On growth and form: a Cartesian coordinate system of Wnt and BMP signaling specifies bilaterian body axes.
The regulation of body axis specification in the common ancestor of bilaterians remains controversial. BMP signaling appears to be an ancient program for patterning the secondary, or dorsoventral, body axis, but any such program for the primary, or anteroposterior, body axis is debated. Recent work in invertebrates indicates that posterior Wnt/beta-catenin signaling is such a mechanism and that it evolutionarily predates the cnidarian-bilaterian split. Here, I argue that a Cartesian coordinate system of positional information set up by gradients of perpendicular Wnt and BMP signaling is conserved in bilaterians, orchestrates body axis patterning and contributes to both the relative invariance and diversity of body forms.
Niehrs
Christof
C
Division of Molecular Embryology, DKFZ-ZMBH Alliance, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 280, D-69120 Heidelberg, Germany. Niehrs@DKFZ-Heidelberg.de
D000818:Animals; D019521:Body Patterning / Q000502:physiology*; D019485:Bone Morphogenetic Proteins / Q000378:metabolism / Q000502:physiology*; D002816:Chordata, Nonvertebrate / Q000033:anatomy & histology / Q000196:embryology / Q000235:genetics / Q000502:physiology; D003063:Cnidaria / Q000033:anatomy & histology / Q000196:embryology / Q000235:genetics / Q000502:physiology; D004625:Embryo, Nonmammalian; D019143:Evolution, Molecular; D018507:Gene Expression Regulation, Developmental; D048788:Growth and Development / Q000502:physiology*; D008954:Models, Biological; D008962:Models, Theoretical; D010802:Phylogeny; D015398:Signal Transduction / Q000502:physiology; D051153:Wnt Proteins / Q000378:metabolism / Q000502:physiology*
D019485:Bone Morphogenetic Proteins; D051153:Wnt Proteins