Developmental Patterning of the Vertebrate Limb

Following pioneering work by Harrison on amphibian limbs in the 1920s and by Saunders (1948) on the apical ridge in chick limbs, limb development became a classical model system for investigating such fundamental developmental issues as tissue interactions and induction, and the control of pattern formation. Earlier international conferences, at Grenoble 1972, Glasgow 1976,and Storrs, Connecticut 1982, reflected the interests and technology of their time. Grenoble was concerned with ectoderm-mesenchyme interaction, but by the time of the Glasgow meeting, the zone of polarizing activity (ZPA) and its role in control of patterning was the dominant theme. Storrs produced the first intimations that the ZPA could be mimicked by retinoic acid (RA), but the diversity of extracellular masrix ~olecules,particularly in skeletogenesis,was the main focus of attention. By 1990, the paradigms had again shifted. Originally, the planners of the ARW saw retinoic acid (as a possible morphogen controlling skeletal patterning), the variety of extracellular matrix components and their roles, and the developmental basis of limb evolution as the leading contemporary topics. However, as planning proceeded, it was clear that the new results emerging from the use of homeobox gene probes (first developed to investigate the genetic control of patterning of Drosophila embryos) to analyse the localised expression of "patterning genes" in limb buds would also be an important theme.

Some Problems in Limb Development.- The Molecular Basis of Limb Patterning: A Review.- Expression of the Msh-like Homeobox-containing Genes During Mouse Limb Development.- The Limb Deformity Gene Encodes Evolutionarily Highly Conserved Proteins.- The Role of Homeobox Genes in Amphibian Limb Development and Regeneration.- Homeobox-Containing Genes and Gap Junctional Communication in Pattern Formation During Chick Limb Development.- Functional Studies of Genes in the Limb.- Hox-7: Temporal Patterns of Expression in Normal and Limbless Chick Embryos.- Expression Profile of Two Homeobox Genes During Chicken Embryogenesis.- Characterisation of Three Zebrafish Genes Related to Hox-7.- A Comparison of the Expression Domains of the Murine Hox-4, RARs and CRABP Genes Suggest Possible Functional Relationships During Patterning of the Vertebrate Limb.- Retinoic Acid Nuclear Receptors.- The Role of Retinoic Acid and Cellular Retinoic Acid-Binding Protein in the Regenerating Amphibian Limb.- Retinoic Acid Treatment Alters the Pattern of Retinoic Acid Receptor Beta Expression in the Embryonic Chick Limb.- Expression Pattern of an RXR Nuclear Receptor Gene in the Chick Embryo.- Retinoic Acid and Limb Pattern Formation in Cell Culture.- Growth Factors Produced by the Polarising Zone - a Complement to the Retinoic Acid System.- Biochemical and Molecular Aspects of Retinoid Action in Limb Pattern Formation.- Position-Dependent Properties of Limb Cells.- Retinoic Acid and Limb Patterning and Morphogenesis.- Does Retinoic Acid Organise a Limb or Induce a ZPA?.- Retinoic Acid Effects on Experimental Chick Wing Buds: Patterns of Cell Death and Skeletogenesis.- A Comparison of Reaction Diffusion and Mechanochemical Models for Limb Development.- The Pathway of Polarising Activity from Hensen’s Node to the Wing Bud in the Chick Embryo.- Extracellular Matrix in Early Limb Development.- Molecular Heterogeneity of Chondroitin Sulphate in the Developing Chick Limb.- Special Properties of the AER/Mesenchyme Interface in the Chick Wing Bud: Analysis of ECM Molecules and Integrin Receptors.- Physical Forces and Pattern Formation in Limb Development.- Extracellular Material Organization and Long Tendon Formation in the Chick Leg Autopodium. In Vivo and In Vitro Study.- Hyaluronan-Cell Interactions in Limb Development.- The Role of the Transforming Growth Factor-ß (TGF-ß) Family, Extracelluiar Matrix and Gap Junctional Communication in Limb Cartilage Differentiation.- Vascular Involvement in Cartilage and Bone Development.- Patterning of Connective Tissues in the Regenerating Amphibian Limb.- The Interdigital Spaces of the Chick Leg Bud as a Model for Analysing Limb Morphogenesis and Cell Differentiation.- A “Packaging Model” of Limb Development.- The Somite-Muscle Relationship in the Avian Embryo.- Observations Concerning the Control of Directed Myogenic Cell Migration.- Extracellular Matrix and Muscle Formation.- Control of Muscle Morphogenesis and Endplate Pattern in Limb Muscles of Avian Chimeras.- Review of the Extracellular Matrix in Relation to Limb Development.- Evolution of Connective and Skeletal Tissues.- Developmental Approaches to the Problem of Transformation of Limb Structure in Evolution.- New Palaeontological Contributions to Limb Ontogeny and Phylogeny.- The Fin-Limb Transformation: Palaeontological and Embryological Evidence.- The Development of the Teleost Fin and Implications for our Understanding of Tetrapod Limb Evolution.- Phylogenetically Ancient Pattern in Ontogenesis of Limb Muscles.- Mutation and Limb Evolution.- Insights into Limb Development and Pattern Formation from Studies of the Limbless and Talpid2 Chick Mutants.- Proximal Elements in the Vertebrate Limb: Evolutionary and Developmental Origin of the Pectoral Girdle.- Evolutionary Transformation of Limb Pattern: Heterochrony and Secondary Fusion.- Plasticity in Skeletal Development: Knee-Joint Morphology in Fibula-Deficient Chick Embryos.- The Implications of “The Bauplan” for Development and Evolution of the Tetrapod Limb.- Molecular Biology and Evolution: Two Perspectives — A Review of Concepts.- The Developmental Basis of Limb Evolution: a Review.- Participants.