Fig. 6.

Rescue of OE neurogenesis in Foxg1^-/- mutants is dependent on Gdf11 gene dosage. ISH for OE neuronal lineage markers (Mash1, Ngn1 and Ncam) and sustentacular cells (Otx2), performed on horizontal sections through the OE of E16.5 wild-type and mutant littermates. Insets show high magnification views of septal OE. (A,B) OE and cell types within it are similar in wild-type and Gdf11^-/- mice at this age, except that Ngn1- and Ncam-expressing cell layers (and hence OE overall) are thicker, as reported previously (Wu et al., 2003). (C) No OE structure (apart from a truncated septum), nor any cell type-specific markers, are evident in sections from Foxg1^-/- mice at the same dorsoventral level. (D) Loss of one Gdf11 allele (Foxg1^-/-;Gdf11^+/-) rescues all cell types in the OE, and the OE appears to be of normal thickness, although planar expanse of the OE and morphogenesis of nasal cavity are clearly deficient in the compound mutant. (E) Rescue is more pronounced in Foxg1^-/-;Gdf11^-/- double mutants, particularly in terms of OE planar expanse and nasal cavity morphogenesis. For all panels, posterior is left, anterior is right. Sus, sustentacular cells; BL, basal lamina. Scale bar: 400 μm.