Gdf3 is required for robust Nodal signaling during germ layer formation and left-right patterning.

Abstract

Vertebrate embryonic patterning depends on signaling from Nodal, a TGFβ superfamily member. There are three Nodal orthologs in zebrafish; <i>southpaw</i> directs left-right asymmetries, while <i>squint</i> and <i>cyclops</i> function earlier to pattern mesendoderm. TGFβ member Vg1 is implicated in mesoderm formation but the role of the zebrafish ortholog, Growth differentiation factor 3 (Gdf3), has not been fully explored. We show that zygotic expression of <i>gdf3</i> is dispensable for embryonic development, while maternally deposited <i>gdf3</i> is required for mesendoderm formation and dorsal-ventral patterning. We further show that Gdf3 can affect left-right patterning at multiple stages, including proper development of regional cell morphology in Kupffer's vesicle and the establishment of <i>southpaw</i> expression in the lateral plate mesoderm. Collectively, our data indicate that <i>gdf3</i> is critical for robust Nodal signaling at multiple stages in zebrafish embryonic development.