EXPRESSION OF PHOSPHORYLATED HIGH-MOLECULAR-WEIGHT NEUROFILAMENT PROTEIN (NF-H) AND VIMENTIN IN HUMAN DEVELOPING DORSAL-ROOT GANGLIA AND SPINAL-CORD

The expression of vimentin and the phosphorylated variant of high mole cular weight neurofilament protein (NF-H) was studied in developing hu man fetal dorsal root ganglia and spinal cord. The technique used for examination of cryosections was double-label fluorescence with monoclo nal antibodies. Both proteins were present in the nerve fibres inside the ganglia of 6- and 8-week-old embryos. During further development t he expression of vimentin continued to increase in the satellite cells , but was found to be decreasing in the ganglion cells. Phosphorylated NF-H was found in the processes of ganglion cells, as well as in the perikarya at all developmental stages. In the spinal cord of 6- and 8- week-old embryos, phosphorylated NF-H protein was found in the longitu dinal fibres of the marginal layer and in processes of the mantle zone ; some of the fibres also contained vimentin. Later the co-expression of the two proteins ceased and vimentin was found only in glial and me senchymal derivatives. Phosphorylated NF-H was located, at all develop mental stages, in the axons of both white and grey matter, but not in the neuronal perikarya. The results indicate that phosphorylation of t he NF-H in human dorsal root ganglia starts in the perikarya of the ga nglion cells while in the ganglion cells of the spinal cord it takes p lace in the axons.