Delayed but not loss of gliogenesis in Rbpj-deficient trigeminal ganglion.

Somatosensory ganglia including dorsal root ganglion (DRG) and trigeminal ganglion (TG) are derived from a common pool of neural crest stem cells (NCCs), and are good systems to study the mechanisms of neurogenesis and gliogenesis. Previous studies have reported that deletion of Rbpj, a critical integrator of activation signals from all Notch receptors, in NCCs and their derived cells resulted in the delayed gliogenesis at early stage and a loss of glial cells at later stage in the DRG. But the phenotypes in the TG have not been described. Here we reported although the gliogenesis was also delayed initially in Rbpj-deficient TG, it was recovered as the development progressed, as shown by the presence of large number of glial cells in the TG at later stages. However, neuronal reduction was observed in Rbpj-deficient TG, which is similar to what observed in Rbpj-deficient DRG. Taken together, our data indicate the function of Rbpj is diversified and context dependent in the gliogenesis of somatosensory ganglia.