Figure 5.

Effects of primer grip mutations on telomerase elongation. (A) Primer extension assays were performed using TEL15 and telomerases that have been purified by IgG-Sepharose adsorption. The assays also include 0.2 µM dGTP and 50 µM dTTP. The positions of the P + 3 and P + 6 products are indicated at the left side. Several low molecular weight RNase-insensitive products (indicated by asterisks) can be observed in this set of assays. A prelabeled 46-nt primer was added before ethanol precipitation as a recovery control (indicated by an arrow at the right). (B) The processivity of telomerase at the P + 3 and P + 6 positions are plotted for both the wild-type and mutant enzymes.