EGFL7 is required for proper reorganization of tight junctions.

<p>(<b>A-H</b>). Representative confocal images of transverse sections of the dorsal aorta (DA) and posterior cardinal veins (PCV) stained with ZO-1 (red), GFP to mark cell membranes (MEM-GFP; green), and DAPI to mark nuclei (blue). Phase contrast images for the PCVs represent the <i>Erg</i> in situ signal. All images taken at 63x magnification with scale bars indicating 20 μm. Dotted white and red lines in all panels delineate the endothelial cells comprising each vessel. As anatomical references, the hypochord in (A-D) and the kidney in (E-H) are indicated by solid white lines. (<b>A</b>). ZO-1 localizes to tight junctions between endothelial cells of the DA in late tailbud stage (stage 33/34) control embryos. (<b>B</b>). ZO-1 tight junctions between endothelial cells of the DA in late tailbud stage (stage 33/34) EGFL7-depleted embryos appear similar to controls. (<b>C</b>). Tight junctions are redistributed to distinct puncta between endothelial cells at the periphery of the lumen in early tadpole stage (stage 35/36) control embryos. (<b>D</b>). Tight junctions are retained between endothelial cells of the DA in early tadpole stage (stage 35/36) EGFL7-depleted embryos. (<b>E</b>). Tight junctions assemble along the cord center between endothelial cells of the PCV in late tailbud stage (stage 33/34) control embryos. (<b>F</b>). Similar to controls, tight junctions assemble between adjacent endothelial cells of the PCV in late tailbud stage (stage 33/34) EGFL7-depleted embryos. (<b>G</b>). Tight junctions are redistributed to the periphery of the lumenized PCV and appear as distinct points of cell-cell contact in early tadpole stage (stage 35/36) control embryos. (<b>H</b>). Tight junctions are retained along the cord center of the PCV in early tadpole stage (stage 35/36) EGFL7-depleted embryos. 3–4 embryos from each condition/stage were assessed from at least 3–4 independent injection batches at the same position along the anterior-posterior axis of the embryo.