Figure 5.

Accumulated interneurons in Tbr2-misexpressing areas are derived from ganglionic eminences by tangential migration. (A) Outline of the ex vivo experiment in which GFP, Tbr2-I-GFP, or Cxcl12-I-GFP electroporated brains were sliced 12 h after in utero eletroporation and cultured for 2 d in vitro, maintaining or removing the ganglionic eminences. (B–G) In GFP electroporated cortices (control), none or very few Calbindin⁺ cells are present regardless of whether ganglionic eminences are kept or removed. (H–S) In contrast, many Calbindin⁺ interneurons are accumulated in the Tbr2-I-GFP (H–J) or Cxcl12-I-GFP (N–P) electroporated cortical region of those brain slices that include the ganglionic eminences. (K–M,Q–S) This cellular migration does not occur when ganglionic eminences are removed from the brain slices. (T) Quantification of Calbindin⁺ cells in an electroporated field: GFP + GE = 7.5 ± 2.38; GFP − GE = 5 ± 3.16; Tbr2 + GE = 20.5 ± 4.2; Tbr2 − GE = 7.5 ± 4.12; Cxcl12 + GE = 27.5 ± 6.45; Cxcl12 − GE = 10.25 ± 4.42; error bars indicate SEM. (*) P < 0.001; (**) P < 0.01. Bars: B, 250 μm; C, 150 μm; D, 50 μm.