Figure 7

Distribution of Sonic Hedgehog protein in the telencephalon of perlecan-null embryos. (A-H) SHH immunostaining in the forebrain of wild-type (A, E) and perlecan-null (B, F) embryos at E10.5 (A-D) and E12.5 (E-H). C, D, G and H are higher magnifications of the boxed areas in A, B, E and F. In the absence of perlecan, the diffusion of SHH into the brain is still present, but there is a significant decrease in the signal intensity in the ventral telencephalon, especially in the medial ganglionic eminences. Note that the floor plate basal lamina shows a strong SHH immunostaining in the wild-type brain (arrows in C and G) whereas no signal is detectable in the perlecan-null embryos (D and H). (I-K) Laminin immunostaining shows basal lamina continuity in the E12.5 wild-type (I) and perlecan-null (J) floor plate. The deposition of perlecan immunostaining in wild-type embryo coincides with that of laminin (K). The region shown in I-K is the same shown between arrows in (G). (L-O) Immunostaining for Patched 1 (Ptch1), the receptor of SHH, in wild-type (L, N) and perlecan-null (M, O) brains at E12.5. Ptch1 distributes in the mantle of the ganglionic eminences and is absent in the midline, the site of strongest SHH signal. In the mutant there is normal distribution of Ptch1. Scale bars: 100 μm (A, B, E, F, L-O), 50 μm (C, D, G, H), 40 μm (I-K).