Fig. 5. Mutational disruption of TERT nucleolar localization does not affect its telomerase enzymatic activity in both normal and cancerous human cells. BJ cells (at around 45 PDs in culture) and U2OS cells were infected with recombinant lentivirus expressing GFP-TERT or GFP–TERT-3A. (A,C) Western-blotting assay with specific anti-GFP antibodies demonstrated that the stable expression of wild-type GFP-TERT and the mutant GFP–TERT-3A was at approximately the same level in corresponding stable BJ (A) and U2OS (C) cells. (B,D) TRAP assay demonstrated that stable expression of both GFP-TERT and of the GFP–TERT-3A mutant can activate telomerase activity with the same efficiency in both BJ fibroblasts (B) and in cancerous U2OS cells (D). Tubulin was used as the control to show the amounts for each loading sample in the western-blotting assays. Vector-infected BJ cells and U2OS cells were used as controls for these experiments.