FIG. 4.

PARG activity and inhibition of PARPs by PJ34 restore TOP2B-mediated kDNA decatenating activity in a dose-dependent manner in vitro. A) Addition of PARG to reactions where TOP2B is inhibited by the addition of 1 pmol PARP1 or PARP2 in the presence of 1 mM NAD⁺ reduced the inhibition in a PARG enzyme concentration-dependent fashion. PARG itself had no decatenating activity and no inhibitory effect on TOP2B activity. B) Addition of PJ34 to inhibit PARP1 and PARP2 activity prevented the inhibition of TOP2B in a dose-dependent manner but by itself did not inhibit or activate TOP2B. Similarly, PARP enzymes did not cause kDNA decatenation or DNA strand breakage. Error bars indicate the standard deviations.