Fig. 5. F-Actin delocalization in nak1/orb3-167 cells blocked at different stages of the cell cycle. Wild-type (WT), nak1/orb3-167, nak1/orb3-167 cdc2-M26 and nak1/orb3-167 cdc25-22 cells were grown at 25°C and shifted to 35°C for 2 hours. The nak1/orb3-167 culture was split in half before the temperature shift. One half was directly shifted to 35°C (orb3-167 –HU) and the other half was incubated with 15 mM hydroxyurea for 4 hours at 25°C before the shift up (orb3-167 +HU). Cells were fixed and stained with rhodamine-phalloidin, and the proportion of cells with polar F-actin patches at the tips was determined. 200 cells were counted for each mutant; experiments were performed at least twice.