Figure 5: TRF2-induced telomeric UFBs correlate with stochastic telomere shortening.
From: Elevated levels of TRF2 induce telomeric ultrafine anaphase bridges and rapid telomere deletions
(a) Long telomere length exacerbates TRF2-induced telomeric UFBs. Left panel: quantification of telomeric UFBs in cells with different mean telomere lengths. Approximately 50 anaphases from each cell line were analysed for telomeric UFBs. Mean values are indicated in red. Two-tailed Student’s t-tests were performed to make pairwise comparison for statistical significance. No telomeric UFBs were detected in HeLa1.2.11 and HT1080 cells infected with lentivirus overexpressing GFP. Telomeres in UM-UC-3 cells (∼3 kb) were pre-extended by expression of the telomerase RNA subunit (hTR) for 11 days (to ∼8 kb) and 20 days (to ∼15 kb). Cells were infected with lentivirus expressing TRF2, and then fixed for telomeric FISH 48 h after infection. TRF2 overexpression did not induce any telomeric UFBs in control UM-UC-3 cells that were infected with an empty lentiviral vector. Right panel: terminal restriction fragment analysis in UM-UC-3 cells expressing vector control or hTR using a telomeric repeat probe. (b) TRF2 overexpression fails to induce telomere shortening in cells containing very short telomere length.
