FIGURE 5.

A CP2 mutant demonstrates telomerase activity defects. Telomerase activity assays performed from rabbit reticulocyte lysate-reconstituted telomerase, using either WT TERT or TERT harboring a CP2 mutation (R237A). Assays were performed in the presence or absence of the assembly protein p65 and in the presence or absence of dATP as indicated. Numbers (+1, +2, +7, etc.) indicate the number of nucleotides incorporated by telomerase at the indicated band. R237A TERT displayed a template boundary defect as indicated by an increase in the +2 product upon addition of dATP (asterisks). LC, loading control.