Telomere analysis of transduced T-cell clones.

(A) Q-FISH analysis of metaphase chromosomes isolated from subclones transduced with the GFP vector (G11.1, second cloning step) and the TERT/GFP vector (T11.9 and T11.14, sixth cloning step). DAPI-stained chromosomes and Cy-3–labeled telomeres are shown in blue and yellow, respectively. (B) Distribution of TFUs in metaphase chromosomes from subclones transduced with GFP vector (G11.1) and TERT/GFP vector (T11.9 and T11.14). The average telomere fluorescence at individual chromosome ends was calculated to be 4.3 TFU for G11.1, 11.5 TFU for subclone T11.9, and 8.9 TFU for subclone T11.14. These values correspond closely to estimates of the average telomere length in these cells obtained by flow FISH (respectively 10.9, 21.7, and 14.9 kMESF units corresponding to an estimated18 5.4, 10.9, and 7.5 kb of telomere repeats for G11.1, T11.9, and T11.14 cells).