Characterization of boundary cap cells using novel markers obtained by RNA profiling

Neural crest (NC) cells are a multipotent, highly migratory cell population that generates most of the components of the peripheral nervous system (PNS), including the glial satellite and Schwann cells. In addition, NC cells also gives rise to another type of PNS glial cell, the boundary cap (BC) cells. These latter cells are located at the interface between central nervous system and PNS, at the exit/entry points of ventral motor and dorsal sensory axons. We have shown that in absence of BC cells motor neurons translocate their cell bodies along their axons into the periphery. Moreover, in vivo tracing of BC cells revealed that they give rise to all Schwann cells in the nerve roots and to a subset of nociceptive neurons and satellite cells in the dorsal root ganglia. To identify novel molecular markers for BC cells, we have performed RNA profiling experiments to compare mouse BC cells with two closely related cell types, NC cells and Schwann cells precursors, and tested the most promising candidates by in situ hybridization. This work defined a set of 10 genes that show specific expression in BC cells and/or in their derivatives located along nerve roots. Using this collection we show that dorsal and ventral BC cells and their derivatives express different genes, suggesting that they have distinct properties. We also establish that BC cells undergo a major modification between embryonic days 14.5 and 17.5. The identification of these novel makers opens the way for further characterization of BC cells in both mouse and man. Two biological replicates each in dye swap