenosine Diphosphate Ribose / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism*; D004249:DNA Damage; D004121:Dimethyl Sulfoxide / Q000494:pharmacology*; D014644:Genetic Variation; D006657:Histones / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D010954:Plasmacytoma; D012016:Reference Values
D006657:Histones; D000246:Adenosine Diphosphate Ribose; D004121:Dimethyl Sulfoxide