Figure 4.

Inverse correlation between telomerase activity and telomere length distribution in newly established and old LCLs. (a) Representative SYBR gold-stained polyacrylamide gels of TRAP assay performed with untreated and heat-inactivated protein extract from newly established and old LCLs. Cell extracts from the telomerase-negative U2OS cell lines were used as control. (b) Plot illustrating the inverse correlation between telomerase activity, expressed in total product generated (TPG) units, and telomere length, measured as number of pixel per telomere, in newly established and old LCLs. The TPG units are the mean of three independent experiments and telomere length was obtained by measuring individual telomeres in 25 metaphase plates. The shaded area indicates the background levels of telomerase activity detected in lysates of U2OS cells (mean+2 s.d.).