FIG. 1.

Telomerase activity assays using the template mutant enzymes. (A) Sequence of the wild-type (WT) template domain (residues 484 to 468 from the 5′ end) of the TLC1 RNA. (B) Telomerase was partially purified from wild-type cells or the various single- and double-mutant strains and assayed for telomerase activity using a telomeric oligonucleotide in the presence of [³²P]dTTP and unlabeled dGTP, dATP, and dCTP (lanes marked ddG−). In lanes marked ddG+, dGTP was replaced with ddGTP. Extension products were purified and separated on a denaturing gel before being exposed to X-ray film. Primers differed only at the 3′ end and matched the sequence of the RNA template from positions 475 through 483 (GTGTGGTGTGTGCA, GTGTGGTGTGTGCG, GTGTGGTGTGTGGA, or GTGTGGTGTGTGGG).