Development of the left-right axis in amphibians

Ciba Found Symp. 1991;162:165-76; discussion 176-81. doi: 10.1002/9780470514160.ch10.


The heart and viscera of vertebrates are formed from primordia that are apparently bilaterally symmetrical. This symmetry is broken during development, yielding organs that develop characteristic asymmetries along the left-right axis. Results from three lines of experimentation on embryos of the amphibian Xenopus laevis indicate that left-right asymmetries are established early in development and that cellular interactions transmit left-right information from one primordium to another. First, a cytoplasmic rearrangement that occurs during the first cell cycle after fertilization may establish left-right asymmetry in some regions of the embryo. Second, a variety of experimental results indicate that embryonic ectoderm or its basal extracellular matrix may transmit left-right axial information to cardiac mesoderm and visceral endoderm. Third, inhibition of proteoglycan synthesis during a narrow period of development, concurrent with the migration of the cardiac primordia to the ventral midline, prevents asymmetrical development of the heart.

Publication types

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

MeSH terms

  • Amphibians / embryology*
  • Animals
  • Cell Movement
  • Endoderm
  • Gastrula
  • Heart / embryology
  • Mesoderm
  • Morphogenesis*
  • Ultraviolet Rays / adverse effects