Fig. 2.

VEGF-A regulates neural cell migration. a Schematic of facial branchiomotor neuron migration in the segmented mouse hindbrain. Facial branchiomotor neurons express Neuropilin-1 and migrate along a VEGF-A₁₆₄-rich pathway from rhombomere (r) 4 into r6 where they form the facial motor nucleus (VIIn). b Disruption of VEGF-A₁₆₄-Neuropilin-1 signaling leads to mispositioned and mishaped facial motor nucleus. c Schematic of neural crest cell migration from r4 to the second branchial arch in the chick embryo. VEGF-A is expressed in the ectoderm overlying the NCC migratory stream and in the second branchial arch tissue. d Neural crest cells fail to properly invade the second branchial arch when VEGF-A or Neuropilin-1 signaling is disrupted. e Schematic of cerebellar granule cell migration during early postnatal mouse development. Granule cell precursors in the external granule cell layer proliferate, then differentiate and migrate through the molecular layer past the Purkinje cells to their destination, the internal granule cell layer. A radial concentration gradient of VEGF-A isoforms provide one of the directional signals responsible for the inward migration of VEGFR2-expressing granule cells. f Inhibition of VEGF-A-VEGFR2 signaling delays granule cell migration. ba2 second branchial arch; EGL external granular cell layer; fbm neurons facial branchiomotor neurons; GC granule cells; IGL internal granular cell layer; ML molecular layer; NCC neural crest cells; nt notochord; PCL Purkinje cell layer; r, rhombomere; VIIn facial motor nucleus