XB-IMG-130839
Xenbase Image ID: 130839
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FIG. 3. Schema of Nodal-related TGF signaling in Xenopus (left) and zebrafish (right) endoderm development. A variety of Nodal-related
ligands probably interact at the cell surface with a complex between selected Activin class IB-receptors and Cripto-related EGF-CFC
proteins (One-eyed pinhead in zebrafish, ? in Xenopus). These interactions activate latent transcriptional regulators, Smads, and FAST
proteins, that function in nuclear complexes to activate lineage-specific genes. One important challenge is to understand how the same
factors mediate a wide range of developmental effects, and one possibility, suggested for organizer genes (Germain et al., 2000) but yet
unproven in endoderm development, is depicted here. Besides established transcriptional mechanisms for responding to TGF signals (2),
Mix-like DNA-binding proteins, induced independently or in response to TGF signals, may act in conjunction with Smads (1) to activate
Nodal-responsive endoderm-specific genes. Zebrafish Bon is inferred by analogy to participate in gene regulation similar to the proposed
role of Xenopus Mix-like factors. Image published in: Shivdasani RA (2002) Copyright © 2002. Image reproduced with permission of the Publisher, Elsevier B. V. Larger Image Printer Friendly View |