Fig. 5

 Rescue of gata1 and runx1a Expression in cdx-deficient Embryos. (A) Whole mount in situ hybridizations showing gata1 transcripts (purple) in wild-type, doubly deficient (cdx1a^mo;cdx4^−/−), hoxb7a-injected, and hoxa9a-injected doubly deficient embryos at the 18-somite stage (flatmounted embryos shown in dorsal views of the trunk with anterior to the left). (B) Expression of runx1a, fli1a, and rag1 in cdx-deficient embryos (lateral views, anterior to the left). Arrows in the runx1a-stained embryos at 36 hpf indicate the extent of artery expression, and higher magnification views of the posterior trunk are shown alongside. A similar region in fli1a-stained embryos is shown with short arrows indicating the dorsal aorta and axial vein. Transcripts for rag1 in the thymus of 4 dpf embryos are indicated by arrowheads. (C) Expression of runx1a in wild-type, cdx4^−/− mutants, and hoxa9a-injected cdx4^−/− embryos at 48 hpf. Arrows indicate the extent of runx1a staining in the dorsal aorta. Asterisks mark runx1a⁺ cranial motorneurons in the hindbrain, and the arrowhead in the hoxa9a-rescued embryo indicates the short yolk tube extension.