Fig. 1.

Selective labeling of progenitor cells in the MGE and the PoA. (A) Schematic diagram of the strategy. (B) Image of a section of an E14 mouse brain stained for β-gal (blue). β-gal is expressed specifically in the MGE and the PoA. Ncx indicates Neocortex; E, eye. Scale bar indicates 400 µm. (C) Image of a section of an E16 mouse brain injected with EGFP-expressing RCAS retrovirus (green) at E12 and stained with the DNA dye 4´,6´-diamidino-2-phenylindole (DAPI) (blue). There is robust labeling of progenitor cells in the ventricular zone of the MGE (arrow) but not the LGE or the Ncx (arrowheads). Scale bar, 400 µm. (D) Images of a section of an E16 mouse brain injected with EGFP-expressing RCAS retrovirus (green) at E12 and stained with nestin (red) and DAPI (blue). (Right) High-magnification images of the MGE (area 1) and the Ncx (area 2). EGFP-expressing cells are present in the ventricular zone of the MGE but not the LGE or the Ncx, and they are nestin-positive (arrowheads, inset). Scale bars (from left to right): 400 µm, 20 µm, 100 µm, and 50 µm. (E) Images of a section of an E14 mouse brain injected with EGFP-expressing RCAS retrovirus (green) at E12 and stained with Nkx2.1 (red) and DAPI (blue). (Right) High-magnification images of the MGE (area 1), the LGE (area 2), and the Ncx (area 3). EGFP-expressing progenitor cells in the ventricular zone, including those in mitosis with condensed DNA (arrowheads and broken circles, middle), are restricted to the MGE (broken rectangle, area 1) and the PoA and express Nkx2.1. (Inset) An EGFP-expressing cell in the Ncx with the characteristic morphology of a migrating interneuron. Scale bars, 400 µm, 50 µm, 10 µm, 100 µm, and 10 µm.