Progenitor cells with the capacity to differentiate into sympathetic-like neurons are transiently detected in mammalian embryonic dorsal root ganglia

We have identified a population of progenitor cells in embryonic dorsal root ganglia (DRG) of the mouse. These cells can be induced into proliferating and differentiating into neurons that display multiple characteristics of the sympathetic lineage by a brief exposure to a defined medium. The sympathetic neuronal characteristics include immunoreactivity for the transcription factors MASH-1 and Phox2a and for the neurotransmitter markers tyrosine hydroxylase, choline acetyltransferase, and NPY. The progenitor cells are detected in DRG from embryonic day 11.5 (E11.5) to E15. An identical time course is observed in primary cultures of neural crest, suggesting that the competency of these cells is intrinsically regulated. We also present evidence that the environment of the sensory ganglion, unlike that of a sympathetic ganglion, prevents these cells from differentiating into neurons.