Figure 9.

Null mutation of NeuroD1 results in discrete areas that lack or have thinner layers of mature neurons. Sections from 4-week-old (A–C) ΔNeuroD1-LacZ null (D–F) ΔNeuroD1-LacZ heterozygous, and (G–I) wildtype mice. A, D, G: Anti-OMP staining to mark mature neurons. B, E, H: Anti-β-Gal staining to mark the cells that are, or recently derived from, a NeuroD1-expressing progenitor. C, F, I: Anti-PGP9.5 staining to mark both immature and mature neurons. In its most severe case, loss of NeuroD1 results in an epithelium containing isolated patches that lack mature neurons, while retaining a population of immature neurons and detectible NeuroD1-expressing progenitors, determined by LacZ expression (A₂-C₂, white arrow). In its least severe case, affected areas of the OE have a thinning in the labeling for mature neurons, while retaining ample expression of β-gal indicative of NeuroD1-expressing progenitors (A₁–C₁, black arrowhead). In contrast, within the heterozygote, loss of one functional allele has no overt effect similar to wildtype OE (D–I). Scale bar = 20 μm.