Recombinant sea urchin vascular endothelial growth factor directs single-crystal growth and branching in vitro.
Biomineralization in sea urchin embryos is a crystal growth process that results in oriented single-crystalline spicules with a complex branching shape and smoothly curving surfaces. Uniquely, the primary mesenchyme cells (PMCs) that construct the endoskeleton can be cultured in vitro. However, in the absence of morphogenetic cues secreted by other cells in the embryo, spicules deposited in PMC culture lack the complex branching behavior observed in the embryo. Herein we demonstrate that recombinant sea urchin vascular endothelial growth factor (rVEGF), a signaling molecule that interacts with a cell-surface receptor, induces spiculogenesis and controls the spicule shape in PMC culture. Depending on the rVEGF concentration, PMCs deposit linear, "h"- and "H"-shaped, or triradiate spicules. Remarkably, the change from linear to triradiate occurs with a switch from bidirectional crystal growth parallel to the calcite c axis to growth along the three a axes. This finding has implications for our understanding of how cells integrate morphogenesis on the multi-micrometer scale with control over lattice orientation on the atomic scale. The PMC model system is uniquely suited to investigate this mechanism and develop biotechnological approaches to single-crystal growth.
Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208, USA.
Regina T
RT
Knapp
Ching-Hsuan
CH
Wu
Kellen C
KC
Mobilia
Derk
D
Joester
D000818:Animals; D002478:Cells, Cultured; D059630:Mesenchymal Stem Cells / Q000737:chemistry*; D011956:Receptors, Cell Surface / Q000737:chemistry; D011994:Recombinant Proteins / Q000737:chemistry; D012617:Sea Urchins / Q000737:chemistry* / Q000166:cytology / Q000196:embryology; D042461:Vascular Endothelial Growth Factor A / Q000737:chemistry*
D011956:Receptors, Cell Surface; D011994:Recombinant Proteins; D042461:Vascular Endothelial Growth Factor A