Fig. 1. Ventral telencephalic neurons express Dlx, Mash1, Islet 1/2 and/or Nkx2.1 in distinct and overlapping populations of cells. Coronal sections of rat E14. I (A) Dlx (green), (B) Mash1 (red), and (C-F) Dlx and Mash1 co-expressing cells (yellow). (D-F) Enlargements of the boxed regions in A-C. (D) Proliferative zone of the LGE, double labeled; (E) proliferative zone of the MGE, double labeled; (F) post-mitotic region bordering the LGE and MGE, double labeled. II (A) Dlx (green), (B) Islet 1/2 (red) and (C-F) Dlx and Islet 1/2 co-expressing cells (yellow). (D-F) Enlargements of the boxed regions in A-C. (D) Proliferative zone of the LGE, double labeled; (E) proliferative region of the MGE, double labeled; (F) post-mitotic region of the region bordering the LGE and MGE, double labeled. III (A) Islet 1/2 (green), (B) Mash1 (red) and (C) Islet 1/2 and Mash1 co-expressing cells (yellow, not detected). IV (A) Dlx (green), (B) Nkx2.1 (red) and (C) Dlx and Nkx2.1 co-expressing cells (yellow) – only found in the MGE. (D-F) Enlargements of the boxed regions in A-C. (D) Proliferative zone of the LGE, double labeled; (E) proliferative region of the MGE, double labeled; (F) post-mitotic region of the region bordering the LGE and MGE, double labeled. V Schematic summarizing the protein expression pattern of Shh, Dlx (1,2,5,6), Nkx2.1, Islet 1/2, Dlx 2 and Mash1, based on I-IV, and those previously reported (Kohtz et. al., 1998). L, LGE; M, MGE, white arrow points to the border between the LGE and MGE.