Nodal flow and the generation of left-right asymmetry

Cell. 2006 Apr 7;125(1):33-45. doi: 10.1016/j.cell.2006.03.002.


The establishment of left-right asymmetry in mammals is a good example of how multiple cell biological processes coordinate in the formation of a basic body plan. The leftward movement of fluid at the ventral node, called nodal flow, is the central process in symmetry breaking on the left-right axis. Nodal flow is autonomously generated by the rotation of cilia that are tilted toward the posterior on cells of the ventral node. These cilia are built by transport via the KIF3 motor complex. How nodal flow is interpreted to create left-right asymmetry has been a matter of debate. Recent evidence suggests that the leftward movement of membrane-sheathed particles, called nodal vesicular parcels (NVPs), may result in the activation of the non-canonical Hedgehog signaling pathway, an asymmetric elevation in intracellular Ca(2+) and changes in gene expression.

Publication types

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

MeSH terms

  • Animals
  • Body Patterning*
  • Calcium Signaling
  • Embryo, Mammalian / embryology*
  • Embryo, Mammalian / metabolism*
  • Embryo, Nonmammalian*
  • Gene Expression Regulation, Developmental
  • Hedgehog Proteins
  • Organizers, Embryonic / embryology
  • Trans-Activators / metabolism


  • Hedgehog Proteins
  • Trans-Activators