Fig. 4.

Aps3p- and Vps21p-dependent pathways make additive contributions to polarized hyphal growth. (A) Cell suspensions of each strain were applied as spots to M199 agar and incubated at 37°C for 4 days. (B) Each strain was induced to filament in 10% FBS at 37°C for 5 h. (C) A minimum of 200 cells grown in FBS at 37°C for 5 h were scored for each strain, according to the morphology index (MI) described by Odds and colleagues (29, 33). MI of 1, spherical and nearly spherical cells; MI of 2, ovoid cells with length up to twice the cell width; MI of 3, pseudohyphal cells with obvious constrictions; MI of 4, parallel-sided true hyphal cells. Data are the means of results of three separate experiments; error bars represent standard deviations. Pearson's chi-square test was used to determine whether the proportion of MI categories observed differed between the control strain (YJB6284) and each of the other strains. *, P < 0.001. (D) Cells of each strain were sandwiched between two layers of YPD agar and incubated at room temperature for 3 days.