Xenbase Image ID: 82124

Fig. 5. ADMP inhibition promotes head-organizer activity in explanted anterior endoderm. (A) Simplified scheme depicting the molecular interactions between Nodal, ADMP, and ACVR2a. (Left) In a Xenopus gastrula, the organizer is formed of dorsal mesodermal cells (blue), and of the abutting anterior endoderm (yellow expressing head-inducing molecules. D, dorsal; V, ventral. The expression pattern of ADMP, Cerberus, Dkk, Nodals, and ACVR2a has been previously described (6, 14, 17, 22, 27). Right, corresponding to the boxed region on the Left, depicts a model for the interplay between Nodal, ADMP, and Nodal antagonists. Darker and lighter backgrounds correspond to the intracellular and extracellular space, respectively. Nodal signals through ACVR2a and activates the expression of head inducers, such as Cerberus and Dkk-1. Cerberus secretion limits Nodal diffusion, enabling ADMP signaling, that, in turn, feedbacks on the expression of head inducers, including Cerberus itself. N, Nodal; A, ADMP; C, Cerberus. Italicized names indicate gene transcription. (B) Anterior endoderm explants dissected from early gastrula embryos (stage 10.5) injected with control or ADMP morpholinos were transplanted into the blastocoel of wild-type recipient embryos (Einsteck grafts). Recipient embryos were allowed to develop until tadpole stage, when they were scored for the presence of ectopic head structures (white arrowheads, cement glands; black arrows, eyes). Percentage of induced heads: control, MO-injected grafts, 0/40; ADMP, MO-injected grafts, 5/30. Image published in: Inui M et al. (2012) Copyright © 2012. Image reproduced with permission of the publisher and the copyright holder. This is an Open Access article distributed under the terms of the Creative Commons Attribution License. Larger Image Printer Friendly View

Return to previous page