Injected Xwnt-8 RNA Acts Early in Xenopus Embryos to Promote Formation of a Vegetal Dorsalizing Center

Cell. 1991 Nov 15;67(4):753-65. doi: 10.1016/0092-8674(91)90070-f.

Abstract

Expression cloning from a pool of gastrula cDNAs identified the Wnt family member Xwnt-8 as having dorsal axis-inducing activity in Xenopus embryos. Microinjected Xwnt-8 mRNA was able to rescue the development of a dorsally complete anterior-posterior axis in embryos ventralized by exposure to UV light. Axis induction was observed in embryos injected in either marginal or vegetal blastomeres at the 32-cell stage. Vegetal blastomeres receiving Xwnt-8 mRNA contributed progeny not to the induced dorsal axis, but to the endoderm, a result consistent with Xwnt-8 causing cells to act as a Nieuwkoop center (the vegetal-inducing component of normal dorsal axis formation), rather than as a Spemann organizer (the induced dorsal marginal zone component that directly forms the dorsal mesoderm). Xwnt-8, which is normally expressed ventrally in midgastrula and neurula embryos, appears to mimic, when injected, maternally encoded dorsal mesoderm-inducing factors that act early in development.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Blotting, Northern
  • Chlorides / pharmacology
  • Embryonic Induction / drug effects
  • Embryonic Induction / radiation effects
  • Gene Expression
  • Lithium / pharmacology
  • Lithium Chloride
  • Microinjections
  • Morphogenesis* / drug effects
  • Morphogenesis* / radiation effects
  • Nucleic Acid Hybridization
  • RNA, Messenger / genetics*
  • Ultraviolet Rays
  • Xenopus laevis / embryology*

Substances

  • Chlorides
  • RNA, Messenger
  • Lithium
  • Lithium Chloride