Fig. 3
PP2A-Tws promotes the timely localization of Polo to microtubules and timely abscission during cytokinesis in D-Mel cells. (A) Cells expressing Polo-GFP and mCherry-Tubulin were filmed during their divisions. In control cells (RNAi NT, top), Polo-GFP becomes strongly localized to microtubules during telophase and cytokinesis. By contrast, in Tws-depleted cells (RNAi Tws, bottom), Polo-GFP is less strongly localized to microtubules (backets). However, the localization of Polo-GFP to centrosomes (asterisks), kinetochores (arrowheads) and the recently constricted midbody core (arrow) are not affected. Scale bar: 5 μm. (B) Quantification of Polo-GFP localization to microtubules relative to the midbody core during cytokinesis. Top: GFP fluorescence intensity measurements were taken on central spindle microtubules (MT, magenta boxes) and at the midbody core (MB, green boxes). Scale bar: 5 μm. Bottom: the ratio of MT/MB fluorescence over time was plotted as a function of time. T0: end of furrow ingression. Between 10 and 20 cells were quantified per condition. All error bars: S.D. * p < 0.05, **p < 0.01, ***<0.001, **** p < 0.0001, ns: non-significant from two-way Anova. (C) Quantifications of the durations of furrow ingression, retention of Polo-GFP at the midbody core and complete cytokinesis (until abscission) relative to anaphase onset in D-Mel cells depleted of Tws or control cells. The cartoons at the bottom illustrate the stages quantified. Between 7 and 13 cells were quantified in each condition. All error bars: S.D. * p < 0.05, **p < 0.01, ***<0.001, **** p < 0.0001, ns: non-significant from unpaired t-tests