Immunofluorescence demonstration of neurofilament polypeptide expression in fetal human neurons in culture

Sensory neurons from 10-week human fetal dorsal root ganglia were dissociated and grown in vitro and immunostained with monoclonal antibodies specific for neurofilament triplet polypeptides (non-phosphorylated 70 kDa peptide, NF-L; phosphorylated 150 kDa peptide, NF-M; and phosphorylated 200 kDa peptide, NF-H). All 3 neurofilament subunits appeared early in neuronal perikarya, but they were demonstrated in neurites at different times of culture. The phosphorylated 150 kDa subunit was the first to be expressed in neurites and was followed first by the phosphorylated 200 kDa subunit, and then by the 70 kDa subunit.