|Endothelial tubulogenesis is a crucial step in the formation of functional blood vessels during angiogenesis and vasculogenesis. The transgenic line is a in-vivo model to define a novel cord hollowing process that occurs during the initial stages of tubulogenesis in intersegmental vessels (ISVs) in the embryo.mCherry-b-Actin fusion proteins specifically in endothelial cells using the kdrl promoter. In polarized epithelial and endothelial cells, Actin is enriched at both the apical membrane and adherens junctions. Similar patterns of localization for mCherry-b-Actin fusion proteins were observed in epithelial cells in the zebrafish otic vesicle. Additionally, mCherry-b-Actin localized to putative Actin filaments in the periderm.