Inhibition of DNA polymerase α, DNA polymerase β, terminal deoxynucleotidyl transferase, and DNA ligase II by poly(ADP-ribosyl)ation reaction [formula omitted

Abstract

Incubation of DNA polymerase α 1 1 Abbreviations used are : DNA pol α-primase; DNA polymerase α with primase activity, DNA pol β; DNA polymerase β, and TDT; terminal deoxynucleotidyl transferase , DNA polymerase β, terminal deoxynucleotidyl transferase, or DNA ligase II in a reconstituted poly(ADP-ribosyl)ating enzyme system markedly suppressed the activity of these enzymes. Components required for poly(ADP-ribose) synthesis including poly(ADP-ribose) polymerase, NAD +, DNA, and Mg 2+ were all essential for the observed suppression. Purified poly(ADP-ribose) itself, however, was slightly inhibitory to all of these enzymes. Furtheremore, the suppressed activities of DNA polymerase α, DNA polymerase β, and terminal deoxynucleotidyl transferase were largely restored (3 to 4-fold stimulation was observed) by a mild alkaline treatment, a procedure known to hydrolyze alkaline-labile ester linkage between poly(ADP-ribose) and an acceptor protein. All of these results strongly suggest that the four nuclear enzymes were inhibited as a result of poly(ADP-ribosyl)ation of either the enzyme molecule itself or some regulatory proteins of these enzymes.