Figure 3.

Analysis of photoproducts excision activity after H₂O₂ treatment. Mock and APP751-expressing cells were cultured for 48 h and either left untreated or incubated with H₂O₂ (115 µM) in the cell culture media for an additional 24 h. Total cell extracts were generated, and photoproducts excision capacity was analyzed on damaged genomic DNA substrates for 30 min using a modified version of the comet assay. The excision capacity of cell extracts was analyzed as the mean tail intensity of the comet. Three biological replicates were tested in triplicate in three independent experiments. The mean tail intensity of each cell extract (n = 3) was calculated and then a Student’s t-test was performed. Ctrl-: negative control (corresponds to the reaction buffer alone). T4: T4-endonuclease, positive control for the excision of the UV-induced DNA damage; *^#§ data significantly different from Ctrl-, *** (p = 0.0005); ^### (p = 0.0005); ^§§§ (p = 0.0005).