Fig. 3.

Testing the existence and requirement of the terminal arm. (A) Schematic showing the nucleotide replacements in each single mutant and the double mutant. Nucleotides 22–102 were replaced with the sequence (CG)₅, predicted to pair in the double mutant (ΔΔ) with the (CG)₅ that replaced nucleotides 846–914 on the other side of the predicted terminal arm. (B) Growth of four independent isolates of each mutant is shown after ≈100 generations. (C) Length of telomeric DNA from helix replacement mutants. Numbers to left indicate size markers (bp). (D) Northern blot showing expression of TLC1 RNA in terminal arm mutants. A second probe for U1 small nuclear RNA was used as an internal control for loading and relative mobility. Cells were grown to stationary phase before being harvested.