Fig. 8. Progenitor cell specification at E12.5 in Gsh2 and Gsh1/2 double homozygous mutants. MASH1 protein is detected in many cells of the MGE and LGE VZ of the wild type (A). In the Gsh2 mutant the LGE level of MASH1 is lower and confined to the ventromedial VZ (B). In the Gsh1/2 double mutant, only a few MASH1-positive cells are seen in the LGE, close to the MGE (C). The majority of VZ and SVZ cells of the wild type are positive for DLX (D). In the Gsh2 mutant, only cells of the medialmost LGE SVZ express DLX proteins (E) while DLX-positive cells in the Gsh1/2 double mutant LGE are very rare (F). In situ hybridization for Raldh3 marks cells in the ventromedial LGE of the wild type (G). Raldh3 expression is present at low levels in the same region of the Gsh2-/- LGE (H) but completely absent in the double mutant (I). High levels of PAX6 protein show a sharp boundary in the dorsal LGE of the wild type (J). Ectopic PAX6 is found in a large region of the LGE VZ in both Gsh2 mutants (K) and Gsh1/2 double mutants (L).
