Fig. 4

HuR regulates telomerase activity. a, b HeLa cells were infected with a lentivirus vector expressing shHuR at the times indicated. Telomerase activity (a) and telomere length (b) were analyzed by TRAP assays and southern blot analysis (a and b, left), respectively. The means ± SD from three independent experiments were analyzed for significance by Student’s t-test (a and b, right) (*p < 0.05; **p < 0.01). c, d HeLa (c) or U2OS (d) cells were transfected with a vector expressing flag-TERT. Twenty-four hours later, cells were further transfected with a siRNA targeting HuR (c) or with a vector expressing TERC variants (d) (Supplementary Fig. 1b) and cultured for additional 48 h. UV-crosslinking followed by RNP IP assays were performed by using an anti-flag antibody. RNA isolated from IP materials was used for reverse transcription (RT) followed by real-time quantitative (q)PCR analysis to test the levels of flag-TERT-bound TERC (c) or its variants (d). Data in d were normalized against the levels of TERC or its variants. Data in c and d represent the means ± SD from three independent experiments; significance was analyzed by Student’s t-test (**p < 0.01)