PUBLICATION

Egfl7 knockdown causes defects in the extension and junctional arrangements of endothelial cells during zebrafish vasculogenesis

Authors
De Mazière, A., Parker, L., Van Dijk, S., Ye, W., and Klumperman, J.
ID
ZDB-PUB-080226-10
Date
2008
Source
Developmental Dynamics : an official publication of the American Association of Anatomists   237(3): 580-591 (Journal)
Registered Authors
Parker, Leon
Keywords
zebrafish, EGFL7, angiogenesis, vasculogenesis, hematopoiesis, endothelial cells, cell junctions, desmosome, polarity, transferrin receptor
MeSH Terms
  • Animals
  • Blood Vessels/embryology*
  • Cell Polarity
  • Embryo, Nonmammalian
  • Endothelial Cells/physiology
  • Endothelial Cells/ultrastructure*
  • Endothelium, Vascular/ultrastructure
  • Erythroblasts/ultrastructure
  • Intercellular Junctions/ultrastructure
  • Microscopy, Electron, Transmission
  • Neovascularization, Physiologic*
  • Zebrafish/embryology*
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/metabolism*
PubMed
18224713 Full text @ Dev. Dyn.
Abstract
The endothelial cell (EC) -specific secreted protein EGFL7 is important for tubulogenesis in newly forming blood vessels. We studied its role in vascular tube formation by a quantitative ultrastructural analysis of Egfl7-knockdown zebrafish embryos. At 24 hours postfertilization, the endothelia of dorsal aorta (DA) and posterior cardinal vein (PCV) were correctly anchored to the hypochord and endoderm, respectively, but failed to expand into the vascular area. This resulted in vessels with reduced or split lumen and open sheets of ECs. Concomitantly, the organization of hematopoietic cells-identified by the presence of previously undescribed membrane tubules-between DA and PCV, and within the vessels, was severely disturbed. Strikingly, ectopic cell junctions occurred across the obstructed vessel lumen, on the luminal EC surfaces, which in control conditions never display junctions of any kind. These data suggest that Egfl7 provides ECs with a cue for their extension into the vascular area and in establishing EC cell polarity.
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