(A–O) Shield stage Tg(lhx1a:EGFP)pt303 embryos, animal view. (A,D,G,J,M) Untreated control embryos. (B,E,H,K,N) Embryos treated with 0.8% DMSO. (C,F,I,L,O) Embryos treated with 800 µM SB-431542. (A–C) Tg(lhx1a:EGFP)pt303 expression. (D–F) In situ hybridization for lhx1a. (GO) Fluorescent in situ hybridization. (G–I) egfp. (J–L) eve1. (M–O) Merged images.