Fig. 8. Misexpression of Ngn2 inhibits choroid plexus formation and enhances Cajal-Retzius cell formation in the dorsal telencephalic midline. (A-G) pEF-EGFP alone (A-C) or the Ngn2 expression vector together with pEF-EGFP (D-F) was introduced into the dorsal telencephalic midline at E9.5 by in utero microelectroporation, and the region was analyzed at E12.5. Misexpression of Ngn2 inhibited formation of the choroid plexus (E', asterisk) and increased the number of Cajal-Retzius cells in the piriform cortex (F,G). (H-K) Ngn2 was overexpressed in the prospective choroid plexus and cortical hem regions by electroporation at E11.5, and the coronal sections were examined at E12.5. Forced expression of Ngn2 at E11.5 increased Cajal-Retzius cell (reelin⁺) formation in the cortical hem (H,I, arrows) but did not affect the choroid plexus development (J,K). ^*P<0.05, t-test. Scale bars: 200 µm in A,B,D,E,H-K; 50 µm in C,F.