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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 1. Mouse ventral midbrain organization.

Figure 1

A, B, E, F. Wholemounts with rostral to the top and ventricular surface facing the viewer. C, D. Transverse sections with ventricular surface to the top. G. Embryo in sagittal view with rostral to the right and dorsal to the top. A, B. Wild-type E12.5 midbrain (A) and a schematic (B) showing the ventral midbrain stripes of cell-fates (midbrain arcs) and their relationship to Shh expression in the rostral floor plate (rFP). Here, most of dorsal midbrain (blue, B) has been removed to facilitate a viewing of ventral midbrain. Midbrain arcs are labeled medial to lateral by the expression of the homeobox (HX) genes Phox2a (1/P2), Pax6 (P6) and Evx1 (E1) and are arrayed parallel to the rFP source of Shh. The Phox2a+ oculomotor complex neurons (1/P2) are obscured in A by the ventricular expression of Shh and are shown in the schematic in B and cross sections in C and D. C, D. Cross-sections of wholemounts shown in A and B (through positions marked by the horizontal lines in A and B). The labeling conventions in A-D and the color schemes in B and D are identical. E. Isl1+ labeling marks the oculomotor complex (OMC) neurons of the first arc (1) in an E12.5 wholemount. F. Expression of homeobox genes, Pax6 (blue) and Evx1 (brown) marks arcuate territories lateral to the OMC. G. Sagittal view of E12.5 midbrain demonstrating that the Pax7-negative/Evx1+ (blue) neurons lie immediately ventral to the dorsoventral boundary of the midbrain, here identified by the expression of Pax7 (brown) in dorsal midbrain. uAbbreviations: 1: first arc; III: third ventricle; E1: Evx1; P2: Phox2a; P6: Pax6; HX: Homeobox expression of Phox2a, Pax6, Evx1; FB: forebrain; HB: hindbrain; MHB: midbrain-hindbrain boundary; OMC: oculomotor complex; rFP: rostral floor plate, TEC:Tectum/dorsal midbrain.