FIG. 5.

Est1 and Ku70 are required for catalytically inactive TERT to inhibit recombination-based telomere maintenance in taz1Δ trt1Δ cells. (A to C) PFGE analysis of taz1Δ trt1Δ rad3Δ, taz1Δ trt1Δ est1Δ, or taz1Δ trt1Δ pku70Δ cells transformed with indicated plasmids after extensive restreaking on appropriate selection plates. (D) Telomere length analysis for the indicated strains. After digestion with EcoRI, genomic DNA was fractionated on a 1% agarose gel and processed for Southern blot analysis with a telomere probe. (E) Trt1 association with telomeres requires Est1, but not Ku70 or Rad3. Telomere association of myc-tagged Trt1 was determined by ChIP assay using quantitative PCR against the TAS1 sequence. For taz1Δ pku70Δ cells, the recruitment of myc-tagged catalytically dead Trt1 (Trt1-D590A and Trt1-D743A) was also examined. Error bars represent the standard deviation from at least three independent experiments.