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. Author manuscript; available in PMC: 2008 Jul 25.
Published in final edited form as: Cell. 2006 Jan 13;124(1):147–159. doi: 10.1016/j.cell.2005.12.018

Figure 1. Sizzled Is Expressed Ventrally Yet Requires a Dorsal Component to Function.

Figure 1

(A–C) Szl-depleted embryo is ventralized, as marked by the accumulation of Szl ventro-posterior transcripts and phenocopies knockdown of Chd.

(D) Chd and Szl are expressed at opposite poles of the Xenopus gastrula.

(E) DV patterning is regulated via proteins secreted by the dorsal and ventral signaling centers. (F) Embryo bisected at blastula across the DV axis can self-regulate to form a well-proportioned dorsal-half embryo, while the ventral half forms a belly-piece. Sox2 marks the CNS tissue. Uninjected wild-type embryo shown on top.

(G) Injection of Szl mRNA increases Sox2 staining in intact (top) and dorsal-half embryos but is without phenotypic effect in the ventral-half embryo (n = 40).

(H) A Spemann organizer transplant on the ventral side of a wild-type embryo forms a Y-shaped Siamese embryo with two heads and a single tailbud (n = 10).

(I) Wild-type Spemann organizer grafted into a Szl-depleted host forms an H-shaped embryo with CNS induction and two distinct tailbuds (n = 11).