Figure 6.

Telomerase activity in rad50 mutant cells. Protein extracts were prepared from heterozygous (+/−) and homozygous (−/−) rad50 mutant cells. Telomerase activity was detected by the TRAP assay as described in Materials and Methods. Products were separated on a 10% sequencing gel to reveal the periodic band profile. The TRAP assay was realized with extracts prepared from heterozygous (lanes, 3, 6, and 9) and homozygous (lanes 2, 5, and 8) rad50 mutant cells as indicated at the top of the figure. Lanes 1, 4, and 7 are the no-extract controls. Lanes 1–3 are from the TRAP assay under standard conditions. For, lanes 4–6, cell extracts were treated with RNaseA before the telomerase step. For lanes 7–9, samples were treated with RNaseA after the telomerase step and before the PCR step.