Figure 5. Abasic site incision and nick ligation activities in nuclear extracts from DIV7 neurons are differentially affected by exposures to H2O2 and oligomycin.
Reactions were assembled with radioactively labeled substrates. Products resolved in denaturing polyacrylamide gels were visualized by autoradiography; representative autoradiograms are shown. Time points are indicated and a substrate-only lane is included (lane 1). (A) Incision assay of abasic site (THF) carrying substrate. Reaction with recombinant human Ape1 serves as positive control (lane 14). 5′-end labeled 20-mer substrate (S) and the 9-mer incision product (P) are indicated. (B) Nick ligation assay. 5′-end labeled 21-mer substrate (S) and ligated 45-mer product (P) are indicated. Labeled oligonucleotides resolved in parallel provide size markers (M). Bar graphs represent product yields calculated from phosphorimager values and expressed as pmoles/min/mg protein. Values for three or four independent assays for each substrate in the linear range of reaction were used to obtain mean ± SEM. *P<0.05 versus control.