Fig. 3

PAX6 restricts the lateral extent to which the hem can expand when LHX2 is lost. (a-c; f) Tamoxifen was administered at E8.5 to Control (a), CreER;Lhx2 ^lox/lox(b), and CreER;Lhx2 ^lox/lox ;Pax6 ^lox/lox (c, f) animals, and the embryos were harvested at E12.5. Coronal sections were examined for the expression of hem markers Wnt2b and Lmx1a. Wnt3a was examined at rostral, mid, and caudal levels of sectioning. In each condition, the length of the hem was scored as a fraction of the total length of the dorsal telencephalic neuroepithelium measured up to the ventral extent of Dbx1 expression in an adjacent section (shown in Additional file 3: Figure S3). d cartoon illustrating the length measurement (yellow dotted line) of the hem (green). Blue dotted line indicates the length measurement of the dorsal telencephalic neuroepithelium measured upto the ventral extent of antihem (pink). e Quantification of the fractional length of the hem in control Lhx2 single conditional mutants, and Lhx2;Pax6 double conditional mutants, at rostral, mid, and caudal levels of sectioning. For each level, the single mutant hem was significantly longer than that in the control, and the double mutant hem was significantly longer than that in the single mutant or the control (**p < 0.005, ***p < 0.0005). f Adjacent sections from three different double conditional mutant embryos in which Lhx2 was incompletely recombined were examined. In each case, when Pax6 is completely removed, but Lhx2 is present in patches (open arrowheads), the hem is suppressed in Lhx2 expressing regions. A false-color overlay shows that hem (green) is not seen in patches that show Lhx2 expression (red; open arrowheads). Scale bar is 200 μm