Telomere length analysis by Southern blotting of cells expressing a Cdc13DBD–Est3 fusion protein and various template mutant telomerase RNAs. Except for the wild-type strain, three independent colonies were analyzed for each genotype. Genomic DNA was prepared 50–75 generations after introduction of the Cdc13DBD–Est3 fusion protein. The library candidates were chosen at random. Lane 1, GA426 WT; lanes 2–4, YKF20 + pVL1292 + pTLC1-URA3 + pSD107; lanes 5–7, YKF20 + pVL1292 + pTLC1-URA3 + pRS314; lanes 8–10, YKF20 + pVL1292 + pTLC1-URA3 + candidates from Library480–471; lanes 11–13, YKF20 + pVL1292 + pSD107, pTLC1-URA3 shuffled out; lanes 14–16, YKF20 + pVL1292 + pRS314, pTLC1-URA3 shuffled out; lanes 17–19, YKF20 + pVL1292 + candidates from Library480–471, pTLC1-URA3 shuffled out. Terminal restriction fragments of the Y′-telomeres are indicated by the bracket on the right.