Fig. 3.

Striatopallidal-enriched genes are derepressed in striatonigral cells of the Nolz-1 KO striatum. (A and B) Dopamine D2 receptor (D2R) and enkephalin (Enk), markers of striatopallidal neurons, are expressed in both the CP and the OT of WT E18.5 brains. D2R and Enk are markedly increased in both CP and OT of Nolz-1 KO brains. The bracketed regions in the CP and OT are shown at high magnification in the second and third rows of the panels. (C–F) In situ hybridization shows robust derepression of Drd2 mRNA (C and E) and Six3 mRNA (D and F) in both dorsal and ventral striata of the Nolz-1 KO brain from R to C levels. (G) qRT-PCR assay confirms up-regulation of striatopallidal-enriched genes in the E18.5 Nolz-1 KO striatum except that Gpr6 is reduced. (H) Deletion of Nolz-1 in Isl1 cell lineages results in hyperplasia of the ventral striatum and hypoplasia of the dorsal striatum in Isl1-Cre;Nolz-1^fl/fl;CAG-CAT-EGFP conditional KO (CKO) brains compared to control E18.5 Isl1-Cre;Nolz-1^fl/+;CAG-CAT-EGFP brains. (I and J) D2R (arrows) and GFP (arrowheads) are not colocalized in many striatal cells of the CP and OT in control brains. Colocalization of GFP and D2R (empty arrows) is increased in striatal cells of the CP and OT-like regions in CKO brains. (K) Validation of the successful deletion of Nolz-1 in GFP-expressing Isl1 cell lineages in the striatum by the absence of Nolz-1 immunoreactivity (red, arrowheads) in GFP-positive cells (green, arrows) of CKO brains. OTe: enlarged OT. *P < 0.05; **P < 0.01; ***P < 0.001; n = 3/group. (Scale bars, 200 μm [A and B], 50 μm [A and B)] for the Bottom, 500 μm [C], 200 μm [D and H], and 10 μm [I and J].) The low-magnification images in A and B are stitched images.