Repressing CaCDC5 expression results in the formation of filaments under conditions favoring yeast growth. (A) Strains CB104 (cacdc5Δ::hisG/cacdc5Δ:: HIS1/PCK1::CaCDC5) and CB102 (cacdc5Δ::hisG/CaCDC5 PCK1:: CaCDC5) were incubated for 24 h on solid SD or SS medium. Bar, 30 μm. (B) Time course analysis of the formation of filaments in liquid SD medium. Strains CB104 and RM1000 were grown in SS medium (0 h), washed, diluted into SD medium, and fixed in 70% ethanol after 3, 9, and 24 h of incubation at 30°C. Bars, 10 μm. (C) Filament formation upon repressing CaCDC5 with the MET promotor. Strains CB108 (cacdc5Δ::hisG/MET:: CaCDC5) and CB109 (cacdc5Δ::hisG/MET::) were grown in SD medium lacking methionine for promotor induction, then diluted to an OD600 of 0.25 in SD medium containing methionine and cysteine to repress the promotor for 24 h. Bar, 10 μm. (D) Hyphal growth in strain RM1000 incubated in the presence of 10% serum at 37°C for 4 h. Bar, 10 μm.