Main description:

"Who would believe that so small a space could contain the images of all the universe?" Leonardo da Vinci The last years of the 20th century have found the discipline of Developmental Biology returning to its original position at the forefront of biological re search. This progress can be attributed to the burgeoning knowledge base on molecules and gene families, and to the power of the molecular genetic ap proach. Topping the list of organ systems which have provided the most significant advances would have to be the eye. The vertebrate eye was one of the classic embryologic models, used to demonstrate many important prin ciples, including the concepts of inductive tissue interactions first put forth in the early 1900s. Within the last decade of this century, a return to some of the old questions with the new approaches has put eye development back into the limelight. I find this a highly appropriate topic for a book which aims to spark research for the new millennium. We begin with a chapter that discusses the anatomy of eye development, providing the basic reference information for the chapters that follow. A novel aspect of this introduction is the connection made between develop mental strategies and the eye's optical function. What also emerges from this chapter is the number of important eye structures that have barely been touched by the modern developmental biologist. Work on cornea and ante rior chamber development has lagged behind lens and retina.

Contents:

Overview.- Vertebrate Eye Development and Refractive Function: An Overview.- 1 Introduction and General Eye Development.- 1.1 Early Embryogenesis.- 1.2 Formation of the Optic Cup.- 1.3 Lens Development.- 1.4 Mesenchyme.- 1.5 Development of the Sclera, Choroid, Ciliary Body, and Iris.- 1.6 Retina.- 1.7 Corneal Development.- 2 Eye Development and Optical Function.- 2.1 Cornea.- 2.2 Lens.- 3 Visual Environment and Eye Development.- References.- Early Pattern Formation.- Pax6 and the Genetic Control of Early Eye Development.- 1 Introduction.- 2 Pax6 Plays a Critical Role in Vertebrate Ocular Development.- 3 Molecular Biology of the Pax6 Gene Product.- 4 Genomic Structure and Transcriptional Regulation of Pax6.- 5 Pax6 in Drosophila: Master Regulator or Network Manager?.- 6 From Fly to Mouse: Identifying Pax6 Target Genes.- 7 Conclusions.- References.- Early Retinal Development in Drosophila.- 1 Introduction.- 2 Specification of the Eye Primordium.- 3 Dorsal-Ventral Patterning and Growth of the Eye Disc.- 4 Initiation of Differentiation.- 5 How are Specification and Initiation Related?.- 6 Progression of Differentiation.- References.- Embryonic Induction.- Induction of the Lens.- 1 Introduction.- 2 A Historical Overview of the Study of Lens Induction.- 3 Competence.- 4 Bias.- 5 Inhibition.- 6 Specification.- 7 Differentiation.- 8 Conclusions.- References.- Retinal Differentiation.- Molecular Control of Cell Diversification in the Vertebrate Retina.- 1 Introduction.- 2 Does a Code of Transcription Factors Define Retinal Cell Identities?.- 2.1 Homeodomain Transcription Factors.- 2.2 bHLH Transcription Factors.- 3 Do Extracellular Signals Define Retinal Identities?.- 3.1 Ganglion Cells.- 3.2 Horizontal Cells.- 3.3 Amacrine Cells.- 3.4 Photoreceptor Cells.- 3.5 Bipolar Cells.- 3.6 Muller Glia.- 4 Conclusion.- References.- Cell Fate Specification in the Drosophila Retina.- 1 Introduction.- 2 The R8 Photoreceptor Cell.- 3 The R7 Photoreceptor Cell.- 4 Concluding Remarks.- References.- Roles of the Extracellular Matrix in Retinal Development and Maintenance.- 1 Introduction.- 2 Multiple Extrinsic Cues are Involved in Retinal Development.- 3 Laminins.- 3.1 Photoreceptor Development.