Fig. 6-. Acetylable lysine residues in Ape1 N-term are necessary for G4 oligonucleotide binding.

A) Crosslinking analysis of immunopurified (IP) recombinant Ape1-Flag proteins obtained from U2OS cells were performed as described in Materials and methods section and run onto an SDS-PAGE 10%. Recombinant protein, rApe1^WT was used as control. Values reported at the bottom of the Figure, in correspondence of each lane, indicate the signals intensity of the retarded complex expressed as fold of change with respect to the wild-type protein. See also supplementary Figs S9A and B for the gels.

B) Graphs depicting AP site incision activity of IP for Ape1^WT, Ape1^N∆33, Ape1^K4pleA, Ape1^K4pleQ and Ape1^K4pleR on the specified substrate in a solution containing 5 mM KCl. Graphs describe the percentage of conversion of substrate into product as a function of the dose of protein on the indicated substrate. Average values are plotted with standard deviations of three loadings of the same experiment as a function of protein dosage. Standard deviation values were always less than 10% of the mean of experimental points. See also supplementary Figs S9D for the gels.

C) ChIP analysis on telomeric sequences. U2O2 cells were transfected with pCMV plasmids for the expression of Flag-tagged Ape1 mutants as indicated in Materials and methods section. Empty vector used as control. Histogram shows the amount of telomeric sequence that was immunoprecipitated for the different Ape1 mutant. Data represent the binding of the telomeric sequences by each mutant of Ape1 resulting from ChIP experiments as percentage of input DNA. Error bars correspond to SDs of qPCR from one ChIP experiment.