Figure 5. Temperature sensitive kar3-64 mutants show syntelic attachment.

G₁-arrested WT, kar3-64, sgo1Δ, and kar3-64 sgo1Δ cells with CEN4-GFP TUB1-mCherry were released into YPD at 35°C. Cells were collected at the indicated time points and fixed for the examination of fluorescence signals. A. Budding index. B. The percentages of cells with mis-segregated sister CEN4-GFP among those with an elongated spindle (n>100) is shown in the upper panel. The CEN4-GFP signal and spindle morphology in some representative kar3-64 sgo1Δ mutant cells are shown in the bottom panel. C. Chromosome mis-segregation generates cells with zero or two CEN4-GFP dots after mitosis. Cells with the indicated genotypes were collected at 180 min after G₁ release into 35°C YPD medium, and fluorescence signals were examined in cells in G₁ phase (n>100). The percentage of cells with zero, one, or two CEN4-GFP dots is shown. D. kar3-64 sgo1Δ double mutant cells lose viability after incubation at 35°C. Cells were collected after G₁ release for 180 min and spread onto YPD plates. After overnight incubation at 25°C, the plating efficiency was determined and the percentage of viable cells is shown (n>100).