Fig. 5. Undifferentiated neural crest progenitors persist in the sympathetic chain in the absence of Rbpsuh and can undergo gliogenesis in culture in the presence of neuregulin (Nrg). (A,B) E13.5 sympathetic ganglia from control and Wnt1-Cre⁺ Rbpsuh^fl/fl mouse embryos were dissociated and plated at clonal density (500 cells per 35 mm dish) under adherent conditions in the absence (A, standard medium; nine independent experiments) and presence (B, four independent experiments) of 5 nM Nrg. In standard medium (A), Wnt1-Cre⁺ Rbpsuh^fl/fl cells formed significantly (^*, P<0.05) fewer multilineage colonies (N+G+M) and all glia-containing colonies (G-containing). In the presence of Nrg (B), Wnt1-Cre⁺ Rbpsuh^fl/fl cells and controls cells formed similar numbers of all colony types, including multilineage and glia-containing colonies. (C-R) Typical photos of a single field of view from within a multilineage colony formed by control cells under standard conditions (C-F), an N+M colony formed by Rbpsuh-deficient cells under standard conditions (G-J), a multilineage colony formed by control cells in the presence of Nrg (K-N) and a multilineage colony formed by Rbpsuh-deficient cells in the presence of Nrg (O-R).