Figure 3.
Single-stranded TG1–3 DNA appears in a cell cycle-controlled manner on chromosomal telomeres of tlc1Δ cells. Total DNA was isolated from yeast strain RWY14 (tlc1::LEU2) at the following time points: 0, cells at 37°C were arrested at START due to the temperature-sensitive cdc7 gene; 25, 35, and 90, cells were released into a synchronous S phase for 25, 35, or 90 min, respectively. The control DNA loadings (Controls) were as in Fig. 2B. M, molecular weight standards. Above the actual time points, the corresponding approximate cell cycle phases are indicated. The DNAs were digested with the restriction enzyme XhoI and separated on a 0.7% agarose gel. The gel in A was treated as a nondenaturing gel and hybridized to the end-labeled CA-oligo. The gel in B was identical to the gel in A except that this gel was then treated as a regular Southern blot (i.e., the DNA was denatured in the gel) using a Y′-specific probe.