Figure 1.

Reduced Dlx1 and Dlx2 gene expression in Rb conditional mutant brain. In situ hybridization with Dlx1 and Dlx2 antisense RNA probes in the ventral forebrain at E13.5 (A–B′, E15.5 (C, C′; F, F′) and P0 (E, E′; G–H′). Dlx1 and Dlx2 mRNA levels were severely reduced in Rb conditional mutants compared with controls between E15.5 and P0 in the LGE, MGE, Sp, RMS and inside the OB (arrowheads in A′–C′, E′–H′). Dlx2 protein level was also reduced in these regions (I–J′; arrowheads). D, D′, GAD67 mRNA (glutamic acid decarboxylase enzyme), a downstream target of Dlx gene, was also decreased in the ventral forebrain of Rb mutant mice at E15.5. K, Quantitative real-time PCR performed on ventral forebrain lysates confirmed the significant reduction in Dlx1 and Dlx2 gene expression at E15.5 but not earlier. Cx, Cortex; Sp, septum; SVZa, anterior subventricular zone; Pi, piriform cortex; MCL, mitral cell layer; SEL, subependymal layer. Scale bar, 100 μm.