Spindle elongation is blocked in CaCDC5-repressed filaments. (A) Tub1p-GFP was visualized in strains CB110 (CaCDC5/CaCDC5, TUB1-GFP) and CB112 (cacdc5::hisGΔ/cacdc5Δ:: HIS1/PCK1::CaCDC5, TUB1-GFP) grown in SD medium for 3, 5, and 24 h. Bar, 10 μm. (B) Paired images of immunolocalized α-tubulin and DAPI-stained DNA in strains CB104 (cacdc5Δ::hisG/cacdc5Δ:: HIS1/PCK1::CaCDC5) and RM1000 (CaCDC5/CaCDC5) grown in SD medium for 3 h. Note the cytoplasmic microtubules in the filaments. The short spindle in strain CB104 is indicated by an arrow. Bar, 5 μm. (C) Microtubule organization in serum-induced hyphae. Cells of strain CB110 (CaCDC5/CaCDC5, TUB1-GFP) were incubated in SD medium containing 10% fetal calf serum at 37°C for 2 h to induce hyphal formation and visualize microtubules. Bar, 10 μm.