Cilia propel the embryo in the right direction

Am J Med Genet. 2001 Jul 15;101(4):339-44. doi: 10.1002/1096-8628(20010715)101:4<339::aid-ajmg1442>;2-p.


Cilia have long been suspected to play a role in the determination of left-right asymmetry. Humans with the dominantly inherited condition Kartagener syndrome have defective cilia and a 50% incidence of mirror-image positioning of their organs (situs inversus). Analysis of mouse mutations affecting ciliary biogenesis and motility has demonstrated that the molecular motors kinesin and dynein are required to establish normal handed organismal asymmetry. The cilia that propel formation of the embryonic left-right axis are not conventional cilia, but monocilia. They are found on the node, or organizer, of the gastrulation-stage mouse embryo where they drive net leftward movement of the fluid surrounding the node, and initiate left-right asymmetry.

MeSH terms

  • Animals
  • Body Patterning / genetics
  • Body Patterning / physiology*
  • Cilia / genetics
  • Cilia / physiology*
  • Dyneins / genetics
  • Embryo, Mammalian / metabolism*
  • Embryonic and Fetal Development / genetics
  • Embryonic and Fetal Development / physiology*
  • Gene Expression Regulation, Developmental
  • Humans
  • Kartagener Syndrome / genetics
  • Kinesin / genetics
  • Mice
  • Models, Biological
  • Mutation


  • KIF3A protein, human
  • KIF3B protein, human
  • Kif3a protein, mouse
  • Kif3b protein, mouse
  • Dyneins
  • Kinesin