Figure 6.

Chromatin condensation by hypertonic shock impedes 8-oxoG repair. (A) NT cells pre-incubated or not with 250 mM sucrose for 3 h and washed with CSK–0,5% triton buffer prior to fixation. DNA is stained with DAPI. (B) OGG1–GFP cells are treated with 40 mM KBrO₃ for 30 min and allowed to recover in DMEM supplemented with 250 mM sucrose. In the last row of images, sucrose was removed after 3 h and replaced by fresh medium for 3 h. Cells were washed with CSK buffer prior to fixation. Graph represents GFP intensity for each condition (number of nucleus > 10). Scale bar = 10 µm. (C) 8-OxoG quantification by alkaline elution of cells treated with 40 mM KBrO₃ and recovered in 250 mM sucrose supplemented medium. Bilateral Student test (*P > 0.1 compared to the point 0; **P< 0.04 and P< 0.02 compared to the points 0 and 3 h sucrose respectively). (D) western blot of cells treated with 40 mM KBrO₃ and recovered in 250 mM sucrose supplemented medium. Antibodies against GFP are used and lamin B1 is used as a loading control. Quantification of signals using Scan GBox is represented on the graph on the right. Bilateral Student’s test (*P < 0.05).