Ras-MAPK signaling is upstream of Ets-1 and promotes radial glia formation. (A–E) High magnification images of the injected and uninjected side of the hindbrain in 250 pg dn-Ras-injected (A) vimentin and XIF3, (A') vimentin and GFAP, 100 pg at-MAPKK-injected, (B) vimentin, dn-Ras at-MAPKK-injected (C) vimentin, 100 pg Ets1-GRT36A-injected, (D) vimentin and XIF3, and at-MAPKK/Ets1-GRT36A-injected, (E) vimentin embryos. DEX was added at stage 18. Scale bar: 25 µm. (F) The ratio of radial processes (RPratio) between the injected and uninjected side of the hindbrain for each injection experiment. Gray bars or white bars indicate with DEX treatment at stage 18 or without DEX treatment, respectively. *p < 0.001 compared with the ratio of nucβ-Gal-injected embryos. **p < 0.001 compared with the ratio of at-MAPKK/Ets1-GRT36A-injected embryos without DEX treatment. ***p < 0.001 compared with the ratio of Ets1-GRT36A-injected embryos without DEX treatment. Each value represents the average of 12 independent measurements. The original figure contains color pictures.