Vertebrate left-right asymmetry: old studies and new insights.
During vertebrate embryonic development, the organs of the chest and abdomen, heart, lung and gastrointestinal tract, acquire characteristic asymmetric positions with respect to the left-right body axis. In the beginning of the 20th century Hans Spemann and his co-workers described manipulations of amphibian embryos which resulted in inversion of organ laterality in a predictable manner. Hedwig Wilhelmi concluded from these experiments that determinants on the left side of the embryo specify laterality, and Meyer postulated that a mediator should transfer this positional information to the forming heart. In this review we discuss the classical experiments in the light of recent advances in the molecular understanding of left-right development, with a focus on the mediator role of the homeobox gene Pitx2.
Blum
M
M
Forschungszentrum Karlsruhe, Institute of Toxicology and Genetics, Germany. martin.blum@itg.fzk.de
Steinbeisser
H
H
Campione
M
M
Schweickert
A
A
D000663:Amphibians / Q000196:embryology; D000818:Animals; D019521:Body Patterning / Q000502:physiology*; D015509:Developmental Biology / Q000379:methods* / Q000639:trends; D004625:Embryo, Nonmammalian; D007839:Functional Laterality; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D009024:Morphogenesis; D055457:Nodal Protein; D009687:Nuclear Proteins; D051761:Paired Box Transcription Factors; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism; D014714:Vertebrates / Q000196:embryology*; D000097577:Homeobox Protein PITX2
D018398:Homeodomain Proteins; D055457:Nodal Protein; D009687:Nuclear Proteins; D051761:Paired Box Transcription Factors; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D000097577:Homeobox Protein PITX2; C101485:homeobox protein PITX1; C433629:homeobox protein PITX3