Limb initiation and development is normal in the absence of the mesonephros

Dev Biol. 1997 Sep 15;189(2):246-55. doi: 10.1006/dbio.1997.8680.


With rapid progress in understanding the genes that control limb development and patterning interest is becoming focused on the factors that permit the emergence of the limb bud. The current hypothesis is that FGF-8 from the mesonephros induces limb initiation. To test this, the inductive interaction between the Wolffian duct and intermediate mesoderm was blocked rostral to the limb field, preventing mesonephric differentiation while maintaining the integrity of the limb field. The experimental outcome was monitored by following expression of cSim1 and Lmx1, molecular markers for the duct and the mesonephros, respectively. Evidence is presented that the intermediate mesoderm undergoes apoptosis when the inductive interaction with the Wolffian duct is blocked. fgf-8 expression was undetectable in the mesonephric area of embryos with confirmed absence of mesonephros; nevertheless, limb buds formed and limb development was normal. The mesonephros in general, and specifically its fgf-8 expression, was shown to be unnecessary for limb initiation and development; the hypothesis linking the mesonephros and limb development is not supported. Further studies of axial influences on limb initiation should now concentrate on medial structures such as Hensen's node and paraxial mesoderm; the alternative that no axial influences are required should also be examined.

Publication types

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

MeSH terms

  • Animals
  • Basic Helix-Loop-Helix Transcription Factors
  • Bone and Bones / embryology
  • Cell Death
  • Cell Differentiation
  • Chick Embryo
  • Extremities / embryology*
  • Fibroblast Growth Factor 8
  • Fibroblast Growth Factors*
  • Growth Substances / genetics
  • Growth Substances / physiology*
  • Helix-Loop-Helix Motifs
  • Homeodomain Proteins / physiology
  • LIM-Homeodomain Proteins
  • Mesoderm / cytology
  • Mesonephros / embryology
  • Mesonephros / physiology*
  • Mutation
  • Repressor Proteins / physiology
  • Transcription Factors


  • Basic Helix-Loop-Helix Transcription Factors
  • Growth Substances
  • Homeodomain Proteins
  • LIM-Homeodomain Proteins
  • Lmx1a protein, mouse
  • Repressor Proteins
  • SIM1 protein, human
  • Transcription Factors
  • Fibroblast Growth Factor 8
  • Fibroblast Growth Factors