Ganglion Cell Differentiation and Intermediate Filaments in the Cervical Dorsal Root Ganglion of the Chick Embryo
To examine the differentiation processes of cervical dorsal root ganglionic cells, vimentin, nestin and neurofilament-H protein were immunohistochemically detected in chick embryos from stages 15 through 43. During stages 15-17, migrating neural crest cells exclusively expressed vimentin. At stage 20, there was a marked decrease in vimentin, and appearance of nestin in most cells of the ganglionic primordia. However, a few Schwann precursor cells containing only vimentin were also observed. During stages 24-26, spindle-shaped precursors of pseudounipolar neurons containing neurofilament-H protein increased in number in the primordia of the ganglia. During stages 28-30, large round immature neurons containing neurofilament-H protein in both their perikaryon and neurites were recognized. At stage 36, the neurons contained neurofilament-H protein and transiently vimentin. In addition, the precursors of satellite cells, containing neither vimentin, nestin, nor neurofilament-H protein, could be observed around the neurons. At stage 43, three mature cell types could be distinguished; pseudounipolar neurons containing neurofilament-H protein, Schwann cells containing vimentin, and satellite cells containing neither vimentin, nestin, nor neurofilament-H protein. These results clearly demonstrate that differentiation of neural crest cells into neurons, Schwann cells and satellite cells, is reflected by the intermediate filament composition.