- 4 Laminins and Photoreceptor Development.- 4.1 Photoreceptor Fate Determination.- 4.2 Photoreceptor Morphogenesis: Inner and Outer Segment Development.- 4.3 Photoreceptor Synaptogenesis.- 5 Role of the Interphotoreceptor Matrix in Maintaining Photoreceptor Viability.- 5.1 Retinal Adhesion.- 5.2 Photoreceptor Survival.- 6 Conclusion.- References.- Adhesive Events in Retinal Development and Function: The Role of Integrin Receptors.- 1 Introduction.- 1.1 The Integrin Family of Receptors.- 2 Integrins in the Developing Retina.- 2.1 Which Integrins are Expressed?.- 2.2 When and Where are Integrins Expressed?.- 2.3 What Functions Do Integrins Fulfill?.- 3 Integrins in the Mature Retina.- 4 Future Directions.- References.- Formation of Neural Pathways for Vision.- Connecting the Eye with the Brain: The Formation of the Retinotectal Pathway.- 1 Introduction.- 2 The Retinotectal Pathway.- 2.1 Navigation of the Optic Nerve Head.- 2.2 Exiting the Eye at the Optic Nerve Head.- 2.3 Fiber Organization in the Optic Nerve.- 2.4 Crossing at the Optic Chiasm.- 2.5 Climbing the Optic Tract Toward the Tectum.- 2.6 Target Recognition.- 2.7 Finding the Proper Tectal Target - Topographic Mapping.- 2.8 Preventing Retinal Axon Escape.- 3 Conclusion.- References.- Regeneration.- Regeneration of the Lens in Amphibians.- 1 Phylogeny.- 2 Histological and Cellular Events.- 3 Molecular Biology and Gene Regulation.- 3.1 Expression and Role of FGFs and FGFRs in Lens Regeneration.- 3.2 Regulatory Factors.- 3.2.1 Expression of Pax and Hox Genes.- 4 In Vitro Systems for Lens Regeneration.- 5 Clinical Applications.- References.- How the Neural Retina Regenerates.- 1 Neurogenesis and Neuronal Stem Cells.- 2 Regeneration of the Neural Retina in Adult Urodele Amphibians.- 2.1 The Classical Model of Retinal Regeneration.- 2.2 Molecular Mechanisms of RPE Transdifferentiation.- 3 Regeneration of the Neural Retina in Adult Teleost Fish.- 3.1 Source of the Regenerated Neurons - Stem Cells.- 3.2 Injury-Induced Gene Expression.- 3.3 Cellular and Synaptic Anatomy is Restored.- 3.4 Vision is Restored.- 4 A Model of Retinal Injury in Fish, Amphibians and Mammals.- References.- Genetic Models.- Mouse Mutants for Eye Development.- 1. Introduction.- 2. Mutations Affecting Early Eye Development.- 2.1 Mutations Affecting the Formation of the Lens Placode.- 2.2 Mutations Affecting the Optic Cup as the Prospective Retina.- 2.3 Mutations Affecting the Optic Stalk as the Prospective Optic Nerve.- 2.4 Mutations Affecting the Lens Vesicle.- 2.5 Further Genes Important for Early Eye Development.- 3. Maturation of the Eye (1): Lens Development.- 3.1 Cataracts: Inherited Anomalies of the Lens.- 3.2 Differentiation Process in the Developing Lensthe Crystallin Connection.- 3.3 Senile Cataracts at the End of Development.- 3.4 Transgenic Mice to Study Cataract Formation.- 4 Maturation of the Eye (2): Cornea, Iris, and Ciliary Body.- 4.1 Mouse Mutants with Lens-Corneal Adhesion.- 4.2 Mutations Affecting the Anterior Eye Development.- 5 Maturation of the Eye (3): The Retina.- 5.1 Mutations Affecting the Formation of the Retina.- 5.2 Mutations Leading to the Retinal Degeneration.- 5.3 Mutations Affecting the Optic Nerve.- 6 Conclusions.- References.- Genetic Analysis of Eye Development in Zebrafish.- 1 Introduction.- 2 Genetic Screens in Zebrafish.- 3 Currently Available Eye Mutants.- 3.1 Specification of Eye Field and Optic Cup Morphogenesis.- 3.2 Growth of the Eye.- 3.3 Specification and Differentiation of Distinct Cell Populations.- 3.4 Patterning of Cell Populations.- 3.5 Cellular Survival.- 3.6 Targeting of Retinotectal Projections.- 3.7 Other Mutants.- 4 Future Prospects of Zebrafish Genetics.- References.