Fig. 3: Transcription-dependent TERRA foci increase in response to IR-induced DNA damage/DSBs.
From: Telomeric RNA (TERRA) increases in response to spaceflight and high-altitude climbing
a Human U2OS cell populations were exposed to γ-rays (2 Gy) or sham-irradiated (0 Gy) and TERRA foci/cell quantified using 3-D image analyses following RNA-FISH. Quantification of the mean number of TERRA foci/cell revealed a significant increase post IR exposure (4 h) compared to unirradiated controls (DMSO). Inhibition of transcription via treatment with ActD for 3 and 8 h prior to IR exposure prevented the radiation-induced increase of TERRA foci. Error bars are SEM. Significance was assessed by two-way ANOVA followed by Dunnett’s multiple comparison test. ****p < 0.0001. b TERRA colocalizes at telomere-specific DSBs. Human U2OS cell populations were transiently transfected with EN-T, TRF1-only (positive control), empty vector (EV), or they remained untransfected (UT). Quantification of mean number of colocalized foci/cell: Telomere (TRF2)-TERRA foci represent TERRA at undamaged telomeres (background); Telomere-FLAG foci represent transfected/damaged telomeres without TERRA; and Telomere-FLAG-TERRA foci represent colocalization of TERRA at damaged telomeres. Error bars are SEM. Significance was assessed by two-way ANOVA followed by Tukey’s multiple comparison test. ****p < 0.0001, ns not statistically significant. See Supplementary Data 5 for all comparison statistics.
