Ectopic lhx1 expression causes a fate transformation event.

Embryos were injected (1xV2) with 200 pg of LL-VP16 mRNA at the 8-cell stage. Embryos were treated with hydroxyurea and aphidicolin (HUA) at stage 10.5/11. (A–D) In situ hybridization of embryos at stage 20 for pax8. (A) Uninjected embryo. (B) Uninjected embryo treated with HUA. (C) Injected embryo. Expansion of pax8 expression was observed in 91% of the embryos (n = 35). (D) Injected embryo treated with HUA. Expansion of pax8 expression was observed in 82% of the embryos (n = 33). (E–H) Whole-mount immunostaining analysis of proliferation with anti-phospho-Histone H3 antibody, αPH3. (E) Uninjected embryo. (F) Uninjected embryo treated with HUA. (G) Injected embryo. (H) Injected embryo treated with HUA. (I–L) In situ hybridization of embryos for the paraxial mesoderm marker myoD. (I, J) Uninjected and injected embryos at stage 20. Reduced myoD expression was observed in 63% of the embryos (n = 51). (K, L) Control and injected sides of the same embryo at stage 26. Reduced myoD expression was observed in 87% of the embryos (n = 30). Anterior somites are highlighted with black brackets. (M–P) In situ hybridization of embryos for the lateral plate mesoderm marker scl. (M, N) Uninjected and injected embryos at stage 20 (n = 45). Midline of the embryos is marked with a dotted line with anterior to the left. (O, P) Control and injected sides of the same embryo at stage 26 (n = 43). The injected side of the embryos is marked with an asterisk.