Fig. 7. Interneuron losses in NsCre:Shh^Fl/Fl mutants do not appear to result from defects in postmitotic development. (A) RT-PCR experiments on samples from P0 cortex collected from genotypes NsCre:Shh^Fl/Fl (lanes 1, 2 and 3), NsCre:Shh^Fl/Wt (lanes 4 and 5), NsCre(–):Shh^Fl/Wt (lanes 6 and 7), and NsCre(–):Shh^Fl/Fl (lanes 8 and 9). (B,C) Anti-calbindin immunolabeling of 12 µm cryosections from E16.5 embryos shows a reduction of calbindin-expressing cells in the cortical subventricular zone (SVZ; arrows) of the NsCre:Shh^Fl/Fl section (C). (D) Dlx5/6Cre:floxed ß-gal reporter expression in a 12 µm section at E16.5. Little reporter recombination is seen at E14.5 (not shown), but by E16.5 many stained cells are evident in the striatum (St) and cortex. (E,F) Immunofluorescence co-labeling of Dlx5/6Cre:floxed-GFP reporter and Pv (E) or Som (F) in layers III-V of somatosensory cortex at P25. Over 90% of cortical interneurons expressing either of these interneuron subgroup markers co-label with GFP. (G) Counts of interneuron subgroups in the postnatal (P25) somatosensory cortex of Dlx5/6Cre:Smo^Fl/FL mutants. CP, cortical plate; Ctx, neocortex; IZ, intermediate zone; MZ, marginal zone; VZ, ventricular zone. Scale bar: 50 µM.