FIGURE 6.

The SEED is essential in a Cdc13-Est2 fusion-protein strain. (A) Schematic showing Est1-bypassing recruitment of telomerase to the telomere in a Cdc13-Est2 protein fusion strain. CDC13-Gly₈-EST2 is genomically encoded in either an EST1 or est1Δ background. TLC1 alleles are expressed from centromeric plasmids. (B) Telomere Southern blot from CDC13-EST2 cells from two biological replicates at 500 generations. Brackets indicate different observed classes of telomere clusters: bracket “a,” extremely hyperlengthened telomeres seen in lanes 1 and 2; bracket “b,” stably shorter but still hyperlengthened telomeres seen in lanes 3–8; bracket “c,” telomeres shortening like a tlc1Δ strain, seen in lanes 9–24. Marker sizes are based on [γ-³²P]-labeled λHindIII DNA ladder.