Fig. S5
The DA appears to form normally in the absence of VE-cad and Esama (A-D) Deconvolved projections of DAs of Tg(fli1a:EGFP)y1 (blue) wt (A), esamaubs19 (B), ve-cadubs8 (C) and esamaubs19; ve-cadubs8 double mutant (dKO, D) embryos stained for Zo-1 (red) and Pdxl (green), around 32hpf. Single channels are shown in inversed contrast. (A) In wild-type embryos the DA is lumenized and the strongest signal for apical Pdxl is usually observed close to junctions (Zo-1, and see red arrowheads in A). (A') shows a cross-section through the DA. Several ECs surround the lumen (L); apical staining (green) is seen between junctions (arrowheads) and on the luminal side of ECs. (B) The DA in esamaubs19 mutant embryos forms similar to wild-type ones. (B') shows lumen (L) surrounded by several cells and also here the apical Pdxl is located between junctions (arrowheads) and on the luminal side of cells. (C) In the absence of VE-cad, the DA is lumenized only partially. Cell-cell junctions look more disorganized compared to wild-type siblings (red arrowheads in the Zo-1 panel). (C') But even in collapsed portions of the DA, apical signal (green) is observed between junctions, where lumen would be expected. Section was chosen where three cells (two nuclei and one cell body form the DA; only two junctions are observed (red arrowheads), because two junctions overlap between the two cell nuclei (n). (D) Similar to vecadubs8 mutants, the DA of dKO embryos is only partially inflated and the junctions appear disorganized (red arrowheads in the Zo-1 panel). (D') However, apical polarization appears normal with signal (green) between junctions and on the luminal (L) side of the endothelial cells. Section shows lumenized portion of the DA surrounded by 4 cells. DA, dorsal aorta; L, lumen; asterisk, nucleus; c, cell body; white arrowheads, junctions; Pdxl, Podocalyxin; cross-section is located at the dotted line; scale bars, 10μm. |