Visualization of poly(ADP-ribose) synthetase associated with polynucleosomes by immunoelectron microscopy.
Antibodies showing a high specificity for poly(ADP ribose) synthetase have been purified. A fraction binding nonspecifically to histones present in antiserum and non-immune serum has been demonstrated by immunoblotting and separated by histone-Sepharose chromatography. The antibody without the nonspecific binding fraction was analyzed by Western blot with calf thymus protein extract and was found to react only with a band at 116 kDa. There was no reaction with purified topoisomerase I, this weak activity was copurified with poly(ADP-ribose) synthetase preparation. The specific IgG fraction has been used for the visualization of the interaction of poly(ADP-ribose) synthetase with chromatin by indirect gold-labelling. This immunomicroscopic study suggests that the synthetase is located in the inner part of polynucleosomes and would be associated preferentially with the core nucleosome.
Leduc
Y
Y
de Murcia
G
G
Lamarre
D
D
Poirier
G G
GG
D000818:Animals; D000918:Antibody Specificity; D002417:Cattle; D006046:Gold; D007158:Immunologic Techniques; D008854:Microscopy, Electron; D009707:Nucleosomes / Q000201:enzymology*; D011065:Poly(ADP-ribose) Polymerases / Q000032:analysis* / Q000276:immunology; D013205:Staphylococcal Protein A
D009707:Nucleosomes; D013205:Staphylococcal Protein A; D006046:Gold; D011065:Poly(ADP-ribose) Polymerases