Telomere length analysis of human CD4⁺ T cells transduced with DN-hTERT. Graphs show the quantification of individual telomere length expressed as the distribution of TFUs of Q-FISH telomere analysis of metaphase chromosomes from human CD4⁺ T cells that have undergone approximately 45 PD and were transduced with DN-hTERT (Asp868Ala, Asp869Ala)–GFP, hTERT-GFP, or control GFP. Analyses were performed on 16 metaphases of DN-hTERT (Asp868Ala, Asp869Ala)–GFP–transduced CD4⁺ T cells, 20 metaphases of hTERT-GFP–transduced cells, and 28 metaphases of GFP-transduced cells. The average telomere fluorescence of individual chromosome ends was calculated to be 1.35 TFU for DN-hTERT (Asp868Ala, Asp869Ala)–GFP–transduced cells, 1.92 TFU for hTERT-GFP–transduced cells, and 1.60 TFU for control GFP-transduced cells.