Fig. 5. Gata1-scl/tal1-lmo2 injection induced anterior erythropoiesis without causing overt ventralisation/posteriorisation. (A-D,G-J) Whole mounts; anterior, left in A-D, top in G-J. (E,F) Flat mounts; anterior, left. (A-D) alas2 expression was restricted to posterior regions in uninjected (A) and gata1-scl/tal1-injected (G1S, C) embryos. gata1-scl/tal1-lmo2 injection (G1SL, B) induced alas2 expression in the head (black arrowheads) (A-C) Red arrows mark pax2.1 expression in the optic stalk and in the midbrain-hindbrain boundary in the head. (D) Equimolar amounts of gata2 mRNA (G2SL) could not replace gata1. (E,F) gata1-scl/tal1-lmo2 injection (F) induced anterior expression of gata1^end.. (G,H) gata1-scl/tal1-lmo2 injection (25 pg of each mRNA) induced anterior erythropoiesis without inducing bmp4. (I,J) At 100 pg, the three mRNAs delayed development and bmp4 expression was maintained longer ventrally but not induced dorsally. Arrowheads in J indicate the ventral side of the embryo.