Figure 3.

cdc45-10 and dpb11-10 mutants affect S-phase progression. (A) Asynchronous cultures of EKY4 (wt), RRY71 (dpb11-10), RRY72 (cdc45-10), and MSY32 (dpb11-10, cdc45-10), grown at 26°C, were split, and half of the sample was shifted to 35°C. Each hour, aliquots were fixed, stained with propidium iodide, and sorted on a Coulter Profile II flow cytometer. (B) α factor-arrested cultures were shifted to 35°C for 2 hours and were released into the cell cycle. At 10-minute intervals, aliquots were collected and examined for cell cycle distribution. (C) At t = 0, an asynchronous culture of dpb11-10, cdc45-10 cells was split; half remained at 26°C, and half was shifted to 35°C. At the times indicated, aliquots were serially diluted and plated. The number of viable cells forming colonies at 26°C were counted and plotted relative to t = 0. All strains were top1-null.