Fig. 4. The mfr1
/mfr1 mutant completes meiosis II but fails to undergo sporulation. The strains h-/h- pat1-114/pat1-114 (Sp964) and h-/h- pat1-114/pat1-114 mfr1/mfr1 (Sp965) were synchronized through meiosis as indicated in Fig. 2. (A) FACS analysis. Pre-meiotic S-phase took place between 2 and 3 hours in both cases. Haploid spores (as cells with 1C DNA content) were observed in the control cells after 7 hours but not in the mfr1/mfr1 mutant. Exp, exponentially growing cells before nitrogen starvation. (B) Percentage of cells with 1, 2 and 4 nuclei and of asci with spores during the experiment. Spores were not observed in the mfr1/mfr1 strain during this experiment. (C) Spindle-pole body (SPB) staining with anti-sad1 antibodies and DAPI staining in cells undergoing meiosis I (M I) and meiosis II (M II). The two cells shown in the right panels in each case have modified SPBs.
