DNA strand breaks alter histone ADP-ribosylation.
AUTOR(ES)
Boulikas, T
RESUMO
Histone ADP-ribosylation was studied using two-dimensional gel electrophoresis after cleavage of the nuclear DNA with nucleases. Modified histones carrying different numbers of ADP-ribose groups form a ladder of bands above each variant histone. Cellular lysates containing unfragmented DNA mainly synthesize mono(ADP-ribosylated) histones. Cleavage of the DNA with either DNase I or micrococcal nuclease to fragments of an average size of 10-20 kilobases (kb) dramatically induces the formation of poly(ADP-ribosylated) species of histones in nuclei. As the number of DNA strand breaks produced by either DNase I or micrococcal nuclease increases and a great number of DNA cuts is introduced (fragments of 0.4-0.2 kb), the size of the poly(ADP-ribose) chains on the histones decreases. Finally, in the presence of 10 mM cAMP as an inhibitor of poly(ADP-ribose) glycohydrolase, human lymphoid nuclei synthesize hyper(ADP-ribosylated) histone H2B with at least 40 ADP-ribose groups attached to it. Lateral ladders emanating at precise points of the linear ladder on hypermodified H2B can arise from branching of poly(ADP-ribose) or from multiple monomodifications of glutamic (or aspartic) acid residues. Branching or de novo monomodifications occur after a precise number of ADP-ribose groups have been added to a histone molecule. Poly(ADP-ribosylated) histones thus appear to be intermediates in nuclear processes involving DNA strand breaks.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=287165Documentos Relacionados
- Pertussis toxin induces structural changes in G alpha proteins independently of ADP-ribosylation.
- Glycine 100 in the dinitrogenase reductase of Rhodospirillum rubrum is required for nitrogen fixation but not for ADP-ribosylation.
- A Family of ADP-Ribosylation Factor Effectors That Can Alter Membrane Transport through the trans-Golgi
- Nonenzymic ADP-ribosylation of specific mitochondrial polypeptides.
- Mutations in the draT and draG genes of Rhodospirillum rubrum result in loss of regulation of nitrogenase by reversible ADP-ribosylation.