Figure 3. Effects of hTERT and its mutants on growth and senescence of human primary neonatal fibroblasts. (A) Growth dynamics of primary cells transduced with either empty vector (control), vector expressing wildtype hTERT (WT), IA mutant (IA), N-DAT116 mutant (N116) or N-DAT92 mutant (N92). (B) Cells from a selection of passages were subjected to senescence assay and the senescence index is plotted against cumulative population doubling that corresponded to the passage of cells that were analysed.