Ccw12p localizes to the shmoo tip and ccw12 Δ cells display pheromone induced cell lysis. (A) Wt (SEY6211) and ccw12 Δ mutant (MEY12B) strains were treated with α-factor (20 μg/ml) for two hours. Cells were stained with the vital dye methylene blue. (a) Wt cells display a typical elongated shmoo. (b) Shmoos of mutant cells are rounder and less polarized. (c) Mutant cells dye during shmoo formation (10% of ccw12 Δ vs. 1% of wt cells). (d, e) Buds of mutants cells released from G1-arrest undergo cell lysis after cytokinesis is completed; a representative cell stained with methylene blue (d) and DAPI (e) is shown. (f) Mutant cells tend to lyse as small budded cells after re-entry of the mitotic cell cycle (23% of ccw12 Δ vs. 5% of wt cells). (B) Localization of Ccw12p-GFP to the shmoo during pheromone treatment. Yeast strain described in figure 7B was treated with α-factor as indicated in 7A.