Fig. 3

Fissured cells remain connected through cell-cell junctions (A) Surface projections (see STAR Methods) from a time lapse following wounding of 3-dpf larvae expressing mCherry in basal cells and E-cadherin in basal and superficial cells: TgBAC(ΔNp63:Gal4); Tg(UAS:mCherry); TgBAC(cdh1:cdh1-sfGFP). E-cadherin remains localized at the cell periphery in both layers, despite fissuring in the basal layer. To facilitate comparison of the distribution of E-cadherin, image intensity was bleach-corrected at each time point by rescaling (see STAR Methods). (B) Electron micrograph of the cell-cell junction between two basal cells at 2 mpw. Blue arrowhead in the inset indicates the electron-dense staining characteristic of desmosomal plaques, and the yellow arrowhead indicates intermediate filaments. (C) Serial histological sections of epidermis at 20 mpw, taken at 1-μm increments along the y (dorsal-ventral) axis. White arrowhead: the gaps on either side of the basal cells are revealed in the y = 3 μm section to be contiguous across the apical surface of the cell. Black arrowhead: large rounded gap between two basal cells. Yellow arrowheads: tethers connect basal cells to other basal cells and to superficial cells. (D) 3D reconstruction of basal cells from 20 mpw larva shown in (C). Gaps between cells resemble fissures in confocal microscopy and are contiguous with each other along the interface between basal and superficial layers. (E) Live single-plane images of basal layer cells 20 mpw of a 3-dpf larva expressing Lifeact-GFP in basal cells and Cdh1-tdTomato in all epithelial cells: TgBAC(ΔNp63:Gal4); Tg(UAS:LifeAct-EGFP); Tg(cdh1-tdTomato) that were wounded in the presence of E3 media and imaged using an instantaneous structured illumination microscope (iSIM). Red arrowheads indicate a tether between neighboring basal cells containing both E-cadherin and F-actin.