Dev. Dyn. 227: 552-562 (2003)
Establishment of a ventral cell fate in the spinal cord.
K.S. Moghadam, A. Chen & R. D. Heathcote
The neural plate is
induced during gastrulation when the organizer affects the ectoderm around it.
Recent experiments show that axial mesoderm can stimulate formation of specific
ventral cell types in the spinal cord, including floor plate, motor neurons, and
several types of interneurons. We have eliminated or disrupted axial mesoderm by
using a variety of methods to show that ventral columns of intermittent
dopaminergic neurons in the frog Xenopus also appear to be induced by
axial mesoderm. Inversion of the dorsal-ventral neural axis by splitting the
presumptive neural plate in vivo, produced two spinal cords with ectopic
dopaminergic neurons. The location and number of neurons suggest that even a
brief association with axial mesoderm can specify the identity of the first or
primary dopaminergic neurons and that notochord retains the ability to induce
cells to become secondary dopaminergic neurons.