To validate our system, EGFP-tagged TRF1 fused with HP1α (Fig. 1a) was transiently cotransfected with mCherry-tagged TRF2, a core shelterin component, and tested for colocalization at telomeres (Fig. 1b) in human bladder cancer UM-UC3 cells. This evidence concerns the gene TERF1 and urinary bladder carcinoma.