Abnormal septin localization and organization in PGR mutants during RTG. (A–C) Time-lapse images of septin localization in WT cells during RTG (A) and mitosis (B) and during RTG in the mutants (C). Numbers indicate time in minutes after initial recruitment of septins to the site of polarization. DIC, differential interference contrast. (D) Percentage of cells with abnormal septin localization in the bud during RTG and mitosis (n = 100 each). (E) Superresolution images showing the organization of bud-neck septin structures during RTG. Examples shown are observable defects, with each mutant having a range of defects. Bars: (A–C) 3 µm; (E) 1 µm. (F) Percentage of cells with defective bud-neck septin structures during RTG and mitosis from superresolution imaging (n = 50 each). (D and F) Differences between RTG and mitosis are statistically significant (Two-tailed Fisher’s exact test; P < 0.05) unless marked ns.