Figure 6.

Failure of DRG formation from sox10-expressing neural crest–derived progenitor cells. Sox10-expressing cells were present in condensing DRG of control embryos (A) and lateral to the neural tube (nt) of mutant embryos (B, arrow) at E10.5. Near-adjacent sections hybridized with Notch1 riboprobes demonstrate lack of notch1 expression in sox10-positive progenitors of mutant embryos (D, open arrow), whereas Notch1 is expressed in progenitors of control embryos (C, arrow). Furthermore, ngn1-expressing cells were virtually absent lateral to the neural tube of mutant embryos (F, open arrow), whereas extensive ngn1 expression was found in the forming DRG of control embryos (E, arrow). In contrast to control embryos (G and I, arrows), only a few neuroD- and nf-expressing cells were present in mutant embryos (H and J, arrows). Bar, 20 μm.