AbstractThe phenotypic development of satellite cells in mouse sympathetic ganglia was examined by localizing the transcription factors, Sox10 and Phox2b, the neuronal marker, tyrosine hydroxylase (TH), and brain‐derived fatty acid binding protein (B‐FABP), which identifies glial precursors and mature glia. In E10.5 mice, most cells in the sympathetic chain expressed both Sox10 and Phox2b, with a minority of cells expressing Sox10 only or Phox2b only. In E11.5 mice, the majority of cells expressed Sox10 only or Phox2b only. B‐FABP was colocalized with Sox10 in satellite glial precursors, which were located on the periphery of the ganglion. There was no overlap between B‐FABP and Phox2b or B‐FABP and TH. During subsequent development, the number of B‐FABP+ cells increased and they became more common deep within the ganglion. In E12.5 and E18.5 mice, there was no overlap between Sox10 and Phox2b, and 98% of Sox10 cells were also B‐FABP+. Satellite glial precursors in E11.5–E15.5 mice also expressed the GDNF‐binding molecule, GFRα1. B‐FABP immunoreactive cells did not express Ret or NCAM, two potential signaling molecules for GDNF/GFRα1. In E12.5 and E18.5 mice lacking GFRα1 or GDNF, the development of B‐FABP immunoreactive satellite cells was normal, and hence neither GDNF or GFRα1 are essential for the development of satellite glia in sympathetic ganglia. © 2008 Wiley‐Liss, Inc.