Effect of PARP-1 on APE1-dependent BER.

Abstract

<p>(A) A schematic representation of the DNA substrate containing the AP-site and the reaction scheme is shown. The BER reaction conditions and product analysis are described under Materials and Methods. (B) The BER reaction mixtures containing purified proteins XRCC1, PNKP, DNA ligase I and APE1 were supplemented either with PARP-1 (lanes 1–3) or dilution buffer (lanes 4–6). Repair was initiated by transferring the reaction mixtures to 37°C. Aliquots were withdrawn at 5, 10 and 20 min. The reaction products were analyzed as in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0124269#pone.0124269.g001" target="_blank">Fig 1</a>. The positions of the BER intermediate (unligated) and ligated BER products are indicated. (C) Quantification of the BER products was performed using ImageQuant software and data plotted as a function of incubation time (min). The plot demonstrates that BER product formation was linear during the 20 min incubation and that PARP-1 stimulated BER at least 2-fold as compared to the reaction without additional PARP-1.</p