The vertebrate segmentation clock: the tip of the iceberg

Curr Opin Genet Dev. 2008 Aug;18(4):317-23. doi: 10.1016/j.gde.2008.06.007. Epub 2008 Aug 15.


The vertebrate segmentation clock was identified 10 years ago as a molecular oscillator associated with the rhythmic production of embryonic somites. Since then, three major signaling pathways--Notch, FGF, and Wnt--have been shown to be activated periodically during segmentation and proposed to constitute the clockwork of the system. However, recent results from zebrafish embryonic studies demonstrate that Notch signaling is involved in the coupling of oscillations among cells rather than in the pacemaker of the oscillator. Furthermore, genetic analyses in mouse indicate that Wnt and FGF play only a permissive role in the control of the oscillations. Therefore, the nature of the segmentation clock pacemaker still remains elusive.

Publication types

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

MeSH terms

  • Animals
  • Biological Clocks / genetics
  • Biological Clocks / physiology*
  • Cleavage Stage, Ovum / physiology*
  • Fibroblast Growth Factors / genetics
  • Fibroblast Growth Factors / physiology
  • Humans
  • Mesoderm / embryology
  • Mesoderm / physiology
  • Models, Biological
  • Receptors, Notch / genetics
  • Receptors, Notch / physiology
  • Signal Transduction / genetics
  • Signal Transduction / physiology
  • Vertebrates / embryology*
  • Vertebrates / genetics
  • Wnt Proteins / genetics
  • Wnt Proteins / physiology


  • Receptors, Notch
  • Wnt Proteins
  • Fibroblast Growth Factors