title: Growth and patterning in the limb: signaling gradients make the decision.
abstract: The vertebrate limb bud provides a unique system to investigate the coordinated regulation of growth and patterning, two key processes that govern the formation of a complex multicellular organism from a fertilized egg. Two studies have advanced our understanding of limb development by elucidating that signaling gradients from the limb ectoderm, including the apical ectoderm ridge (AER), act in concert to establish a basic pattern of tissue layers by coordinating cell proliferation and cell fate determination. These studies reveal that cell proliferation and fate determination in development can be two faces of the same coin in that they are regulated by the same signaling pathways. Alterations in the duration and range of the signaling gradients may underlie many of the morphological differences in the evolution of vertebrate limbs.
authors.affiliation: Developmental Genetics Section, Genetic Disease Research Branch, National Human Genome Research Institute, Building 49, Room 4A68, 49 Convent Drive, MSC 4472, Bethesda, MD 20892, USA. yingzi@mail.nih.gov
authors.forename: Yingzi
authors.initials: Y
authors.lastname: Yang
mesh_terms: D000818:Animals; D019521:Body Patterning / Q000502:physiology*; D002455:Cell Division; D019070:Cell Lineage; D004475:Ectoderm / Q000502:physiology; D047108:Embryonic Development / Q000502:physiology; D005121:Extremities / Q000196:embryology*; D005346:Fibroblast Growth Factors / Q000502:physiology; D036341:Intercellular Signaling Peptides and Proteins / Q000502:physiology; D008648:Mesoderm / Q000502:physiology; D009024:Morphogenesis; D009994:Osmolar Concentration; D015398:Signal Transduction / Q000502:physiology*; D014714:Vertebrates / Q000196:embryology*; D051153:Wnt Proteins / Q000502:physiology
chemical_list: D036341:Intercellular Signaling Peptides and Proteins; D051153:Wnt Proteins; D005346:Fibroblast Growth Factors