Figure 2.

Wnts inhibit neuronal differentiation reversibly. Cortical explants were infected with control or Wnt 7a virus at E10.5 and cultured for 6 d. Explants were then dissociated and stained for expression of the early neuronal marker TuJ1, or cells were cultured as a monolayer to reduce cell-to-cell signaling and promote differentiation. After 1 d in monolayer culture, cells were stained with anti-TuJ1 and anti-β-gal. The proportion of neurons among Wnt7a-infected cells was reduced after 6d in explant culture compared with control infected cells but rose to the level seen in control infected explant cultures when allowed to differentiate for 1 d in monolayer culture. This suggests that Wnts reversibly inhibit the differentiation of progenitors that are competent to produce neurons. ^*p ≤ 0.04 comparing Wnt 7a with control virus.