Early commitment of precursor cells from the rat superior cervical ganglion to neuronal or nonneuronal fates.

To determine whether postmigratory neural crest cells retain the capacity to give rise to multiple cell types, the clonal progeny of embryonic rat superior cervical ganglion (SCG) cells were examined in culture. Double labeling with BrdU and neurofilament antibodies demonstrated that neuron precursors from the E14.5 SCG continued to proliferate for several days in culture. Using the BAG retrovirus to examine the progeny of single cells, we obtained several kinds of distinct clones from SCG cultures after 3 days. At E14.5, during peak neurogenesis in vivo, neuron-containing clones composed of one to seven cells were common. At E17.5, after neurons have been born in vivo, most clones in vitro contained flat cells, primarily reflecting glial cell division. Even in cultures from E13.5 ganglia, mixed clones containing neurons and flat cells were rarely observed. These observations suggest that neuronal and nonneuronal cell precursors are specified during or before early gangliogenesis.