
Fig. 6. Pdgfra+ OLPs fail to develop in the anterior hypothalamic neuroepithelium of Nkx2.1 null mice. (A,B) Adjacent coronal sections from the telencephalon of wild-type E12.5 embryos. Pdgfra+ OLPs arise in the ventral forebrain (arrow in A) near the region of Shh expression (arrowhead in B). Shh is also expressed in the diencephalon in the zona limitans intrathalamica (arrow in B) but no Pdgfra+ cells are visible there. (C, D) Adjacent coronal sections from the telencephalon of E12.5 Nkx2.1 null embryos showing a complete absence of Pdgfra+ OLPs (arrow in C) and Shh expression (arrowhead in D) in the ventral forebrain. In contrast, expression of Shh in the zona limitans intrathalamica is maintained in the Nkx2.1 null (arrow in D).