title: Morphogen gradients, in theory.
abstract: The idea that morphogen gradients are established by a process of repeated cycles of exocytosis and endocytosis-so-called planar transcytosis-has been gaining acceptance. This is now challenged by a theoretical approach that experimental biologists should not dismiss; diffusive mechanisms of gradient formation may be correct after all.
authors.affiliation: MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, United Kingdom.
authors.forename: Matthew
authors.initials: M
authors.lastname: Freeman
mesh_terms: D000818:Animals; D001692:Biological Transport; D019521:Body Patterning / Q000502:physiology*; D004330:Drosophila / Q000196:embryology / Q000235:genetics; D004705:Endocytosis / Q000502:physiology; D005089:Exocytosis / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D019476:Insect Proteins / Q000235:genetics / Q000502:physiology; D008954:Models, Biological; D009024:Morphogenesis / Q000502:physiology*; D015398:Signal Transduction; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000502:physiology
chemical_list: D019476:Insect Proteins; D016212:Transforming Growth Factor beta