Figure 4.

Nf1 mutation resulted in increasing ERK signaling in lens ectoderm. (A) Western blot analysis affirmed that phospho-ERK, but not phospho-Akt, was up-regulated in whole-embryo lysates of E12.5 Nf1 mutants. (B, C) E9.5 whole-mount immunohistochemistry showed that phospho-ERK was up-regulated throughout the Nf1 mutant head surface ectoderm compared with the wild-type (dotted ovals outline ocular region). (D–G) Ras-ERK signaling response genes, Erm and Pea3, were also induced in the Nf1-null lens ectoderm (dotted ovals). Scale bars: 50 μm (A, B, E, F); 1 mm (C, D, G, H).