Figure 4.

Radial Cell Intercalations Are Dispensable for Blastoderm Spreading but Required for Blastoderm Thinning during Doming

(A) Schematic of the deep cell-depletion experiment. (1) Deep cells were removed with a thick needle, (2) the removal reduced blastoderm volume, and (3) the blastoderm volume was restored to its original size by injection of embryo medium.

(B) Single-plane confocal images of deep cell-depleted WT embryos before (−30 min) and after completion of doming (+90 and +150 min). Plasma membrane was marked by mem-GFP in green. Nuclei were marked by H2A-mCherry in magenta. BYI was marked by dextran in white.

(C) Bright-field images of deep cell-depleted embryo at the onset (+10 min) and after doming (+90 min).

(D–G) Comparison of experimentally measured embryo shape changes with simulation results adjusted to reproduce experimental observations of deep cell-depleted embryos (D) and (E) and intact WT embryos (F) and (G) during doming. Simulation parameters are listed in Table S1C. Left plots are comparison of embryo surface area, height and contact angle with pale blue and red curves showing the experimental measurements, and dashed red and blue thick lines showing the simulation results. Right panels show simulated embryo shapes at 10 and 90 min of doming with black arrows marking the blastoderm velocity field. The experimental data in (F) were taken from Figures 1K–1M. n = 5 embryos (deep cell-depleted) and 6 embryos (control).

Error bars, ±SD. Scale bars, 100 μm.

See also Figures S3 and S4; Movie S4.