FIG. 6.
(A) The expression of POT1 decreased the loss of telomeric overhang induced by TRF2ΔBΔM. (Top) The T-OLA was used on genomic DNA derived from the IMR90 cells expressing the indicated constructs for 5 days after infection. Lane 1, no genomic DNA. (Middle) Quantitative PCR was performed, using primers specific for genomic GAPDH for equal amounts of genomic DNA in each sample. (Bottom) Myc-POT1- and Myc-TRF2ΔBΔM-expressing levels were determined by immunoblotting. (B) POT1 blocked the senescent phenotype induced by TRF2ΔBΔM. IMR90 cells were stained for β-Gal activity at pH 6.0. Graphs showed the effect of infection of Myc-TRF2ΔBΔM (P < 0.01), Myc-TRF2ΔBΔM plus Myc-POT1 (P > 0.5), Myc-POT1 (P > 0.5), empty vector (P > 0.5), and the untreated control for 16 days. The data show the results of three experiments; the error bars represent standard deviations. P values were determined by Student's t test representing each indicated group and untreated control group. The P value between Myc-TRF2ΔBΔM and Myc-TRF2ΔBΔM plus Myc-POT1 was <0.05.