Fig. 6

Midbrain markers are not directly repressed by Pax6 but are regulated indirectly by Wnt/β-catenin signaling. (a) A Pax6 overexpression construct together with a GFP-expressing vector (Pax6OE) or a GFP-expressing vector alone (Control) were delivered by in utero electroporation into the dorsal midbrain at E13.5. Two days later the proportion of GFP⁺ cells expressing midbrain markers Pax3 and Pax7 was analyzed. Overexpression of Pax6 does not affect the proportion of midbrain marker-expressing cells. n = 3 in each group, two different litters (also see Additional file 1: Figure S7B). (b, c) Immunostaining for Pax3 (b) and Pax7 (c) at E12.5 reveals decreased protein levels in midbrains with ablated Wnt/β-catenin signaling (Ctnnb1 sign mt) compared to control. Cartoon insets show regular expression pattern, asterisk indicates basal. DAPI staining serves as nuclear marker: b, c; Scale bars: b, c, 500 μm (upper panel); b, c, 40 μm (lower panel); Error bars indicate SD; IUE, in utero electroporation; ctrl, control; Ctnnb1 sign mt, Wnt/β-catenin signaling mutant; MB, midbrain