gata5 expression in zebrafish embryos at dome (4.3 hpf; A), germ ring (5.7 hpf; B), 90% epiboly (9 hpf; C), bud (10 hpf; D), 4-somite (11.3 hpf; E), 28 hpf (F,H), and 80% epiboly (8.3 hpf; G) stages. A,B,C, and G show lateral views with dorsal to the right. D,E,F, and H show dorsal views with anterior to the top. (A) At dome stage, gata5 is expressed in the yolk syncytial layer (arrow) and the most marginal tiers of the blastoderm (arrowhead). (B) During early gastrulation, gata5 expression is maintained in the marginal zone (bracket) and yolk syncytial layer (arrow). (C) Late in gastrulation, gata5 is expressed by cells of two different morphologies. Predominantly dorsally, endodermal cells displaying a characteristically large and flat morphology (arrowhead) express gata5. Ventrally, hypoblast cells with a rounder, more mesodermal appearance (arrow) also express gata5. (D) After the completion of gastrulation, gata5 is expressed in the endoderm (stippled staining) and ALPM (arrow). (E) During early somitogenesis, both the endoderm and lateral plate mesoderm (arrow) continue to express gata5. (F) At 28 hpf, gata5 is expressed most strongly in the endocardium (arrow) and weakly in the surrounding noncardiogenic ALPM. (G) faus26 mutants display markedly reduced gata5 expression. At 80% epiboly, gata5 mRNA is undetectable in the YSL and observed only faintly (arrow) in the blastoderm of faus26 mutants. (H) gata5 expression is undetectable in faus26 mutants at 28 hpf.