PDGF signalling controls the migration of mesoderm cells during chick gastrulation by regulating N-cadherin expression
Xuesong Yang, Holly Chrisman and Cornelis J. Weijer
Development 135, 3521-3530(2008) doi:10.1242/dev.023416
In the early chick embryo, Pdgfais expressed in the epiblast, outlining the migration route that mesoderm cells expressing the receptor,Pdgfrα,follow to form somites. Both expression of a dominant-negative PDGFRαand depletion of endogenous PDGFRα ligands through injection of PDGFRα-Fc fragments, inhibit the migration of mesoderm cells after their ingression through the primitive streak. siRNA-mediated downregulation of Pdgfaexpression in the epiblast on one side of the streak strongly blocks the migration of mesoderm cells into that side. Beads soaked in PDGFA elicit a directional attractive movement response in mesoderm cells,showing that PDGFA can provide directional information. Surprisingly, however, PDGF signalling is also required for directional movement towards other attractants,such as FGF4. PDGF signalling controls N-cadherin expression on mesoderm cells, which is required for efficient migration. PDGF signalling activates the PI3 kinase signalling pathway in vivo and activation of this pathway is required for proper N-cadherin expression.