Injected Wnt RNA induces a complete body axis in Xenopus embryos.
Studies in Xenopus have shown that growth factors of the TGF beta and Wnt oncogene families can mimic aspects of dorsal axis formation. Here we directly compare the inductive properties of two Wnt proteins by injecting synthetic mRNA into developing embryos. The results show that Wnt-1 and Xwnt-8 can induce a new and complete dorsal axis and can rescue the development of axis-deficient, UV-irradiated embryos. In contrast, activin mRNA injection induces only a partial dorsal axis that lacks anterior structures. These studies demonstrate that the mechanism of Wnt-induced axis duplication results from the creation of an independent Spemann organizer. The relationship between the properties of the endogenous dorsal inducer and the effects of Wnts and activins is discussed.
Sokol
S
S
Department of Biochemistry and Molecular Biology, Harvard University, Cambridge, Massachusetts 02138.
Christian
J L
JL
Moon
R T
RT
Melton
D A
DA
D028341:Activins; D000818:Animals; D002454:Cell Differentiation / Q000528:radiation effects; D004627:Embryonic Induction / Q000528:radiation effects; D015870:Gene Expression; D007265:Inhibins / Q000502:physiology; D008648:Mesoderm / Q000502:physiology; D008845:Microinjections; D009024:Morphogenesis / Q000528:radiation effects; D015513:Oncogene Proteins / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D012333:RNA, Messenger / Q000008:administration & dosage / Q000494:pharmacology*; D014466:Ultraviolet Rays; D051153:Wnt Proteins; D051155:Wnt1 Protein; D029867:Xenopus Proteins; D014982:Xenopus laevis / Q000196:embryology*; D029961:Zebrafish Proteins
D015513:Oncogene Proteins; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; C495249:WNT1 protein, Xenopus; D051153:Wnt Proteins; D051155:Wnt1 Protein; D029867:Xenopus Proteins; D029961:Zebrafish Proteins; C495248:wnt8a protein, Xenopus; D028341:Activins; D007265:Inhibins