title: Ontogenetic cell death and phagocytosis in the visual system of vertebrates.
abstract: Programmed cell death (PCD), together with cell proliferation, cell migration, and cell differentiation, is an essential process during development of the vertebrate nervous system. The visual system has been an excellent model on which to investigate the mechanisms involved in ontogenetic cell death. Several phases of PCD have been reported to occur during visual system ontogeny. During these phases, comparative analyses demonstrate that dying cells show similar but not identical spatiotemporally restricted patterns in different vertebrates. Additionally, the chronotopographical coincidence of PCD with the entry of specialized phagocytes in some regions of the developing vertebrate visual system suggests that factors released from degenerating cells are involved in the cell migration of macrophages and microglial cells. Contradicting this hypothesis however, in many cases the cell corpses generated during degeneration are rapidly phagocytosed by neighboring cells, such as neuroepithelial cells or Müller cells. In this review, we describe the occurrence and the sites of PCD during the morphogenesis and differentiation of the retina and optic pathways of different vertebrates, and discuss the possible relationship between PCD and phagocytes during ontogeny.
authors.affiliation: Departamento de Biología Celular, Facultad de Ciencias, Universidad de Extremadura, Badajoz, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Francisco-Morcillo
authors.forename: Ruth
authors.initials: R
authors.lastname: Bejarano-Escobar
authors.forename: Joaquín
authors.initials: J
authors.lastname: Rodríguez-León
authors.forename: Julio
authors.initials: J
authors.lastname: Navascués
authors.forename: Gervasio
authors.initials: G
authors.lastname: Martín-Partido
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics; D016923:Cell Death / Q000235:genetics; D005123:Eye / Q000166:cytology / Q000196:embryology*; D006801:Humans; D009024:Morphogenesis / Q000235:genetics; D009474:Neurons / Q000502:physiology; D009799:Ocular Physiological Phenomena / Q000235:genetics; D010587:Phagocytosis / Q000235:genetics / Q000502:physiology*; D014714:Vertebrates / Q000196:embryology / Q000235:genetics; D014795:Visual Pathways / Q000166:cytology / Q000196:embryology / Q000378:metabolism
keywords: apoptosis; cell degeneration; development; optic pathways; phagocytic cells; retina