Fig. 1

Fig. 1

Doming Is Associated with EVL Cell Expansion and Radial Deep Cell Intercalations

(A) Bright-field images of a zebrafish WT embryo at sequential stages from the pre-doming stage (−30 min) to the end of doming (+90 min).

(B, B′, E, E′, H, and H′) Schematic representation of a zebrafish embryo before and after doming illustrating deep cell radial movement (B) and (B′), BYI upward bulging (E) and (E′), and EVL expansion (H) and (H′). BYI, blastoderm-to-yolk cell interface. Arrows, radial movement of deep cells.

(C, C′, F, F′, I, and I′) Confocal images of the blastoderm before the onset (−30 min) and after completion of doming (+90 min) where membrane, green in (C) and (C′) and white in (I) and (I′); nuclei, magenta in (C) and (C′); and BYI, white in (F) and (F′) were labeled by membrane-targeted GFP (mem-GFP), H2A-mCherry, and fluorescent dextran, respectively. Dashed lines mark the BYI in (C) and (C′) or outer surface of the blastoderm in (F) and (F′). Solid lines in (I) and (I′) outline measured surface area, and dashed line in (I′) marks the measured surface area at −30 min (I).

(D) Average deep cell speed along the radial direction of the embryo plotted as a function of time during doming.

(G) Relative BYI surface area measured within the observed region of the embryo and plotted as a function of time during doming.

(J) Relative EVL surface area measured for a continuous patch of cells within the observed region of the embryo and plotted as a function of time during doming.

(K–M) Geometrical parameters of WT embryos during doming with relative surface area (K) (S_b, entire blastoderm surface area; S_y, entire yolk surface area), relative height (L) (h_b, height of the blastoderm between animal pole and contact line; h_m, height of the blastoderm at the center of the embryo; h_t, total height of the embryo) and contact angles (M) (φ_b, angle between EVL and BYI; φ_y, angle between BYI and yolk membrane; φ, angle between yolk membrane and EVL) quantified from bright-field embryo images.

n = 6 embryos. Error bars, ±SEM (D), (G), and (J) and ±SD (K–M). Scale bars, 100 μm. Time point 0 min always indicates the beginning of doming recognizable by an upward bulging of the BYI. Embryo images are lateral views with the animal pole up unless otherwise stated. (I) and (I′) are animal pole views.

See also Figure S1 and Movie S1.