Fig. 2. (A,B) Cell cycle progression of cells expressing mutant forms of CLB2. The indicated cells were synchronously released from an -factor-induced G1 arrest at 30°C. Aliquots were taken every 15 minutes. (A) DNA content was analyzed by flow cytometry and (B) the percentage of budded (crosses), pre-anaphase (triangles) and binucleate (squares) cells determined microscopically after a brief sonication. Pre-anaphase cells were defined as having the nucleus located at the bud neck. Note that in our strain background, about 20% of clb2 cells had the nucleus at the bud side of the neck just before anaphase and were classified as pre-anaphase cells. Each panel is representative of at least two independent experiments. More than 200 cells were counted for each time point. (C) Cells from the strain W303 clb1,3,4 clb2ts (Amon et al., 1993) were transformed with the indicated vectors and assayed for growth at 36°C. Serial 5x dilutions of saturated cultures were spotted on YPD plates and incubated at the indicated temperatures for 36 hours.