Figure 3.

Oxidative DNA damage at telomeres in TERT/TERC mutants. Oxidative DNA damage at telomeres was analyzed by qPCR in VA-13 cells transfected with pBABE empty vector (transfection control), pBABE-WT TERT/TERC (WT telomerase) or the different TERT (panel A) and TERC (panel B) mutants. Potassium bromate (KBrO₃) was used as a positive control. The differences in PCR kinetics (Ct) between FPG-digested vs undigested DNA are represented for each sample as ΔCt Telomere (FPG/Buffer) and normalized to pBABE-WT TERT/TERC. Colors of the bars represent the different gene domains in which the mutations are found: yellow (controls: pBABE and pBABE-WT TERT/TERC), light green (TEN: p.Leu55Gln to p.Ala202Thr), light blue (RT: p.Val694Met to p.Arg865Cys), orange (CTE: p.Val1090Met and p.Thr1101Met) for TERT and pink (P1a stem: n.23G>C), purple (t/PK: n.96_97delCT and n.98G>A), dark blue (CR4/5: n.269G>A and n.325G>T for TERC. Graph bars represent mean values ± SEM of eight technical replicates from two independent experiments. Statistical significance between pBABE-WT TERT/TERC and each TERT or TERC mutant was calculated using two-tailed unpaired t-test (^*P < 0.05; ^**P < 0.01; ^***P < 0.001).