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. 2008 May 30;283(22):15381–15389. doi: 10.1074/jbc.M710296200

FIGURE 6.

FIGURE 6.

Loss of E2F1 attenuates DNA repair. A, comet assay expressed as average tail moment on E2F1+/+ and E2F1-/- MEFs untreated (left-hand graph, control), after incubation for 1 h in medium containing 50 μg/ml MMS (middle graph, 0 h), and after incubation for 1 h in medium containing 50 μg/ml MMS followed by recovery with incubation in fresh drug-free medium for 2 h (right-hand graph, R). Experiments were performed in duplicate, and measurement of mean tail moment was from 50 cells/slide from 15-20 randomly selected fields representing the whole area of each slide. Statistical analysis was performed using unpaired two-tailed t test on comet tail moments that were determined using Comet Assay II software (Perceptive Instruments; Suffolk, UK). Error bars, S.D. from separate experiments. B, indirect immunofluorescence microscopy on XRCC1 immunostaining (top), DNA polymerase I-mediated FITC-dUTP labeling assay (middle), and 4′,6-diamidino-2-phenylindole (DAPI) staining (bottom) performed on E2F1-/- and E2F1+/+ MEFs untreated (C), after incubation for 1 h in medium containing 50 μg/ml MMS (0 h panels), and after incubation for 1 h in medium containing 50 μg/ml MMS followed by recovery with incubation in fresh drug-free medium for 6 h (R panels). C, percentage of apoptosis as determined by Annexin V staining and flow cytometry 48 h after infection of the indicated cells with adenovirus expressing wild-type E2F1 (Adeno-E2F1) or adenovirus expressing GFP (Adeno-control). Error bars, S.D. of triplicate experiments and statistical analysis performed using Student's unpaired two-tailed t test.