Fig. 5. (A) Partial nuclear division in slk19 results from the force exerted by the spindle. G1 synchronized cdc20 GAL-CDC20 (US3398) and cdc20 slk19 GAL-CDC20 (US3399) strains were released into YEPD containing nocodazole (15 µg/ml). Panel a shows cdc20 and panel b cdc20 slk19 cells. Top row shows cells at 240 minutes after release from factor into YEPD. Middle row shows cells at 240 minutes after release from factor into YEPD containing nocodazole. Bottom row shows cells that were first arrested in G2-M with short spindle (240 minutes) and then treated with nocodazole for 1.5 hours. (Panel c) Co-localization of Ndc10 with Slk19 in cdc20 GAL-CDC20 cells (US4194) arrested in G2-M by Cdc20 depletion in glucose medium. (B) Spindle length distribution in cdc20 and cdc20 slk19 cells. cdc20 GAL-CDC20 (US3398) and cdc20 slk19 GAL-CDC20 (US3399) cells were arrested in G1 using factor and released into YEPD at 24°C. At the end of 4 hours, cells were stained with anti-tubulin antibodies. The spindle length was determined using Metamorph software (a total of 270 cells were counted). (C) Greater variation in distance between SPBs in slk19 cells. WT (US3786) and slk19 (US4164) strains expressing Spc42-GFP integrated at the TRP1 locus were immobilized onto gelatin coated slides and immunofluorescent signals were observed every 5 minutes. The distance between the Spc42-GFP spots is plotted versus time.