Fig. 7
Myosin flows are instrumental in establishing sibling cell size asymmetry. a Schematic illustration of the model to be tested: if cleavage furrow positioning and thus physical asymmetry depends on Myosin flows, then altering Myosin flow onset on the apical and/or basal cortex will misposition the cleavage furrow. b Scatter plot showing basal Myosin clearing time in relation to apical Myosin relocalization in wild-type, neuroblasts exposed to Flavopiridol or colcemid, dlg;;pins and pins mutants. c Scatter plot showing the correlation between Myosin clearing on the apical and basal cortex and the asymmetry of the division in anaphase. A Pearson coefficient of “1” indicates a perfect correlation between Myosin clearing and furrow positioning. d Representative image sequence and (e) kymograph showing a wild-type neuroblast (endogenous untagged Sqh still present) expressing Sqh::GFP (Myosin, white; top row, green; bottom row) and Cherry::Jupiter (MTs; red; bottom row). f Representative image sequence and g kymograph of a sqh mutant neuroblast, coexpressing Sqh::GFP and ALD-RockCA::VhhGFP4, a fusion between the single-chain GFP antibody (VhhGFP4), Inscuteable’s apical localization domain (ALD) and Rho kinase’s kinase domain. h Kymographs were used to calculate apical/basal Myosin intensity ratios and (i) apical and basal cortical expansions. The resulting ratios are represented as a scatter plot. Center values and error bars represent the mean and standard deviation (s.d), respectively. Asterisks denote statistical significance, derived from unpaired t-tests: *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001, ****p ≤ 0.0001. Each measured cell (n) is represented with a dot in the scatter plots. For each experiment, the data were collected from at least 3 independent experiments. For each independent experiment, at least 5 larvae were dissected. Time: seconds (s). Scale bar: 5 µm. Time scale bar (open white box) in (e, g): 58 s. n.s. not significant
