Fig. 7

Rescue of the Antivin-mediated loss of mesoderm by Activin Receptor type IIA and Taram AD. (A,B) Rescue of the Atv inhibitory effect by coinjection of increasing doses of Activin receptor type IIa. Bars indicate the percentage of embryos displaying an overinduced expression (black), a wild-type expression (red), a reduced expression (yellow), or a complete loss of expression (white) of shh, (A), or of gsc (B). (C) Embryo injected with 500 pg of TARAM-AD RNA in one blastomere at the 16-cell stage develops a complete secondary axis including a fully differentiated notochord (n). (D) Embryo injected with 10 pg of antivin RNA showing a lack of all mesendodermal derivatives in head and trunk and an absence of axial mesoderm in tail. (E) Focus on the cyclopia phenotype of an embryo injected with 10 pg of Atv RNA (ventral view). (F) Coinjection of 500 pg of TARAM-AD RNA rescues Atv-mediated cyclopia phenotype and (G) a differentiated notochord. (H) Front view of an embryo injected with Atv (10 pg) at the 2-cell-stage followed by injection of TARAM-AD RNA (500 pg) in a marginal blastomere at the 16-cell-stage. Two axes are formed, the primary axis (I) is devoid of mesendoderm and displays a cyclopia phenotype as the result of Atv effect while the secondary axis (II) induced by TARAM-AD comprises axial mesendoderm and two separated eyes. Scale bar: 150 μm in C,D,G; 100 μm in E,F,H.