View the Current Issue

Article

  • The EMBO Journal (2003) 22, 3303 - 3313
  • doi:10.1093/emboj/cdg328

A role for maternal bold beta-catenin in early mesoderm induction in Xenopus

Anne Schohl1,2 and François Fagotto1,2

  1. Department of Cell Biology, Max-Planck Institute for Developmental Biology, Tübingen, Germany
  2. Present address: Department of Biology, McGill University, 1205 Dr Penfield, Montreal, H3A 1B1, Canada

Correspondence to:

François Fagotto, E-mail: francois.fagotto@mcgill.ca

Received 19 September 2002; Accepted 13 May 2003; Revised 8 May 2003

Mesoderm formation results from an inducing process that requires maternal and zygotic FGF/MAPK and TGFbeta activities, while maternal activation of the Wnt/beta-catenin pathway determines the anterior–dorsal axis. Here, we show a new role of Wnt/beta-catenin signaling in mesoderm induction. We find that maternal beta-catenin signaling is not only active dorsally but also all around the equatorial region, coinciding with the prospective mesoderm. Maternal beta-catenin function is required both for expression of dorsal genes and for activation of MAPK and the mesodermal markers Xbra and eomesodermin. beta-catenin acts in a non- cell-autonomous manner upstream of zygotic FGF and nodal signals. The Wnt/beta-catenin activity in the equatorial region of the early embryo is the first example of a maternally provided mesoderm inducer restricted to the prospective mesoderm.

  • Keywords:

    • embryonic development,
    • FGF,
    • MAPK,
    • Wnt pathway,
    • Xnr