FGF-mediated mesoderm induction involves the Src-family kinase Laloo

Nature. 1998 Aug 27;394(6696):904-8. doi: 10.1038/29808.


During embryogenesis, inductive interactions underlie the development of much of the body plan. In Xenopus laevis, factors secreted from the vegetal pole induce mesoderm in the adjacent marginal zone; members of both the transforming growth factor-beta (TGF-beta) and fibroblast growth factor (FGF) ligand families seem to have critical roles in this process. Here we report the identification and characterization of laloo, a novel participant in the signal transduction cascade linking extracellular, mesoderm-inducing signals to the nucleus, where alteration of cell fate is driven by changes in gene expression. Overexpression of laloo, a member of the Src-related gene family, in Xenopus embryos gives rise to ectopic posterior structures that frequently contain axial tissue. Laloo induces mesoderm in Xenopus ectodermal explants; this induction is blocked by reagents that disrupt the FGF signalling pathway. Conversely, expression of a dominant-inhibitory Laloo mutant blocks mesoderm induction by FGF and causes severe posterior truncations in vivo. This work provides the first evidence that a Src-related kinase is involved in vertebrate mesoderm induction.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Culture Techniques
  • DNA, Complementary
  • Embryonic Induction*
  • Fibroblast Growth Factors / physiology*
  • Gene Expression Regulation, Developmental
  • Mesoderm / physiology*
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Phosphorylation
  • Signal Transduction
  • Xenopus
  • Xenopus Proteins*
  • ras Proteins / physiology
  • src-Family Kinases / isolation & purification
  • src-Family Kinases / physiology*


  • DNA, Complementary
  • HCK protein, Xenopus
  • Xenopus Proteins
  • Fibroblast Growth Factors
  • src-Family Kinases
  • ras Proteins

Associated data

  • GENBANK/AF081803