Figure 1.

ATF7 is required for TNF-α–induced telomere shortening in MEFs. Telomere length of WT, Atf7^–/– or Tert^–/– MEFs prepared from TNF-α–treated or non-treated pregnant mice were analyzed by Q-PCR (A, B), Q-FISH (C, D), or telomere restriction fragment (TRF) assay using the G24 probe (E, F). MEFs from G2 Atf7^–/– mice and G4 Tert^–/– mice were used. Three primary MEFs from independent pregnant mice were used. (A, B) Average T/S ratio is shown ± SD. * < 0.05; **P < 0.01; ***P < 0.001; NS, not significant. See Supplementary Figure S1A, B for control data. (C, D) Middle lines in the colored boxes indicate medians; top and bottom edges, 25th and 75th percentiles; and whiskers, 10th and 90th percentiles. Note that data in Figure 2C and D cannot be directly compared because those experiments were separately performed. See Supplementary Figure S1C, D for raw data. (E, F) In TRF assays performed using mouse samples, the fragment detected was relatively long, and determination of the precise size was difficult. Therefore, the radioactivity of each slice in each lane (slice number is shown on the right) was quantitated using Image Analyzer, and the position of mean radioactivity was calculated. White bars indicate the position (slice number) of mean radioactivity in various samples: E, lanes 1–10; 47.2, 46.4, 49.6, 49.5, 52.0, 54.6, 42.0, 41.6, 58.7 and 57.7, respectively; F, lanes 1–4; 61.9, 61.3, 58.8 and 58.4, respectively. Note that we determined the position of mean length here, because the mouse telomere size is big and hard to determine precisely, and also the purpose of this experiment is the comparison of telomere size.