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. 2018 Feb 8;7:e32943. doi: 10.7554/eLife.32943

Figure 3. Myosin II is required for early elongation and apical pulses.

(a) WT and (a′) sqh knockdown stage 7 follicles stained for F-actin (red) and FasIII (white). (b) Elongation coefficient of WT or sqh knockdown follicles during the early elongation phase (D, Driver; U, UAS line) (n > 30). (c) Fluorescence video-microscopy images of a stage 4 WT follicle that expresses BAZ-GFP and Sqh-mCherry. (d) Higher magnification of the area highlighted in (c) showing a pulsing cell. (e) Quantification of the cell apical surface (green) in the cell shown in (d) and of Sqh signal intensity in the apical area (red) over time. (f) Cross-correlation analysis over time of apical surface and Sqh apical signal intensity based on 86 cells from six follicles at stages 3–4. (g) Incubation with the Rok inhibitor Y-27632 strongly reduces pulse activity in stages 3 to 5 WT follicles. Each dot corresponds to one follicle, and at least 10 cells per follicle were analyzed. Red bars represent mean and ± SD (n ≥ 7 follicles). (h) Quantification of the length variation of the follicle cell AP and mediolateral axes during pulses indicates that pulses are isotropic (n > 13 follicles, at least 10 cells per follicle were analyzed). (i) Quantification of the relative BAZ-GFP and Sqh-mCherry signal intensity in cell bounds in function of their angle relative to the AP axis (n = 41 follicles). Relative intensity is given over the mean bond intensity. (j) Fixed stage 7 WT follicle that expresses GFP-Baz and Sqh-mCherry. Scale bars are 10 μm throughout. (p ***<0.001.) Full details of the genotypes and sample sizes are given in the supplementary files.

Figure 3.

Figure 3—figure supplement 1. Myosin II is required for early elongation.

Figure 3—figure supplement 1.

Follicles stained for pSqh (white in a,b, green in a’,b’) and F-actin (pink in a’b’). (a) WT follicle. (b) sqhRNAi in follicle cells driven with Tj:Gal4. The signal is mainly apical in WT follicle cells and is strongly reduced in the knockdown. (c) AR quantification in WT or sqh knockdown follicles during the early elongation phase. (p ***<0.001.)Scale bars are 10 μm throughout.