Bud3 activates Cdc42 in early G1. (A and B) Time-lapse imaging of PBD-RFP and Cdc3-GFP in WT (A) and bud3ΔCR2 (B) cells at 22°C. Arrowheads mark first appearance of new septins in mother cells. Numbers indicate time (in minutes) from the onset of cytokinesis (t = 0). (C) Quantification of PBD-RFP in mother and daughter cells shown in A and B. PBD-RFP intensity is normalized to intensity at t = 0. (D) Time-lapse imaging of PBD-RFP and Cdc3-GFP in cdc24-4 cells every 2 min at 37°C, and selected images are shown. Numbers (white) indicate the time (minutes) relative to the onset of cytokinesis (t = 0); numbers (black) below images indicate the time after shifting to 37°C. PBD-RFP intensity is normalized as in C. Bars, 3 µm.