Expression of admp in wild-type zebrafish embryos analyzed by whole-mount in situ hybridization: (A) 40% epiboly, animal pole view; (B) shield stage, lateral view; (C) shield stage, dorsal view; (D) 70% epiboly, lateral view; (E) 70% epiboly, dorsal view; (F) tailbud stage, dorsal view (the embryo is slightly tilted upward to expose the tailbud region); (G) 8-somite stage, lateral view; (H) 8-somite stage, dorsal view of the tailbud region. Arrows in C,E,F point to expression in the mesoderm; arrowheads in C–E point to expression in the neuroectoderm.

admp overexpression leads to a reduction of the organizer and a ventralization of the embryo; admp knock-down leads to an enlarged organizer and a dorsalization of the embryo. A–G: Live embryos at 60 hr postfertilization (hpf). H–S: Whole-mount in situ hybridizations at indicated stages and with indicated probes. (A,H–K) Un-injected controls; (B–D,L–O) embryos after injection of admp mRNA (50–100 pg/embryo); (E–G,P–S) embryos after injection of admp antisense morpholino oligonucleotide (50–300 pmol/embryo). Arrows in B,D point to enlarged blood islands, a sign of ventralization; arrow in C to U-shaped somites, resulting from the absence of the notochord; arrowheads in C,D to the lost head; arrow in E to the broadened notochord; and arrowheads in F,G to the reduced tail. The shortened axis in admp mRNA-injected embryos (B–D) is due to the partial loss of the dorsal axis, resulting in impaired extension movements, similarly to the situation in dino mutants. H,L,P: gsc, 60% epiboly, animal view, dorsal right. Length of the gsc expression domain along the dorsoventral axis is indicated by bars. I,M,Q: flh, 70% epiboly, vegetal view, dorsal right. J,N,R: gsc (indicated by arrows) and eve1, 70% epiboly, vegetal view, dorsal right. Note that in comparison to P, the gsc expression domain in R has become narrower and thicker, most likely due to dorsal convergence movements of gastrulation. K,O,S: cdx1, 90% epiboly, lateral view, dorsal right. Length of the cdx1 along the animal-vegetal axis on the ventral side of the embryos is indicated by bars.

admp expression in positively regulated by Nodal signaling, Bozozok, and Chordin: (A–C,J) wild-type, (D–F) mzoep; (G–I) boz^m168; (K,L) din^tt250. (A,G) 40% epiboly, animal view; (D) 45% epiboly, animal view; (B,E,H) 70% epiboly, animal view; (C,F,I,L) 70% epiboly, lateral view; (J,K) 70% epiboly, dorsal view. Note that in the din mutant shown in L, admp expression is restricted to the mesoderm in the inner cell layers, whereas the neuroectoderm in the outer cell layers lacks admp transcripts (in contrast to the wild-type [WT] sibling shown in C).

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