Fig. 7. Changing temporal requirement for total and Gli2A- and Gli3R-mediated Shh signaling in mes/r1 development. Schematic representation of wild-type, Shh-null, Smo-En1 cko, Smo-Nes cko, Gli2-null, Gli2-En1 cko and Gli2-Nes cko mutant mes/r1 phenotypes. The neural tube at E9.5 or E12.5 at the level of the posterior mes is depicted on the left-hand side; a schematic drawing of the midbrain, cerebellum and anterior ventral hindbrain at E18.5/P0 is indicated on the right side of each panel. The range of Gli2A-mediated Shh signaling (green arrow) and Gli3R-mediated Shh signaling (red line) is indicated. Light green dots indicate weak Gli1 expression/GliA; the purple gradient shows Gli3R levels (dark to light indicating high to low).