Figure 1.

The Bub2 checkpoint pathway does not regulate actin ring formation. A. and B. Actin ring formation in synchronized cells. Isogenic wild type (KSY3), bub2Δ (KSY19), bub2Δmad2Δ (KSY47), mad2Δ (KSY51), bub2Δbfa1Δ (KSY110) and mad2Δbfa1Δ (KSY111) strains were arrested in G1 with α mating factor, released from arrest and fixed at regular intervals during mitosis. Cells were stained for actin with Alexa 586 phalloidin and ≥ 300 cells were examined microscopically at each time point to calculate the percentage of cells with an actin ring. Reproducible results were obtained in three independent experiments, and representative results from a single experiment are shown. C. and D. Actin ring formation in nocodazole. The same strains as in A. and B. were treated as above, except for the addition of nocodazole at release from α mating factor (time 0).