C. Representative images for TIF quantification: co-localization between 53BP1 (green) and telomeres (red FISH probe) in U2OS or IMRB cells with or without ectopic hTR overexpression. White arrows indicate TIF. Quantification of TIF is on the right. A total of 110-170 nuclei were scored from three independent experiments. Each dot represents the number of TIF per nucleus. Data information: All scale bars: 5 μm. Data are shown as mean ± SD. , C, the red line marks the mean value. Statistical analyses were performed with Student's two-tailed unpaired t-tests with Welch's correction for normality of distribution, unless specified otherwise. 