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. 2018 Jul 2;46(1):23–39.e5. doi: 10.1016/j.devcel.2018.06.006

Figure 3.

Figure 3

The Wing Elongates by Convergent Extension Followed by Isotropic Expansion

(A) E-cad-GFP live imaging (top) and fixed imaging (bottom) of developing wings from 4 to 8 hr APF. From 4 to 5 hr APF, the wing contracts along the anterior-posterior (blue arrows) axis and elongates along the proximal-distal axis (orange arrow) consistent with convergent extension. From 6 to 8 hr APF, the wing expands isotropically in all directions (orange arrows). Scale bar, 50 μm. See also Video S1. Wing Convergent Extension and Expansion, Related to Figures 3A, S2A, and S2C, Video S6. High-Magnification View of Convergent Extension, Entire Wing View, Related to Video S1 and Figure 3A.

(B) Quantification of the maximal width and length of fixed samples from 4 to 7 hr APF. Wing anisotropy is established from 4 to 5 hr APF, through width decrease and length increase. From 6 to 7 hr APF both parameters increase at the same rate, maintaining a constant ratio. Average, SD, and individual data points are presented; n > 8 for each developmental stage. Statistically significant differences are indicated (∗∗p < 0.005, ∗∗∗p < 0.001).

(C) Cell division (phospho-histone-H3-positive nuclei, red) is very rare in the developing wing from 4 to 8 hr APF. Scale bar, 50 μm.

(D and E) E-cad-GFP live imaging during convergent extension (D, see Video S2. T1 Resolution during Wing Convergent Extension, Related to Figures 3D and S2A, Video S3. Rosette Resolution and Shape Cell Change during Wing Convergent Extension, Related to Figures 3D and S2A, Video S4. Cell Shape Change during Wing Convergent Extension, Related to Figure 3D) and expansion (E, see Video S5). Cell tracking (colored cells) shows how the epithelia contract along the anterior-posterior axis during convergent extension by cell rearrangements (T1, T2 transitions and rosettes) and cell shape changes, whereas they expand isotropically during expansion. Scale bar, 10 μm.

(F) Quantification of cell rearrangements detected in high-space-resolution live-imaging experiments during convergent extension (CE) and expansion (E) in E-cad-GFP-expressing wings (n = 4 wings, >1,500 cells per wing). Cell rearrangements only take place during convergent extension. Average and SD are presented.

(G) Quantification of cell shape anisotropy and apical surface area of epithelial cells from 4 to 7 hr APF. Data were obtained by segmentation of fixed pupal wings expressing E-cad-GFP (n = 13 wings, >5,000 cells per wing). Cell anisotropy decreases while apical area remains constant during convergent extension. During expansion, cells maintain their isotropy and apical surface area increases. Average and SD are presented, and statistically significant differences are indicated (∗∗∗p < 0.001).

See also Figure S2.