Endodermal Sox17‐dependent pathways & cardiac specification

tbx2a Is Required for Specification of Endodermal Pouches during Development of the Pharyngeal Arches

Tbx2 is a member of the T-box family of transcription factors essential for embryo- and organogenesis. A deficiency in the zebrafish paralogue tbx2a causes abnormalities of the pharyngeal arches in a p53-independent manner. The pharyngeal arches are formed by derivatives of all three embryonic germ layers: endodermal pouches, mesenchymal condensations and neural crest cells. While tbx2a express...

Retinoic Acid Signaling Organizes Endodermal Organ Specification along the Entire Antero-Posterior Axis

BACKGROUND Endoderm organ primordia become specified between gastrulation and gut tube folding in Amniotes. Although the requirement for RA signaling for the development of a few individual endoderm organs has been established a systematic assessment of its activity along the entire antero-posterior axis has not been performed in this germ layer. METHODOLOGY/PRINCIPAL FINDINGS RA is synthesiz...

Early Activation of FGF and Nodal Pathways Mediates Cardiac Specification Independently of Wnt/β-Catenin Signaling

BACKGROUND Cardiac induction, the first step in heart development in vertebrate embryos, is thought to be initiated by anterior endoderm during gastrulation, but what the signals are and how they act is unknown. Several signaling pathways, including FGF, Nodal, BMP and Wnt have been implicated in cardiac specification, in both gain- and loss-of-function experiments. However, as these pathways r...

A post-mid-blastula transition requirement for TGFβ signaling in early endodermal specification

In Xenopus, endodermal cell fate is determined gradually from late blastula to early gastrula stages; cell-cell interaction plays an important role in this process. Here we use a cell dissociation assay to show that extracellular signaling is required continuously before endoderm determination. Activin and Vg1, but not BMP2 or basic FGF, rescue the expression of endodermal markers in dissociate...

Intracardiac endodermal heterotopia.