Changes in poly(adenosine diphosphate-ribose) and poly(adenosine diphosphate-ribose) polymerase in synchronous HeLa cells

Abstract

An antibody was prepared which is highly specific for poly(ADP-ribose). Neither poly(A), DNA nor a variety of adenine-containing nucleosides or nucleotides were effective in competing with poly(ADP-ripose) for binding to the antibody. Of all compounds tested, only ADP-ribose competed for binding to the antibody. Unlabeled poly(ADP-ribose) was about 10,000 times more effective in competing with labeled polymer for antibody binding than was ADP-ribose. Using the antibody, the amount of poly(ADP-ribose) increased from early S phase to a peak at mid S with a 2nd, even larger increase seen at the S-G2 transition point in synchronously dividing HeLa cells. Pulse labeling of the polymer with [2-3H]adenosine was also maximal at the same time points. changes in the levels of poly(ADP-ribose) polymerase activity measured in isolated nuclei coincided with the changes in amounts of polymer present in intact cells during progression from S phase into G2.