Figure 1.

Regulated elongation of short T₂AG₃ seed sequences by yeast telomerase is Tbf1 dependent. (A) Schematic representation of the modified subtelomeric regions of Chr. VII-L and Chr. V-R. (B) Southern blots monitoring HO cleavage and elongation of the indicated T₂AG₃ tract ends in a wild-type (TBF1) strain. An internal loading control (‘INT’), a fragment arising before HO cutting (‘U’), and a fragment derived from ‘U’ following HO digestion (‘C’) are marked. (C) Analysis by ChIP of the binding of Tbf1–myc in wild-type strains after HO induction. Results are reported as average fold enrichment (bar) and standard deviation (lines) relative to an internal control sequence within the PDI1 gene on Chr. III (see Materials and methods for details). (D) Southern blots monitoring HO cleavage and elongation of the indicated T₂AG₃ tract ends in a tbf1-Δi mutant strain.