TitleResistance of ADP-ribosylated histones and HMG proteins to proteases.
Publication TypeJournal Article
Year of Publication1992
AuthorsBoulikas T, Poirier GG
JournalBiochem Cell Biol
Date Published1992 Oct-Nov
KeywordsAdenosine Diphosphate Ribose, ADP Ribose Transferases, Animals, Cattle, Chymotrypsin, High Mobility Group Proteins, Histones, Mice, Poly(ADP-ribose) Polymerases, Protein Processing, Post-Translational, Serine Endopeptidases, Tumor Cells, Cultured

Calf thymus histones (individually isolated or mixtures) and high mobility group proteins were ADP-ribosylated in vitro using [32P]NAD+ and immobilized purified poly(ADP-ribose) polymerase. The modified histones were then subjected to V8 protease or alpha-chymotrypsin digestion and the resulting peptides were separated by electrophoresis on acetic acid-urea-Triton gels. It was found that in vitro ADP-ribosylated histones were much more resistant to proteases than unmodified histones. A similar approach was applied to histones modified by the endogenous poly(ADP-ribose) polymerase in permeabilized NS-1 mouse myeloma cells in culture. In this case, the proteases could not discriminate between modified and unmodified histones and putative mono(ADP-ribosyl)ated peptides appeared in a digestion frame corresponding to that of bulk peptides. These differences are most probably due to the specificity or number of ADP-ribose groups added to the histones by the endogenous or exogenous poly(ADP-ribose) polymerase. Thus, depending on the size of poly(ADP-ribose) attached to nuclear proteins, these modified proteins might display different degrees of resistance to proteolysis.

Alternate JournalBiochem. Cell Biol.
PubMed ID1297346