FIGURE 6:

Septins regulate Cdc42p polarization in small-budded cells but not during bud emergence. Wild-type, rvs161Δ, cdc12-6, and rvs161Δ cdc12-6 cells expressing Cdc3-GFP were grown to early log phase, shifted to 37°C for 90 min, and then immunostained for Cdc42p. (A) For cells during early bud emergence, Cdc42p remained polarized at the presumptive budding sites in both the wild-type and mutant cells. Scale bar represents 2 μm. (B) For cells that had generated small buds, Cdc42p was depolarized in some of the cdc12-6 mutant, and diffused in most of the rvs161Δ cdc12-6 double mutant cells. Scale bar represents 2 μm. Cdc42p polarization was quantified in cells during early bud emergence (C) and small-budded stage (D). Groups of 50 cells were counted (n = 3) for the wild-type and each mutant. Error bars represent standard error. *, p < 0.01 vs. WT cells. **, p < 0.01 between cdc12-6 and cdc12-6 rvs161Δ cells.