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Fig. 3 Microridge organization during cytokinesis and wounding.
(A) Time-lapse maximum intensity projection images show changes in microridge pattern during cytokinesis at 30 hours post fertilization (S4 Movie). Mosaic transient expression of GFP-UtrCH in epithelial cells allows visualization of microridges. Microridges gradually became shorter before cytokinesis (i and ii). Microridges transiently disappear (iii; in cells labeled with green asterisk) shortly before the appearance of the cleavage furrow (iv and v; arrows); reappear quickly during cleavage furrow formation (iv and v; in cells labeled with red stars); and then gradually become longer after cytokinesis (vi; arrowheads). Data are representative of 6 individual cells from 3 zebrafish larvae. Scale bar, 10 µm. (B) Maximum intensity projection of epithelial cells expressing GFP-UtrCH alone (i) or with constitutive active Rho (Rho Q63L-mCherry; ii) in zebrafish larvae at 2.5 dpf. Active Rho expression in epithelial cells results in cell rounding and apical protrusion but microridges are maintained. YZ, maximum intensity projection on the YZ axis. Data are representative of 63 individual cells in 21 larvae from three separate experiments. Scale bar, 10 µm. (C) Rearrangement of microridges during epithelial wound healing in vivo. Laser cell ablation was performed on a single cell (red asterisk) in a zebrafish larva at 2.5 dpf that transiently expresses GFP-UtrCH in epithelial cells. Maximum intensity projection images before (i) and after laser ablation (ii and iii) show the change in microridge pattern and cell shape in the epithelial cells (green asterisk) adjacent to the wound (S5 Movie). Data are representative of 5 individual experiments. Scale bar, 10 µm.