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. Author manuscript; available in PMC: 2008 Nov 25.
Published in final edited form as: Dev Dyn. 2008 May;237(5):1359–1372. doi: 10.1002/dvdy.21536

Figure 4. Ventral midbrain induction in the Shh-/- and Smo-/- midbrains is likely to be HH-independent.

Figure 4

A-F. Embryos shown in sagittal view, with rostral to the right. G-L. Wholemounts oriented as in 1A. Columns 1, 3: wild type controls; Columns 2, 4. Shh-/- or Smo-/- mutants. A, B. Upregulation of Ihh in the foregut (FG; B) of the Shh-/- mouse. Note that Ihh expression in the controls (A) is confined to the hindgut (HG). C-F. Gli1 (C) and Ptc1 (E) expression in control midbrains flanks the Shh+ region of rFP (data not shown; (Aglyamova and Agarwala, 2007). Note the normal Gli1 and Ptc1 expression domains in the gut. A complete loss of Gli1 (D) and Ptc1 (F) expression from the midbrain of the Shh-/- mouse. Note the continued expression of Gli1 (D) and Ptc1 (F) in the mid- (Ptc1) and hind- gut (Ptc1, Gli1). G, H. The expression of Pax7 is restricted dorsally in the midbrain of the control (G) and Smo-/- mouse (H) at E8 (7 somites). I, J. Pax7 expression is dorsally restricted in the Smo+/? (I) midbrain and is rostrally and dorsally restricted in the Smo-/- midbrain (J) at E8.5 (8 somites). Compare G-J with Fig. 3 A, B, E-H. The bracket in J marks the rostrocaudal extent of the midbrain. K, L. Ubiquitous Gli3 expression in the E8.5 Shh-/- midbrain (L) compared to its restricted expression in control littermates (K). Abbreviations: FG: foregut; HB: hindbrain; HG: hindgut; MB: midbrain; MG: midgut; rFP: rostral floor plate.