Fig. 4. Septin ring diameter increases with age-dependent mother cell volume.

a Newborn cells trapped in a cavity were imaged for multiple generations. Phase contrast images are shown for a representative mother cell at the time points of cytokinesis from first to fifteenth division. Mother and daughter segmentations are shown in blue and red, generation numbers are denoted in the images. b Zooms of phase contrast (top) and mCitrine fluorescence (bottom) images corresponding to the aging cell shown in a are shown for time points where the septin ring is visible. c Mother and daughter cell volumes at the time point of cytokinesis are shown as a function of generation number. d Cell volumes normalized on the volume at the first division are shown as a function of generation number. e Median septin ring diameter during the time when the ring is detected based on Cdc10-mCitrine fluorescence is shown as a function of generation number. f Septin ring diameter normalized on the diameter during the first bud event is shown as a function of generation number. g For each cell, the normalized ring diameter is shown as a function of the corresponding normalized mother cell volume. A linear fit to the double-logarithmic data as well as binned means with standard error is shown. Boxplots in c, e show medians and 25 and 75 percentiles. Whiskers denote extreme values still within 1.5 interquartile ranges, symbols denote outliers. Error bars in d, f denote 95% confidence intervals as determined from 50,000 bootstrap samples. Cells were grown on SCD. Data are based on 44 cells from four independent experiments tracked over at least nine generations. Source data are provided as a Source Data file.